Head Flow numbers
10-25-2003, 06:59 PM
#16
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951 head? Or, is it a 2.7, N/A head. Are the seats fully radiused? Work on head done w/CNC? What materials are the ex. valve head and faces. What h/p range is the turbo being sized for? With proper oil passage increases, stock lifters fine. The heavier the spring rates the more likely for a lifter to operate poorly. Usually only when cold. When shutting off a motor they tend to stop in one of 3-4 (can't recall) same places in terms of rotation. This can contribute to a noisy lifter. They can sound like a rod-knock if heavily sprung. They can be eliminated by a proper starting technique.
10-26-2003, 09:16 AM
#17
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PS. Having outside sources perform machining and the like is not necessarily bad, or even a compromise. Holding them to the desired specs is the key. Just like suspension parts sold by engine builders, there are extremely qualified companies that do nothing but head work, or cam profiles, or turbo building, valves, etc. Holding them to the specs, is key. I thought that 28" was standard use industry wide. Does the Super Flow 600 really have a standard setting? 180 on ex. w/lower lift should be exceeded. 210 min. on intake w/2.5 head. Dyno #'s helpful, I guess. Everybody has a different take on what to do with the I/C on dyno. Some actually have used Nitrous Oxide to cool the thing. Heat them up to the temps you'll see when it's in the car at the end of the straight, on a hot day. Nothing like under promising and over delivering. That crap out of the way, your investing in an engine builder, not one who builds engines. As I would expect from you, intelligent move. That said, when it's done, let's race. If the cars weigh the same and your's is 2.5, I'll run 80% of the boost you choose. That gives you advantages 1) Newer motor, more recent tech. 2) H/P to cid is not a linear correlation. 3) I shift slow and w/6spd. often, too.
10-26-2003, 12:28 PM
#18
Rennlist Junkie Forever
m42racer
Actually Tony you are quite wrong about your theory. I had the Intake manifold flowed and each runner was measured for flow, the difference measured, the velocities, and the overall. We have a really good idea now how it flows and where to make some improvements. A very simple change inside made a substainial increase in flow.
OK so? Old news. What do you consider substantial? 15cfm at a given pressure/velocity? Define substantial.
And if you have forgotten that not all the Intakes Valves are open at the same time. This then allows the manifold to flow way more than the ports do.
I've not forgotten. But I think you are confused. Your statement applies to plenum volume sizing and throttle body sizing. Not intake runners.
Once you bolt that intake manifold to the head, the intake port becomes one with the intake runner up to the plenum or throttle butterfly... which ever comes first.
The stock manifold flows way more than the choke limit of the Intake port.
Way more? 50 cfm - 100 cfm + at a given valve lift is way more. And that's not the case.
Define "choke limit"....
You also need to understand that whatever the port does flow, it can flow more when the air can attach its self to more surface.
What's the relevance of this statement?
The multi angle shapes rally do make a difference.
Nobody said they didn't. What I said was that the minor difference they make won't do much on an otherwise stock engine, and thus the 2x cost of the valve grind wasn't worth it in my opinion (on an engine that was going to be kept stock).
As for the cost of the head work, I asked about this too. I was told that a proper Cylinder Head recondition should take just over 8 hours work, which can costs upwards or $ 800.00.
"Proper" head prep can take how ever long it requires depending on what you are doing. There is no fixed time value here. The time required, again, would depend on what is not in spec.
If you want to pay less, go to a production machine shop and pay the $ 250- 300 amount. You get what you pay for. Do they check everything? Not at that price. Do they measure the guide clearances, Valve stem dia's , Valve runouts, Seat heights, measure and check the springs for spring rates, seat pressures, coil bind distance etc. Most, if not all do not.
Uh... you quoted $550-$650 for the valve grind. Not for the entire head prep. Maybe I misread what you wrote. But in that context, of just the cost of the vavle grind portion of the head prep, and on an otherwise stock engine, I don't feel the additional money for a 15cfm increase is worth the extra cost, and thus the reason for my comments.
Now if they are going to do the vavle grind that gets the additional 15cfm, and do the entire head prep, then it's not a bad deal.
Otherwise, I'd rather take the money saved by using a conventional valve grind techniques, again... on an otherwise stock engine, and apply it towards an aftermarket wastegate... where the difference in engine performance will be night-and-day. Money better spent.
Remember, the 944 heads need to be very accurate with Valve seat heights, or the tappet goes into oil lock.
How many of these have you seen? I've never seen, nor ever head of this occuring from anybody on a 944 engine. For this to happen... the installed heights would have to be WAY off.
Actually Tony you are quite wrong about your theory. I had the Intake manifold flowed and each runner was measured for flow, the difference measured, the velocities, and the overall. We have a really good idea now how it flows and where to make some improvements. A very simple change inside made a substainial increase in flow.
OK so? Old news. What do you consider substantial? 15cfm at a given pressure/velocity? Define substantial.
And if you have forgotten that not all the Intakes Valves are open at the same time. This then allows the manifold to flow way more than the ports do.
I've not forgotten. But I think you are confused. Your statement applies to plenum volume sizing and throttle body sizing. Not intake runners.
Once you bolt that intake manifold to the head, the intake port becomes one with the intake runner up to the plenum or throttle butterfly... which ever comes first.
The stock manifold flows way more than the choke limit of the Intake port.
Way more? 50 cfm - 100 cfm + at a given valve lift is way more. And that's not the case.
Define "choke limit"....
You also need to understand that whatever the port does flow, it can flow more when the air can attach its self to more surface.
What's the relevance of this statement?
The multi angle shapes rally do make a difference.
Nobody said they didn't. What I said was that the minor difference they make won't do much on an otherwise stock engine, and thus the 2x cost of the valve grind wasn't worth it in my opinion (on an engine that was going to be kept stock).
As for the cost of the head work, I asked about this too. I was told that a proper Cylinder Head recondition should take just over 8 hours work, which can costs upwards or $ 800.00.
"Proper" head prep can take how ever long it requires depending on what you are doing. There is no fixed time value here. The time required, again, would depend on what is not in spec.
If you want to pay less, go to a production machine shop and pay the $ 250- 300 amount. You get what you pay for. Do they check everything? Not at that price. Do they measure the guide clearances, Valve stem dia's , Valve runouts, Seat heights, measure and check the springs for spring rates, seat pressures, coil bind distance etc. Most, if not all do not.
Uh... you quoted $550-$650 for the valve grind. Not for the entire head prep. Maybe I misread what you wrote. But in that context, of just the cost of the vavle grind portion of the head prep, and on an otherwise stock engine, I don't feel the additional money for a 15cfm increase is worth the extra cost, and thus the reason for my comments.
Now if they are going to do the vavle grind that gets the additional 15cfm, and do the entire head prep, then it's not a bad deal.
Otherwise, I'd rather take the money saved by using a conventional valve grind techniques, again... on an otherwise stock engine, and apply it towards an aftermarket wastegate... where the difference in engine performance will be night-and-day. Money better spent.
Remember, the 944 heads need to be very accurate with Valve seat heights, or the tappet goes into oil lock.
How many of these have you seen? I've never seen, nor ever head of this occuring from anybody on a 944 engine. For this to happen... the installed heights would have to be WAY off.
10-26-2003, 04:30 PM
#19
I don't know where to start. Maybe first, I am trying to convey what I learn as we do the development on my engine project and parts. I will disagree when statements are made that differ from what I am told or know. We debate here, and maybe we all can learn how the other does something. There are many ways to skin a cat.
I am told that SuperFlow 600 Flow benches are calibrated at build @ 25" of H2O. Any use of higher or lower pressures during testing have to be corrected to the correction factors supplied by Superflow. If the 600 Flow bench is calibrated @ 25", then all tests done at 25" need no correction. The software does the calculation of flow manometer times the flow scale value for that bench. The flow scale value is based upon the flow thro a calibrated hole. Like dyno's, flow benches need to be checked regularly.
Now to answer Tony.
The flow numbers I posted were on a stock head, showing the extra which can be had from different value seat angles. On the most radically ported head, I know engine builders who get all warm and fuzzy over 1 CFM. If up to 15 can be had on a stock head from just good reconditioning, they will take it. If we stick to numbers, 15 CFM is felt in the car for sure. So 15CFM is substainial in any engine with any port work. As for the Intake manifold, again, any gain from what you already own is valuable if it comes without emptying the bank.
To answer some of your other questions is somewhat hard as we seem to be talking apples tp oranges here. Based upon the tests done to date, the Intake flows more than the stock head does. That was my point. If you are talking a ported head with big Valves etc, then maybe the Intake will need more work or repalcing. No argument here. But to talk stock head, and stock Intake with stock TB, any gains found in the reconditioning of the head is felt.
Choke limit of a stock port is the maximum flow without restiction in the port. No guide, no Valve. This test is done with a very special inlet trumpet which measures flow, airspeed and temperature. If the Intake flow more than a port with a guide and Valve in it, then any work done on the Intake would gain little. If the opposite applied, then work done on the Intake should show a gain.
As for the seat shape and angles, you can stay with old fashion, or you can keep up with the new. Most head machines like the one PD has can cut any shape you want. Its the cutter that is different. As for the increase in flow, its free.
The cost is based on what is required. We agree here. My point is that production machine work skips over many important areas which need attention. Only those who know exactly what a 944 Head required will give this extra attention to the details. You get what you pay for. I have had heads done before by these types. One time I had a problem with oil consumption and P/V clearance. I took it back and was told it would cost more to look at these problems.
The price I posted was PD's minimum cost to do the complete head recondition. when they do a head its from top to bottom. Nothing is left untouched. If the customer does not want to pay for ceratin work to be done, they at least are notified of any problems. If you are talking just a Valve job only, I think their cost would be around $ 200.00. Only a valve seat cut and valve dressing here. You disassemble, you clean etc. Again, the cost I posted was a dirty head in a bag delivered to PD, and a clean completely rebuild head ready to go back on your engine. Their normal costs are around $ 800.00. But for approx $ 550.00 , a basic full rebuild can be had. I have seen Heads leave their shop after having the $ 800.00 job done. Wow, they look great, and come with a written report of all dimensions, clearances, spring rates, seat pressures, over the nose sring rates, distances to coil bind, compression ratio check,(if stock) and more. You cannot get this sort of work on any street corner.
For the additional 15 CFM, many would kill for this. Not sure what you think is worth it. Many spend thousands to get less than that. Remember, this is free flow. Its what you are missing from stock. As for buying a Wastegate, I've never heard of a Wastegate giving more Torque or HP. I thought it just controlled the boost level. If you have a Wastegate that does not control boost, then your problems are different. Maybe money better spent is on a Wastegate. But again its the apples and orange theory.
As for the tappet problem, I bought a head with this problem, and PD have seen this more times than they care to recall. It appears to very common. If these engines were solid tappets, they would never start, or if they did, most would have Valve to Piston problems. The hydraulic tappets are masking the problem. Compress a tappet and see with very little change in compression, how long extra it atkes to pump up. This is something very commom with hydraulic tappets. Add different valve lifts to this and the problem gets even more complicated.
At the end of the day, it comes down to what you want and what you think is important.
I am told that SuperFlow 600 Flow benches are calibrated at build @ 25" of H2O. Any use of higher or lower pressures during testing have to be corrected to the correction factors supplied by Superflow. If the 600 Flow bench is calibrated @ 25", then all tests done at 25" need no correction. The software does the calculation of flow manometer times the flow scale value for that bench. The flow scale value is based upon the flow thro a calibrated hole. Like dyno's, flow benches need to be checked regularly.
Now to answer Tony.
The flow numbers I posted were on a stock head, showing the extra which can be had from different value seat angles. On the most radically ported head, I know engine builders who get all warm and fuzzy over 1 CFM. If up to 15 can be had on a stock head from just good reconditioning, they will take it. If we stick to numbers, 15 CFM is felt in the car for sure. So 15CFM is substainial in any engine with any port work. As for the Intake manifold, again, any gain from what you already own is valuable if it comes without emptying the bank.
To answer some of your other questions is somewhat hard as we seem to be talking apples tp oranges here. Based upon the tests done to date, the Intake flows more than the stock head does. That was my point. If you are talking a ported head with big Valves etc, then maybe the Intake will need more work or repalcing. No argument here. But to talk stock head, and stock Intake with stock TB, any gains found in the reconditioning of the head is felt.
Choke limit of a stock port is the maximum flow without restiction in the port. No guide, no Valve. This test is done with a very special inlet trumpet which measures flow, airspeed and temperature. If the Intake flow more than a port with a guide and Valve in it, then any work done on the Intake would gain little. If the opposite applied, then work done on the Intake should show a gain.
As for the seat shape and angles, you can stay with old fashion, or you can keep up with the new. Most head machines like the one PD has can cut any shape you want. Its the cutter that is different. As for the increase in flow, its free.
The cost is based on what is required. We agree here. My point is that production machine work skips over many important areas which need attention. Only those who know exactly what a 944 Head required will give this extra attention to the details. You get what you pay for. I have had heads done before by these types. One time I had a problem with oil consumption and P/V clearance. I took it back and was told it would cost more to look at these problems.
The price I posted was PD's minimum cost to do the complete head recondition. when they do a head its from top to bottom. Nothing is left untouched. If the customer does not want to pay for ceratin work to be done, they at least are notified of any problems. If you are talking just a Valve job only, I think their cost would be around $ 200.00. Only a valve seat cut and valve dressing here. You disassemble, you clean etc. Again, the cost I posted was a dirty head in a bag delivered to PD, and a clean completely rebuild head ready to go back on your engine. Their normal costs are around $ 800.00. But for approx $ 550.00 , a basic full rebuild can be had. I have seen Heads leave their shop after having the $ 800.00 job done. Wow, they look great, and come with a written report of all dimensions, clearances, spring rates, seat pressures, over the nose sring rates, distances to coil bind, compression ratio check,(if stock) and more. You cannot get this sort of work on any street corner.
For the additional 15 CFM, many would kill for this. Not sure what you think is worth it. Many spend thousands to get less than that. Remember, this is free flow. Its what you are missing from stock. As for buying a Wastegate, I've never heard of a Wastegate giving more Torque or HP. I thought it just controlled the boost level. If you have a Wastegate that does not control boost, then your problems are different. Maybe money better spent is on a Wastegate. But again its the apples and orange theory.
As for the tappet problem, I bought a head with this problem, and PD have seen this more times than they care to recall. It appears to very common. If these engines were solid tappets, they would never start, or if they did, most would have Valve to Piston problems. The hydraulic tappets are masking the problem. Compress a tappet and see with very little change in compression, how long extra it atkes to pump up. This is something very commom with hydraulic tappets. Add different valve lifts to this and the problem gets even more complicated.
At the end of the day, it comes down to what you want and what you think is important.
10-26-2003, 05:21 PM
#20
Rennlist Junkie Forever
On the most radically ported head, I know engine builders who get all warm and fuzzy over 1 CFM. If up to 15 can be had on a stock head from just good reconditioning, they will take it. If we stick to numbers, 15 CFM is felt in the car for sure. So 15CFM is substainial in any engine with any port work. As for the Intake manifold, again, any gain from what you already own is valuable if it comes without emptying the bank.
I can guarantee you that you will not feel 15cfm on an otherwise stock 951 engine. In fact, you won't feel it on a stock engine 951 that has an upgraded turbo, MAF, injectors, and a test pipe.
How do I know? Because I've done before and after tests with mildly ported heads that I know for a fact flowed over 15cfm more. The DynoJet showed no change to the wheels in either HP or TQ.
There are many other problems in the way of feeling 15cfm besides the ports.
Now I'm not saying that this is bad (gaining 15cfm). It's good. It's just that you had said (or I thought you had said) that the $550+ was valve grind portion of the head work. And for that money, and the effect of 15dfm on an otherwise stock engine, I'd rather put the money elsewhere.
My point concerning the wastegate investment was simply an example of things that MUST be replaced on these cars. And the difference between an aftermarket wastegate compared to a stock wastegate is night-and-day. Yes it controls boost... but if it's weak, and all the stock or modified stock wastegates are, you're loosing HP/TQ, and will have a slower spooling turbo, because of the poor boost control. If not the wastegate, then larger injectors, a test pipe, a this or that... it doesn't matter. There are tons of places with respect to 951 performance that $550 get you far more bang-for-the-buck vs 15cfm of port flow.
If you're at the end of the development cycle, and you've spent all the money on everything else... then 15cfm will make a big difference because you've already done the things that will utilize the additional 15cfm.
I can guarantee you that you will not feel 15cfm on an otherwise stock 951 engine. In fact, you won't feel it on a stock engine 951 that has an upgraded turbo, MAF, injectors, and a test pipe.
How do I know? Because I've done before and after tests with mildly ported heads that I know for a fact flowed over 15cfm more. The DynoJet showed no change to the wheels in either HP or TQ.
There are many other problems in the way of feeling 15cfm besides the ports.
Now I'm not saying that this is bad (gaining 15cfm). It's good. It's just that you had said (or I thought you had said) that the $550+ was valve grind portion of the head work. And for that money, and the effect of 15dfm on an otherwise stock engine, I'd rather put the money elsewhere.
My point concerning the wastegate investment was simply an example of things that MUST be replaced on these cars. And the difference between an aftermarket wastegate compared to a stock wastegate is night-and-day. Yes it controls boost... but if it's weak, and all the stock or modified stock wastegates are, you're loosing HP/TQ, and will have a slower spooling turbo, because of the poor boost control. If not the wastegate, then larger injectors, a test pipe, a this or that... it doesn't matter. There are tons of places with respect to 951 performance that $550 get you far more bang-for-the-buck vs 15cfm of port flow.
If you're at the end of the development cycle, and you've spent all the money on everything else... then 15cfm will make a big difference because you've already done the things that will utilize the additional 15cfm.
10-26-2003, 05:37 PM
#21
Tony, if you did not feel 15cfm, I do not understand. On any engine 5 cfm can be felt. maybe a Dynojet with all the losses that are inheritant, 15 or more are not felt. Any measurements of engine development or gains would be done on an engine dyno where no other factors are having an affect. If you port heads and make changes over stock and not change fuelling etc, no effect may not be felt. If you increase the amount of air comsummed, you do make a difference in the dymanic compression of an engine. If fuel and timing are not changed, some engine performance must be felt, unless other engine parameters are off.
You seem to not place any imporatance on good machining. Your statement of more places, seems to show this. Good engines start with good machining. Again, make your choice to where you want to spend YOUR money. I've been to many races where this same rationale has been evident, followed by,"how come he has more straight line speed". Been there done that alright. I've said it.
You seem to not place any imporatance on good machining. Your statement of more places, seems to show this. Good engines start with good machining. Again, make your choice to where you want to spend YOUR money. I've been to many races where this same rationale has been evident, followed by,"how come he has more straight line speed". Been there done that alright. I've said it.
10-26-2003, 06:29 PM
#22
Rennlist Junkie Forever
Tony, if you did not feel 15cfm, I do not understand. On any engine 5 cfm can be felt. maybe a Dynojet with all the losses that are inheritant, 15 or more are not felt. Any measurements of engine development or gains would be done on an engine dyno where no other factors are having an affect. If you port heads and make changes over stock and not change fuelling etc, no effect may not be felt. If you increase the amount of air comsummed, you do make a difference in the dymanic compression of an engine. If fuel and timing are not changed, some engine performance must be felt, unless other engine parameters are off.
I'm well aware of the effects of porting, effective compression, etc, and don't need the engine building 101 lessons.
Facts are facts. And 15cfm on a stock engined 951 will show no gain on a DynoJet.
You seem to not place any imporatance on good machining. Your statement of more places, seems to show this. Good engines start with good machining.
That statement is almost funny. In fact it would be funny if I didn't have $5,000 invested in my porting/valve train.
I'd have to say that you're a little off here....
Again, make your choice to where you want to spend YOUR money.
OK, but can't I choose where you spend yours too? :-)
I've been to many races where this same rationale has been evident, followed by,"how come he has more straight line speed". Been there done that alright. I've said it.
Must be because he didn't have that additional 15cfm.
I'm well aware of the effects of porting, effective compression, etc, and don't need the engine building 101 lessons.
Facts are facts. And 15cfm on a stock engined 951 will show no gain on a DynoJet.
You seem to not place any imporatance on good machining. Your statement of more places, seems to show this. Good engines start with good machining.
That statement is almost funny. In fact it would be funny if I didn't have $5,000 invested in my porting/valve train.
I'd have to say that you're a little off here....
Again, make your choice to where you want to spend YOUR money.
OK, but can't I choose where you spend yours too? :-)
I've been to many races where this same rationale has been evident, followed by,"how come he has more straight line speed". Been there done that alright. I've said it.
Must be because he didn't have that additional 15cfm.
10-26-2003, 07:31 PM
#23
Tony, I don't understand you. I'm adding info from whats been found. You seem to challenge what some very good engine people have found. maybe you have not had good work done. If you can never feel any additional air flow, then maybe you have other problems. Your engine appaears to be different from many other ones. I'm ceratainly not saying that your wrong. I don't want this to go where it seems to be going. You seem to be well informed, but also seem to diifer from some very high end proffessional engine people with much experience and success. To each his own. Hey good luck. You have spent alot of $. Hope you got the sucess that you were looking for. I'm sure you have a very good engine. I am not trying to give you any engine building lesson. The one thing I know fro sure, I could not attempt to offer sort of information that the likes of Neil @ PD could. I get lot of my info from him and his engine people. But I can tell you, he thinks that the basics are needed always. Never tries to make anything more complicated than it needs to be. Several of the guys that work there race shifter karts. They for sure do engine work that nets 1 to 5 CFM, and they can measure this and tell that it makes a difference. The fact you cannot could speak to the dyno or its data logging ability.
Lets not make this an issue here. Good luck and disregard my info. I'm posting what is found on the development of my engine and parts and what PD have found on reconditioning stock heads for customers. If it does not apply to you, thats ok. I've choosen who is going to do my work, is doing the parts development etc. I'm very happy with what I've seem to date. I hope to post pics this week of the block. It is a little behind, and the finished block will show the deck plate, Liners, Girdle mod, Head studs etc. The cylinder head is taking more time than first thought.
This is the last I will post about this or reply. I think it must be boring to most. We seem to be going back and forth to much on issues which are from your posts "not worth it" or money poorly spent. My choice is to go with, believe, and accept the info from those who have knowledge, experience, doing or done testing with a high level of accuracy and alot of motorsport success.
From now on I will post the new parts and developement progress on another thread.
Tony
Lets not make this an issue here. Good luck and disregard my info. I'm posting what is found on the development of my engine and parts and what PD have found on reconditioning stock heads for customers. If it does not apply to you, thats ok. I've choosen who is going to do my work, is doing the parts development etc. I'm very happy with what I've seem to date. I hope to post pics this week of the block. It is a little behind, and the finished block will show the deck plate, Liners, Girdle mod, Head studs etc. The cylinder head is taking more time than first thought.
This is the last I will post about this or reply. I think it must be boring to most. We seem to be going back and forth to much on issues which are from your posts "not worth it" or money poorly spent. My choice is to go with, believe, and accept the info from those who have knowledge, experience, doing or done testing with a high level of accuracy and alot of motorsport success.
From now on I will post the new parts and developement progress on another thread.
Tony
10-26-2003, 08:09 PM
#24
Rennlist Junkie Forever
m42racer
Debate is a very important part of this list. It's not a matter of who is right and who is wrong.
I don't profess to be the end-all in engine cylinder porting. If I was... I wouldn't have spend all the money I spent with John Milledge for my head/valve train. And inline with your comments about quality of engine building/attention to detail.... I've gone to the best in the 951 world for my work.... John Milledge.
As you do, I too report my findings. And, since I've been doing this 951 thing for quite some time (as well as extensive engine building of Nissans and blown Chevy's), and as I've thrown stupid amounts of money at it over the years, I can comment on a lot of what I've seen that works... and what doesn't.
I've spent a ton of money with some of the biggest names in engine building when I was running blown Chevy's, as well as 20 years ago when I raced 510's and 240Z's.
Consequently, I'll be the first person in line that will shouting that attention to detail, and quality of engine building is extremely important.
Lastly, and again to reiterate.... 15cfm is good, not bad. It's just that unless you need to have your cylinder head rebuilt for some reason, you can get a much better "return on your performance dollar" with other modifications unless you're at the end of the development cycle (as I am now).
Debate is a very important part of this list. It's not a matter of who is right and who is wrong.
I don't profess to be the end-all in engine cylinder porting. If I was... I wouldn't have spend all the money I spent with John Milledge for my head/valve train. And inline with your comments about quality of engine building/attention to detail.... I've gone to the best in the 951 world for my work.... John Milledge.
As you do, I too report my findings. And, since I've been doing this 951 thing for quite some time (as well as extensive engine building of Nissans and blown Chevy's), and as I've thrown stupid amounts of money at it over the years, I can comment on a lot of what I've seen that works... and what doesn't.
I've spent a ton of money with some of the biggest names in engine building when I was running blown Chevy's, as well as 20 years ago when I raced 510's and 240Z's.
Consequently, I'll be the first person in line that will shouting that attention to detail, and quality of engine building is extremely important.
Lastly, and again to reiterate.... 15cfm is good, not bad. It's just that unless you need to have your cylinder head rebuilt for some reason, you can get a much better "return on your performance dollar" with other modifications unless you're at the end of the development cycle (as I am now).
10-26-2003, 09:03 PM
#26
Race Car
I think this will be one of those threads that I search for 6 months or 1 year from now when I'm looking for good info, this topic has a lot to offer.
I can confidently suggest that both of you step back and appreciate each other's point of view...seriously, step back for a second and attempt to understand where the other is coming from. m42racer is giving us specific info on a cylinder head that has been built with QUALITY in mind. High quality is all he's trying to get across, he is not saying that everyone should be going after the extra cfm to make themselves happy at the next dyno day. The flow numbers and other specs are an INDICATION that this shop does good solid work. If you think this is about squeezing 5 extra horsepower then I think you're missing the point. Who knows how a poorly built head will perform - it's questionable at best and may likely be worse than stock! Who wants poor quality? For many, including myself, the risk of getting low quality work is not worth a little money saved.
I know for one that when my 944 needs a head rebuild I will strongly consider sending it to these guys because they do great work with the proof to back it up. I want somebody meticulous and honest, I could give a **** how much power and torque my 86 NA gains from this work but I'm confident it will be strong and reliable.
Excellent info, thanks!
I can confidently suggest that both of you step back and appreciate each other's point of view...seriously, step back for a second and attempt to understand where the other is coming from. m42racer is giving us specific info on a cylinder head that has been built with QUALITY in mind. High quality is all he's trying to get across, he is not saying that everyone should be going after the extra cfm to make themselves happy at the next dyno day. The flow numbers and other specs are an INDICATION that this shop does good solid work. If you think this is about squeezing 5 extra horsepower then I think you're missing the point. Who knows how a poorly built head will perform - it's questionable at best and may likely be worse than stock! Who wants poor quality? For many, including myself, the risk of getting low quality work is not worth a little money saved.
I know for one that when my 944 needs a head rebuild I will strongly consider sending it to these guys because they do great work with the proof to back it up. I want somebody meticulous and honest, I could give a **** how much power and torque my 86 NA gains from this work but I'm confident it will be strong and reliable.
Excellent info, thanks!
10-26-2003, 09:21 PM
#27
Rennlist Junkie Forever
PorscheG96
Here's the deal.
If it's high quality that's the issue, then the mention of additional cfm shouldn't come into play.
Properly building a head is one thing. Improving the breathing capability is definitely another. One has nothing to do with the other, thus I would have to disagree.
Nobody here, including myself, has ever said that quality is not an issue.
Don't mix apples and oranges.
The issue that I raised was the cost/benefit ratio of an additional 15cfm... and that the indicated additional cost could be better spent elsewhere where the gains would be readily apparent.
The sheer fact that you can get 15cfm from one type of valve grind over another has nothing to do with properly building and setting up a cylinder head.
Here's the deal.
If it's high quality that's the issue, then the mention of additional cfm shouldn't come into play.
Properly building a head is one thing. Improving the breathing capability is definitely another. One has nothing to do with the other, thus I would have to disagree.
Nobody here, including myself, has ever said that quality is not an issue.
Don't mix apples and oranges.
The issue that I raised was the cost/benefit ratio of an additional 15cfm... and that the indicated additional cost could be better spent elsewhere where the gains would be readily apparent.
The sheer fact that you can get 15cfm from one type of valve grind over another has nothing to do with properly building and setting up a cylinder head.
10-26-2003, 09:39 PM
#28
Race Car
I will say it again, step back for a second and think about what's being presented. From the second post:
"As promised, here are the numbers I got today. These numbers are after a typical repair,(valve job) and are what should be expected after proper repair work is done on existing seats."
From the fourth post:
"Remeber this is a standard Head rebuild, with NO porting. The gains are from good seat work only. If the flow across the seats is better, and you do no porting, your gains are thoe lost from inferior seat work. No majic here, just good repair work."
This has nothing to do with cutting-edge all-out track performance headwork. There was also no mention of porting. This is a complete head rebuild with emphasis on 'proper work' to the valve seats/angles. The reason he posted the flow numbers is because people asked, including me because I was curious. I did not ask hoping to get good dyno results if they rebuild my cylinder head, I asked to see how the numbers compared before/after good head work. QUALITY head work.
The flow numbers apply to m42's project because the performance of his engine is being built around the capability of the head. Most people are not doing this. Therefore he is emphasizing the quality of PD's work for those of us who aren't making big hp.
If it helps try reading the topic again.
EDIT: I also said that I appreciate your point of view. But you're talking about something else...engine performance vs. value based on hp figures alone [ie. better wastegate]. This thread is about head work and it interests me because I will need a head rebuild soon [worn guides, leaky seals].
"As promised, here are the numbers I got today. These numbers are after a typical repair,(valve job) and are what should be expected after proper repair work is done on existing seats."
From the fourth post:
"Remeber this is a standard Head rebuild, with NO porting. The gains are from good seat work only. If the flow across the seats is better, and you do no porting, your gains are thoe lost from inferior seat work. No majic here, just good repair work."
This has nothing to do with cutting-edge all-out track performance headwork. There was also no mention of porting. This is a complete head rebuild with emphasis on 'proper work' to the valve seats/angles. The reason he posted the flow numbers is because people asked, including me because I was curious. I did not ask hoping to get good dyno results if they rebuild my cylinder head, I asked to see how the numbers compared before/after good head work. QUALITY head work.
The flow numbers apply to m42's project because the performance of his engine is being built around the capability of the head. Most people are not doing this. Therefore he is emphasizing the quality of PD's work for those of us who aren't making big hp.
If it helps try reading the topic again.
EDIT: I also said that I appreciate your point of view. But you're talking about something else...engine performance vs. value based on hp figures alone [ie. better wastegate]. This thread is about head work and it interests me because I will need a head rebuild soon [worn guides, leaky seals].
10-26-2003, 10:24 PM
#29
Rennlist Junkie Forever
PorscheG96
OK... So?
Do you need to step in to moderate this thread or what?
I am entitled to, just as anybody here is entitled to, question people that sling a product or service.
It's the debate that exposes the strenghts and/or weaknesses of such product or service.
If this product or service is not to be exposed to argument, then m42racer (or the company in which he is promoting the product/service for) should be come a paid advertiser on the Rennlist.
I call em as I see em.
OK... So?
Do you need to step in to moderate this thread or what?
I am entitled to, just as anybody here is entitled to, question people that sling a product or service.
It's the debate that exposes the strenghts and/or weaknesses of such product or service.
If this product or service is not to be exposed to argument, then m42racer (or the company in which he is promoting the product/service for) should be come a paid advertiser on the Rennlist.
I call em as I see em.
10-27-2003, 12:07 AM
#30
Racer
Join Date: Nov 2001
Location: California
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What about my other comments/questions?
1) Please check again on the Superflow 600. I'm almost certain they have no standard setting. Anyway, why 25, not 28?
2) Cam profiles, where an engine stops when turned off and spring rates push the limits of these lifters. There is a 3L solid lifter motor on tracks back east. It dyno'd well over 600 h/p, dry sump. Probably need dry sump and solids above 7000.
3) 3 & 5 angle valve jobs are very old school, as you mentioned.
4) If you don't mind, what other builders did you interview? N. Harvey has an impeccable record, what h/p range is the turbo going to be sized for?
5) Does Harvey do inhouse R&D on these motors? I'm not questioning hiscredentials. I do not have enough knowledge to even consider that. I hold Jon Milledge in high regard, but I'm not married to him. I think it's crucial to keep an open mind. Many believe their builder/tuner is the best. Quite often it's due to their investment and they want to believe they made the right choice. It's our money! I question Jon all the time, to the point of really irritating the man. Mainly 'cause his experience with checking, evaluating ideas I mention, are old. I asked him about a number of setting for various channels on the MoTeC. He told me, I have no business, questioning them, 'cause it's difficult to determine (from my end) what the channel is controlling. By the way. I've never asked him a question that he did not have a very convincing reply as to why, or why not. He gets tired of this, I'm sure. I'm just TRYING toget what I paid for and an education, as well.
6) So, do not take my questions/comments as an attack. I love understanding quality builder's approaches.
7) Oil pan mods? Dry sump?
8) Ignition choice?
9) Intake manifold and prep work. Ex-hone toake 1/4-3/8 from the inside of the ports.
10) Boost levels/s? Fuel?
(One builder I seriously considered was using pump fuel. I asked how much more power w/race? BIG? I could not leave that much H/P on the table.) Hence, I have 3 maps with the exact same switch that was in the Yellow 968. I alway thought that extra H/P at the flip was fascinating. It's all of that and more. Pluse, I get to program the clamping tables through the MoTeC gain and derivative logarithms. Therefore, w/pump fuel, I run v-low boost (9#) w/hopefully no chance of detonation. W/race fuel (GT-Plus 104 unleaded) I switch to medium (17~). High is currently set @ 20. I do not use this much anymore. If I think, I'll need it, yes. Even when I've used it, I didn't really need it. The fuel can be delivered to you home, w/pump. Only one outlet. Safer than gas tanks. Probably 130-150 more h/p.
11) Ex. size? If not stainless (5k) coat entire ex.
12) Muffler choice and how selected. When I got my car, WAY loud. Jon appologized. At tracks that have Decibel limits, he uses these. Lap time differences, he said could be attributed to the weight of the muffler. I struggle a little w/that, but less restriction would mean an even louder one. This car wakes the dead.
13) Bigger valves?
14) I belive you're the guy w/the friend, that profiles cams. Yes/No? I fairly certain I have 2, possibly 3 of his cams. Tell us more about this guy.
15) Valve spring rates. Your friends cams are (so I'm told and I believe) are one of the main reasons that these motors can be VERY tightly sprung (300+) w/o failures, or need for frequent replacements. The last grind I purchased had very little increase in lift, but developed 25 more ponies, due, at least in part, to the ramping profile that greatly reduced valve bounce. 25 more H/P and easier on the valvetrain. Like eating you cake and keeping it. I told Jon, I think I can feel the difference (could not on the 2.5 change). Reply, Probably not.
1) Please check again on the Superflow 600. I'm almost certain they have no standard setting. Anyway, why 25, not 28?
2) Cam profiles, where an engine stops when turned off and spring rates push the limits of these lifters. There is a 3L solid lifter motor on tracks back east. It dyno'd well over 600 h/p, dry sump. Probably need dry sump and solids above 7000.
3) 3 & 5 angle valve jobs are very old school, as you mentioned.
4) If you don't mind, what other builders did you interview? N. Harvey has an impeccable record, what h/p range is the turbo going to be sized for?
5) Does Harvey do inhouse R&D on these motors? I'm not questioning hiscredentials. I do not have enough knowledge to even consider that. I hold Jon Milledge in high regard, but I'm not married to him. I think it's crucial to keep an open mind. Many believe their builder/tuner is the best. Quite often it's due to their investment and they want to believe they made the right choice. It's our money! I question Jon all the time, to the point of really irritating the man. Mainly 'cause his experience with checking, evaluating ideas I mention, are old. I asked him about a number of setting for various channels on the MoTeC. He told me, I have no business, questioning them, 'cause it's difficult to determine (from my end) what the channel is controlling. By the way. I've never asked him a question that he did not have a very convincing reply as to why, or why not. He gets tired of this, I'm sure. I'm just TRYING toget what I paid for and an education, as well.
6) So, do not take my questions/comments as an attack. I love understanding quality builder's approaches.
7) Oil pan mods? Dry sump?
8) Ignition choice?
9) Intake manifold and prep work. Ex-hone toake 1/4-3/8 from the inside of the ports.
10) Boost levels/s? Fuel?
(One builder I seriously considered was using pump fuel. I asked how much more power w/race? BIG? I could not leave that much H/P on the table.) Hence, I have 3 maps with the exact same switch that was in the Yellow 968. I alway thought that extra H/P at the flip was fascinating. It's all of that and more. Pluse, I get to program the clamping tables through the MoTeC gain and derivative logarithms. Therefore, w/pump fuel, I run v-low boost (9#) w/hopefully no chance of detonation. W/race fuel (GT-Plus 104 unleaded) I switch to medium (17~). High is currently set @ 20. I do not use this much anymore. If I think, I'll need it, yes. Even when I've used it, I didn't really need it. The fuel can be delivered to you home, w/pump. Only one outlet. Safer than gas tanks. Probably 130-150 more h/p.
11) Ex. size? If not stainless (5k) coat entire ex.
12) Muffler choice and how selected. When I got my car, WAY loud. Jon appologized. At tracks that have Decibel limits, he uses these. Lap time differences, he said could be attributed to the weight of the muffler. I struggle a little w/that, but less restriction would mean an even louder one. This car wakes the dead.
13) Bigger valves?
14) I belive you're the guy w/the friend, that profiles cams. Yes/No? I fairly certain I have 2, possibly 3 of his cams. Tell us more about this guy.
15) Valve spring rates. Your friends cams are (so I'm told and I believe) are one of the main reasons that these motors can be VERY tightly sprung (300+) w/o failures, or need for frequent replacements. The last grind I purchased had very little increase in lift, but developed 25 more ponies, due, at least in part, to the ramping profile that greatly reduced valve bounce. 25 more H/P and easier on the valvetrain. Like eating you cake and keeping it. I told Jon, I think I can feel the difference (could not on the 2.5 change). Reply, Probably not.