2 V headflow figures - project update
03-01-2007, 12:00 PM
#16
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Originally Posted by Greg Gray
Guys as promised I have some of the flow figures from my recent port work. I haven't got a graph to post I will wait for them to send it to me but some headline figures are;
On the intake side we have at 0.500" lift @ 28" of water 274.4 cfm and at max lift of 0.550" we have 298.1 cfm, so I failed to crack the 300 barrier, I was hoping to reveal that I had achieved 305 cfm or about 625 hp in airflow, that figure would have allowed me to be confident in predicting more than 500 RWHP. For the record a flow of 298.1 equals a max HP at the flywheel of 610 hp, so 500 RWHP is still within reach of my 2 valve 6.0 litre Honda mini stroker. (Stroke is 3.55")
---snip---
Cheers Greg
On the intake side we have at 0.500" lift @ 28" of water 274.4 cfm and at max lift of 0.550" we have 298.1 cfm, so I failed to crack the 300 barrier, I was hoping to reveal that I had achieved 305 cfm or about 625 hp in airflow, that figure would have allowed me to be confident in predicting more than 500 RWHP. For the record a flow of 298.1 equals a max HP at the flywheel of 610 hp, so 500 RWHP is still within reach of my 2 valve 6.0 litre Honda mini stroker. (Stroke is 3.55")
---snip---
Cheers Greg
Nice work, Greg! Would you mind discussing what you did for port & polish work on the heads? Are these numbers with the runner & plenum attached?
03-01-2007, 12:14 PM
#17
Captain Obvious
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Greg,
When I had a Mustang ( back in the early 90’s), I used to hear about the BXR (Balanced Cross Ram intake manifold manifold) manifolds. Back then they were sort of a unique design. They had variable internally adjustable end caps. When I read that you were working on an intake setup for your 928 I remembered this design. I think they have been out of business for some time but I found some info on them. Should be enough to get you some ideas what this intake was all about. Maybe something similar can work in your application. Here is a mirrored site of the original: http://ollav.com/naturalaspiration/bxr/
Here's a pic of what one configuration looks like.
When I had a Mustang ( back in the early 90’s), I used to hear about the BXR (Balanced Cross Ram intake manifold manifold) manifolds. Back then they were sort of a unique design. They had variable internally adjustable end caps. When I read that you were working on an intake setup for your 928 I remembered this design. I think they have been out of business for some time but I found some info on them. Should be enough to get you some ideas what this intake was all about. Maybe something similar can work in your application. Here is a mirrored site of the original: http://ollav.com/naturalaspiration/bxr/
Here's a pic of what one configuration looks like.
03-03-2007, 02:53 AM
#18
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Guys just recieved my flow chart and they also informed me that they was a misunderstanding, 298 cfm was achieved at 0.600" not 0.550" so that is a bit disapointing. However I still believe that 600 flow HP is achievable with these heads. That will hopefully result in 500 RWHP.
Maybe 500 RWHP is too much of an expectation? If you come off the LS7 engine, when they mod them, i.e a cam and exhaust they are supposedly getting over 600 crank hp, so they have about 25% more headflow, about 17% more capacity but need to run cats and meet emmisions. The only advantages I have is a bigger cam, and probably a lower friction engine and more revs available if they end up useable. I will continue to try and get that magic 600 flow hp, so I suppose to get that 500 RWHP number, I will need everything optimized.
Can it be done? I wish I could have seen some of the early heads that Devek did, maybe I'm missing something?
Greg
P.S the other intake valve was the porting job I had previously, it used a 2.08" valve.
Maybe 500 RWHP is too much of an expectation? If you come off the LS7 engine, when they mod them, i.e a cam and exhaust they are supposedly getting over 600 crank hp, so they have about 25% more headflow, about 17% more capacity but need to run cats and meet emmisions. The only advantages I have is a bigger cam, and probably a lower friction engine and more revs available if they end up useable. I will continue to try and get that magic 600 flow hp, so I suppose to get that 500 RWHP number, I will need everything optimized.
Can it be done? I wish I could have seen some of the early heads that Devek did, maybe I'm missing something?
Greg
P.S the other intake valve was the porting job I had previously, it used a 2.08" valve.
03-03-2007, 07:43 AM
#19
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Good stuff Greg! 
03-03-2007, 08:25 AM
#20
Three Wheelin'
Those are still some good flow numbers. Sounds like your doing everything right. If you give it bigger intake runners, a good exhaust, 400+ cubes and a cam in the 240-250ish @ .050 range you'll be able to get 500 rwhp. Actually if you strive for 500 rwhp you'll get 499 when you dyno it due to dyno karma, to make it worse, when you post your results here someone will ask what brand of dyno you used and it will undoubtedly be the one that reports higher numbers.
03-03-2007, 11:46 AM
#23
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anyone thought of finding a used C5 intake manifold and see if some adapter plates could be used to fit it to our 928s. those little 5.7 liter engines seem to make 420rwhp on a regular basis with not much modified.
mk
mk
03-03-2007, 01:11 PM
#24
Drifting
Originally Posted by mark kibort
anyone thought of finding a used C5 intake manifold and see if some adapter plates could be used to fit it to our 928s. those little 5.7 liter engines seem to make 420rwhp on a regular basis with not much modified.
mk
mk
Those engines do make good power though. My dad has a 5.7 LS-1 with AFR heads, short tube headers, 90mm throttle, custom cam, and an intake. His truck puts down over 400 at the wheels.
03-03-2007, 01:30 PM
#25
Drifting
I have been following greg's work closely too because I want to see what a 2 valve NA can do. I understand most of what has been done but i am far from an expert on the flow situation.
Can somebody tell me if the shape of the stock spider intake mattered? I thought I read that the shape and size of the legs had an impact on the performance of the engine. If Greg is reshaping and resizing how can he know what will happen.
If its just a question of making a bigger size plenum with shorter wider runners that will fit in the space there? If so I could see a 2 piece carbon fiber shape that would fit together and make a plenum/legs finished part.
Can somebody tell me if the shape of the stock spider intake mattered? I thought I read that the shape and size of the legs had an impact on the performance of the engine. If Greg is reshaping and resizing how can he know what will happen.
If its just a question of making a bigger size plenum with shorter wider runners that will fit in the space there? If so I could see a 2 piece carbon fiber shape that would fit together and make a plenum/legs finished part.
03-03-2007, 11:39 PM
#26
Drifting
Really generally speaking, a higher volume plenum with lower volume runners will produce more hp and less torque. It has to do with pressure waves moving up and down the intake runners with respect to when the intake valves close.
03-04-2007, 06:44 AM
#27
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I should add that all the flow tests done were done on a 103 mm bore, this does affect the numbers, especially when comparing the stock valves in a stock bore (97 mm) versus the larger 103 mm bore. Thanks for the comments guys.
Cheers Greg
Cheers Greg
07-03-2010, 09:53 AM
#28
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Well I closed a rather long chapter in this engine build today, the intake and exhaust port design has been finalized. It will need mapping for CNC and maybe there will be some tweaking there but it will be minor, I know what works and what doesn't now after many many tests.
The exhaust figures are not at hand as somehow I have misplaced them, if I have posted them late last year or early this year please let me know. The exhaust numbers are more impressive than the intake. The intake is not bad itself. In the end I achieved with quite a bit of help and some generous people sharing their knowledge and me parting with a fair wad of cash I got another 100 cfm of the stock head when compared and the same lift. The head is line ball with many top aftermarket heads such as the AFR 210 cc competition CNC head.
The new cam should be around 0.650" and as such that is where I hoped that the port would taper off as when you design ports they are not optimized in all lift ranges. That is not possible, it is possible to get the best with what you have but a port will not be the best down low and the best up high, the ports need different characteristics to do this and that is why it can't happen.
Below is a PM from a while ago from one of the chaps that has been assisting, we discussed the 366 ci engine again today and pulled up the flow figures and charted mine against theirs. It was line ball, almost exactly the same except mine doesn't drop off and go crazy turbulent at 0.700". The manifold he talks about having a problem was made the wrong way round! Can you believe that? What I mean is the Windsor ports all face in one direction, they are not straight like the Porsche's. So the manifold was made with the runners linking up but this caused a kink in the runner like a V but not as bad as a V of course.
So if the Windsor can make 660 hp at 7,000 I should be able to match it as all my other major components are the same or better such as the cam,(we are lucky to have 38 mm buckets) exhaust and the induction, that Windsor had a horrible push rod pinch too. I have another 1,000 rpm also.
When I was there today, I had to wait to get the head flowed, they had some very big heads there. The Big Chiefs and the Pro Filer, one head cam off an engine that made 1130 hp and that was the smaller of the heads, the bigger head they were hoping for 1250 to 1300 hp, these are 622 ci engines or mountain motors.
"Hi Greg,
So slowly getting there, no point bolting of great parts if the lungs of the engine are not up to the task, that is what all this time has been about. It has also been about acquiring parts and upgrading skills. Learning as you go, so to speak.
The final numbers are as follows, tested at 28" with a 2.10" valve
0.050" 32.4
0.100" 65.9
0.200" 137.4
0.300" 205.9
0.400" 254.7
0.500" 292.1
0.600" 311.4
0.700" 319.6
0.800" 322.9
0.900" 324.6
1.000" 326.6
You can see how it starts to taper off around 0.650" It also should attain very good air speed. For that extra 100 cfm of air it only needs to be 15% bigger than stock which shows you how big the stock port is. I may need to increase the port size depending on how the engine runs but better to be smaller than bigger.
I also found some unique throttle bodies, they have no throttle shaft, this alllows for smoother air flow around the blade, they were tested against roller barrels and were very close in performance on the bench and real world dyno testing. So those throttles with some nice tapered carbon runners and a large carbon plenum which I will make.
The one thing they were all concerned about was that the port would flow so well that at low revs it will knock as the cylinder pressure will be too high even though the cam is pretty big and bleeding off pressure. Good knock control required they reckon.
Greg
The exhaust figures are not at hand as somehow I have misplaced them, if I have posted them late last year or early this year please let me know. The exhaust numbers are more impressive than the intake. The intake is not bad itself. In the end I achieved with quite a bit of help and some generous people sharing their knowledge and me parting with a fair wad of cash I got another 100 cfm of the stock head when compared and the same lift. The head is line ball with many top aftermarket heads such as the AFR 210 cc competition CNC head.
The new cam should be around 0.650" and as such that is where I hoped that the port would taper off as when you design ports they are not optimized in all lift ranges. That is not possible, it is possible to get the best with what you have but a port will not be the best down low and the best up high, the ports need different characteristics to do this and that is why it can't happen.
Below is a PM from a while ago from one of the chaps that has been assisting, we discussed the 366 ci engine again today and pulled up the flow figures and charted mine against theirs. It was line ball, almost exactly the same except mine doesn't drop off and go crazy turbulent at 0.700". The manifold he talks about having a problem was made the wrong way round! Can you believe that? What I mean is the Windsor ports all face in one direction, they are not straight like the Porsche's. So the manifold was made with the runners linking up but this caused a kink in the runner like a V but not as bad as a V of course.
So if the Windsor can make 660 hp at 7,000 I should be able to match it as all my other major components are the same or better such as the cam,(we are lucky to have 38 mm buckets) exhaust and the induction, that Windsor had a horrible push rod pinch too. I have another 1,000 rpm also.
When I was there today, I had to wait to get the head flowed, they had some very big heads there. The Big Chiefs and the Pro Filer, one head cam off an engine that made 1130 hp and that was the smaller of the heads, the bigger head they were hoping for 1250 to 1300 hp, these are 622 ci engines or mountain motors.
"Hi Greg,
Sorry for the long delay. Started a new job recently, been quite busy, missed your PM.
I discussed a Windsor 366ci engine a friend of mine built recently for a GT40 circuit racer with you that Saturday morning a few months ago if you remember. It had Air Flow Research 205cc SBF heads, you can check flow figures on their website. I flowed them and found their numbers to be spot on up to 0.600" lift but backed up with major turbulence at 0.700". Just over 300cfm at 0.600" lift. However, manifold wasn't made properly which dropped quite a bit of flow, about 10-15 cfm from memory. I measured Min CSA, was 2.23 sq" at pushrod pinch. IR induction, 14" total length from bellmouth to valve seat, 4.25 sq" entry where radius of bellmouth meets straight section of ram tube. Camshaft was 258/268 @ 0.050", about 0.670" lift. This engine made 670HP at 7000rpm and 560ft/lbs on VP MS109 fuel. This was dynoed at Kim Bakers.
I really can't see a problem with your engine making more than 700HP if camshaft and induction & exhaust diameters & lengths are chosen correctly, you certainly have the flow to support it.
I can't remember if I showed you the plaster casting I made back then. You may have seen it sitting under the flowbench. I've been flow testing various mods. It's a 408ci Cleveland. We dynoed it 2 weeks ago. 709HP at 7200rpm. It only had about 330cfm at 0.700" lift through the manifold. 2.65 sq" min CSA in inlet, 266/270 @ 0.050" camshaft. Single plane manifold. Dynoed at Westend which gives same figures as Ned's dyno (One of Kim Bakers)
Another 427 SBC which was dynoed recently at Westend. I measured the head, 313cfm @ 0.700", very small min CSA for that capacity at 2.3 sq". Single plane manifold. Made 717HP. These were 18 degree Chev heads which are fairly high port and so can handle higher velocities before choking but had quite a big cam which also compensates somewhat for small CSA.
I discussed a Windsor 366ci engine a friend of mine built recently for a GT40 circuit racer with you that Saturday morning a few months ago if you remember. It had Air Flow Research 205cc SBF heads, you can check flow figures on their website. I flowed them and found their numbers to be spot on up to 0.600" lift but backed up with major turbulence at 0.700". Just over 300cfm at 0.600" lift. However, manifold wasn't made properly which dropped quite a bit of flow, about 10-15 cfm from memory. I measured Min CSA, was 2.23 sq" at pushrod pinch. IR induction, 14" total length from bellmouth to valve seat, 4.25 sq" entry where radius of bellmouth meets straight section of ram tube. Camshaft was 258/268 @ 0.050", about 0.670" lift. This engine made 670HP at 7000rpm and 560ft/lbs on VP MS109 fuel. This was dynoed at Kim Bakers.
I really can't see a problem with your engine making more than 700HP if camshaft and induction & exhaust diameters & lengths are chosen correctly, you certainly have the flow to support it.
I can't remember if I showed you the plaster casting I made back then. You may have seen it sitting under the flowbench. I've been flow testing various mods. It's a 408ci Cleveland. We dynoed it 2 weeks ago. 709HP at 7200rpm. It only had about 330cfm at 0.700" lift through the manifold. 2.65 sq" min CSA in inlet, 266/270 @ 0.050" camshaft. Single plane manifold. Dynoed at Westend which gives same figures as Ned's dyno (One of Kim Bakers)
Another 427 SBC which was dynoed recently at Westend. I measured the head, 313cfm @ 0.700", very small min CSA for that capacity at 2.3 sq". Single plane manifold. Made 717HP. These were 18 degree Chev heads which are fairly high port and so can handle higher velocities before choking but had quite a big cam which also compensates somewhat for small CSA.
The final numbers are as follows, tested at 28" with a 2.10" valve
0.050" 32.4
0.100" 65.9
0.200" 137.4
0.300" 205.9
0.400" 254.7
0.500" 292.1
0.600" 311.4
0.700" 319.6
0.800" 322.9
0.900" 324.6
1.000" 326.6
You can see how it starts to taper off around 0.650" It also should attain very good air speed. For that extra 100 cfm of air it only needs to be 15% bigger than stock which shows you how big the stock port is. I may need to increase the port size depending on how the engine runs but better to be smaller than bigger.
I also found some unique throttle bodies, they have no throttle shaft, this alllows for smoother air flow around the blade, they were tested against roller barrels and were very close in performance on the bench and real world dyno testing. So those throttles with some nice tapered carbon runners and a large carbon plenum which I will make.
The one thing they were all concerned about was that the port would flow so well that at low revs it will knock as the cylinder pressure will be too high even though the cam is pretty big and bleeding off pressure. Good knock control required they reckon.
Greg
07-03-2010, 11:32 AM
#30
Man of many SIGs
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Congratulations on another milestone Greg.
Do you have stock baseline flow #'s for comparison? Which heads did you start with? I remember you were looking for some 4.5 US style heads at one point.
Do you have stock baseline flow #'s for comparison? Which heads did you start with? I remember you were looking for some 4.5 US style heads at one point.