2 V headflow figures - project update
02-28-2007, 03:25 AM
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2 V headflow figures - project update
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")
I still might make it, it is only a rough port job at present, the heads will flow amazing amounts at 0.600" lift, the head guys think I should get custom cams made to take advantage of the flow at that level. I think at 0.600" you would be on par or very close to of a 4 valve engine.
On the exhaust side the port flowed 190 cfm, this should be O.K as my exhaust system is awesome if you ask me.
As to other little bits and pieces, I have designed my dry sump system and with the help of Kevin Johnson I hope to build a fab scraper system with it too. The system will be 4 stage and store its oil in the position where the 928's Hoover dam is held. All piping on the scavenge side will be internal, this is for safety as much as anything. Also I will cut away a section of the sump to fit the pump in the recess of the cut away sump. The pump drive belt will have a spring loaded idler wheel. I will also compartmentize the sump ala F1 and Nascar when it was allowed that is.
There may well be some big gains in the dry sump system just because the oil control in the standard 928 engine is so woeful. Also I will go ahead with the DLC coating of the lifters to try and cut down some of the friction in this area given that it will increase due to my increased lift, i.e from 0.472" to 0.550".
I have also designed the intake system, I haven't the money for individual throttle bodies, not at the moment and maybe never, so I have had to come up with an alternative, a design parameter that I have always have was to keep the car looking ALL Porsche, so I thought what would still look OEM but deliver the goods especially for a engine that want to be feed at 7500 rpm?
Well I decided to shorten my intake runners even further than what they are now and also extend the plenum. I will extend the plenum about an inch, I will be able to do this because the current oil separator and oil filler on the Euro will be gone. I will also try to push the plenum back a bit too. So I will hope to cut an inch or maybe two from the current length. This will help with flow and the cylinder pulsing for the higher rpms.
My throttle body at first may well stay at the standard 80 mm size although my head guys say that's O.K. but can we have two of them? In reality I wont to run the LS2/LS7 throttle body which is electronic and 90 mm in diameter. Louie Ott's management system will be able to run electronic throttle in the future, so that is my game plan there. I will also run the DTA S8 system that Louie sells as I believ it is outstanding value for money. Motec was my plan but I haven't robbed that bank yet.
Tell me what you think, views on my insanity I mean sanity aren't at this stage required.
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")
I still might make it, it is only a rough port job at present, the heads will flow amazing amounts at 0.600" lift, the head guys think I should get custom cams made to take advantage of the flow at that level. I think at 0.600" you would be on par or very close to of a 4 valve engine.
On the exhaust side the port flowed 190 cfm, this should be O.K as my exhaust system is awesome if you ask me.
As to other little bits and pieces, I have designed my dry sump system and with the help of Kevin Johnson I hope to build a fab scraper system with it too. The system will be 4 stage and store its oil in the position where the 928's Hoover dam is held. All piping on the scavenge side will be internal, this is for safety as much as anything. Also I will cut away a section of the sump to fit the pump in the recess of the cut away sump. The pump drive belt will have a spring loaded idler wheel. I will also compartmentize the sump ala F1 and Nascar when it was allowed that is.
There may well be some big gains in the dry sump system just because the oil control in the standard 928 engine is so woeful. Also I will go ahead with the DLC coating of the lifters to try and cut down some of the friction in this area given that it will increase due to my increased lift, i.e from 0.472" to 0.550".
I have also designed the intake system, I haven't the money for individual throttle bodies, not at the moment and maybe never, so I have had to come up with an alternative, a design parameter that I have always have was to keep the car looking ALL Porsche, so I thought what would still look OEM but deliver the goods especially for a engine that want to be feed at 7500 rpm?
Well I decided to shorten my intake runners even further than what they are now and also extend the plenum. I will extend the plenum about an inch, I will be able to do this because the current oil separator and oil filler on the Euro will be gone. I will also try to push the plenum back a bit too. So I will hope to cut an inch or maybe two from the current length. This will help with flow and the cylinder pulsing for the higher rpms.
My throttle body at first may well stay at the standard 80 mm size although my head guys say that's O.K. but can we have two of them? In reality I wont to run the LS2/LS7 throttle body which is electronic and 90 mm in diameter. Louie Ott's management system will be able to run electronic throttle in the future, so that is my game plan there. I will also run the DTA S8 system that Louie sells as I believ it is outstanding value for money. Motec was my plan but I haven't robbed that bank yet.
Tell me what you think, views on my insanity I mean sanity aren't at this stage required.
Cheers Greg
02-28-2007, 07:23 AM
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Hi Stuart, Honda is just a term that is in common use in engine building circles, it should be Honda style, that is refering to the 48 mm journal, or 1.888" if you so prefer, my rods were made by Lentz. Here's some pics.
They are a fully machined forging and use the Carrillo SPS bolts which have the highest rating of any bolt, they are also immune from stress corrosion and can be reused. I used Honda rods to lower the rotating and reciprocating weights.
Thanks Greg
They are a fully machined forging and use the Carrillo SPS bolts which have the highest rating of any bolt, they are also immune from stress corrosion and can be reused. I used Honda rods to lower the rotating and reciprocating weights.
Thanks Greg
02-28-2007, 09:45 AM
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Race Car
As usual, thanks for sharing your progress! 
I"m not so sure that is a good idea. 0.600" lift will require some heavy-duty valve springs to keep the rotating assembly under control at high RPM, which in itself is not a big deal. But what is a big deal is the added stress those valve springs will impart to the timing belt which can possibly fatigue and break since it wasn't designed for such high lift and corresponding spring pressure.
Food for thought at the very least.
Originally Posted by Greg Gray
I still might make it, it is only a rough port job at present, the heads will flow amazing amounts at 0.600" lift, the head guys think I should get custom cams made to take advantage of the flow at that level. I think at 0.600" you would be on par or very close to of a 4 valve engine.
Food for thought at the very least.
02-28-2007, 10:45 AM
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Looks really good Greg,
Truly exciting project and I like your low weight strong material approach!
Now regarding the drysump, what is it that you show us here?
It doesnt look like a sump fitting a 928 engine as shown?
Cheers/Peter
Truly exciting project and I like your low weight strong material approach!
Now regarding the drysump, what is it that you show us here?
It doesnt look like a sump fitting a 928 engine as shown?
Cheers/Peter
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02-28-2007, 12:27 PM
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As for the Hoover dam bit I thought the Americans on the board would get it, I simply meant where the 928 keeps all its water, in the windscreen washer bottle, it is that big it is like a dam.
The dry sump system shown is from a Chevy LS1 engine, it is shown for concept purposes only. I believe it just shows another way of doing things, I will make things quite compact around that area and as such you should be able to employ a small air cond compressor. I think the actual weight of the sump will be neutral as there is savings to be had from cutting away the front of the original. The pipes I have are all lightweight alloy. I will make it my next project if you like.
As to spring pressures, I totally agree, the spring pressures will be quite low with the new Comp Cams beehive springs, 60 pounds seat pressure on the intake, 75 on the exhaust and then approx 250 pounds open pressure on the both, the key to making it work is the lightweight material employed. E.g the valves weigh approx 70 grams instead of 108 grams and the spring and retainer weights are greatly reduced too. From memory the old retainer was 26 whereas the new one is 12 grams, I could go Ti here and save another 3 grams but the ti retainers are real expensive. The other aspect of friction control is that the DLC lifters shoud help here.
Cheers Greg
The dry sump system shown is from a Chevy LS1 engine, it is shown for concept purposes only. I believe it just shows another way of doing things, I will make things quite compact around that area and as such you should be able to employ a small air cond compressor. I think the actual weight of the sump will be neutral as there is savings to be had from cutting away the front of the original. The pipes I have are all lightweight alloy. I will make it my next project if you like.
As to spring pressures, I totally agree, the spring pressures will be quite low with the new Comp Cams beehive springs, 60 pounds seat pressure on the intake, 75 on the exhaust and then approx 250 pounds open pressure on the both, the key to making it work is the lightweight material employed. E.g the valves weigh approx 70 grams instead of 108 grams and the spring and retainer weights are greatly reduced too. From memory the old retainer was 26 whereas the new one is 12 grams, I could go Ti here and save another 3 grams but the ti retainers are real expensive. The other aspect of friction control is that the DLC lifters shoud help here.
Cheers Greg
02-28-2007, 01:42 PM
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Wow, that's a bundle of very interesting development projects.
The dry-sump alone is one hot topic, as it's a high-risk item to fine-tune. You offered to make it the next step to tackle, I'll bet every racer here will be all over it.
I'm curious to see what will probably be a later part of your plan, the modifications to the 16v intake system. Same diameter shorter runners, with more plenum volume, sounds like a recipe for high-end power without sacrificing too much low-end flow - and all for the cost of considerable fab time. But like you I've always wondered how much a hot 16v motor would like 8 shiny throttle bodies, though...
The dry-sump alone is one hot topic, as it's a high-risk item to fine-tune. You offered to make it the next step to tackle, I'll bet every racer here will be all over it.
I'm curious to see what will probably be a later part of your plan, the modifications to the 16v intake system. Same diameter shorter runners, with more plenum volume, sounds like a recipe for high-end power without sacrificing too much low-end flow - and all for the cost of considerable fab time. But like you I've always wondered how much a hot 16v motor would like 8 shiny throttle bodies, though...
02-28-2007, 03:06 PM
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Originally Posted by Greg Gray
As for the Hoover dam bit I thought the Americans on the board would get it, I simply meant where the 928 keeps all its water, in the windscreen washer bottle, it is that big it is like a dam.
02-28-2007, 06:02 PM
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By JEC 31
As for the induction, who said that they would be the same diameter runners? 
They are bigger and shorter. The plenum will be increased by about 30 to 35%, the reasoning for this is that the engine has increased in volume by about 27%, so I will need that size to stay level pegging with what was there. Then you have the aspect of increased rpms, you need a larger plenum for the increased rpms so then you also need to take into consideration packaging and asthetics. So I think if I end up 35% bigger than the stock plenum that will be O.K. Also the plenum will look stock except bigger.
The runners need to be increased in diameter the latest flow test proved that, otherwise all that will happen is that the torque curve will be lower in the rpm range, this will mean that I won't be able to take advantage on the increased rpm limit. So they will get bigger and shorter, my head guys will advise on what they believe to be the best there and it will be a joint decision.
Cheers Greg
I'm curious to see what will probably be a later part of your plan, the modifications to the 16v intake system. Same diameter shorter runners, with more plenum volume, sounds like a recipe for high-end power without sacrificing too much low-end flow - and all for the cost of considerable fab time. But like you I've always wondered how much a hot 16v motor would like 8 shiny throttle bodies, though...
They are bigger and shorter. The plenum will be increased by about 30 to 35%, the reasoning for this is that the engine has increased in volume by about 27%, so I will need that size to stay level pegging with what was there. Then you have the aspect of increased rpms, you need a larger plenum for the increased rpms so then you also need to take into consideration packaging and asthetics. So I think if I end up 35% bigger than the stock plenum that will be O.K. Also the plenum will look stock except bigger.The runners need to be increased in diameter the latest flow test proved that, otherwise all that will happen is that the torque curve will be lower in the rpm range, this will mean that I won't be able to take advantage on the increased rpm limit. So they will get bigger and shorter, my head guys will advise on what they believe to be the best there and it will be a joint decision.
Cheers Greg
02-28-2007, 08:15 PM
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nice work greg!!! 
I've been talking to a guy about a custom dry sump like that for the last week or so...
Rob,
Nothing to date for the 928. Here's the scenario to make something. If there is a possbility as far as design goes the pan cost would be similar to my LS1 design. This pan goes for $1650. Cost varies as the size and thickness of goes up. The pump starts at $1870. If you only buy one pan there is a $1000 tooling and programming fee. If you buy 2 it is $500 and 3 the fee is waived.
To design it I would need the interface details for the pan rail and would work with you on where we can position the pump. time frame is usually 6-8 weeks to make something happen.
Bill
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the roots style pump can pull 20" of vacume and weighs 30% less than conventional dry sump setups... a group buy would be awesome....
I've been talking to a guy about a custom dry sump like that for the last week or so...
Rob,
Nothing to date for the 928. Here's the scenario to make something. If there is a possbility as far as design goes the pan cost would be similar to my LS1 design. This pan goes for $1650. Cost varies as the size and thickness of goes up. The pump starts at $1870. If you only buy one pan there is a $1000 tooling and programming fee. If you buy 2 it is $500 and 3 the fee is waived.
To design it I would need the interface details for the pan rail and would work with you on where we can position the pump. time frame is usually 6-8 weeks to make something happen.
Bill
_____________________________
Bill Dailey
Dailey Engineering
42095 Zevo Dr. #7
Temecula, CA 92590
Ph. 951-296-2110
Fax 951-296-2111
bill@daileyengineering.com
www.daileyengineering.com
the roots style pump can pull 20" of vacume and weighs 30% less than conventional dry sump setups... a group buy would be awesome....
02-28-2007, 08:21 PM
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Originally Posted by Sterling
what would be cool is a lower sump with the pump mounted on the side of the sump in such a way that you could just run a belt where the smog pump belt used to be routed. Maybe a new pulley with cogs where the smog belt used to be........ so you could run a small cogged belt like the 928 timing belt...... the only thing about mounting the sump pump that low might be clearance issues and it may need a shield to protect the belt from debris.
03-01-2007, 09:39 AM
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Originally Posted by Greg Gray
As for the induction, who said that they would be the same diameter runners?
They are bigger and shorter. The plenum will be increased by about 30 to 35%, the reasoning for this is that the engine has increased in volume by about 27%, so I will need that size to stay level pegging with what was there. Then you have the aspect of increased rpms, you need a larger plenum for the increased rpms so then you also need to take into consideration packaging and asthetics. So I think if I end up 35% bigger than the stock plenum that will be O.K. Also the plenum will look stock except bigger.The runners need to be increased in diameter the latest flow test proved that, otherwise all that will happen is that the torque curve will be lower in the rpm range, this will mean that I won't be able to take advantage on the increased rpm limit. So they will get bigger and shorter, my head guys will advise on what they believe to be the best there and it will be a joint decision.
Cheers Greg
The bigger bore +shorter runners should serve your 2v design well.
Every now and then I let my demented little mind gnaw on an intake design I saw on the LeMan's winning Mazda 787B's 4-rotor Wankel (loudest motor ever!). It has variable length intake runners tuned to be the optimum length for "resonant supercharging" (or whatever you what to call it) at any RPM. I can't get a clear mental picture of how to set it up on a V8 though...