Neil Haughey
New member
Al Melling perhaps?
Flow rates of available stock heads??
- Thread starter 333pg333
- Start date
Well I've found out and have been asked to not repeat exact numbers so suffice to say that my initial idea of the stock 8v being 188cfms is very close. The stock 16v is not double, but it's not too far away. Modified heads will net some impressive gains if done correctly as shown by my 8v at 247cfms. What you can get out of a modded 16v is very impressive according to the person who has tested these on a proper bench flow. Let's just say that there is a '4' involved. It is just then a matter of how much you want to spend v's how much more power or potential you want to make. This includes getting custom cams as well so you can imagine it can get very pricey. I'm sorry to be vague but the person who has spent a lot of time and money doing these mods and tests deserves the right to ask for secrecy.
DivineE
New member
I had a really interesting discussion with Mike Costin (the 'Cos' of Cosworth) about this at the weekend and although 80% of what he was saying went straight over my head the small amount that I was able to understand was that the cfm figures on their own mean almost nothing and that its the 'cfd'? with the speed, pressure and efficiency which actually translates into bhp.
He also mentioned that Formula 1 car are now actually running into the 140% efficiency band just through the design of the intake and exhaust! All sounds unbelievably impressive to me. I would love to have been able to understand more as he is clearly a man of unearthly knowledge on these topics!
He also mentioned that Formula 1 car are now actually running into the 140% efficiency band just through the design of the intake and exhaust! All sounds unbelievably impressive to me. I would love to have been able to understand more as he is clearly a man of unearthly knowledge on these topics!
Neil Haughey
New member
I don't know which is more impressive, the 140% VE for a current F1 engine or the fact that you where chopsing with Mike Costin. Talk about shameless name dropping 
)
)Neil Haughey
New member
Just picked up on that one! AFAIK it is down to the fact that the surprisingly effective 8v heads like the old A series promote swirl into the chamber whereas 16v heads typically promote tumble into the chamber, this is all AFAIK of course!
DivineE
New member
lol [] was just added the name so you'd know it came from a reputable source and not my mate Dave from Dave's dodgy car repair shop. Mr. Costin is a friend of the family so often at family parties, unfortunately I never usually have anything intelligent enough to discuss with him on engines.
] was just added the name so you'd know it came from a reputable source and not my mate Dave from Dave's dodgy car repair shop. Mr. Costin is a friend of the family so often at family parties, unfortunately I never usually have anything intelligent enough to discuss with him on engines.Neil Haughey
New member
I could easilly agree anyway given that I have been very sceptical about the benefits of flow bench tuning for some time now. As a simple example if one takes a turbo or SC engine and increases the air mass used by the engine by for sake of arguement fiddling with the boost pressure then one see's an increase in power loosely commensurate with the increase in air mass. Hardly surprising given that the power comes from burning fuel mass X with air massY, simple chemistry when it is boiled down.
However the same has never seemed to be true with flow bench improvement of NA engines. You get these massively bigger numbers that lo and behold often sadly result in tiny power gains.
Personally I would like to see what the change is in air mass breathed in by an engine after flow bench tuning. Not sure about what would be the most acceptable way of calculating or measuring this short of bolting the thing into a fully working engine.
Basically IMHO motor tuning should be based on metrics that take into account the pulsing effects at both the inlet and exhaust sides of the motor. Unfortunately these don't seem to exist at the moment at least not at the consumer tuning end of the market.
I wish I had family friends as impressive as Mike Costin(
However the same has never seemed to be true with flow bench improvement of NA engines. You get these massively bigger numbers that lo and behold often sadly result in tiny power gains.
Personally I would like to see what the change is in air mass breathed in by an engine after flow bench tuning. Not sure about what would be the most acceptable way of calculating or measuring this short of bolting the thing into a fully working engine.
Basically IMHO motor tuning should be based on metrics that take into account the pulsing effects at both the inlet and exhaust sides of the motor. Unfortunately these don't seem to exist at the moment at least not at the consumer tuning end of the market.
I wish I had family friends as impressive as Mike Costin
(I would not be so skeptical with flowbench work. If you said that to any F1 builder(who spends millions of $$ in flowbench r&d) they would throw you out of their shop. Also, in your example, your left out the heat generated from the increased pressures. Our 8v heads (mainly the exhaust valve/port) are huge bottlenecks. Turning up the boost only gets you so far.
There can be many reasons why you see little gains from headwork on a n/a or turbo for that matter.
This is how I would explain it best. Headwork/flowbench work means nothing unless you can get the motor to pass more air through it. How do you do that?? Well, you have to A, increase engine speed or B, force more air through it. Both would have larger gains if you increase the flow and decrease resistance.
A ported n/a head will do nothing at stock rpms(it will actually hurt performance). Add the proper cam and increase your rpms and you will see big gains. Of course you will be limited by displacement. This is only an air pump!
A ported turbo head at stock boost/rpms will gain you power because there is less friction/heat in forcing air through the head. Again, add a cam, open the valves up even more and it can pass more air through. Increase the rpms and watch the gains grow. Also, less friction = less heat. Cooler charge = HP
Costs($$) vrs. HP
On a n/a engine, a side from increasing displacement, You have no choice but to increase rpm's, port the intake/t-body/head, possibly add larger valves, add a header and exhaust. The costs to do that are huge. Custom cams(to add more lift over oem lift or re-grind ) ground from billet blanks costs a lot of money. But in terms of extracting HP from a n/a, you can't do any less.
A turbo is different. Add a few psi boost and gain xyz results. Do all the above and keep the boost where it was = free hp.
Dave
Patrick,
The problem with back to back testing on a stock head, is that its not cost effective to build 2,3,4 or 5 cams and test them as"drop in" cams. It would only be worth it if you were looking for that last bit of HP or you really wanted to fine tune the head. That being said, adjustable cam gears do wonders. There are 3 or 4 grinds already out there that are WAY better than a stock grind on a stock head. There is no reason to re invent the wheel..
For non stock applications, its best to design the head, based on power/powerband goals, and then make a cam to match. Thats were knowledge of cam and head design come in play.
Dave
The problem with back to back testing on a stock head, is that its not cost effective to build 2,3,4 or 5 cams and test them as"drop in" cams. It would only be worth it if you were looking for that last bit of HP or you really wanted to fine tune the head. That being said, adjustable cam gears do wonders. There are 3 or 4 grinds already out there that are WAY better than a stock grind on a stock head. There is no reason to re invent the wheel..
For non stock applications, its best to design the head, based on power/powerband goals, and then make a cam to match. Thats were knowledge of cam and head design come in play.
Dave
Absolutely Dave. I mean in a perfect world where money and time were no objects it would be nice to see just what power differences are available divided by how much money you have to spend to attain whatever level you want to get off the 'Money-go-round' at. [] Very little is spoken about cams and heads and of course that has something to do with our 20 year old cars on average. Not many are going to sink lot's of time/money into R&D. There are a few out there like yourself, Neil Harvey of Performance Developments (U.S.), Jon Mitchell, Simon at SPS (U.K.) and a few select others out there. I guess it ultimately comes down to the end users goals. Just how fast do we want to go? I find it's like a drug. You get used to your current dose and need to up the ante. Porsche did a great job on the original cars but they were meant for fast Hwy cruising. We can improve on some of the stock parts and as you know some of us are prepared to find out by just how much. Hopefully I can report back soon just how much difference your new cams and heads etc will give us!!! []
] Very little is spoken about cams and heads and of course that has something to do with our 20 year old cars on average. Not many are going to sink lot's of time/money into R&D. There are a few out there like yourself, Neil Harvey of Performance Developments (U.S.), Jon Mitchell, Simon at SPS (U.K.) and a few select others out there. I guess it ultimately comes down to the end users goals. Just how fast do we want to go? I find it's like a drug. You get used to your current dose and need to up the ante. Porsche did a great job on the original cars but they were meant for fast Hwy cruising. We can improve on some of the stock parts and as you know some of us are prepared to find out by just how much. Hopefully I can report back soon just how much difference your new cams and heads etc will give us!!! []I guess Patrick, I didn't do a real good job explaining that, if your good at cam profiling, you don't have to do a lot of trial and error testing. Rather than you can narrow it down to a couple choices. The 16v cams are made from new billets because you can only put a mild re grind on the stock lobes. There is not enough material to increase the lift of the cam.
8v motors and people have it made because there are many choices to choose from.
8v motors and people have it made because there are many choices to choose from.
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