Exhausts and other stuff.
06-15-2012, 09:17 AM
#61
Rennlist Member
Thread Starter
Crazy isn't it!? Function is beautiful 
It seems Holinger is a top choice for high hp seq gearboxes. The main drawback of all these race sequential boxes is the maintenance. Rebuild every ~25-40 hours. And the rebuild isn't cheap! Around $3500 plus 10-15 hours for the Porsche unit IIRC.
Quaife have released a bolt-on replacement sequential box for the Cup cars that have cheaper rebuilds. Cost is about $20k.
Race transmissions are just so darn expensive. I think I will have to make do with my 968 gearboxes..
It seems Holinger is a top choice for high hp seq gearboxes. The main drawback of all these race sequential boxes is the maintenance. Rebuild every ~25-40 hours. And the rebuild isn't cheap! Around $3500 plus 10-15 hours for the Porsche unit IIRC.
Quaife have released a bolt-on replacement sequential box for the Cup cars that have cheaper rebuilds. Cost is about $20k.
Race transmissions are just so darn expensive. I think I will have to make do with my 968 gearboxes..
06-15-2012, 09:22 AM
#62
Nordschleife Master
There also seems to be a trend for building virtual n/a motors and putting turbos on them. People are running 11-13:1 c/r and pumping boost through them for racecars. Seems amazing, especially when most of us are running around on 8:1 but I guess with better control via ECUs etc and fuels such as E85 more options are becoming available. In which case I assume headers and exhausts are becoming more important to forced induction cars also. Pulsing and reversion which seemed virtually undiscussed with old school turbo cars are now topics written about in various forums.
the exhaust after the exhaust manifold collector is not pulse tuned so that's why you want to minizme backpressure there.
The good thing about maximing VE is that boost works as a multiplier of the engine's N/A power. Crude calculation - if you increase your engine's N/A power with 30 hp you will get 60 hp more when boosting 1.0 bar.
Another thing I'd like to discuss is that of intakes. I know again that there is a school of thought that intakes and heads don't make that much difference with forced induction. Just stuff more in there via boost. But of course everything can have an influence on the outcome of our motors. The thing in the wooden crate has a modified stock intake. It's been extruded honed and had some steps welded in to help balance the runners. However this would seem a compromise. I wish there was more quantifiable results on the LR intake as it's seemed to have had a few question marks raised over it from time to time. Some have suggested that it's really for a race motor as it shifts the torque across to the rhs with it's short runners. Others have hinted that it flows even worse that the stock intake. I discussed the stock intake briefly with the guy that installed the Motec etc on my car and he felt that the factory would have spent a lot of time and money on the stock one and it should by rights be fine. There just seems not to be much info or choice out there on intakes for our cars. SFR has clouds hanging over them too. Hopefully DNovak / Dave puts some of his together and flows them as he mentioned some time ago. It would be great if someone did some back to back tests of the options out there. Unlikely to happen but one can only dream. 
Check this thread out, once again for Evo's but it shows very clearly how different intake manifolds can give very different results - even though many of them are extremely similar in shape and form!
http://highboostforum.com/forum/show...and-facts-only
06-15-2012, 10:34 AM
#63
Three Wheelin'
You have got me thinking. If I put a 968 head and intake manifold on a supercharged 944S2, would I get appreciable power increase above the stock head? Granted, I would need to run without Variocam unless I swapped the DME and harness as well, but nevertheless would I then increase peak power from 210 NA to 240NA and hence increase peak power from 285 hp to 325 hp (ie equivalent power increase of 968/944S2)? Remembering that Variocam has no effect at peak power.
06-15-2012, 10:51 AM
#64
Nordschleife Master
If you have a 968 head, camshafts and intake manifold it would be a worthwhile swap, but not quite a 30 hp bump. Variocam is for midrange gains and in boosted applications it gives about the same power at redline with and without Variocam.
In fact, the best gain if you cannot control the Variocam would be to constatly have it activated.
In fact, the best gain if you cannot control the Variocam would be to constatly have it activated.
06-15-2012, 11:09 AM
#65
Rennlist Member
Interesting read, thanks for the link. I am no expert, but the tests unofficially confirmed my suspicion that unless you are going for the absolute hp and in racing conditions, having a highly modded, custom, lots of bling and expensive intake, at least for my hp goal, is certainly not needed. Money saved can be spent else where to improve on other performance aspect of our car. Things got to work together as a unit so strapping on the nicest custom intake wont do you any good but it sure looks nice! Even with the max gains, it's typically in the higher rpm where max cfm can be realized, however; our engines are not made to be rev into the 9K rpm so the gains is not worth it imo. If you look at the internal mod of the runners, the high performing ones all have a smooth transition welds inside the chamber. I believe this will keep air turbulence to a minimum and prevent A/F ratio to fluctuates wildly, in the upper rpm as the test showed. Some roughness right at the entrance points is okay to aid swirl but no clunky, speed-bumps right before the air entering the engine. Our stock set up is pretty decent in the 400 rwhp range and if anything for this power level, I'd do a mild porting if any to the stock intake and call it a day. Really is how fast you wanna go and for what purpose. And if everything else is taken care off and you want to get that last bit of rwhp, albeit in the high rpm range, then by all means go for it. With all that said, I do like looking at expensive, $$$ custom intakes. 
06-15-2012, 07:54 PM
#66
Rennlist Member
Thread Starter
Yes, interesting read and thanks for that Gustaf. I wonder how much of that is transferable to our cars? I'm sure a lot of it could be as it's just physics but with quite different motors (not to mention 8v vs 16v too) I am still somewhat bereft of what to possibly do with my 3L 8v motor? Assuming bigger i/c, pipes, t-b, headflow, headers, X-over, turbo etc...(then there's whatever exhaust I go with)...Perhaps the stock or modified stock intake will be sufficient for now. So long as we don't run into the aforementioned tuning problems....
Wonder if Sid has struck any intake issues with his builds?
Wonder if Sid has struck any intake issues with his builds?
06-15-2012, 08:58 PM
#67
Interesting read, thanks for the link. I am no expert, but the tests unofficially confirmed my suspicion that unless you are going for the absolute hp and in racing conditions, having a highly modded, custom, lots of bling and expensive intake, at least for my hp goal, is certainly not needed. Money saved can be spent else where to improve on other performance aspect of our car. Things got to work together as a unit so strapping on the nicest custom intake wont do you any good but it sure looks nice! Even with the max gains, it's typically in the higher rpm where max cfm can be realized, however; our engines are not made to be rev into the 9K rpm so the gains is not worth it imo. If you look at the internal mod of the runners, the high performing ones all have a smooth transition welds inside the chamber. I believe this will keep air turbulence to a minimum and prevent A/F ratio to fluctuates wildly, in the upper rpm as the test showed. Some roughness right at the entrance points is okay to aid swirl but no clunky, speed-bumps right before the air entering the engine. Our stock set up is pretty decent in the 400 rwhp range and if anything for this power level, I'd do a mild porting if any to the stock intake and call it a day. Really is how fast you wanna go and for what purpose. And if everything else is taken care off and you want to get that last bit of rwhp, albeit in the high rpm range, then by all means go for it. With all that said, I do like looking at expensive, $$$ custom intakes.
06-16-2012, 01:51 PM
#68
Nordschleife Master
My opinion is that the stock intake is probably very good at what it is supposed to do. Good midrange. But increasing VE at higher RPM's using longer duration cams, a larger turbo, larger valves, ported head, 4-1 header etc and the stock intake is most likely not the best setup to make use of all these mods.
Remember the stock engine makes peak power around 6000 rpm and it's not uncommon for a modded engine with an agressive cam to make peak power upwards 7000 rpm.
In short, the stock intake manifold is most likely not the optimal design for maximizing power throughout the 4000-7000 rpm area.
Patrick, as you say it's all about physics and so the same principles apply for our engines (compared to the Evo's). But since all variables are different we cannot use their exact dimensions as a template for our engines.
What is interesting is that when they just cut of the stock manifold to use short runners and a larger plenum the total effect was negative (loss everywhere except a tiny gain in a short rpm area up top).
It clearly displays that engineering and testing is needed to make a good intake manifold and not just fabbing something up that looks nice.
Patience, time, fabrication skills and a dyno - that's all we need to create a new killer intake for our engines
Remember the stock engine makes peak power around 6000 rpm and it's not uncommon for a modded engine with an agressive cam to make peak power upwards 7000 rpm.
In short, the stock intake manifold is most likely not the optimal design for maximizing power throughout the 4000-7000 rpm area.
Patrick, as you say it's all about physics and so the same principles apply for our engines (compared to the Evo's). But since all variables are different we cannot use their exact dimensions as a template for our engines.
What is interesting is that when they just cut of the stock manifold to use short runners and a larger plenum the total effect was negative (loss everywhere except a tiny gain in a short rpm area up top).
It clearly displays that engineering and testing is needed to make a good intake manifold and not just fabbing something up that looks nice.
Patience, time, fabrication skills and a dyno - that's all we need to create a new killer intake for our engines
06-16-2012, 04:42 PM
#69
Rennlist Member
Thread Starter
Yes, that's the exact conclusion that I came to as well Gustaf. Seemed like the factory did a good job for the Evos and some of the alternatives weren't worth the time and money to change to. Guess I'm being greedy in wishing that there was a proven intake upgrade for us. Perhaps the LR one mightn't be such a bad option for a race motor?
06-16-2012, 04:52 PM
#70
Duke, have you ever seen a dyno graph from Corleone's old 2.5 engine? The one with the carbon fiber intake...
The figures I have of this engine are 528 bhp @ 7050 rpm. 611 nm @ 4980 rpm. Boost 1.65 down to 1.5 bar at redline
The figures I have of this engine are 528 bhp @ 7050 rpm. 611 nm @ 4980 rpm. Boost 1.65 down to 1.5 bar at redline
06-16-2012, 05:03 PM
#71
Rennlist Member
If I was to pick an intake to try, I'd chose the one from IMA- it's pretty nice looking imo. Anybody know of anyone had it on a 951? The cf one is nice too as well as being extremely light. Would be nice to see the cfm and specs on those.
06-16-2012, 07:44 PM
#72
Rennlist Member
Thread Starter
Which one Muddy? I've seen the C/F on Henk's great motor. Got me thinking if this was who produced the c/f Milledge setup? I've not seen their non c/f version. Pics or links?
Thom, I'd forgotten about Corleone's old 2.5L motor. That's a great result by the looks of it.
Thom, I'd forgotten about Corleone's old 2.5L motor. That's a great result by the looks of it.
06-17-2012, 12:17 AM
#73
Rennlist Member
I think the intake pix is from the IMA site- it's one of those ITB intake. The one above is nice too and I bet it's expensive. Artwork, I could just hang it on a wall or something...
https://rennlist.com/forums/944-turb...ght=IMA+intake
https://rennlist.com/forums/944-turb...ght=IMA+intake
06-18-2012, 02:29 PM
#74
Drifting
