Intake upgrade and dyno results
10-20-2011, 12:31 PM
#32
Three Wheelin'
Join Date: Jan 2010
Location: Durham Region/GTA East, Canada
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It wouldn't take much more to hit 150 RWHP. You said it had a stock exhaust? Still have a cat too? performance exhaust (or simple cat delete), and add some minor p&p work (see my thread on my work with the intake), add a mild cam and or a maf, and you could easily break 150hp.
Do you have any other plans to improve the intake system?
Do you have any other plans to improve the intake system?
10-20-2011, 02:08 PM
#33
Drifting
ram air absolutely works at "automotive" speeds. There is plenty of data to show it. Hell even Porsche themselves claim 10-15hp gain at speed (I forget exaclty what they quote but like 100 or 115mph)
on 996GT3 & 997 GT3 with their rear deck inlet scoops - this is about 3-4% depending on which model you are talking about
on 996GT3 & 997 GT3 with their rear deck inlet scoops - this is about 3-4% depending on which model you are talking about
10-20-2011, 02:24 PM
#35
Interesting good to hear your seeing a gain through RAM air, talking as an engineer who runs CFD (aerodynamics, not my main job) its normaly accepted that below 80mph RAM effects are negligable and purely marketing related. Pressure distribution around a car can be quite complicated to predict accurately. Some day I hope to publish on this site a pressure map for the 944 but like all thes thing it keeps getting left for another day.
10-20-2011, 02:40 PM
#36
Rainman
Rennlist Member
Rennlist Member
Interesting good to hear your seeing a gain through RAM air, talking as an engineer who runs CFD (aerodynamics, not my main job) its normaly accepted that below 80mph RAM effects are negligable and purely marketing related. Pressure distribution around a car can be quite complicated to predict accurately. Some day I hope to publish on this site a pressure map for the 944 but like all thes thing it keeps getting left for another day.
10-20-2011, 04:02 PM
#38
Race Director
The gains in the 944 spec car test with ram air were 80 mph and higher. Most noticeable in 5th gear which is about 100 mph when you shift from 4th at redline.
10-20-2011, 06:05 PM
#39
Drifting
10-21-2011, 05:13 AM
#40
10-21-2011, 05:56 AM
#41
Three Wheelin'
10-21-2011, 09:26 AM
#42
Burning Brakes
Done this
There is tons of info online about intake properties and factors. Runner length and diameter are important, as is the plenum feeidng them. The 951 and 944Na intake runners are essentially the same, but the 951 has a smaller plenum.
I customized a 944Na intake, shortening the runners and increasing the plenum volume to feed the motor at high RPM. It moved the peak Hp & Tq points up several hundred RPM's, desireable, and helped flatten the top end of the Tq for better power utilization. Lot's of work for minimal gains, but in a race car worth exploring.
I customized a 944Na intake, shortening the runners and increasing the plenum volume to feed the motor at high RPM. It moved the peak Hp & Tq points up several hundred RPM's, desireable, and helped flatten the top end of the Tq for better power utilization. Lot's of work for minimal gains, but in a race car worth exploring.
10-21-2011, 09:37 AM
#43
Race Director
as i said before, the concept of ram-air is that you are going fast enough that incoming air backs up on and compresses itself so that you get a sort of supercharging effect. this is the principle that ramjets/scramjets rely on. the air when compressed resonates at the speed of sound but you are going faster than that so it can't bounce out of the intake.
automotive 'ram air' setups put a scoop or intake of some type in a place that will be in a high pressure area so that it is best for drawing intake from. cowl induction works the same way. cutting a hole in your hood to feed your air filter won't do you any good. it would probably run ok but you wouldn't get quite as much potential as if the intake were in a high-pressure area. at subsonic speed the 'ram' is so minimal it might be a few percent at best.
automotive 'ram air' setups put a scoop or intake of some type in a place that will be in a high pressure area so that it is best for drawing intake from. cowl induction works the same way. cutting a hole in your hood to feed your air filter won't do you any good. it would probably run ok but you wouldn't get quite as much potential as if the intake were in a high-pressure area. at subsonic speed the 'ram' is so minimal it might be a few percent at best.
10-21-2011, 10:29 AM
#45
Three Wheelin'
Join Date: Jan 2010
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The spec racers are just that. Spec racers. They are much more limited due to the sanctioning body rules that keep things fair. Unless the OP is doing his work for his spec racer? Is he? As for the rest of us, we don't have to follow anyones rules. The restrictive Jboot can go!
North Coast Cab. Nice manifold! You may have been giving up some of your gains with all the accordian hoses. If the intake was placed as a "ram air" setup, it would have helped though. (can't tell in the pic)
North Coast Cab. Nice manifold! You may have been giving up some of your gains with all the accordian hoses. If the intake was placed as a "ram air" setup, it would have helped though. (can't tell in the pic)