bgiere

Anyone ever used an intake restrictor to lower peak HP on a NA 944? Need to knock off approximately 10 HP in order to fit into a class. I know there are some cars up north that had a system installed in order to slightly block the MAF intake, they were actually sliding,adjustable doors...saw them at a scrutineering check one day. Any ideas out there?

J richard

now let me get this straight...you want a 944 to make LESS power?...just checking...I mean LESS...as in the opposite of MORE....right? Am I getting this right? or am I confused?.... I didn't know they could make LESS power....is this a soap box derby class?...

...seriously what class are you trying to fit in?...

Kurt R

Banana in the tailpipe?
Heat the intake air.
Buy an eBay performance cold air intake.
Retard the timing (if you have a DME with the switch)
Run the early camshaft.
Run straight 60 weight oil.

Is this for a certified dyno run only, that you would want to reverse for actual racing?

bgiere

I want to run NASA GTS 1 and run at a certain weight...In order for the car to fit the class, at the weight I want to run I'd need to knock it down by approx 10 HP. It looks like an intake restrictor plate ala NASACAR is what we will use.

krystar

maybe adjust the FQS on the DME? it can retard ignition by like 3 and 6 degrees i think. or just fab up a exahust restrictor.

does the car weigh like a feather or something? 130hp limit?

Potomac-Greg

Yank a plug wire?
I suppose intake restrictor is the only option. Hopefully the computer doesn't freak out.

Lemming

Probably easier to bolt in a little ballast. Given that GTS is wt/hp, you can play with both.

Bryan Watts

Sure, if his goal is to cheat...

bgiere

I am going to the dyno today with a few different intake restrictor plates. According to the head/camshaft builder that should accomplish it. Weight of the car is indeed quite low and I'm running a 2.7 engine.

Bryan Watts

Restrictor plates should work fine. BMW guys have done similar in the past to fit into GTS classes.

J richard

Not really knowing what you've done to the motor (in spec you're going to get a second look in impound if you're pulling 140 or so..) gts is a power/wt tims suggestion of ballast is the best bet. A throttle stop would do the same thing as a plate. If I was forced to reduce power I would try to affect peak hp (that's the metric the rules use) while maintaining as much torque as possible. If you have an open or big exhaust (as was suggested, but not with the bannana) increasing the backperssure, smaller diameter or a more restrictve tailpipe has the benefit of maintaining or increasing torque. A tuneable cap like a supertrapp would be the easiest way of doing this. Other option is a custom chip or play with cam timing.

M758

I agree.

This past year NASA Nationals saw a GTS1 won by a 944 spec car. The driver swapped out toyo's for hoosiers and removed ballast. His min weight was something like 2380, but was still 40 lbs over weight. He gained maybe 2 seconds a lap, but that was from the ho-ho vs the RA-1's.

Add in some weight and be smart where you place it. You can either add ballast or put in some heavy part where you need weight.

bgiere

Ok, the "problem" is that I have a 2420 lb. car making 155 RWHP. I need to add 300ish pounds to make GTS1. Too much weight. I have spoken to the head and camshaft builder and exhaust restrictions will not do it. They use restrictor plates of various sizes to accomplish the task...so back to the dyno!

J richard

Whoa!...yea that's alot of doughnuts...the plate is easy, but if this is a long term deal you might check with your cam guy to see if you could advance the cam timing a few degrees to max your torque and shave peak hp before you put the restrictor on...no sense giving away anything you don't have to... Let us know the results of you run...

Bryan Watts

Agreed...cam timing is the ultimate solution. Though not exactly the same idea, thanks to ECU controlled variable cam timing on our intake/exhaust cams, we are able to just have two separate tunes for our car. One is "full power" that puts us somewhere in the middle of GTS5. The other keeps essentially the same torque curve up until a point where we then hold the horsepower steady at our desired max hp all of the way to redline. That tune puts us right where we want to be at the top of GTS4.