GSR IAB Dyno Comparison

xenocron · Post by **xenocron** » Wed Oct 10, 2007 4:29 pm

Not a perfect test, but I dont think I have had two more similar setups come in. The 290 HP GSR was a stock Intake Manifold with IABs disconnected (P28 with no control), running a Peak Boost Ramhorn and a Garrett T3/T4 @ 9psi and Precision 525cc Injectors The 300 HP Gsr was a stock Intake Manifold with IABs working properly and controlled by an OBD1 P72 ECU. This setup was a cast log manifold, running an SC34 (looked smaller to me, but this is what the customer said) at 8psi and RC 550cc Injectors. Both on 2.5\" Downpipes and stock map sensor. I actually used the tune from the 290HP as my base tune and made slighly change with adding fuel. You can see where the IABs helped carry the torque further down the road... Just thought it would be interesting to see.

Post by **calvin** » Wed Oct 10, 2007 6:06 pm

baseline.. For a gsr or h22 don't disconnect it.

denn · Post by **denn** » Wed Oct 10, 2007 9:56 pm

thanks for information look good Chris

yc underground · Post by **yc underground** » Thu Oct 11, 2007 10:54 am

Good HP & TQ curves for such low level boost. Keep up the good work Chris.

Joey Misanthropy · Post by **Joey Misanthropy** » Fri Oct 12, 2007 9:06 am

So the IABs were disconnected and closed, or disconnected and reomved from the manifold? I was always under the impression that - for H22, anyway - removing the IABs and retuning provided gains to the midrange with no loss of top end.

xenocron · Post by **xenocron** » Sat Oct 13, 2007 9:22 am

Joey Misanthropy wrote:So the IABs were disconnected and closed, or disconnected and reomved from the manifold? I was always under the impression that - for H22, anyway - removing the IABs and retuning provided gains to the midrange with no loss of top end.

Hooked up like normal but with no activation from the ECU. You'll notice on a stock vehicle, at idle...the IABs are pulled 'up' by vacuum which I believe is held by the canister until the ECU disconnects the ground breaking the circuit to the solenoid. I still cant remember which is the short runners or long runners

I'd have to look it up to be certain.

Post by **Bugermass** » Sat Oct 13, 2007 12:25 pm

long runners are for low RPM tq short ones are for topend.. supposedly

redshade5 · Post by **redshade5** » Mon Oct 15, 2007 3:23 pm

Yeah that is correct. Long runners produce more torque. It has to do with changing the air frequency so that is maintains more speed across the rpm range. That is why when you look at the base maps on gsr and h22's you will see they require less timing at part throttle, high rpm. Much better fuel suspension. Your ideal air speed is right at supersonic.

Boosted K20 · Post by **Boosted K20** » Mon Oct 15, 2007 4:10 pm

xenocron wrote:
Joey Misanthropy wrote:So the IABs were disconnected and closed, or disconnected and reomved from the manifold? I was always under the impression that - for H22, anyway - removing the IABs and retuning provided gains to the midrange with no loss of top end.
Hooked up like normal but with no activation from the ECU. You'll notice on a stock vehicle, at idle...the IABs are pulled 'up' by vacuum which I believe is held by the canister until the ECU disconnects the ground breaking the circuit to the solenoid. I still cant remember which is the short runners or long runners I'd have to look it up to be certain.

haha i get confused too. i cant remeber which is open/close until i put it on the dyno