Ok i finally installed the S2 IM, on my GS-R motor. Before the install my dyno #'s consisted of 168whp peak, and 122 tq peak at the wheels SAE corrected.. After I installed the S2 IM and ran it on the dyno again, it was bumped up to 170@wheels peak and 117tq and i lost a ton of mid-range tq from 4000-5600rpm about 10-12 lbs of torque on average. I thought the S2 IM was actually supposed to make me gain some peak HP and torque as well. I only did 3 runs that day and 2 out of the 3 runs actually had lower HP figues than with the GSR manifold. Only one of my runs were higher than 168 (the 170 run) but that may be due to a small spike in the graph when i hit the rev limiter.
The only Mods i have changed since dynoing the GSR manifold is the S2 IM manifold, a Type-r AEM CAI (i had a GSR AEM CAI before), and custom 2.5" b-pipe cause my header is 2.5" collector, and my exhaust is 2.5", but the b-pipe was 2.25" (long story). BUt everything underneath is 2.5" now. Anyways how could this be ...i basically lost HP and TQ and gained no where in the power band at all. I know i can gain some back if i tune my VAFC and cam gears on the dyno, but i may never get back the 6-7 torque peak i lost, and i can maybe increase the HP to more than the 168@wheels i originally got before the S2 IM. But all the ton of midrange i lost i think is gone for good. I may of been better off with my GS-R manifold and tuned the vafc and cam gears with that instead. Could it be from the combination of the S2 IM, bigger AEM diameter, and 2.5" b-pipe that i lost so much torque? I have a GS-R throttle body that is bored out as well, but not sure to how many MM.

Need some help guys, Thanks!

 

I think you should try to dyno both the GSR and the Skunk 2 IM at the same day with the same mods. then you can see if it really make you loss power!

 

get some cams and make that baby suck in more air
like toda b's

 

The GSR manifold does not need to be replaced unless your running high lift cams and higher redline. Install some cams and increase your redline - and you'll love that manifold.

 

Sleeper:

You have basically prepared for the future. The S2IM will be VERY helpful once you increase your RPM range (entire valvetrain + chipped ECU, 4-1 header). You are NOT going to get that torque back now. That's the nature of the ITR-style manifolds.

Loc

 

Well i'm running the Spoon Header with Mugen Twin-Loop exhaust and Custom 2.5" b-pipe. I know i've lost a lot or TQ AND HP. But i've seen some R's with tq figues at about 125 with just i/h/e. While they now have the same style manifold as me. I'm not sure if i will upgrade the cams or pistons. The head is already fully p/p, the head is milled 40thou, and i'm currently using Type-r cams. The only crap thing is that my redline is 8000. I seem to be peaking HP now at about 7900 with the manifold with fuel cutoff at 8200. Will tuning my vafc and cam gears on the dyno give me a some of the HP and TQ back? And by how much? I think raising my rev limiter may help a little as well.

 

If I am not mistaken the SK2 mani is more or less for the turbo apps. You are losing the torque because you no longer have the 2 runner intake mani system any longer. So unless you push more air into that thing you will definately lose tq and possibly even hp throughout the rpm band. Take a look at the following link. This person neted 14 ft lbs of tq gain with the SK2 mani and lost 4 horses. It's on a turbo app though...

https://honda-tech.com/zerothread?id=38716

 

It weird how on some cars with less engine work and mods than me, actually have gains throughout the entire powerband, and for me i lose basically everywhere.

 

I think u need some cams and some tuning done. a guy gained 15lbs for torque but gave up 4hp for it. i think thats a nice trade. but u should look into some cams as future mods.

 

I think if you get the cam gears tuned, they can raise the power band to increase your midrange. When I dyno'd my car, my peak whp dropped from 166 to 163 but my tq jumped up to 125wtq from 120. The power band was much better throughout the whole graph. So i think tuning will help you. But note that I still am running the GSR manifold w/CTR cams and gears.

I think it is the design of the manifold that causes the loss in TQ. The GSR dual runner mani is better for midrange, whereas the Skunks is geared more for high end. At least that's the idea I got when researching the Skunks.

 

Well i knew for sure that my midrange tq would have been lost, but i thought i would AT LEAST gain peak HP and TQ, and none of that really happened.

 

Mayfay: It takes takes forever to install and take out the manifolds. I don't know any 24 hour dyno places here! haha, plus the cost of labour would kill me. But good point though.

 

Hmm i've allways heard with R cams that you should use the skunk2 manifold to get the fullest out of them. I can understand the midrange loss because of the fact there are no secondarys to help out but i dont understand only gaining 2whp. Also with those mod's that whp looks somewhat low to me.

 

Maybe you should consider your fuel system while you're at it. You've got the new AEM, bored throttle body, SKUNK2 IM, ported and polished head, Spoon headers, and 2.5 inch Mugen exhaust improving the engine's breathing capabilities.

However, your fuel system hasn't been upgraded at all. You don't have a fuel pressure regulator or upgraded fuel pump. You can try to correct all day with the V-AFC, but the fuel pump is still SOHC Civic spec!

I do think that TODA cams will also complement your current set-up quite nicely.

 

35Mugen: Thanks for the advice, i shall consider getting a new upgraded fuel pump (GS-R should do) and FPR.
Toda cams is not really on my shopping list right now as i am happy with the OEM R cams at this moment. But i may consider that for next summer.
Lets see the results of the upgraded fuel pump and installing a FPR, get some fuel and Cam Sprocket tuning done on the dyno, and see where i stand. If things don't turn out the way i like, i would most definitely strengthen the bottom end, get some High Compression pistons with either JUN type III, or Toda spec B Cams.

 

Anyone else lose power like me with their S2 IM? Or get very minimal gains?

 

here is a car with skunk2 intake manifold that I tuned, didn;t seem to have that issue:


Perhaps you haven't changed your vtec cross-over to switch at a higher rpm, liek the 53-5500rpm range.

Greg

 

Actually I did bump my vtec x-over to 5600rpm.. that seems to be the best x-over point for now, until i tune it on the dyno, i had it 5300 and 5500rpm before respectively, but i lost a little power when i hit vtec at those engagement points when i saw the figues on my baseline dyno runs.
The graph you are showing me, what mods does that car have?? Those figures are nice, but is is a direct comparison between the S2 IM, and the GS-R manifold using either GS-R or Type-R cams? (i am using type-r cams). What i am concerned about is only gaining a little peak HP and losing a bunch of peak torque. I knew ahead of time that my mid-range would be lost, just not by how much. Another crappy thing is i need to raise my redline as well or move my powerband earlier with the cam sprockets.

But thanks for the graph i appreciate it.

 

vtec4gs,

wow nice graph, what other mods? I'm getting my skunk2 manifold installed on my GSR this weekend. Mind tuning my car too?

 

Vtec4gs: Those are the HP figures only. DO you have any torque graphs to correspond to those numbers? I think the creator of this topic is interested seeing the torque figures, and please accurately state what mods are used, and what kind of tuning was done so we all can have an idea.

Thanks

 

the chart on that car was all Skunk2 intake manifold, no comparison to stock GSR (no time to do the obvious gains in all honest). The mods were JDM 4-1 header, one of my mugen ecu programs, ITR pistons in GSR block with GSR head and CTR intake/ITR exhuast camshafts. Torque was in the 130 lb-ft range.

Here is an even better dyno run of a 2001 ITR with Toda spec B's and 11.2:1 compression and JDM 4-1 header with another version of my ecu program:

The torque was incredible for the low compression that this motor had. I'll be rebuilding his motor for his with CTR pistons in the near future.

Greg

 

ooops, that was his old dynochart with stock compression, here is the latest one I meant to post (he milled the head 15 thousandths, everything else is the same).



Greg

 

CTR and ITR exhaust cams are identical. But those #'s are pretty good, i assume the combination of CTR cams and the increased compression played a factor for the high torque #? Or do you think it was due to the ecu tuning? What's the size of the exhaust and b-pipe??

Also, the first graph u posted it seems to make more power and a LOT more torque than the type-r with Spec b's?

nice #'s keep it up


[Modified by B18C-EG6, 11:27 PM 6/16/2001]

 

Thanks for the numbers, does anyone else have any figures or experiences from the perfomance of their S2 IM on a GS-R?

 

Ok, i didn't read through all the posts, but this is the problem from what I can determine.

First of all, you can't expect to gain power simply by bolting the S2 manifold on and hitting the dyno. The new manifold needs to be tuned with proper fuel maps to see any substantial gains.

Also, the S2 manifold isn't designed specifically for FI apps, although it does benifit the FI motor by elimatating the IAB's and a more effictive runner design.

Here is the dyno plots of from our Project Integra. Before and after with JUST the S2 manifold swap.




As you can see, there is much gains to be had from swapping the manifold over. We gained 15fl/lb of TQ and traded 4whp.

Again, my point here is that we made 0whp and 0ft/lb TQ by swapping the manifold over. We made 7 runs at our sponsors' dyno facility to tune in the manifold. Very pleased with the results.

For more info on the Project Integra and its setup click here:
http://www.c-speedracing.com/integra.html


HTH


[Modified by G3-TEG, 9:07 PM 6/16/2001]