I purchased my Stillen intake several weeks ago but I've been waiting to get my exhaust sorted out before installing it. I dynoed my car last week with my new Brullen exhaust and I got some really good gains. I installed the intake on Friday and dynoed the car last night. The results were very disappointing ! The HP was exactly the same and I LOST 3-4 ftlbs of torque. What the hell !!!! Throughout our exhaust testing, numerous dyno runs, we never lost torque! By the way, I did reset the ECU before the dyno - un-hooked battery for 24 hrs. Any idea what caused this, I thought this thing was supposed to give some decent gains.

 

I am guessing it is the exhaust that is the culprit here. Our cars have an adaptive valve exhaust and it opens or closes to keep pressure (this is where the torque come from)... the new exhaust doesn't, and with the addition of the new intake more air is coming in, and free flowing out the exhaust...

It is also possible that a) car ecu needs a week to fix air fuel ratio...., or b) the dyno was done wrong?

hope this helps, what did the people running the dyno say?

-Eric

'03.5 Bril Silver/Black || Prem || Perf || Aero || Solid Allum Pedals || Allum Matts (Infinit Logo) || Tints

 

i'd say just wait and do another dyno.. really, dynos are all dependent upon conditions too.. i've seen dyno charts that are worlds apart with the same exact mods, just done on different days..

but it also could be what ericinmia said..

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Get your ECU mod'd by Technosquare man. It is a proven fact that the ECU will attempt to return the cars performance to the "original" base line by detuning your mods. The ECU attempts to do this by adjusting Fuel/Air ratio, advancing spark and several other adjustments in order to return the car to it's stock performance levels.

This is why I haven't mod'd my car yet and the first mod will be the ECU mod. In essence most people that don't change the ECU will have varying perfromance gains AND losses because of the adaptive ECU. So in essence your mod does not perform to your expectation.

http://www.technosquareinc.com/g35.htm has been successful in limiting the adaptive feature so as not detune the additional mods as well as removing the speed limiter, moving the rev limiter to 7200RPM and changing the Air/Fuel maps to get a little bit better performance in the top end. Check the site for more detailed info but I bet this would solve your issue and even maybe give a little more HP.

The cost is about $600 if I remember plus and FYI they can also tune the ECU specifically for your mods if you already have them on your car and take into their shop for tuning which can yield even better results. They are located in the Torrance area of So. Cal. though. Good luck if you try it!

-Jason
Laser Red '03 6MT

 

ericinmia (Registered)
10/05/03 09:14 AM

I am guessing it is the exhaust that is the culprit here. Our cars have an adaptive valve exhaust and it opens or closes to keep pressure (this is where the torque come from)... the new exhaust doesn't, and with the addition of the new intake more air is coming in, and free flowing out the exhaust...
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But he has a coupe, only the sedan get's the variable capacity muffler. The coupe gets a performance muffler and when stock coupes (and the Z for that matter) are dyno'd, they aren't showing any meaningfull difference in the torque curve for not having the variable capacity muffler.






Ivry 6mt sed
Crawford Pleneum
Injen CAI
22" resonator
Cusco sway bars
350Z springs&struts
Enkei RPM2

 

when they say that we have an adaptive valve exhaust, they are talking about in the cylinder, not past the manifolds. so i dont think that is where the problem lies. at the dyno today, there were 6 s2000s, 3 modded and 3 stock. everyone of the stock cars dynoed higher, to the tune of about 8 to 10 hp. mods like intakes and exhausts are useless power-adders unless you do something with computer. this is why i havent added anything. i may add the borla exhaust, but that is purely for the sound. everything else is, imho, a waste of money. go get a supercharger.......


Doc

You have been weighed.....You have been measured.....and you have been found WANTING!!!

 

I agree with you about the ECU adapting to compensate for the mods. I do believe, however, that some mods "**** off" the ECU more than others. I find that intake side mods lose thier gains more than exhaust side mods. My Brullen exhaust has been on for quite some time, and with each revision, we have seen the HP numbers go up and the inital torque gains remained the same. We only lost HP and torque once when we switched to 2.25 pipes. Every other dyno run over a period of almost a month showed consistent gains.

 

Actually....that's not Stillen intake fault nor ECU fault.... It's the dyno shop fault.

Dynopower do not have the appropriate blowers which can accurately simulate high-pressure airflow while at speed. A simple fan blowing on the front of car will not allow a cold air intake to function efficiently.



Borla Exhaust
Grounding Kit
GruppeM Intake (ETA: early October... [img]/w3timages/icons/frown.gif[/img])

 

I see your point, however, they used the same fans for my runs with the stock intake. I can see not getting any gains due to the fans, but why losses? I had some pretty big losses in the 4-4.5K range. Secondly, the Stillen uses the same factory ram intake points and has less shielding from the engine heat. All they have really done is replace the flat paper filter with a cone filter. Other than that the design is pretty much the same. After installing the intake, I immediately noticed the loss, the dyno just confirmed it. Please enlighten me if I am missing something.

 

Probably is the design of cone filter needs more air pressure in the ram box (but I don't have any technical prove here). But since you can feel the loss in real-world driving situation, then maybe you got a defect product from Stillen[img]/w3timages/icons/tongue.gif[/img].

My friend's 330ci dynoed there 2 weeks ago, and it showed no gain with the GruppeM short ram air filter (similar design as the Stillen one) and pulley mods. We pretty sure the pulley can bring some HP up, so the loss should came from CAI.


Borla Exhaust
Grounding Kit
GruppeM Intake (ETA: early October... [img]/w3timages/icons/frown.gif[/img])