Installing crawford plenum, z-tube, crawford hi-flow cats and stillen exhaust on my coupe, how much HP gain do you think I can get?

TB/Black, 6MT coupe

 

Approx 20-25 ponies at peak...



"See, the problem is that God gives men a brain and a *****, but only enough blood to run one at a time."

 

so.. how much difference can I get if I also install crawford header?

TB/Black, 6MT coupe

 

Not much, maybe more twd the 25+ side, but thats it. You have to understand, you can bolt on as much as you want, but without modifying the ecu and or ignition / fuel supply, to allow for more fuel and a better spark / timing curve, your mods will be limited to their ability to add HP....



"See, the problem is that God gives men a brain and a *****, but only enough blood to run one at a time."

 

the headers are not a very effective addition to this particular car for hp gains, at least from a cost/benefit standpoint. The only really cool element is that they give that characteristic "growl" that otherwise is not available. You may get another 3hp or so from the mod, in addition to all the others you listed, so for $600 it is not the best investment to make. Unless you just gotta have the sound, or are going to shove FI down it, which changes the consideration slightly, as you want to do everything you can to help the exhalation flow when pushing more air through it.

Cpe 6MT/Aero/Prem/ATI/RT cats/Borla hdrs-catbcks/Nismo flywhl-cltch/TS-ECU/Tein flex EDFC/Stillen sways

 

I'm starting to wonder about the header arguement. I've been talking to Doug a little bit lately and these 2 threads show that headers will really help you out NA if you do CAM and head work...

New Cams and ported heads &

Doug's Crawford Tune Up

According to Doug, the headers are an intergral part of the package. Infact, Doug states that the headers are as good as the cats and plenum combined. I'm almost tempted to see if he's telling the truth...

As far as hp, 20-25 is the right call as ducati said above.

 

Saying the headers arent effective is from a cost subjective point only. The Crawford headers (specifically, because all other headers for the z/g arent created equal) are the best mod I've done to date. DG is absolutely right though. Without the TS ecu upgrade, your just putting a bigger pipe in place, and will maybe pull down 5-10 more hp, if your lucky. With the TS ECU that is designed for the way that the crawford headers "Suck" the exhaust out, Doug is absolutley right, 20+ hp from just the headers is more than expectable. Doug explained it to me this way (and its too bad he doesn't post up on here to explain this, because I was in awe when he explained it to me). The headers are CAD'd designed to be the perfect length compared to displacement vs bore vs stroke. There were a few more variables, but I forget the exact specifics. Having the "perfect dimensions" for headers for the car, they found a way to make them fit, instead of adjusting them to fit. The difference is the same as mid lengths vs long tubes on a v8. The stock manifolds allow flow. The crawfords create a suction effect. With the proper tuning, the cats plenum and headers will net 40+ peak hp, but it all comes down to if you want to pay to play or not.

2003 Black 6MT
JWT/Z tube, UR pulley set, Crawford Headers, Cats and v5 Plenum, Injen SES, TS ECU Crawford tuned, JDM Pedals, JDM battery cover, G-tech RR.
More mods to come....stay tuned.