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What to do after headers?

B

bevernden

New member
I just finished installing ZZPerformance stainless steel headers and 3" downpipe with high-flow cat. I also did the machine LIM with the intention of machining the supercharger housing in the future.

My question is what to mod to take advantage of the headers? Should I get a re-tune (I have a 3800 performance tune now) or a smaller s/c pulley (I have a 3.4" now)? See my sig for all my mods.

I have scanned the car on a few runs and don't see any knock retard going on like I had before the headers.

Brent

2002 GTP - K&N, ZZP Headers, 3800 Perf Tune, ZZP LIM, 3.8" S/C Pulley
 


I don't know if you'll be safe running a sub 3.4. You're going to have to try omit though and scan it or knock. Although you're pobably gonna need rockers or intercooled to run knock free.
 
reset the fuel trims (unhook battery for 20 mins) drive the car around a bit.

enjoy the new performance.

you might be able to drop pullies, will just have to scan and see.
 
hell yea they do. i though headers opened up some topend but i think my rollers helped it more. i wonder what some 1.95s would have done.
 


So are you guys saying a re-tune would not net me much with an adjustment to the timing tables? I was always under the impression that the engine could handle more timing after headers due to increased exhaust scavenging, thus more horsepower.

Wouldn't running rr's net more with a re-tune as well? At what ratio is replacing the valvesprings necessary?
 
the car will always be better off with a tune after any part swap. whether you do it now, or later, you still should get one at some point.
 
Intercooler or rockers. A custom tune will always bring some gains, but its not really going to be cost efficient at this point since you plan to do some more mods. I'd say as long as your checking knock and its maybe 1-2* your fine, your WOT 02's would be something to look at also.
 
^^There are many threads about it...read my Safely Modding Your 3800 to get info on them...I know I've already told you to check it out...it answers PLENTY of your questions.

As for mod after headers. CAM IT...then talk about a 3.25" with a tune.

/done
 


KShef said:
what are your goals? if you want to start dropping pulleys then go for the intercooler...
Click to expand...

Not necessarily true...you can go other routes cheaper, such as methanol injection, a custom tuned PCM, and/or rockers/cam. It isn't always about dropping pulleys...a guy with a larger pulley and a better tune will eat up a smaller pulley car that isn't tuned well enough.
 
bluegtp91 said:
Not necessarily true...you can go other routes cheaper, such as methanol injection, a custom tuned PCM, and/or rockers/cam. It isn't always about dropping pulleys...a guy with a larger pulley and a better tune will eat up a smaller pulley car that isn't tuned well enough.
Click to expand...
can't beat an intercooler....
 


Fullsize intercooler, .2-.4" pulley size decrease with 12's afr and add a few more degrees of timing is where its at. But its at $1000.

Cam is great, but if its done right it pretty much means built tranny. Your initial cost of $500-1000 for cam install really comes out to total $2000-3000 after tranny work/labor. Thats not including larger injectors, tune, etc.

Rockers are pretty straight forward for install. I would go with modified stock rockers to 1.9 ratio and L76/LS6 springs. Should cost $260-400.
 
Thanks for the replies. Just for reference, any future mods would be limited to a ported s/c housing, re-tune or smaller pulley and possibly an intercooler (but that's a bit pricey). I've been toying with rockers/springs but haven't convinced myself yet. I have to keep in mind that I'm supposed to be completing my engine rebuild on my Z28. :-)

I'll probably go with a re-tune to get it cleaned up since there are aspects of the 3800 Perf tune that I'd like to change anyhow.
 
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