I recently changed my muffler from an APEXI WS to an EVO2 muffler. As well as correcting the leak in my header. About 2 or 3 years ago I got my cars A/F ratio corrected by getting it tuned.

Would you guys recommend me getting it retuned due to the new modifications I added/ccorrected. I just wanted to know if its worth it. I have listed the minor boltons below.

Current Mods: Intake, dc header w/ 2.5" collector, high flow cat, Greddy evo2 custom 2.5" piping, FPR, and pulleys.

Thanks guys

 

I'd get a dyno pull with A/F ratio. That should tell you if it needs adjusted.

 

no... minimal change if any at all.

 

ditto

 

and what's with all these preludes running 2.5" exhaust??

 

It's dyno-proven that the Prelude makes more power with 2.5" piping versus the stock 2.0" piping.

 

was the leak in the header before or after the O2 sensor? how bad was the leak? and how are you tuning the air/fuel?

 

The leak was on the top half of the header and yes the leak was pretty bad. there were leaks in 3 different places. I was planning on getting it dynotuned to correct it if necessary.

 

I gained horsepower when I went from 2.5" to 2.36(60mm). For a basically stock prelude, 2.5" is too much is what I was trying to say.

 

go check the threads on 3" exhausts. several people have made gains across the board going to 3" from 2.5" on mildly built n/a motors. so it makes me curious that you apparently gained power going to a smaller size.

 

And what I'm trying to say is that even with a bone-stock Prelude, it still makes more power with 2.5" piping. Hell, there are dynos out there showing that 3.0" piping made power over stock. However, you might lose 1-2hp down low.

 

I guess threads like that are why all these slower than stock civics are running around town with blaring exhaust. I just don't see how those who got more horsepower didn't have more interference with the exhaust waves. So how big is too big? 3" is for 300hp+ but somehow isn't hurting 170whp preludes...why not go to 4"?

 

I'll agree with that. I have just seen a LOT of threads lately with these preludes pushing 190whp tops with 2.5" exhaust. Who knows, maybe all of them are going to get up in the power ranges where 2.5" is ideal.

 

It was in the FAQ. Here ya go. (and no loss down low)

https://honda-tech.com/forums/all-motor-naturally-aspirated-44/3%22-catback-exhaust-stock-jdm-h22a-dyno-2197695/

 

I would like to see a mandrel bent 3" dyno for that car. Even still, he probably still had at least 2.5" at the bends and gained. I would like to see the write ups on flow after the collector. Maybe I need to do a little more research. Thanks, Kronn.

 

yw

 

Correct me if im wrong, but when a car is running rich does the bumper start turning black? Black I mean there are black carbon deposits all over my bumper. I made a drive to san diego yesterday and noticed my bumper was covered in soot.

The soot that covered my bumper started happening after I fixed my leaking header as well as changing my WS I muffler to an EVO2 muffler.

Tuning necessary?

 

classic symptom. yeah, it's likely hydrocarbons (unburned fuel). trying leaning it out a little.

 

Is there anyway I can do it myself? or should I just get it dynotuned? I do have a FPR and guage, but my guage went out on me.:/

 

LOL. Get rid of that cheap aftermarket FPR than. Better off with your stock oem fpr.

You either get a wideband and a means to register your A/F ratio or you go to a dyno shop where they have all the equipment to do it.

Widebands are expensive (for the ones that are accurate enough to base your whole tuning setup off of) so a shop might be your best option.

Your tuned already ie. have programable ecu/ chip (or however you went) so a retune/reflash shouldn't be that expensive especially if you go to the same shop. I couldn't see it being more than an hour of the shops time maybe two(hope not). It would just be fine tuning.

 

I will get it dynotuned asap. Anyone know of any Dynodays coming up in southern cali?

As for the "cheap aftermarket FPR". The shop that installed it for me told me "i needed it to get a better tune". Obviously the stock FPR is more than enough for my minor boltons. This was over 3 years ago, and now I know that the stock FPR is much better than any aftermarket. Thanks for the input