Something wrong with my exhaust?

97GSTspyder · #1 10-21-2004, 05:30 PM

Ok about a week or so ago I purchased a brand new High-flow catalytic converter on E-bay for $25 and $25 for shipping...Came yesterday and I swear this thing is a straight pipe. No 'honey combs' in it...Anyway I took off the whole exhaust last night (from downpipe to cat)...The reason why I bought a new cat is because I noticed a pretty big performance decrease and my exhaust always smelled like rotten eggs...Anyway I got the old cat off, and it was in horrible condition. Installed the new cat, new gaskets and bolts too...Now when my downpipe was off, I checked to see if the catalytic converter built into it was clogged and it wasn't. Just the regular cat was clogged out the ass...So everything flowed nicely through the downpipe and new cat. Got everything put back together, started her up, let it warm up, took it out for a test drive and I noticed just a tad increase in performance...Now when I stick my hand behind the muffler, it feels like it did when the old cat was on. Not much getting through. I don't understand it....Also one other thing...You guys know how turbo cars have their own unique smell? Like when you run boost for a short amount of time you can smell it? My car used to be like that a year ago when I got it...And a few months after having it, the smell went away. And yet I still don't smell it even after putting the new cat on...What could be the problem? Could my muffler be bad or something?

Thanks for the help...

97GSTspyder · #2 10-22-2004, 01:20 AM

ok...why the fuck did my friends GST beat me tonight? we raced on the freeway and i was ahead of him all the way through 3rd gear by about 2 feet then he started pulling on me and eventually pulled ahead of me...all he has done to his car is exhaust, turbo XS BOV, and air filter...my car has a centerforce dual friction clutch, k&n air filter, hallman boost controller running 16psi, 10.4mm wires, short shifter, high flow cat, and gauges...now i know my car weighs more, but the thing is, i have more mods done to my car, have excellent driving skills and my friend is just learning to drive stick...i think it could be the problem with the exhaust...i'm losing top-end power or something, even though there's not much power after 5500rpm cause the turbo is at its max.....WTF could be the problem!?!?

kjewer1 · #3 10-22-2004, 02:01 AM

Sounds like you guys have the same mods. Clutch, wires, shifter, and guages arent going to do shit for you in this scenario

There are 10,000 different variables that could cause the minute difference in acceleration you describe (one car length is EXTREMELY small). And weight is a large factor. Each 100 pounds is worth about 10 HP at your level.

97dsmeclipse · #4 10-22-2004, 02:10 AM

do you have the 2.4L or the 2.0, like gsx racer said it could be alot of thing, as like tunning how many miles are on the turbo, and stuff like that. If your running a T-25 turn it down to 15psi, yea i know its only 1 psi but i ran at the track on 17psi then 15psi and everytime my 15 psi run was faster, not by much but it was a little faster.

and about the exhaust, at idle you problly wont feel any diffrent coming out the exhust i dont think, the turbo smell your talking about

i have never smelled, the only thing i smell in my car after running fuel boost is gas

97GSTspyder · #5 10-22-2004, 02:38 AM

when i first got my car a little over a year ago, the exahust at idle was pretty good...stick your hand back there and it was a nice flow....now there's like a breath coming out...what could it be? could the tailpipe or something be clogged up?

97GSTspyder · #6 10-22-2004, 02:41 AM

also one more thing....if i raced him again, but this time didn't have my friend ride with me and ran the race on almost empty (my tank was FULL earlier), think i'd have a better chance?

LostProphetGsX · #7 10-22-2004, 02:54 AM

You know you might beat him right now if you raced him agian. Cars just act wierd sometimes... My pal has a stock Landcer OZ Rally and he kicked the crap out of a Lancer OZ with Mods. Wierd huh...

GSTRacerNVUS · #8 10-22-2004, 02:24 PM

Well, the reason your car smells like rotten eggs is because you no longer have a Catylitic Conv. That's what cleans up the smellies comin' from behind. Now that you just have the ebay pipe, which is illegal I might add, there is nothing to clean your vehicle's emissions. I hope you don't have emissions testing. I noticed the same thing when I had my Catyl. bored out.

97GSTspyder · #9 10-22-2004, 04:21 PM

well my car doesn't smell like rotten eggs anymore since i put the new cat on, it used to smell like rotten eggs with the clogged cat...but my problem is that there's hardly any exhaust coming out of the tailpipe....also, like i mentioned before, i noticed that all turbo dsm's have their own unique smell...i can't really explain it, but after running boost for a little bit you can smell it. well i can't smell it on my car anymore. last time i was able to smell it on my car was about 8 months ago...but yet my friends gst has the smell and my other friends old gsk had the smell too....i just call it the boost smell, heh...i love the smell of it...i thought if anything, putting that new cat on would free up exhaust flow...well it didn't

so something else must be clogged up right?

97GSTspyder · #10 10-22-2004, 04:23 PM

oops, meant to say 'and my other friends old GSX had the smell too'

GSTRacerNVUS · #11 10-22-2004, 04:58 PM

I just talked to my mechanic and he confirmed that the rotten smell is probably a bad cat, or bad gas. I just had it bored out, so I was assuming that it had something to do with that. I promptly made an appt. with him.

As far as the exhaust not coming out smoothly... That's really vague. Wouldn't even know where to start.

I wish I knew what you were talking about with the whole boost smell thing.

Sorry I haven't been much help.

97GSTspyder · #12 10-23-2004, 04:22 AM

ok, exactly how would i go about checking an exhaust leak? anyone have any ideas? also i guess running 16psi is ponitless snce these stock bov's leask at around 14...maybe he pulls on me because he's holding more boost cause he has a turbo xs. and because my car is a fat ass...anyway any ideas on checking an exhaust leak?

thanks for the help guys

ashah000 · #13 10-23-2004, 08:37 AM

Try to listen under the car you should only hear the exhaust coming out the muffler.

Partizan · #14 10-23-2004, 11:35 AM

You might wanna look into or build a backpressure gauge for the exhaust. Tells you how much psi is in the piping and thus how restrictive. If it's very low you probably have a leak. How big is your exhaust?

EDIT: Also, shouldn't this be in the Problem Diagnostic section?

spyderturbo007 · #15 10-25-2004, 08:30 AM

I ran my best friends stock GST (no mods at all) with my spyder. I had 1g BOV, boost controller set at 15psi, Injen intake, DP and Hi flow cat. It was a really close race (and I know that he knows how to drive). Neither of us missed a shift or anything like that. I had him by about 1 1/2 car lengths at about 80mph. So I can see how your race ended up how it did. Damn extra weight. Oh well, at least you can drop the top sitting at a redlight!!!

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