Catalytic Converter

I've got some kinda issue with my car that no one seems to know what the problem is. I'm loosing a lot of horsepower around 4500-5000rpm and when I accelerate to that point it makes this deep exhaust sound. I've heard a lot of people say so many different things, but they don't own an eclipse gst or ever did.

How do you know you are losing HP?
Does it seem to hit a wall?
Is it abrubt, or gradual?
Do you have any logging ability?
What boost are you running?
What are your mods?

Well... OK. Maybe I'm not loosing horsepower, but it feels like it. once I reach about 3000rpm there is a gradual slow down, then at 4500-5000 it doesn't want me to go any further. The deep exhaust sound gets louder and louder as the rpms go up. It's just a 97 Gst. I don't think there are any mods on it, but I'm the 3rd owner. The guy who owned it before me said he didn't do anything to it, but he didn't know if the guy before him had done anything.

What boost levels? My guess is that it is the shitty 2g stock BOV leaking.

Um... I could probably tell you if I had a boost gauge... Like I said... Stock. You know, I was just thinking about putting on a new one. I want to put the HKS Sequential stage Bov. Thing is NASTY!!! (in a good way)

In my opinion, save the cash and get a 1g BOV with a 2g install kit. The SSQV is a nice BOV, but the 200 could be better spent...for example on the aformentioned BOV and a $30 boost gauge. ;)

Ha ha! :lol: Thank you for the info. I know some about car mods, but not any more than the avg. beginner modder. I'm gettin there :smile:

Maybe your clutch is slipping a bit.

Stock turbo drops boost at ~5500+ rpm, gradually.
Could have a boost leak...

Exactly how sudden does it drop off, or can you barely feel it? I'd say get started with a few basic mods, like checking for boost leaks http://www.vfaq.com/mods/ICtester.html, getting rid of the leaky 2g BOV (to a 1g is cheapest), and of course, before that would be a boost gauge. Cheapo autometer would do just fine. If the drop off is NOT sudden, I'll be willing to bet this will solve your problem, except for that the T25 boost will literally plummet near 6k.

Gotcha, thanks you for the info... I knew, if I asked people who actually owned these cars they could give me better info than the techs at Mitsubishi. It totally kills the confidence I have in dealership staff.