Japanese gt4 exhaust on American gt?

[Ace2424]

Will a Japanese cat-back from a gt4 bolt on to my existing gt exhaust? I found a super rare one and I want to try to get it to work

[RobMilkshakes]

I can't seem to find any exhaust diagrams as of right now, however, keep in mind that the gt4 exhaust will sound completely different on a 5sfe

[Ace2424]

I don't care about sound. I care about performance. This is going to be a street/auto-x car

[RobMilkshakes]

Well in that case, performance won't likely be helped much either. The exhaust will probably be a much larger diameter than what would be ideal for NA

[Ace2424]

I'll find out. My camry was 2" all the way with a 2 1/4 cat and 1.75 manifold and it gave great response. The problem with the 94-95 celica gt lies in the dual cat. When I gun it, I can hear the pressure on the front cat and the exhaust blowing apart the gasket. I'm strting with a 1.75 to 2" manifold and resistors from radio shack to fool the computer into thinking the front cat is still there. Ideally I'd like to do a 2" to 2 1/4" all the way back.

[RobMilkshakes]

That would be best. Most exhausts for the 3sgte that I've seen have been 3" which is just way too big. I'm running a header that replaced the cat that hung from the manifold, and I have a cat, resonator, and 2.5" crush bent pipe back to a striahgt through muffler.

[Ace2424]

Originally Posted by RobMilkshakes

That would be best. Most exhausts for the 3sgte that I've seen have been 3" which is just way too big. I'm running a header that replaced the cat that hung from the manifold, and I have a cat, resonator, and 2.5" crush bent pipe back to a striahgt through muffler.

Thats actually exactly what I want to do. What did you do for the front pipe? Also, will an exhaust from a 90-93 work? I found a hks cat-back.

Also the reason I wanted the gt4 exhaust was because of the rarity. You should see this thing.

[RobMilkshakes]

I used the stock front pipe. It wasn't too long from there til the cat and it was approx 2" so I didn't see much of a problem with that. The same headers will work, however, I believe there are differences, such as the second converter you noted. The Merit and Walker exhaust pages always have stock layout diagrams with part numbers. I have used both of those countless times to compare.

[Ace2424]

What brand straight through muffler do you have and how loud is it?

[RobMilkshakes]

I have an OBX brand muffler and a 27" thrush glasspack as a resonator currently;although, I do plan to swap the resonator in the near future. On a scale of 1-10 (1 being stock, 10 being open pipe) I'd probably put it at about a 5 during normal driving, maybe about a 6 WOT. Its not obnoxious, its loud enough to be heard well but doesn't draw unnecessary attention.

I plan to swap the resonator out due to the drone I currently have. Its not bad on the highway, although any driving around 30-45mph it can become rather boomy and annoying. I'm going to try a little sound deadening in the trunk area, but I think I may try to go to a magnaflow 5" round muffler in the center in the spring.

[Ace2424]

I work at advance autoparts so I have easy access to dc, thrush, flow master, and magnaflow. I was going to do a thrush glasspack with the dc sports straight through... But I would rather have a apexi n1.

Did you have to do anything with the oxygen sensors when you put on the new header? Like use resistors to fool it into thinking the cat was there?

[RobMilkshakes]

Well, I only have one upstream O2 sensor, and there was a flange for it right on the header. I did install a cat since I will have at least one more emissions test here though.

You may want to check one of these out, I don't know how I feel about DC sports. I've heard nothing but good things about these, and they're essentially a direct copy of the n1
muffler finally installed!

Also, its funny that you mention that you work at an Advance, I am a commercial parts pro at a store just outside Baltimore.

[Ace2424]

Wow haha. I work at the top store in our district and have been there for over a year now. Working on moving up and becoming ASC certified. I've got the best GM I've ever had.

Right now I'm looking at a dynomax superturbo muffler and a long thrush glasspack. The GM has the superturbo on his 84 rabbit GTI. It makes a nice sound. He also said it flows well without being loud and getting you in trouble. We also still have one left in back so I'm going to snag it hahaha.

So far I'm planning Konig 16" rims, koni sport struts with eibach springs, better swaybar bushings, and this exhaust setup so I can auto-x it.

[RobMilkshakes]

you mean ASE? I'm going to for my certification this spring. My store goes through employees (including GMs) very quickly (on our 5th set of management in my time being there), I'm the senior most member about only ~18 months at this store, which is not a good thing. Had some time at another local chain as well.

I looked into the superturbo, I've heard good things about it as well. Just don't buy a chambered (thrush welded,flowmaster, etc) they sound pretty good, but drone like crazy.

You may want to look into the autocross rules before doing these mods and enter one in the lowest class to get a feel for it. IIRC these mods will put you into street modified which is usually VERY competitive.

[Ace2424]

Yeah, I know what I'm getting into. And yes, ASE. I'm typing on an iPod and went from e to c quickly and it registered c lmao. Our GM has been with the company for a really long time. He runs a really tight ship. You should see how clean our store is hahaha. Our floors are so shiney you can see your balls.

But anyway, I agree with the droning effect associated with flowmasters and the like. Boss warned me on that as well.

And with the class I'll get put into, I'm not too worried. I was trained with f3's on Michigan motor speed way and also raced NASCAR stock cars when I was 18 through track time racing school. I've got track experience and besides, I'm only interested in beating my own times to start anyway. I've got nothing to prove.