Aftermarket exhaust - help

[erykmedykowski]

Hey, so I recently just bought my S13 - it came with a 3 inch aftermarket exhaust (unsure of brand).
Now since I'm a beginner I need to know a few things before I break anything

So I got the exhaust on, it's a bolt on and there was two parts to it (didn't include downpipe). I never got gaskets with it, so here's where I'm getting all confused.

Do I need to put a gasket between each component? I just bought two HKS 3 inch gaskets, as the exhaust is a three inch and my other gasket was ripped and old. So now, should I have a gasket between the two components that I got? one of them is the silencer, and the other one is the cat. Should I have a gasket between them? I know I should have one between the downpipe, but the downpipe hole is most likely too small, does this mean I need to get a 3 inch downpipe? I wouldn't have a problem with that - but then when I install the downpipe, at the top of it, will it fit onto wherever that connects up to? (sorry I'm a beginner). Basically I'm asking if I need a gasket between every component? and if I get a new downpipe, will the three inch connect up to whatever that's connected up to? and will I need a gasket for that?

Thanks for any help and sorry about the noobiness.

[Bens851]

You are better off using gaskets yes. You may have a 2.25 inch downpipe and a 3 inch system back from there.

[erykmedykowski]

Iv'e found a 3 inch downpipe that I could buy - could I still use that?

[Bens851]

Well it depends on the quality for the start. It its cheap then it will likely crack. Also your turbo elbow will have a 2.25 connection too.

[erykmedykowski]

Ah ok. What would be best? It's that I have a three inch exhaust, didn't come with downpipe. Now I'm really stuck on what to do because it's blowing at high revs and I don't have gaskets and I'm not sure what gaskets to get because I want them to actually fit.

[Bens851]

Well if you want a 3 inch system u will have to fit gaskets. If u want to do it properly. U would need the full system as far as im aware. The turbo elbow is a ballache to fit though

[erykmedykowski]

Okay I see. Well for just now I want to stick with just what I have - the cat and the silencer - so the downpipe is stock, is it still okay to join up with the three inch silencer bit? and what kind of gasket will do? I bought three inch HKS gaskets.

Also, when it spits at high revs, could that be to do with me not having gaskets? or what could that be :/

[Bens851]

Could be a boost leak or not enough back pressure. I mean aslong as the bolts and holes line up. Any gasket will be better than no gaslet for now.

[erykmedykowski]

Ah okay. I have a few problems with the car right now which you could probably help me on.. I got the car a week ago

First of all, I got my exhaust on, was driving up the road and the jubilee snapped off, which meant the hose came off so the whole car lost power but I fixed that (I think it still has a lack of power, unsure why). When I fixed that, I found out that my radiator is leaking (mechanic also checked), so Iv'e just ordered a new radiator. Now its the exhaust that I'm worried about because I don't have gaskets and for some reason it's really annoying me because I feel like it could be a problem, especially the fact that the exhaust is spitting at high revs then stops then does it again..

[Bens851]

Sounds like you have a boost leak mate. U wanna check all your pipe connections. You definately wanna get those gaskets sorted too.

[erykmedykowski]

I see. So should I go ahead and buy 3 inch gaskets? Since the parts are 3 inch, will it still connect up to the stock downpipe fine? And actually that's right. At high revs (when boost kicks in) that's when it spits.
(Iv'e actually already bought my 3 inch gaskets - they came today)

thanks a lot for your help, really appreciate it.

[Bens851]

Well if they fit then yes. You can only try or measure before you buy and hope they fit.

[Bens851]

Unless a gasket is oem you never really know if it's going to fit.

[erykmedykowski]

I'd show you a picture if I could but right now I can't. I have the stock exhaust in my room and I put the 3 inch gasket to compare against it and it's much bigger. Should I put a gasket between the cat and the silencer also? As they're bolt on, same as what it looks like to join the downpipe together.

[Bens851]

Yes you want to use a gasket on every join.

[pointz]

Spitting at high revs?? Stop redlining it then lol! Would help if you put up more details re- mods etc or is it completely standard other than exhaust

[erykmedykowski]

It's not when I redline, it's when boost kicks in. (Maybe around 5/6k revs). Car is completely standard with an aftermarket filter. It never done it before I changed the exhaust, then the jubilee burst and the hose came off but then I fixed that, and then the radiator started leaking so I ordered a new radiator.

[pointz]

Boost should start coming in around 3.5k revs with a standard t25 as ben says sounds like boost leak and if still standard i assume you have stock intercooler these are prone to leaking especially being 20+ years old.

Compression test all your intercooler pipework.

When was its last service?

[erykmedykowski]

Not sure when the last service was, got the car a week ago. It was fine driving back home 500 odd miles. The jubilee snapped the same day I fitted the exhaust, maybe about 10 mins after it so I think it may be boost leak

[Loopy_drifter]

This the one you got?