3" exhaust questions

[smudge]

I think it's time to bite the bullet and except the fact I need a 3" system with the new charger in place

After a bit of advice from Tarmac Sportz and Mark at Abbey, we don't think my current setup below will hack it:

Borla UEL manifold
Cobra overpipe
Berk high flow cat
Invidia Q300 catback

Our main points for concern at the HFC and the Invidia catback. I've seen HFC's blown out on turbo and charged 350z's in the past so it stands to reason that this may also be an issue on my 86.

The Invidia's backbox will be fairly restrictive and we probably need to look at a more free-flowing design to get the most out of the engine now.

I know very few people on here have 3" systems, but what do you have and what has been your experience? The only systems I know of are the Perrin and the Avo. Not really a fan of the look of either which I know isn't really the point but I want something that looks and sounds good obviously, as well as having the function.

Mark informed me that a 3" overpipe is possible. Apparently Cosworth have something?

I've also seen the Full Blown kit on here, looks like a nice piece of kit and has a 3" overpipe, front pipe and catback





I want to still keep my manifold UEL. I know this will lose me some horses but the Scooby burble is just too addictive to go to EL. Are there any UEL manifolds out there with a larger bore than the Borla I currently have?

Thanks in advance!

[cjd]

I have a JDL over-frontpipe and D2 exhaust. Fit is great. Quality is their usual.

Only header I know that's 3" is Nameless.

I'd be surprised if a good 2.5" system is much of a bottleneck. I'm not really sure even today why I went 3" - even pondering a swap of the whole setup to get the car quieter.

C

[smudge]

Thanks cjd

I've been looking at either the JDL, RevWorks or HKS UEL header. These seem to be the best of the offerings out there in terms of performance for the money

As for overpipe to catback, I've got my supplier quoting me on the Full Blown above and might be looking at a custom option being built if I get a chance to visit my fabrication guys this weekend

[fika84]

You don't NEED a 3" system FYI, there are people on this forum that have run into the 400WHP mark on 2.5" and didn't gain anything with 3".

[smudge]

Originally Posted by fika84

You don't NEED a 3" system FYI, there are people on this forum that have run into the 400WHP mark on 2.5" and didn't gain anything with 3".

I'm in a position where I might as well. My 2.5" system is damaged so I may as well go for 3" to make sure I don't have to upgrade in the future

[go_a_way1]

Originally Posted by fika84

You don't NEED a 3" system FYI, there are people on this forum that have run into the 400WHP mark on 2.5" and didn't gain anything with 3".

^ This ^

[fika84]

Originally Posted by smudge

I'm in a position where I might as well. My 2.5" system is damaged so I may as well go for 3" to make sure I don't have to upgrade in the future

Can't argue with that. Just know it's going to be louder and you're not going to get any gains out of it compared to the 2.5"

[smudge]

Originally Posted by go_a_way1

^ This ^

Originally Posted by smudge

I'm in a position where I might as well. My 2.5" system is damaged so I may as well go for 3" to make sure I don't have to upgrade in the future

^ This ^.....

[go_a_way1]

Originally Posted by smudge

^ This ^.....

^^ That ^^

[Marcbrz86]

Originally Posted by go_a_way1

^^ That ^^

This^^^


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[smudge]

Originally Posted by go_a_way1

^^ That ^^

^ Those....? ^

But seriously, I might as well upgrade while I have the opportunity

[BRZoomTX]

CX kit came with 3" to the cat-back position, otherwise I would've gone 2.5. 2.5" is more than sufficient for the stock motor/trans power levels. 3" overpipe is very tight clearance and will rattle against the subframe depending on angle.

[smudge]

Originally Posted by [Ron]

CX kit came with 3" to the cat-back position, otherwise I would've gone 2.5. 2.5" is more than sufficient for the stock motor/trans power levels. 3" overpipe is very tight clearance and will rattle against the subframe depending on angle.

For those that don't know, I'm not stock

I'm on a built motor running the Sprintex 335 kit. Currently running her in and we're already seeing 1.2bar of boost at just 5500revs

[Kodename47]

You might find that the Borla is in fact the issue and getting a good manifold will sort it out. You want a good merge collector and the right runners and I bet that running a quality 2.5" system won't hold you back. 3" is really for those running a turbo and will be a PITA daily unless you silence it alot, in which case a freer flowing 2.5-2.75" with less silencing might be the optimal solution.

If standard manifolds aren't up to your requirement you could always get a custom one made that will be optimal for an/your SC application.