-7/9s Or -5s Garretts

[SiR_RB]

plenty of 3.5" cats around....

if the sard flows the same amount as the nismo fuel pump then up to 400kw will be achievable on e85

[gtr jet]

I've used Venom cats off ebay before with good results. They do a 5" bodied cat with 3.5" ends. Just get some flanges welded on.

[MrStabby]

Twin 3" dumps into a 3.5 decat and 3" cat back

3in catback is too small. Disconnect the cat back and do another dyno run to see how it goes.. Also, decats are only for the sort of people who throw garbage in the street.... ie the anti-social

FWIW the Nismoid rule of thumb for exhaust sizing is;

3in for 300kw

3.5in for 350kw

4in for 400kw

[Ants]

plenty of 3.5" cats around....

if the sard flows the same amount as the nismo fuel pump then up to 400kw will be achievable on e85

Yeah, but the question is will a 3.5in cat match the 3in front pipe or will there be a need for an adapter?

Sard fuel pump flows exactly the same as a Nismo fuel pump.

[Piggaz]

Yeah, but the question is will a 3.5in cat match the 3in front pipe or will there be a need for an adapter?

Sard fuel pump flows exactly the same as a Nismo fuel pump.

They should bolt up.

[Ants]

They should bolt up.

3.5 inch cat it will have to be then

Thanks mate.

[Hattori Hanzo 69]

Also, decats are only for the sort of people who throw garbage in the street.... ie the anti-social

they are worse than hitler

[TheGeniusMoose]

I gained 500rpm in response time by knocking it out. Im waiting til I get my new exhaust to put a bigger one in. supposedly had a 200 cell cat in there before.

they are worse than hitler

[TheGeniusMoose]

The best logical conclusion is that my cam haven't been set up correctly when my timing belt got done after I got another dyno reading for the same HP.

5psi by 4500, 10 by 6000 and 17 by 7500....

[R31Nismoid]

Your setup has major issues - 4500rpm should see pretty much 20psi all in.

Just take it somewhere else, if they current workshop is saying there is no issue, they have no idea.

[Marko R1]

^ exactly my point, +1

[hazjaz]

I have ended up with the -9's and after fitting them and running a compression test I found out that I am now needing a rebuild.. Changing the pistons, rods, cams, injectors, oil pump, cam gears etc.. would it be 'restricting' this build with -9s?

[r32-25t]

If you keep it 2.6, no

If you increase the capacity, yes

[tk80]

FWIW the Nismoid rule of thumb for exhaust sizing is;

3in for 300kw

3.5in for 350kw

4in for 400kw

Anyone with a 400awkw car had a 3.5in and change to 4in and see any gains?

[Marko R1]

I had over 400kw and ran a 3.5inch exhaust. I never upgraded to 4inch for the reason that my tuner advised the exhaust was not a restriction.

Hope that helps

P.S. I'm sure there would be gains but not more than a bees d1ck (bang for buck)

[Ants]

Totally agree. There are many cars running 400kw+ atw . You look at the mines car, it runs low mounts (2530's) and still 2.6 capacity engine and has 621hp and does not have a 4in zorst.

[discoPumpkin]

Can u get billet wheels 4 any of these turbos? cuz with the GTX series , the smallest they do is the gtx2860r

[MrStabby]

Anyone with a 400awkw car had a 3.5in and change to 4in and see any gains?

There's no way to tell over the internet. A rule of thumb is just that. The cat and mufflers are the most restrictive bits after the turbine, if you have a cat and muffler(s) that flow very well, you might see no difference like Marko. Ask your tuner.

[KING87]

If you already have a good flowing 3.5" then i would say keep that but if you need a new one then sure you may see a little gain from going to the 4" set up.

I have a 3.5" cat back making 430kw on 2530's with a stock 2.6L and is not a restriction.

Cheers

Edited May 28, 2013 by KING87

[discoPumpkin]

if u got to big it will be to laggy and not responsive, some backpressure is good! 3.5" is perfect!