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3" Or 3.5" Exhaust

fat_al

By fat_al,
in Engines & Forced Induction

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R31Nismoid Grand Master

R31Nismoid

Posted
Posted

So my guess is its probaly in the centre resonator bit or it doesnt actually go gay at all and my cooler is restriction

Have a good look just before/after resonators/mufflers. Usually it's given away by a small reduction in the outside pipe diameter, it drops down just a bit.

Not always the case but the vast majority of (quiet) Jap exhausts I've seen have it done this way if you cannot see the obvious one from the rear end.

Pretty easy to confirm restriction on dyno anyway, just drop the exhaust post-dump, see what happens

Ke55pig Proficient

Ke55pig

Posted
Posted

Yea rear cannons deffiently staraight through.Theres no drop in the pipe size but could still have some thing in the centre res.Im just going to leave it and find a 3.5-4" exhaust for it for events and put the blitz back on for the st.

Tune with track exhaust and let it be restricted on the st

Nick_GTR Explorer

Nick_GTR

Posted
Posted

I wish this had been discussed a couple of months ago. I recently bought a Kakimoto Hyper Full Mega N1, supposedly 90mm throughout. Upon inspection when it arrived, it was stepped down going into the centre muffler, yet maintained the 90mm external dimensions. Fitted the exhaust anyway and even without dyno results, I can tell you that performance has been choked up. The turbos aren't spooling as quickly and I'm not nearly making as much power. Very disappointing

Ke55pig Proficient

Ke55pig

Posted
Posted (edited)

It is verry dissapointing a big well made jap exhaust has these restrictions i noticed mine with the fact i made 350 on 98 changed to e85 and changed exhaust and still made 350 up top

Dyno shows this fingers crossed it was the change of exhaust that caused it

post-77561-0-85728500-1452310982_thumb.jpeg

Edited by Ke55pig
kingtube69 Experienced

kingtube69

Posted
Posted

It is verry dissapointing a big well made jap exhaust has these restrictions i noticed mine with the fact i made 350 on 98 changed to e85 and changed exhaust and still made 350 up top

Dyno shows this fingers crossed it was the change of exhaust that caused it

Thats unfortunate - Could you possibly go back and get them to drop the exhaust then rerun on the dyno to see if thats the restriction?

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