Downpipe flange bolt to bolt diameter, can anyone help?

**insanekiwi** · 19-05-2009, 08:04 AM

Hi guys,

I am trying to get a custom down pipe made, but need bolt to bolt diameter for the flange... can anyone help??

The exhaust place has 3" one, but wants to confirm before I come down to get it done...

Would really appreciate it... thanks.

**insanekiwi** · 19-05-2009, 02:35 PM

anyone...??
need help urgently.... Jmac? or Guy?

I just can't quite justify paying for a new cat, and just want a new down pipe...

if i could buy downpipe alone from APR, i would!

**Timbo** · 19-05-2009, 04:05 PM

A good exhaust shop with proper cutting and welding gear should be able to retain both your existing flange and cat -- neither are major restrictions (although plenty of people argue the cat is, just not me

)

If your guy can't do this, try another shop.

**insanekiwi** · 19-05-2009, 06:21 PM

Thank you Timbo, I believe this means that, the flange on both ends are NOT part of 'restriction', but the pipe itself that causes restriction.

So flange at turbo end is approx 3" wide?

Thanks for your help, it makes a lot of sense. Retaining original flange also will guarantee an exact fit without leaks.

**Timbo** · 19-05-2009, 08:29 PM

Yes, it's actually the bend before the cat that is the most restrictive part of the stock system, according to the guy that did my DP

**Desmo** · 20-05-2009, 04:38 PM

"A good exhaust shop with proper cutting and welding gear should be able to retain both your existing flange and cat "

Mine exhaust guy did just this, and it looked very good. Id recommend it as well.

**Chipped** · 20-05-2009, 05:38 PM

...funny I was just at a reputable Perth Exhaust shop yesterday morning going thru a similar thing.
I already have a APR DP and HFC. The exhaust guy says he can open up the end of the existing HFC to 3" and do me a full 3" system from the cat back.
He also mentioned that metal HFC flow better than ceramic ones which I was not aware of. I think the APR one is ceramic...not sure if it all worth the dollars tho.....