bigger diameter backbox vx220

drpau

Ive been thinking about trying to get hold of a Vx220 turbo standard exhaust and wacking it in my VX, was thinking the lower backpressure of this exhaust and bigger pipework (I think 2.5inch vs ₂" on the normal vx) would help it breath a bit better, is this a good idea or am I talking bo11ocks? I think it will bolt straight on to the existing pipework without any mods but will it give me any benefit?

Opinions please...

luna_s

its 2.25" i've fitted one, as to the results i'm not sure - i think you also need the turbo U Bend

there was some pics of the internal differences somewhere - but my reckoning was the same as yours.

i'm still considering modding a standard backbox to 2.5" pipework but its a lot of work

drpau

Hmm, so no real benefit then 🙁
Im guessing it didnt really sound any different either!?

markv

Bigger pipe work should help, but you will probably need to get everything bigger. Seems to basically work like a straw, if you don't make the whole straw wider, you won't be able to drink your drink faster 🙂

I don't know what the best diameter is. I have had good results upgrading the whole exhaust to 2.5" (manifold exits in something like 2.7" if I recall correctly, it is 2.5" from there). Before/after graph:

Mark

vocky

I have a 2.5" system, much better flowing than the standard milltek thing

well worth doing 🙂

winstar

I've said this before but IMO the thin u bend is a large loss in the vx system.

The cheapest 2.5" low pressure back box is the blue flame one for the VXT

OAKMERE

Thinking of trying a Blueflame for my NA as it should fit (Larini only have one backbox for both cars)

Cheers Oakmere

vocky

winstar said:
I've said this before but IMO the thin u bend is a large loss in the vx system.

and you are correct cheers..

simply fitting a 2.5" U bend makes so much difference showo..

drpau

So the standard turbo box is 2.25". What is the piper then? I remember Edbutlers mate saying he could get me one of those for a good price ;-)

Is it because the U bend is such a tight one that it is a big restriction?

OAKMERE

drpau

The piper is 2.25" as are most of the after market vx220 exhaust apart form the Milltek which is 2"? The Piper flows well but is apparently quite noisy. I was hoping to get a 2.5" backbox as markv got good results and vocky said the 2.5" u-tube alone made a difference.

Cheers Oakmere

vocky

have a read of my diy 2.5" milltek system :lol:

viewtopic.php?f=61&t=7456

drpau

vocky said:
have a read of my diy 2.5" milltek system :lol:

viewtopic.php?f=61&t=7456

Yeah, I remember reading this - beyond me unfortunately cryb.. I cant even weld cryb.. I can cut things up well though 😃

edbutler

Just get a Piper man! Cheapish and sound luvvverly 😃

winstar

edbutler said:
Just get a Piper man! Cheapish and sound luvvverly 😃

What dimeter Pipe are they?

IIRC the Blue flame turbo exhaust isn't much more than the Piper, if you can put up with the dodgy tail pipes

edbutler

The piper is 2.25" and i think its saves you around 7kg. Also the U-Bend is well thought out so the gas takes a longer, faster apex 🙂

Jase_MK

edbutler said:
The piper is 2.25" and i think its saves you around 7kg. Also the U-Bend is well thought out so the gas takes a longer, faster apex 🙂

Are you talking about the U bend after the back box that leads into the tail pipes? I think people here are talking about the 180 degree bend that joins the cat to the backbox. I used to have a Piper and pretty sure the u-bend after the cat is just a plain and simple one. The one after the backbox, however, does curve out and do a bigger radius bend.

rabidh

I did a vocky-type mod to my standard backbox to get a 2.5" entry into it, then cut out some of the baffles. You'd have to be able to weld, or get someone to do it, but it might be worth a try. NA backboxes are dirt cheap on ebay.

Only issue is the tailpipes are still the same diameter (although you could poss. change that). Definitely a massive improvement to sound! Not roaded it yet, so I'm not sure what performance improvement it would have had, but it feels quick 🙂