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Model specific boards => Golf mk3 => Topic started by: VR6-Joe on 30 October 2009, 07:54

Title: Exhausts
Post by: VR6-Joe on 30 October 2009, 07:54
I'm getting a new car this weekend..

Does anyone know;

Firstly - The diameter of a 16v/VR6 exhaust
Secondly - The diameter of a 1.6 exhaust

I'm hoping I can swap the exhausts over with the help of a reducer but need to know which size reducer to buy.

Cheers
Title: Re: Exhausts
Post by: Len on 30 October 2009, 09:31
Sorry Joe but which way round are you going? Fitting a Vr6 exhaust to a 1.6?

If so that wont do the engine much good as you will get back pressure!
Title: Re: Exhausts
Post by: Mikester on 30 October 2009, 10:11
You can fit a VR exhaust to a 1.6 fine, its fitting a 1.6 exhaust to a VR6 that would cause back pressure.

Depending on your 1.6 engine size and age, it may be able to use the 8v to 16v reducer sleeve, but its certianly usable.

You can run a 16v or VR6 on an 8v bore exhaust, i know someone that done it for a conversion, its not ideal, but it doesnt mean death either.

Basically measure your 1.6 exhaust. 2inch is 8v, and 2.25 inch is 16v and VR size, although if you are planning on tuning the VR engine than 2.5inch is a btter option,and for turbo 3inch really, lol.
Title: Re: Exhausts
Post by: Len on 30 October 2009, 10:34
Back pressure is caused by using too large a diameter! So fitting a larger exhaust causes the gasses to slow down, THAT is what causes back pressure!
Title: Re: Exhausts
Post by: Mikester on 30 October 2009, 10:36
Fitting a larger exhaust will be fine.

Otherwise what is the point with tuners and exhaust manufactures making and fitting a 2.5 inch to a 16v/Vr6 when standard it is 2.25inch.

That would be the same upgrade in exhaust size from a 8v to a 16v/exhaust as said in the original post.

Shut up len. You have no experience with this.
Title: Re: Exhausts
Post by: Len on 30 October 2009, 10:40
No experience sonny! Go back to school!


You only put a larger bore exhaust on when you increase the flow through the engine!
Title: Re: Exhausts
Post by: Mikester on 30 October 2009, 10:43
Or when you ask a question on a forum, to people you trust for answers. To ask if it will work ok.

To which the answer is YES.
Title: Re: Exhausts
Post by: Wayne on 30 October 2009, 10:46
Back pressure is caused by using too large a diameter! So fitting a larger exhaust causes the gasses to slow down, THAT is what causes back pressure!

 :undecided: what is the point of fitting a bigger bore exhaust then.
Title: Re: Exhausts
Post by: Mikester on 30 October 2009, 10:47
Back pressure is caused by using too large a diameter! So fitting a larger exhaust causes the gasses to slow down, THAT is what causes back pressure!

 :undecided: what is the point of fitting a bigger bore exhaust then.

There isnt mate.

Len told me :)
Title: Re: Exhausts
Post by: Adam on 30 October 2009, 10:48
Len is right in what he is saying. So is Mike. Chill out!

(http://i.pbase.com/o4/98/583898/1/63713938.qaEEdjG9.popcorn.gif)

Back pressure is caused by using too large a diameter! So fitting a larger exhaust causes the gasses to slow down, THAT is what causes back pressure!

 :undecided: what is the point of fitting a bigger bore exhaust then.

If uz use a vr6 xhaust it makes it sound like you haz a vr6 init bruv.
Title: Re: Exhausts
Post by: axewielder on 30 October 2009, 10:49
Back pressure is caused by using too large a diameter! So fitting a larger exhaust causes the gasses to slow down, THAT is what causes back pressure!
i was pretty sure smaller bore=more back pressure as it restricts flow and therefore helps stop the engine blowing fresh charge straight out the exhaust port on the overlap
big bore=less back pressure which is good for turbos ect as it is less restriction and increased flow + gas speed to help turbo spooling
if its just cat back system there will still be the origional bore on the first part of the system so wont do anything drasticly massive to the engine performance either way
Title: Re: Exhausts
Post by: Adam on 30 October 2009, 10:50
A NA engine relays on back pressure 
Title: Re: Exhausts
Post by: Wayne on 30 October 2009, 10:51
Back pressure is caused by using too large a diameter! So fitting a larger exhaust causes the gasses to slow down, THAT is what causes back pressure!
i was pretty sure smaller bore=more back pressure as it restricts flow and therefore helps stop the engine blowing fresh charge straight out the exhaust port on the overlap
big bore=less back pressure which is good for turbos ect as it is less restriction and increased flow + gas speed to help turbo spooling
if its just cat back system there will still be the origional bore on the first part of the system so wont do anything drasticly massive to the engine performance either way

I am thinking the same.
Title: Re: Exhausts
Post by: VR6-Joe on 30 October 2009, 11:42
Thanks for the replies, I see some of you are concerned about the damage that my happen to my engine :huh:

The exhaust is a stainless steel cat back system off a 16v

So far from this thread I've established the 16v/VR6 exhaust is 2.25" (thanks Mike) .. my 1.6 is a 1996 if that makes any difference to the size of my exhaust? I would measure it but it's on the car and I'll be needing the car to go to a tyre/exhaust place to buy a reducer lol.
Title: Re: Exhausts
Post by: Mikester on 30 October 2009, 11:45
You can measure it on the car ok.

I know that a 1.8 GL like shadys uses the same as a 8v gti bore, which is 2inch.

But im not sure about yours, i would look on a parts website and see if the exhaust parts are listed the same for a 1.6 and 1.8. That way you will know if it will fit.
Title: Re: Exhausts
Post by: axewielder on 30 October 2009, 11:50
no damage, just noise+shift the power band up a bit, might reduce overall power by 0.1hp too if ure lucky  :smug:
Title: Re: Exhausts
Post by: justalex81 on 30 October 2009, 21:51
i'm gonna put a ferrari exhaust on mine. should add at least 300bhp to my abf  :rolleyes: :laugh: :grin:
Title: Re: Exhausts
Post by: Cable on 30 October 2009, 21:53
Nah they add 400bhp  :wink:
Title: Re: Exhausts
Post by: justalex81 on 30 October 2009, 22:54
oh in that case i'm gonna stick bugatti veyron wing mirrors on it. should be good for 9000 torques  :cool:
Title: Re: Exhausts
Post by: Cable on 30 October 2009, 23:25
haha, yh 0.90000 torques
Title: Re: Exhausts
Post by: boneybradley on 30 October 2009, 23:47
the only issue with fitting a larger bore is it can lower back pressure/compression (and for more power without a turbo you want more compression..look at tuning a 2.0 8v and you'll see loads of higher compression pistons etc..and boost increases compression, hence for big bhp on turbo's you need low compression pistons/head gasket spacers etc..a mate has an evo with a 12mm head gasket so he can run silly boost with loads of lag!)
A vr6 exhaust won't really make that much difference although you'll possibly/maybe notice it needs a few more rev's and have a narrower power band (which on a 1.6 won't really matter!!) I had a rover 1.8k before that when de-catted and with a larger exhaust it lost 5bhp and 14lb/ft of torque and was flat until 3500+ rpm!!