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Re: downpipe/exhaust track car
[Re: jonnyboy54321]
#1628809
21/01/2019 12:10
21/01/2019 12:10
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Joined: Oct 2008
Posts: 6,508 In the coupe.
magooagain
Club member 259
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Club member 259
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In the coupe.
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You won't need anything but standard for your stock turbo .
If you are going the gt route then a new 3"complete system with the five hole flange is what's needed. No silencers needed if it's a dedicated non mot track car.
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Re: downpipe/exhaust track car
[Re: magooagain]
#1628826
21/01/2019 20:32
21/01/2019 20:32
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Joined: Aug 2017
Posts: 221 Surrey
jonnyboy54321
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You won't need anything but standard for your stock turbo .
If you are going the gt route then a new 3"complete system with the five hole flange is what's needed. No silencers needed if it's a dedicated non mot track car.
In that case I will dig out my spare downpipe, and see if I have a centre section somewhere. It is a track only car but do want it to pass mot. Thanks
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Re: downpipe/exhaust track car
[Re: magooagain]
#1628844
22/01/2019 12:36
22/01/2019 12:36
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Joined: Jan 2006
Posts: 9,867 SW London
suba
Je suis un Coupé
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Je suis un Coupé
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SW London
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I would not go without silencers unless you only plan on doing 102db days - most are 98db, and it's not worth being right on the limit as you'll get booted off without warning.
I put two straight through silencers on the RX7 for this purpose - lost 3bhp, and only slightly higher EGT's.
Goes without saying that official MOT needs a CAT in the exhaust...
Rotary fun - 370 bhp per ton. GT30's are small you know?!??!?!?!
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Re: downpipe/exhaust track car
[Re: suba]
#1628857
22/01/2019 19:56
22/01/2019 19:56
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Posts: 221 Surrey
jonnyboy54321
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I would not go without silencers unless you only plan on doing 102db days - most are 98db, and it's not worth being right on the limit as you'll get booted off without warning.
I put two straight through silencers on the RX7 for this purpose - lost 3bhp, and only slightly higher EGT's.
Goes without saying that official MOT needs a CAT in the exhaust... Agree - I do have that cybox back box.... And a blueflame for when the gt goes on
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Re: downpipe/exhaust track car
[Re: jonnyboy54321]
#1628865
23/01/2019 10:07
23/01/2019 10:07
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Joined: Oct 2008
Posts: 6,508 In the coupe.
magooagain
Club member 259
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Club member 259
Forum is my life
Joined: Oct 2008
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In the coupe.
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Straight through 3" stainless steel including down pipe purrs like a cat. It won't get anywhere near 95dcb.
I do understand that it's no good for an mot road going coupe mind.
The blue flame will be louder than a straight through I reckon but still ok for track noise limits.
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Re: downpipe/exhaust track car
[Re: jonnyboy54321]
#1628871
23/01/2019 12:51
23/01/2019 12:51
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Joined: Oct 2008
Posts: 6,508 In the coupe.
magooagain
Club member 259
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Club member 259
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In the coupe.
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Strange mine is nowhere near that amount. Mind you I have a hybrid so still on VBand. What was the turbo you were using Nigel.
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Re: downpipe/exhaust track car
[Re: Nigel]
#1628881
23/01/2019 18:08
23/01/2019 18:08
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Joined: Aug 2017
Posts: 221 Surrey
jonnyboy54321
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My 20vt gave 98db with a straight through 3" system with just one small backbox
However, it got very boomy under load, so I had a big centre silencer fitted (still 3" straight-through) which made a lot of difference
Back to the OP's question - its the first section of exhaust that is critical - as the gasses travel down the pipe, they cool and need less volume.
If you still have the stock V-band adapter fitted, this is the limiting factor - you could fit a 6" exhaust from the V-Band back and it wouldn't improve anything
Don't fit a bigger downpipe until you're about to fit a turbo with a 5-bolt flange - you won't see a benefit until then Nigel - presumably yours was a road car that you track with? This one is a track car that I occasionally road with....keep MOT up etc. At least that's the plan....
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