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Post by zoona on Feb 1, 2022 2:05:06 GMT
I have seen a few threads on this topic, but they are either on the us based troll sites (I find it really difficult to wade through the prarrie canoe talking on turbomiata et al) or address other aspects such as noise.
I have a turbo setup with a 70mm (~2.75") downpipe.
I am about to build a new exhaust, and am trying to decide between 2.5 and 3 inch tubing.
Is there any real advantage to 3", or will 2.5" be enough?
I don't really understand the details of exhausts, so happy to be educated...
Td04 with sturovo manifold and down pipe, forged rods. Was running 192 whp, but want to push it higher with the new engine.
I plan to have a bog standard muffler and a resonator (summit, or flowmaster)
All thoughts welcomed.
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Post by thruxton on Feb 1, 2022 9:08:24 GMT
Hello there.
Yes, interesting topic.
I have spoken at length with RR tuners and engine builders.
Of course it is a very complex subject with such a huge amount of variables.
Also what are you really looking for with regard to torque and outright horsepower?
Where you want the torque and where you want maximum power at what rpm?
A lot depends on the choice of turbo.
Such as a BW or Small TD.
I think you should take your precise specifications and hoped for outcomes and talk with the likes of Kraken
I can tell you for a BW turbo set up then you will win on power and torque with a 3” system.
And to date I have seen no empirical evidence to counter this opinion.
Regards.
Rich.
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Post by scottydugg on Feb 1, 2022 9:08:32 GMT
From what I've gleamed off said sites, 3" is better for faster spool and coping with higher power.
I think at certain power figures it becomes necessary.
I think if you're aiming for 250bhp+ at the flywheel/or even the wheels, I'd go with the 3" unit.
Always worth futureproofing yourself, especially if you're already forged.
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Post by batou on Feb 1, 2022 12:38:42 GMT
I have seen a few threads on this topic, but they are either on the us based troll sites (I find it really difficult to wade through the prarrie canoe talking on turbomiata et al) or address other aspects such as noise. Absolutely this, I just avoid nowadays, the sterotypical Canoe swinging and arrogance is hard to read through. Sorry I can't really help with the rest other than I know that 75mm / 3" was the way to go with the VF41 on the Subaru  |
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Post by zoona on Feb 1, 2022 14:47:57 GMT
Well, just opened YouTube and Google has done it's freaky prarrie canoe again:
Pretty sure my engine can be compared to a 600hp V8... Yeah?
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Post by atlex on Feb 1, 2022 15:26:40 GMT
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Post by dickie on Feb 1, 2022 19:10:50 GMT
I have fitted a 2 1/2" system on my ITB 1800,
I have gone that size as I am after flow at 9000 RPM ( Once I get all the parts together for the next silly engine )
I know its a little on the larger size 2 3/8" would probably be a better size for my application.
For turbo applications you need to size the exhaust for a bigger engine output.
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Post by Zed. on Feb 1, 2022 19:30:15 GMT
I have fitted a 2 1/2" system Id or Od? Rich. |
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Post by dickie on Feb 1, 2022 19:37:39 GMT
Yarp,
Manifold down pipe slips inside the 2 1/2" system pipe so 2 1/2" ID system Manifold back.
See piccy in what have I F##ked up Today.
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le sigh