2.5" or 3" system ?
11 July 2014, 07:00 PM
#1
2.5" or 3" system ?
Hi all
MY03 sti
I currently have a ppp downpipe with straight through centre and ppp back box.
My downpipe is restricting me power wise as the cat has started to break down.
My mapper has suggested a full 3" decat but my goal is 360-380 with my build and the vf43.
Will I be ok with a 3" downpipe that tapers down to 2.5 and fits up to my current centre section ?
At what power level would you go full 3" and at what power level would the above set up run out of puff ?
Siv
MY03 sti
I currently have a ppp downpipe with straight through centre and ppp back box.
My downpipe is restricting me power wise as the cat has started to break down.
My mapper has suggested a full 3" decat but my goal is 360-380 with my build and the vf43.
Will I be ok with a 3" downpipe that tapers down to 2.5 and fits up to my current centre section ?
At what power level would you go full 3" and at what power level would the above set up run out of puff ?
Siv
11 July 2014, 08:48 PM
#2
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I had the same problem with a 3" to 2 1/2" down pipe stright through de-cated exhaust 2 1/2" was really restrictive so fitted a full scooby clinic 3" exhaust how shes opened up lovely......
11 July 2014, 09:55 PM
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You can get 400bhp with a TMIC
You can get 400bhp with a 2.5" System
You can get 400bhp on standard injectors
etc...
I guess the summary of it is, you CAN get 400bhp with any of those things - but probably not with ALL of them at once. You may also need to compensate with a bigger turbo (laaaaaag), or be marginal on fuelling making the map less "safe", etc.
I'll be going FMIC, 3.0" and bigger injectors when my 20G goes on, for the record
11 July 2014, 10:01 PM
#7
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To join the 3" to a 2.5 you can get an adaptor flange, have a look on ebay etc. Thats is what i was going to use but sold the car on before getting round to fitting the downpipe and centre section, while retaining the prodrive back box.
I guess i really should flog it on, i sold the car in feb lol.
I guess i really should flog it on, i sold the car in feb lol.
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18 July 2014, 05:14 PM
#11
That's my 2-12" exhaust you're referring to and the car made 425 bhp with it fitted. However the limiting factors were the Harvey exhaust manifold and up pipe, that were rated by the late Harvey as suitable for up to around 400 bhp. A GT spec manifold and up pipe were fitted and I changed to a 3" exhaust too. But I am confident the 2-1/2" system would have probably made more than 425 bhp. Still got the system by the way if any one wants it!
18 July 2014, 09:13 PM
#12
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I had a 3" downpipe, and 2.5" rest.
made 360bhp on the rollers , changed exhaust to 3" from Revolution , and NPS , and car made 401bhp - no other changes ware made.
made 360bhp on the rollers , changed exhaust to 3" from Revolution , and NPS , and car made 401bhp - no other changes ware made.
19 July 2014, 10:48 AM
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Yep, got the graphs if anyone need to see them.
It was actually Duncan (Racedynamix) who said my exhaust was holding it back , so I changed it and i'm very glad i did lol
It was actually Duncan (Racedynamix) who said my exhaust was holding it back , so I changed it and i'm very glad i did lol
19 July 2014, 08:15 PM
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Yes, blob sti, AFP20g turbo, with billet conversion done by http://www.braveheartracingdevelopments.com/
20 July 2014, 10:15 AM
#20
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Lol Cool. If you decide to sell give me a shout mate. Only after a centre section to replace the resonator,
Don't feel pressured tho mate no worries if you decide against It. I was being cheeky lol
Don't feel pressured tho mate no worries if you decide against It. I was being cheeky lol
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