2.5 or 3" system?
#1
Scooby Regular
Thread Starter
iTrader: (1)
Join Date: Apr 2007
Location: Ayrshire
Posts: 696
Likes: 0
Received 0 Likes
on
0 Posts
2.5 or 3" system?
Will a 2.5" system be ok to use with a vf35 on my 01 WRX?
I've had a look at some downpipes and all I can find are 3" downpipes with the 2.5" ends on the that connect to the standard system. But I have also found a 2.5" stainless system that will fit the rest of my car.
Will this be ok for around 340-350bhp (as I think that'll be the max I can get out the vf35)
Or has anyone ever bought one of these
SUBARU IMPREZA NEW AGE STAINLESS STEEL EXHAUST SYSTEM on eBay, also Exhaust Components, Performance Tuning Parts, Car Tuning Styling, Cars, Parts Vehicles (end time 22-Nov-08 14:00:00 GMT)
I've had a look at some downpipes and all I can find are 3" downpipes with the 2.5" ends on the that connect to the standard system. But I have also found a 2.5" stainless system that will fit the rest of my car.
Will this be ok for around 340-350bhp (as I think that'll be the max I can get out the vf35)
Or has anyone ever bought one of these
SUBARU IMPREZA NEW AGE STAINLESS STEEL EXHAUST SYSTEM on eBay, also Exhaust Components, Performance Tuning Parts, Car Tuning Styling, Cars, Parts Vehicles (end time 22-Nov-08 14:00:00 GMT)
#2
Scooby Regular
iTrader: (9)
Join Date: Oct 2006
Location: midlands
Posts: 2,316
Likes: 0
Received 0 Likes
on
0 Posts
2.5 will be sound you dont want to oversize the system,and i wouldnt bother with that system,i have never used one or know anyone with one but i wouldnt imagine those flexi joints will last on the up pipe
#4
Scooby Regular
iTrader: (9)
Join Date: Oct 2006
Location: midlands
Posts: 2,316
Likes: 0
Received 0 Likes
on
0 Posts
unless he intends on getting a built engine i wouldnt put a 3" on a standard engine,it will do nothing for it performance wise(may even make it slower and more lag than a 2.5" would) just make noise
#5
412/425 of forged love
iTrader: (12)
Join Date: Jan 2008
Location: www.surreyscoobies.com
Posts: 4,238
Likes: 0
Received 0 Likes
on
0 Posts
went from 3" which tapered down to 2.5" at joints. to a true 3" and the diff was quality. earlier spool and more grunt. that was a t 360bhp, not sure what difference that would make
#7
Scooby Regular
The system between the exhaust ports and the turbine inlet are the thing that will make the difference in lag, spool up, outright power etc.
Trending Topics
#8
Scooby Regular
iTrader: (8)
Join Date: Mar 2008
Location: west mids
Posts: 984
Likes: 0
Received 0 Likes
on
0 Posts
on my00 uk i srapped my 2.5" magnex system and went for a full hks 3" supper dragger turbo back (slip jointed) with great improvement and this is with a vf35
currently giving 332bhp @ 1.4 bar with 440s @ 3.5bar
the 2.5" vs 3" exhaust debate does a lot dep on the quality of the exhaust as much as the bore size IMO
currently giving 332bhp @ 1.4 bar with 440s @ 3.5bar
the 2.5" vs 3" exhaust debate does a lot dep on the quality of the exhaust as much as the bore size IMO
#10
Scooby Regular
iTrader: (25)
Join Date: Feb 2008
Location: MSOC
Posts: 3,135
Likes: 0
Received 0 Likes
on
0 Posts
Have a look in here matey, it's second hand but quality stuff for right amount of money...
JPP : TuningParts for Sale
JPP : TuningParts for Sale
#11
Scooby Regular
Thread Starter
iTrader: (1)
Join Date: Apr 2007
Location: Ayrshire
Posts: 696
Likes: 0
Received 0 Likes
on
0 Posts
Will a 2.5" system be ok to use with a vf35 on my 01 WRX?
I've had a look at some downpipes and all I can find are 3" downpipes with the 2.5" ends on the that connect to the standard system. But I have also found a 2.5" stainless system that will fit the rest of my car.
Will this be ok for around 340-350bhp (as I think that'll be the max I can get out the vf35)
Or has anyone ever bought one of these
SUBARU IMPREZA NEW AGE STAINLESS STEEL EXHAUST SYSTEM on eBay, also Exhaust Components, Performance Tuning Parts, Car Tuning Styling, Cars, Parts Vehicles (end time 22-Nov-08 14:00:00 GMT)
I've had a look at some downpipes and all I can find are 3" downpipes with the 2.5" ends on the that connect to the standard system. But I have also found a 2.5" stainless system that will fit the rest of my car.
Will this be ok for around 340-350bhp (as I think that'll be the max I can get out the vf35)
Or has anyone ever bought one of these
SUBARU IMPREZA NEW AGE STAINLESS STEEL EXHAUST SYSTEM on eBay, also Exhaust Components, Performance Tuning Parts, Car Tuning Styling, Cars, Parts Vehicles (end time 22-Nov-08 14:00:00 GMT)
A fully decated 2 ½ bore system is adequate up to 350 bhp. After this a 3 system is recommended. Sports cat systems are available but ultimately still limit power compared to a fully decated setup
The above was taken from AndyF's website so I guess a 2.5 will do
#15
Scooby Regular
iTrader: (9)
Join Date: Oct 2006
Location: midlands
Posts: 2,316
Likes: 0
Received 0 Likes
on
0 Posts
i am running a andy f 20g on a 2.5" exhaust only way to be 100% sure on the gains/loses of each would be to do a bk to bk test on the same car same rollers,i do agree it all depends on the system fitted. its all down to future planning and if you are intending to push the car over the 400+ mark in the near future, but as to my personal choice below 390-400 i would go 2.5" (maybe with 3" down pipe only if mods require)anythin above 3"
#16
Scooby Regular
That's interesting, and somewhat surprising. Did you have it remapped for the bigger exhaust as I would have expected the turbo to spool up quicker with less restriction after the turbine?
#17
Scooby Regular
iTrader: (1)
Join Date: Jan 2008
Location: Oldham
Posts: 1,428
Likes: 0
Received 0 Likes
on
0 Posts
Will a 2.5" system be ok to use with a vf35 on my 01 WRX?
I've had a look at some downpipes and all I can find are 3" downpipes with the 2.5" ends on the that connect to the standard system. But I have also found a 2.5" stainless system that will fit the rest of my car.
Will this be ok for around 340-350bhp (as I think that'll be the max I can get out the vf35)
Or has anyone ever bought one of these
SUBARU IMPREZA NEW AGE STAINLESS STEEL EXHAUST SYSTEM on eBay, also Exhaust Components, Performance Tuning Parts, Car Tuning Styling, Cars, Parts Vehicles (end time 22-Nov-08 14:00:00 GMT)
I've had a look at some downpipes and all I can find are 3" downpipes with the 2.5" ends on the that connect to the standard system. But I have also found a 2.5" stainless system that will fit the rest of my car.
Will this be ok for around 340-350bhp (as I think that'll be the max I can get out the vf35)
Or has anyone ever bought one of these
SUBARU IMPREZA NEW AGE STAINLESS STEEL EXHAUST SYSTEM on eBay, also Exhaust Components, Performance Tuning Parts, Car Tuning Styling, Cars, Parts Vehicles (end time 22-Nov-08 14:00:00 GMT)
#19
Scooby Regular
Join Date: Jul 2008
Location: scooby land
Posts: 128
Likes: 0
Received 0 Likes
on
0 Posts
i had this debate as well about a 2.5" or a 3" for my blob eye sti. i am after 330-340bhp and was told 2.5" is more than adequate up to 350bhp. and my turbo which is a vf35 is only capable of up to 350bhp so i thought i might aswell stick to 2.5" then the thought acured to me that if i did want more power in the future i would upgrade the turbo to a larger unit with supporting mods to around 400bhp but the 2.5" would not support that power so i finnaly got a 3" turbo back milltek system. expensive but i needed to have a sports cat come m.o.t time. so i would say if you arent going to go abouve 350bhp in the future stick to a 2.5" system. try getting a 2nd hand prodrive system they sound awsume much better than the milltek i have fitted now.
hope this helped
hope this helped
#20
Scooby Regular
Thread Starter
iTrader: (1)
Join Date: Apr 2007
Location: Ayrshire
Posts: 696
Likes: 0
Received 0 Likes
on
0 Posts
i had this debate as well about a 2.5" or a 3" for my blob eye sti. i am after 330-340bhp and was told 2.5" is more than adequate up to 350bhp. and my turbo which is a vf35 is only capable of up to 350bhp so i thought i might aswell stick to 2.5" then the thought acured to me that if i did want more power in the future i would upgrade the turbo to a larger unit with supporting mods to around 400bhp but the 2.5" would not support that power so i finnaly got a 3" turbo back milltek system. expensive but i needed to have a sports cat come m.o.t time. so i would say if you arent going to go abouve 350bhp in the future stick to a 2.5" system. try getting a 2nd hand prodrive system they sound awsume much better than the milltek i have fitted now.
hope this helped
hope this helped
350 will be more than enough till I see how the car copes. Its been standard all its life.
I think I'll stick to the 2.5". As for turbo's it'll either be a td05 or something from the VF series and a set of 550's
It just feels gutless as the minute, with what power it has running out at 5000rpm. I had a VF28 on my classic and it pulled all the way to the redline.
#22
Scooby Regular
Thread Starter
iTrader: (1)
Join Date: Apr 2007
Location: Ayrshire
Posts: 696
Likes: 0
Received 0 Likes
on
0 Posts
That would do lovely!! What sort of mileage does your car have?
I'm more than 90% sure thats the route I'm taking.
VF35
550's
3" downpipe
2.5" system
340bhp is amicable for our roads. I'll need brembo's and suspension after that.
Thanks for all the input.
#24
Scooby Regular
Thread Starter
iTrader: (1)
Join Date: Apr 2007
Location: Ayrshire
Posts: 696
Likes: 0
Received 0 Likes
on
0 Posts
My vf28 was still making power at 6000 on my classic!!
#27
Scooby Regular
iTrader: (8)
Join Date: Mar 2008
Location: west mids
Posts: 984
Likes: 0
Received 0 Likes
on
0 Posts
here are my cousins figures for my99 with vf35
on 2.5" h&s(3"downpipe) 322bhp
on 3" full mongoose 328bhp
both with ome headers/up-pipe
only 6bhp so not a lot in it around 320-330 but both runs were on the same dyno so little improvement
on 2.5" h&s(3"downpipe) 322bhp
on 3" full mongoose 328bhp
both with ome headers/up-pipe
only 6bhp so not a lot in it around 320-330 but both runs were on the same dyno so little improvement
Thread
Thread Starter
Forum
Replies
Last Post
crazyspeedfreakz
Wanted
17
05 October 2015 07:19 PM