Trackday friendly 3" exhaust system?
05 January 2011, 05:06 PM
#31
Scooby Regular
The metal is not .25" thick. I wouldn't worry about it. Or splash out a few extra quid for a new down pipe.
The guys at ExhaustsUK are top people and will make the system completely to your spec, with your choice of tailpipe and how it's fitted. I have a 4.5" slash cut, but is slightly longer so that it clears the rear bumper.
Absolutely love it. Check the link in my sig to see it, and being fitted
The guys at ExhaustsUK are top people and will make the system completely to your spec, with your choice of tailpipe and how it's fitted. I have a 4.5" slash cut, but is slightly longer so that it clears the rear bumper.
Absolutely love it. Check the link in my sig to see it, and being fitted
05 January 2011, 08:48 PM
#32
You will find that 2.5" exhausts or those referred to as 2.5" exhausts are good to well over 400 bhp.
3" exhausts or those referred to as 3" exhausts are generally 2.75" in reality and they are good to well over 600 bhp and probably even more. You need a free flowing box and a relatively straight exhaust system but the actual diameter is not a problem.
06 January 2011, 12:14 AM
#33
It just seems a shame considering I want a true complete 3" system. I have no doubt that smallers systems can make the power, heck I'm only making 370odd bhp.
My main concern was the step down and to how it could affect the car's performance and even reliabilty due to it having been mapped on a completely 3" system.
This doubt seems to have been squashed now as many have stated it would be absolutely fine. It would really only be used for track days anyway, and then back on with the Nur Spec. So in due time I will most likely go for one of the above systems without any adverse affects hopefully!
My main concern was the step down and to how it could affect the car's performance and even reliabilty due to it having been mapped on a completely 3" system.
This doubt seems to have been squashed now as many have stated it would be absolutely fine. It would really only be used for track days anyway, and then back on with the Nur Spec. So in due time I will most likely go for one of the above systems without any adverse affects hopefully!
06 January 2011, 07:21 PM
#35
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Hi Guys,
Just want to help with the confusion.
Firstly all tube is measured normally by O/D ( Outside Dia ) and normally in inch's, i.e 2.5" , 3" and so on.
The wall thicknesses are normally 1.5 mm / 1.2 mm.
2.75" O/D pipework ( 70 mm O/D ) is different to 3" ( 76.6 mm O/D ) pipework.
Yes our Cobra exhaust is made in 3" bore... well the Trackday friendly version. we do do others in 2.5" bore.
And the crunch.....
Not sure if this is going to throw a spanner in the works for some people.... But one of the latest tests we've done on a 08 STI. the car was measured at 285 with standard exhaust ( Should have made 300 ) and with out digging the paper work out i remember that rolling road ( Calibrated ) results showed a 2 BHP gain from a 2.5" bore to 3" bore and that is only running at under 300 BHP ?? Sorry guys.... you can see this in action in our news section www.cobrasport.com
Any questions or queries please contact me on pete@exhaustsuk.com
Thanks for the heads up jag
Just want to help with the confusion.
Firstly all tube is measured normally by O/D ( Outside Dia ) and normally in inch's, i.e 2.5" , 3" and so on.
The wall thicknesses are normally 1.5 mm / 1.2 mm.
2.75" O/D pipework ( 70 mm O/D ) is different to 3" ( 76.6 mm O/D ) pipework.
Yes our Cobra exhaust is made in 3" bore... well the Trackday friendly version. we do do others in 2.5" bore.
And the crunch.....
Not sure if this is going to throw a spanner in the works for some people.... But one of the latest tests we've done on a 08 STI. the car was measured at 285 with standard exhaust ( Should have made 300 ) and with out digging the paper work out i remember that rolling road ( Calibrated ) results showed a 2 BHP gain from a 2.5" bore to 3" bore and that is only running at under 300 BHP ?? Sorry guys.... you can see this in action in our news section www.cobrasport.com
Any questions or queries please contact me on pete@exhaustsuk.com
Thanks for the heads up jag
07 January 2011, 10:57 AM
#41
Scooby Regular
Yes it is.
Depending where you live, you're more than welcome to come and have a look, hear what it sounds like etc
Actually had someone follow me into a car park recently to ask about the system as he said it sounded so good!
Depending where you live, you're more than welcome to come and have a look, hear what it sounds like etc
Actually had someone follow me into a car park recently to ask about the system as he said it sounded so good!
07 January 2011, 10:59 AM
#42
Scooby Regular
Just to add, the tail pipe looks really long in the photo on the ramps, but that's just because i used a very wide angle lens to take the shot.
ExhaustsUK will make the tail your specs, in this case, it was left a little longer to allow for any flames that may find their way out the back. Ahem.
ExhaustsUK will make the tail your specs, in this case, it was left a little longer to allow for any flames that may find their way out the back. Ahem.
07 January 2011, 11:26 AM
#45
The exhaust referred to above is on an 08 car with twin tail pipes. I cannot comment on that specifically as I have not done any serious work on one of these but the twin tailpipe design is for asthetic reasons and not performance. the actual exhaust design is wanting.
A well designed single tailpipe exhaust system for that car will probably show the greatest performance increase.
On both Classic and New Age cars I know from testing that changing from a 2.5" system to 2.75 or 3" system will not free up any power until somewhere beyond 422 bhp (from an actual exhaust swap and RR testing) and there is no appreciable change in back pressure between 2.75 system and 3" system at around 550 bhp. The design of the exhaust is far more important than the actual pipe diameter, certainly upto and beyond that level.
Personally I always want and advocate where financially convenient, a 3" full decat exhaust system to allow for project creep and maximum flexibility.
A well designed single tailpipe exhaust system for that car will probably show the greatest performance increase.
On both Classic and New Age cars I know from testing that changing from a 2.5" system to 2.75 or 3" system will not free up any power until somewhere beyond 422 bhp (from an actual exhaust swap and RR testing) and there is no appreciable change in back pressure between 2.75 system and 3" system at around 550 bhp. The design of the exhaust is far more important than the actual pipe diameter, certainly upto and beyond that level.
Personally I always want and advocate where financially convenient, a 3" full decat exhaust system to allow for project creep and maximum flexibility.
07 January 2011, 07:42 PM
#48
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Cheers Costa! Both above runs were v-power only at 1.7 bar (less than 600hp) with full weight of 1,455kg (excl. my weight!) and no launch control, so 11.1 is fairly credible.
http://s60.photobucket.com/albums/h2...t=IMG_0002.mp4
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