Exhaust bore size problem?

[F355GTS]

So I've bought a really nice ex R500 BTB exhaust which has a 4 - 1 collector that takes 1 3/4" primaries and uses a 2 1/2 " Pipe from collector to box.

 

My SLR has 4 -2 -1 with 1 1/2" primaries and a 2 1/4 pipe to box.

 

Whats the best way to get it to fit

 

1) Squash the BTB 2 1/2" pipe to fit the 2 1/4" tube

 

2) Buy new primaries with a 1 3/4" bore?

 

3) Find somebody that will do a step up between my 4 -2- 1 2 1/4 outlet collector and the 2 1/2" pipe on the BTB box

 

Important factors are in order

 

Noise (quietness for trackdays)

Performance (nearly as important!)

Looks

 

 

thanks

 

Mark

[STEVE GILBERT]

Get the 21/4 cut off the collector and TIG on a 2 1/2. Powerspeed did mine recently, no problem and little money

[murph7355]

Was a bit confused for a minuute but guess you're looking at either retaining the 4-2-1 config but using the BTB box, or going 4-1 just retaining the SLR system headers?

 

I can't remember which way round it is, but I'm sure one of these configs is better for torque and one for power, but that there isn't much in it. I know from experience that 4-2-1 works well on an SLR-esque engine, but haven't tries it with anything else.

 

I suspect the cheaper option will be to stay 4-2-1.

 

On the noise front IIRC you've got an ex race SLR? I very much doubt you'd have had any problems noise wise with a std SLR system, as long as it wasn't shot. If you had any hassles it'd be more likely to come from the induction side.

 

Andy

PS I think you may have got the exhaust I was looking at buying you bugger

[F355GTS]

Steve

 

you have mail

 

Andy

 

If the std exhaust is OK on noise test next weekend at Bruntingthorpe and Llandow I'll consider selling it so will drop you a mail

 

 

thanks

 

Mark

[murph7355]

Cheers Mark.

 

May well not be necessary now but drop me a mail to let me know how you get on anyway.