I've heard you can buy a bell mouth 4" de-cat down pipe, i can't find one? Is this true and are they around the same as the 3" and would there be that much of a power gain between the 3" and the 4"??

Due to a little bundle of money for my soon to be delivered JDM STI, (Hopefully it won't go pop!! ) I want to buy a complete decat exhaust system before i get Rich from Powerstation to map the car.

My last STI had a nice Remus twin 4" exit pipes which i loved, but would settle for a 6" oval back box done by Magnex. obviously i need a de-cat mid section in 3".

Magnex of LK Performance tell me they will do me a complete 3" bell mouth de-cat system with the 6" oval exit pipe for £365. Are they any good?

Looks quite nice.

I'd settle with a second hand exhaust, down pipe or mid section if anyone has one thats any good?

Any thoughts on the best all round system, and no that doesn't mean you Pete

 

I don't think you will get any gains from going for a 4" system – in fact you probably lose drivability.

I use a 3" straight milltek on mine which works very well.

 

Nice Scooby!

How much would the whole Milltek system cost and do they do different exit pipes. I get bored of seeing 5" bean cans

 

I have found Magnex to be well made and fit well and are normally good value for money IMHO

I have a MilteK system on My T20 and is probably a better but more expensive

As Pippypips says better to have either a 2.5" of 3" no gains on a 4" IMHO

Sorry not very technical but 2.5" better Torque reponsive engine and 3" better Reving reponsive engine IIRC

Tony

 

I read a white paper not so long ago about increasing the size of the exhaust and what effect it has on N/A and FI cars. It basically stated that you need a certain amount of back pressure in order to help cylinder scavenging. If you go overboard with the diameter size it can have an adverse effect on engine performance.

 

So in principle a complete de-ct front to back 3" magnex with a 6" Oval will be just the job then.!!

Anyone know anytwhere who will do a better price than £365?

I've go to have one now!!