Hey there guys, just had my car tuned by RDP and unfortuantly didnt make as much poswer as what I though it would. On my last tune by them it made 362 RWHP with the standard exhaust, since then I bought and had installed an xforce 4inch dump into 3 1/2 inch cat into twin 2 1/2 inch rears. This exhaust should flow easily up to 350 RWKW yeah??. The final result even after spending an extra hr on the dyno trying to squeeze more out of her was 386.9 RWHP. Lee told me that most BA's that have simalar mods tend to make over 400 overboosting and have to be pulled back from their to be safe and seems to think that everything is pointing towards a blockage in my new exhaust (which was bought second hand) and went on to say that it is very quite compared to others he'd heard. I happy with the way the car runs but think it should be making more. Might take it back to the exhaust place and get them to check out the system for blockages. Hers my mods list so anyways.

Full xforce exhaust 4inch dump into twin 2 1/2

Bosh 42lbs injectors.

Monza cooler.

Rapids under battery pipe.

K/N filter

atomic valve springs

flash 2

walbro pump

made 386.9 Rwhp.

I have the quiet twin 2.5" catback and it flows ok. possible blocked/loose cat?

While I am no expert, Is a 4" dump worthwhile on a mild engine such as this? The standard dump seems to do OK except if chasing big numbers with big add ons. Monza cooler may not be helping either.

Get the cat checked out as said.

How much boost to get this power?

Lee does know his stuff. Blocked/stuffed cat would my guess

Edited 22/12/11 06:48 PM22/12/11 06:48 PM by Gasman

IMO a 4" dump may not be completely necessary but that's not to say it's not a decent thing to have.. Do it once, Do it right..

Also is the old xforce 2.5" twin pipe system that one that reduced the pipe diameter through the mufflers? Didn't they redesign the rear muffler or something to stop the restriction?

I thought that was the 3.5" system?

Even with the exhaust fixed (if its the problem) not sure how much more the cooler will be capable of.

Yer johno 4inch prob is a bit of overkill but I had the chance to pick up a cheap system so I grabbed it. Not sure on the boost it was 10psi and that made 362 rwhp, lee said they tried to up the boost but it wouldnt make anymore power. Lee does know his stuff I am sure of that just spewing bout this little problem want to get it sorted asap. cheers

I thought that was the 3.5" system?

Even with the exhaust fixed (if its the problem) not sure how much more the cooler will be capable of.

So did I, where it goes from 3.5 to twins in the rear muffler was meant to be where the restriction happened wasn't it?

Mick/ratter knows bout the restrictive exhaust, but yeah what Dillz said sounds about right.

kill the cat and get a better cooler.