Xforce Exhaust Thread

[lozza]

It sounds too airy airy (like my old v6 bommodore with a 2.5" system did). Not liking it very much now from the inside, but I'm hoping (fingers crossed) that will change once I get it tuned and the AFR's adjusted. Its prob running a fair bit lean aswell at the moment because of the substantial air flow increase. I'll let you know once its tuned in a couple of weeks if your still interested. I would still have the standard one on now because of the risk of burning out the valves but I was involved in an accident in which the car was pushed over a pole and fuked the standard Y-section of factory exhaust. I decided to get the new system because it wasnt much more than a factory exhausr from fraud and I knew I would be needing the extra size soon enough.

Im not 100% sre about whether you need a tune with just cat-back? but for the full system it is highly recomended

[Covesy]

Hi Guys,

Speaking with xforce guys today they tell me if I go the 3.5" with external gate I wont need a tune but if I go the 4" I will.

The tune will eventually come but would be nice to be able to drive it to the tuners

What are the pros and cons for either 3.5" of 4" dump pipes

Can anyone please advise me on this

Thank heaps guys

[xrturbomatty]

Hi Guys,

Speaking with xforce guys today they tell me if I go the 3.5" with external gate I wont need a tune but if I go the 4" I will.

The tune will eventually come but would be nice to be able to drive it to the tuners

What are the pros and cons for either 3.5" of 4" dump pipes

Can anyone please advise me on this

Thank heaps guys

Hey mate you will need a tune with either one you use. It should be fine to drive to the tuner as long as you keep it off boost and as for pros and cons I think the 3.5 inch is a little more responsive down low that's just what ive heard. I have the 4 inch and its great and I think the 4 inch is bette for more top end power hope I helped a bet

cheers

[bjc]

Yeh as Matty says you'll need a tune and stay off boost if possible. If you haven't got even a generic tune you may find the car overboosts so will limp mode, only guessing this though.

I have the split dump with single 3.5in system. Not sure if they have changed there rear muffler on these systems like they have with the FG but the twin outlet they use is restrictive. For best flow try negotiating a straight through universal rear muffler in the kit.

[Covesy]

Thanks Guys,

I like the idea of boosting up a little earlier might go with the 3.5

but everyone has a diff oppinion of whats good speek to one guy and says go the 4" you can beat it speak to another and says go the 3.5" its better.

so who bloody knows

The xforce guy tells me that they are releasing mild steel down pipes next week I think I will get one of thoes they are only $360.00.

Thanks

[austcro]

If it were me, I would go with the 4 inch dump. To put it in perspective, the standard dump is 3 inches in diameter, gaining half an inch of diameter is not much of an improvement IMHO.

My 2 cents for what it's worth

[straughsberry]

For comparison, on the Pit Lane Mainline dyno I make 369 rwkw @ 17psi using factory crossover, factory hotside pipe, Nizpro I/C, ported turbo and the XForce 3.5 inch split dump to single 3.5 inch system.

[Covesy]

See there ya go 2 guys with diff opinions

I reccon the 3.5 split would have the same if not more volume than the 4 anyway

correct me if im wrong

[straughsberry]

I haven't got an opinion of the difference because I haven't had the chance to test both for comparison. But the general consensus is as stated. The 4 inch flows more up top but the split 3.5 inch spools a little earlier. There's also an argument for the split dump in that it joins the wastegate gases back into the exhaust flow in a more favourable position.

[mattyb]

I have a process west street plenum kit, and a 4 inch dump with twin 2.5. I run 360rwkw on 16psi. So I'm guessing it's really a much of a muchness. I'd put a big 5inch or bigger 100cpi cat..