[Timothy Richard]

ok I have a 98'gsx with a rsr 3' exhaust, and stock gutted cat. 16g/afc/greddy front mount/type-s/profec-b/and some other stuff just to make the list short.....well to make a long story short I just installed my new 3' down pipe with stock gutted cat, and 3' rsr. well it seems my car lost power and didnt gain anything but boost creep. it doesnt hit as hard when the boost comes on and it seems the higher I turn the boost doesnt matter. and not to say I'm insane and run like 20psi on stock fuel I can only hit 18psi before fuel cut which is fine I need more fuel anyway but my question is why with the stock down pipe and gutted cat and 3'rsr was the car pulling harder than it is now with the 3' down pipe? I also have a 3' testpipe I will be putting on sometime next week but it should still make more power or at least pull harder right?....any help would be appriciated......

 

[AluH20]

I don't know how big a stock 2G catalytic converter is, but if it's smaller than your downpipe and the pipe after that (intermediate pipe?) then that could* be a problem.

If you're bottlenecking the air into a hollowed out stock catalytic converter- the air collects inside and then is released out the larger exhaust pipe.

Personally, I'd have just threw on a 3" pipe w/ no cat and just ran the exhaust straight through so there is no blocking or disturbing a constant flow.

Maybe I'm wrong about this though (I never said my theory is correct- I've owned my DSM for a week and a day now so I still have to learn first hand).

It could also be O2 sensor related.

or

Maybe it's a tuning related issue?

See if anyone has other info because I'm not 100% sure but I'll still give my input.

 

[Timothy Richard]

3' downpipe

also when I installed my new dowmpipe there was no where to put the ground strap.....so I just left it hanging...could this be the problem?

 

[dsm1995gst]

Re-connect the ground strap and put on a 3" test pipe.

 

[DSMturbo2]

a gutteed cat is the worst thing to have on your exhaust (well im sure there is worse but thats pretty bad) get rid of that and get the test pipe

 

[Timothy Richard]

test pipe

thank you all for your response, and I will install the test pipe this weekend...one other thig is I talked to bushcur racing this morning and they told me they never hook the ground strap back up after a downpipe install...so my question is what does that ground do exactly....I'm still going to hook it back to the downpipe but I would like to know what it is for.....thanks again guys....sorry so long

 

[dsm1995gst]

Re: test pipe

...so my question is what does that ground do exactly....I'm still going to hook it back to the downpipe but I would like to know what it is for.....thanks again guys....sorry so long

Do a search and read up on it some. There has been a debate, some saying it causes poor gas mileage, others say it doesn't affect it.