NTIMD8

iTrader: (1)

Hey guys, is a tune or any other supporting mods like a ported Wastegate needed with the following....

3" downpipe...
3" midpipe with a highflow 3" cat
3" catback

I plan to keep the air intake stock (maybe drop in a K&N filter).

I know with a midpipe with no cat and the other mods listed you will need a tune and to do something about boost creep but don't know if having a high flow cat changes anything.

Thanks, J

VegasFD

Whenever you open up the exhaust, especially with a midpipe, you run the risk of boost creep. That's why you port the wastegate. However, if you get a boost controller and keep the boost at 10 psi, you wouldn't need an ECU upgrade. But it always recommended to upgrade the ECU to keep things safe.

HardHitter

iTrader: (4)

I have full exhaust with PFC and a stock wastegate. My boost controller is set at all stock. I first did some runs with the controller off to see what kind of boost I would get, would hold 7psi which is what it's supposed to do. Turned the controller on and didn't adjust anything, did a run, help 10psi. Did a few more runs, was around 9.8-10psi on a very cold night. I am already risking it without porting the wastegate, so I just leave the controller on the stock settings with stock pfc map and the max boost I've hit is 10.4psi, but I also have all other bolt ons so that may affect your results. As vegas said, I would suggest looking into a PFC to be safe and makes the car run that much better. Look into a controller too if you don't have one.

It is still a risk with all of this, so do it on your own risk.

jeff p

the stock ecu at 10 psi will be fine with the mods you have. the stock airbox should add enough restriction in flow to keed you from spiking over 10 psi. but if you do go a little over change out the w/g pill to bring it back to 10 psi. the proven rule is 10 psi max for all bolt on parts with stock ecu. check out my sig below. 2 years now still running strong.

Jeff

rynberg

You'll probably need a boost controller (manual or electronic) with that exhaust to maintain 10 psi. You do not need an aftermarket ecu or to port the wastegate.

NTIMD8

iTrader: (1)

Thanks for the tips guys! I will make sure to get a boost controller and keep an eye on the boost. Nice to have guys on the forum who can share their knowledge of these cars.

dgeesaman

iTrader: (7)

Just one note: one person says you could have boost creep, one says no.

If you want more detail about that isse, the truth is that very few people get boost creep with a high flow cat. But if it happens, it shouldn't be severe - just watch your boost on a good cold day and if it holds rock steady, you can leave the wastegate alone.

Dave

NTIMD8

iTrader: (1)

Thanks man. I have a wide band O2 so I will keep an eye on that as well as the boost gauge.

ANyone have any guesses as to what kind of gains one would see with the above mods in terms of 1/4 mile and trap speed? 0.5 seconds and 4 mph?

revsteve

iTrader: (6)

back from the dead....

I just installed an HFC and spiked to 14 PSI before letting off when I saw it (I was doing a boost test as I just installed a boost gauge as well).

Im guessing I need a boost controller and/or need to reinstall the stock cat if i dont want to go that route.

Correct?

dgeesaman

iTrader: (7)

Yep.

I have just enough flow mods to push above stock levels. I installed a couple of JoeP manual boost controllers and now my boost is well regulated at 10psi and a better transition than before. Make sure to install with caps on the other end of the wg and pc actuators.

Dave

revsteve

iTrader: (6)

Thnks Dave -

I'd rather remove the HFC than put in a boost controller (this car was meant to be "stock"