I need a new exhaust mine was used when I got it and it's done sounds like the baffles or whatever is in there have crumbled or something.


Anyone know if I can run 2.5 " with the RRM setup ?

 

Turbo will sound nice non turbo will be loud and annoying.....that just my experience making custom systems

 

I'm concerned with it being too much flow might cause overboost.

 

Dont think that wil be an issue if you are running the RRM turbo. If I remember it is 6psi?

I am running 8 psi with a 2.5 exhaust and I am ok.

 

If your still running the same base psi on the rrm kit you should be fine with a 2.25 inch exhaust. 2.5 would be necessary if you have since turned up the boost and are running close to or over 300whp. Rob from rrm told me 2.5 inch exhausts tend to be too unresrticted with their kit resulting in unwanted overboost. Thats the reason why the magnaflow exhaust they sell is 2.25 inch. RRM knows best so I think you should ask them.

 

I have a 2.5 inch exhaust on my car. When i had the RRM kit STOCK kit, (which was the 7psi stock tune), it would boost up to 7psi, maintain for a small bit, than it was a gradual boost spike (or boost climb, if you will) to 8psi. nothing major. Than when I got it tuned for more boost, and I bought a boost controller from RRM, the car stayed at whatever PSI it was tuned to. No spike after I bought the boost controller.

Now as mentioned above, 2.25 inches should be fine for NA or small boost (7psi) but if you want high boost than you can get 2.5 inch. You would sacrifice back pressure, and loose a little low end power and tourque, but once you up the boost, you will see more power in high RPMs. So its preference really.

But to answer your question, will the larger exhaust give you boost spike. yes, but such a small amount it wont blow your motor up.

 

^^^ Oh and it sounds awesome with the 2.5 inch. check out my youtube vids. I like the way it sounds. its not raspy at all.

 

Hi, I've got a 3'' cut out situated underneath the passenger seat and you can take much advantage of that because when you want to give a pass to the car, you just have to touch a button for 5 seconds and that opens the cut out. When you are in a "normal mood" jejeje you just need to close the cut and the cops don't notice THATS IMPORTANT!

Ahhh!! and remeber that when the car has a bigger exhast, at high boost the engine runs more cooler and efficiently(the turbine likes that) but it has a negative feed because it leans the fuel set up and you need to give the engine more fuel.

With the stock ecu and at 8psi (with cut out) the car gave me 293whp.

Good Luck

 

Turbo kits in general you have to remember that PSI does not equal power and it does not equate to airflow. Since the RRM kit is doing MAF translation I would guess it may not be OK to just increase the VE of the system.

The better the delta pressure (less backpressure) on the turbine the easier it is to compress the air. This means lower backpressure on the manifold side and more efficient flow. More horsepower needs more fuel.

The turbo remap converts the system over with a larger MAP sensor to provide boost cut and I haven't been able to test how well it handles different sized turbos. Since it's using a hybrid between direct measurement (MAF) and speed density (MAP) it's tough but it was done that way to see if I can vent the BOV to atmosphere.

If you bias the MAF sensor enough then you will be directly measuring the increase in airflow and the system will be able to automatically compensate. Knowing the electronics of the system this strategy is not really possible with a piggyback.

-Michael