ExceSSive

iTrader: (13)

I am researching a 4" mufflex cat (catless) back exhaust for my car. I am wanting to do something similar...I want the 4" to go to the axle and then split to dual 3" pipes though to a couple of small mufflers like the SLP PowerFlo exhaust.

Haans249

iTrader: (24)

That is one of the options that I'm considering, but I would run two 3" magnaflow race mufflers.

I do on the other hand have two of the 3" intermediate pipes from SLP that sit perfectly side by side to run to the back for dual exhaust. All I need is the x-pipe to replace my ARH Y, two 3" magnaflow race mufflers, and 3" stainless tubing to run from the axle back, I already have the tips.

ExceSSive

iTrader: (13)

Definitely post up some pics when you get it together...I looked at those SLP pipes they had on clearance and was not sure how I could use them to make my own exhaust...if Mufflex can do it I will pay the extra money for them to do it.

1bdbrd

iTrader: (12)

For your exhaust I would suggest replacing the merge on your existing y pipe with a flowmaster merge, then exiting into a 4 inch cutout. After the cutout, neck it down to 3 inch to whatever muffler you want. All in all, the setup wouldn't be terribly expensive and could still be pretty quiet.

I am doing a similar setup on my car (using a 3" cutout instead of a 4) and I am expecting it to handle whatever power can be made on the street.

03supercobra

iTrader: (38)

This is the same setup i have. 3inch to a 4inch merge, then cutout, then back down to 3 inch for my SLP Dual Dual. I have pictures if anyone needs them.

Haans249

iTrader: (24)

That is exactly what I have right now, my Y-pipe merges to 4", then down to the 3" cat-back. The headers/Y came off a car that had 4" exhaust prior to mine. I just want a complete new system because everything from the 4" back is old, rusting, and a piece of crap haha.

ExceSSive

iTrader: (13)

Post them pics...

03supercobra

iTrader: (38)

Here yah go...

John02SS

iTrader: (47)

Kinda how mine is. I have the ARH Y pipe with a 4 inch outlet merge collecter with a 4 inch electric cutout. After that it goes back to a B&B catback and is nice and quiet cruising. On my old 347 combo that made 500 rwhp the B&B eat 16 rwhp, so I'm sure on the 427 it is at least 25 rwhp but it is a switch away from being open cutout.

Haans249

iTrader: (24)

Only problem with doing that for me, is I'd have to upload a new tune whenever I open the cutout. You can't run and additional 40-50rwhp without adding more fuel. Otherwise, that is a great idea. Opening the 2.5" cutout gained me 38rwhp...opening a 4" would probably be closer to 50rwhp. Now, if I were to upgrade to a Corsa, how much power do you think that'll hold back? It is pretty loud too...

ExceSSive

iTrader: (13)

I hope to pick up a little bit of power when I add the 4" exhaust to mine...

VIPERKLR

iTrader: (11)

yeah u need some 3" true dualls

1bdbrd

iTrader: (12)

Why not tune with the cutout open and just take the mildly rich condition it would make with it closed? I'm no tuner by any means but I would assume it wouldn't be a huge issue, especially at part throttle.

Haans249

iTrader: (24)

I have tried that, and it gets wayyyy too rich. Its really amazing how big of a difference it makes. Plus, i'm very particular with my tune and it would drive me nuts to be driving around very rich (~12.5) at part throttle and idle.

1bdbrd

iTrader: (12)

Wow, didn't think it would make that big of a difference on an all motor setup. Interesting!

ExceSSive

iTrader: (13)

If you had HPtuners or some other software you could keep 2 files...one for each cutout open/closed

That is my plan for my nitrous tune...just load the nitrous tune before I run. Just a thought...I know a pricey one.

Haans249

iTrader: (24)

I do all of my own tuning, and its too much of a PITA to lug my computer around in case I need to upload the "cutout open" tune. It would be lame if I were at a light, and had to say to the other guy, wait, I have to pull over so I can take 5 mins to upload a different tune....hold on.

I would rather just get the dual's out the back, lose 10 rwhp compared to running an open exhaust, and not mess with the tune.

Haans249

iTrader: (24)

Another little update:

I decided to have a 3" cutout installed. Got it done yesterday, and took it to the dyno today.

553rwhp 511ftlbs so I gained +29rwhp +33ftlbs AFR 12.9 28* timing.

So, for those that thought my cam wasn't quite right (Predator-Z)...well its just fine =D It makes 360rwtrq at 2K rpms. I will post up the dyno sheet here soon.

I also tested the Volant CAI. Took it off and lost 7rwhp, so I thought that was rather interesting. Guess my intake manifold is the restriction at this point since my MAP readings are still dropping to 95kpa.

Here is the run: Enjoy.

http://www.youtube.com/watch?v=DdXHd_Huypg

kumar75150

Ross' dyno is also very stingy. 550 is a good number

ExceSSive

iTrader: (13)

I'm talking about the track...I would never try to upload a new tune driving down the street. It definitely would not be worth it for a spur of the moment street light to street light race...