for my ls1/t56 after the ypipe i want to merge into a 4" cutout, my headers are hawks with 3" collectors, will a 4" qtp electric cutout fit?

 

anyone??

 

I would use the same size cutout as your exhaust system. The McCord brand cutout seems to be a bit better quality, and cheaper, then QTP.

 

the collectors on the headers are 3" though...3"+3"=6" seems like i would want as big of a cutout as possible, because its at the start of my exhaust system. 6" of pipe cramming into 3" sounds restrictive for the power im looking at making.

ill check out the mc cord cutout though qtp is expensive.

 

I see that your collectors are 3". What I am saying is, I would get a cutout the same size as the exhaust pipe where you are installing it. Are you running a y pipe, or duals? After the collectors, are you running a 4" exhaust? If so, get a 4" cutout. If your running a 3" exhuast, then run a 3" cutout, ect, ect. No reason of using a 4" cutout if the exhaust pipe is 3". You could also get two cutouts if needed

 

im running single 3" exhaust, but if i have a cutout thats 4" where the two 3" ypipes are going to connect, it will be like having a 4" exhaust when its open. then when its closed it will go from the 4" spot to the 3" exhaust system

 

the best way to do it is just stick with a 3 inch cutout. It won't work well with a 4 inch cutout. What kind of power are you going to make. I am making 470 horse with a 3 inch catback along with a 3 inch cutout and works great for me

 

That makes no sense, a 3" cutout is perfect for you.

 

4in wont be to big for lsx motor should be ok i seen couple of people with them on there 4th gen's.

 

A 4" will be pointless if there is any 3" pipe before it.. If his 3" collectors go into a 4" y pipe, then, a 4" cutout will be fine.

 

there wouldnt be a 3" pipe before it, the 2, 3" ypipes would merge into one 4" pipe, with a cutout, then would taper down to a 3" so when the cutout is closed it would be a 3" system, when its open it would be 4" because the 4" would be at the...heres what ill do, ill draw a picture.

you cant expect a single 3" pipe to be free flowing for 500hp

 

i you make a 3 inch cutout, most of the exhaust will go out the cut out, the rest will go out the exhaust. It will flow more than enough for you.

 

http://www.ls1tech.com/forums/genera...heads-cam.html

here is what im talking about

 

That guy on LS1 obviously knows what he's talking about. So Firechicken76, no a 4" cutout is not too big.
Im putting a dynomax stainless 3" cutout right after the y, then 3" stainless to fill the void between cutout and cat back.

 

If the part of the pipe I circled is 4" in your setup, then your good to go. But if you do it like that, I would just stick with the cheaper 3".

 

yea he does, thats patrick G, he will custom grind you a cam for any application.