5.3 plus a magnum t-70 in a 87 IROC

[1999Black_Z28]

I'm on the west side but my inlaws live over by the airport (76th / Thornapple)...good chance I will be in that area this weekend

Post turbo I would run as big exhaust as possible to cut down on the restriction. I know you said you want it quiet so maybe you could run 3" out of the turbo to behind the k-memeber then step it up to 4" for the remainder. There's a guy on tech that picked up 50hp on the dyno (within minutes of the first run) by hacking off his straight thru 3" turbo muffler. This was a 4.8 turbo in a ford fairmont. Point being that restriction after the turbo is bad. I don't mind my car being a little noisy so I dumped my 3" DP right after the k-member and honestly it's not as loud as I expected...

[Speedfreak391]

I am also debating on what size exhaust I should run. I have both 3" and 4" tubing to make my ex system with. I just don't know what I should run. The exhaust out of the turbo is a 3" v-band. What do you think I should run?

[Speedfreak391]

Im by the airport. Where are you?

[1999Black_Z28]

10 and 2 is just a recommended guideline but I'm pretty sure that even GM doesn't always follow that rule . Where in GR are you located? I have some old narrow bands that I found the other day that you can have if you want. I ran them with leaded race gas once or twice so I don't know how well they work but they would at least be good for mock up.

[Speedfreak391]

10 and 2 huh? I was gonna put them in at 6 o'clock hanging straight down, since I don't want any hood clearance issues. Looks like I need to go get a couple of narrow O2's for fitment. I do have my wide-band already, but that will go in just after the turbo. Like 6" down stream.

[1999Black_Z28]

Looks good! You could put the narrow bands just about anywhere...even in the header collector if you wanted. I would keep them away from the gate though if possible to keep tham as accurate as possible. You should also mount them in the pipe between the 10 o'clock and 2 o'clock position to keep moisture (condensation) from settling on the sensor.

I have my wideband in the DP not too far from the turbo

[Speedfreak391]

Well, here is the almost finished product. As mentioned above I do need to figure out the wast gate location and pluming. I also have to figure out where I will be putting the O2 sensors. I just don't know how far from the headers they need to be.

[DETROITMUSCLE]

I would highly recommend merging two small pipes off of the exsisting ones just as you did with the flange, putting a 90 degree angle off the current merge is not the proper way to do it and its possible the w/g won't function properly.

[Gregs_gsxr]

Sounds like your moving along, keep it up

[Speedfreak391]

Ah, good question! I might have a runner come off each down pipe and merge them together for the wastegate, or I might just take one tube and run it down from just above the flange, so I don't have to build another merge pipe for the WG.
Update, I did salvage my tubing and it has been re-fitted and a new flange has been welded up. By me. No help is good sometimes.
Last night after I got done with the welding I had to do, I dug into pulling the interior out so I could clean the carpet in the car. Well, come to find out there must have been a couple mice living in my car many many moons ago. they had a nice little home under the drives side back seat. That was kind of gross, but its all cleaned up now! I was going to bring in my new seats and install them tonight, but It was raining this morning. So I will look at where the w/g will be placed tonight.

[DETROITMUSCLE]

where are you mounting the w/g?

[Gregs_gsxr]

How is it going Andy any progress made on the cold side? Hopefully you havent hit any bumps in the road

[Speedfreak391]

+2 for inline tube - love that place. And they're local here in Michigan.

Looks great so far! It's amazing to see all those cut pieces put together like a puzzle and form an exhaust!

I am going to do that with the exhaust from the turbo also. It will start at 3" from the turbo and I will run that out past the starter, then flare it to 4" back to the muffler. Yes I want it to be quiet.

[meissen]

+2 for inline tube - love that place. And they're local here in Michigan.

Looks great so far! It's amazing to see all those cut pieces put together like a puzzle and form an exhaust!

[TylerT/AZ28]

i live no more than 20 minutes from them and they had my parts specially bent within a day