ajrothm

We put 2" headers on 650-700hp NA engines and gain power on engine dynos.

2" headers will be fine at 1000 rwhp... I think the restriction is further down the line on C5s.

I have the 3" XS power cat back, I added cut outs right before the mufflers, I haven't track tested them yet.. But the main issue with all of these 3" x pipe/3" cat back systems is that the x pipe "necks down" to 2.5" at the flange, before the catback ...That's the first restriction.. The next restriction is the mufflers neck down inside of them (the transverse C5 style muffs anyway) to 2"...Even the 3" XSP mufflers neck down to 2" inside. That is a major restriction... How much it translates into on the slip, I don't know... Ultimately, that is all that matters. Sometimes what we "think" is a restriction, may not equal power gains..

I know we just swapped headers on my friend's 420" SBC, went from 1 3/4" to 1 7/8" stepped to 2". The rest of the system is the same 3" mandrel bent into a 3.5" exhaust plenum(big box, no H or x pipe) then 3" into Magnaflow race ovals the car had before. Car went from 136 mph to 137.5 mph in 50' worse DA.. This was on a 640 crank hp engine in a 3200lb raceweight.

Point being is, there is power to be had in exhaust tuning.. Most vette guys don't put the effort into this though.

digivex

Before going to turn-downs under the car, I was using a set of 3" catbacks / exhaust

These came from ECS to provide a non-restrictive flow with a full 3" all the way to the rear. They fit my '03 C5 fine but required that trunk floor be modified / flat for it to exit similar to C6 exhaust

I'm no longer using them and think I may have left them at 4DRUSH place when we were rebuilding the car this past year. I posted up a while back that I would entertain any reasonable offer + shipping if someone was interested in giving them a try.

Some Photos:

http://i1176.photobucket.com/albums/...ps02982351.jpg

http://i1176.photobucket.com/albums/...ps4e04259e.jpg

Back of car shot... exhaust exit:
http://i1176.photobucket.com/albums/...ps114a4371.jpg


Here's a video of them in use when we ran the car in True Street at Bowling Green during 9/13..

robert miller

Dave don't think these will fit under his car from him having the c6 cradle under his car. I think I ask you back then and you had the c5 cradle under your car. But these can be cut and about a 2 inch be added to just over the hump and they will work then. This is a great set up.

o1Z0sick

I started with the borla stingers but they were on the original cam head 346 and still loud, fun but too loud. Next on a 416 i went with the XS 3" or 3" over the axle necking waaay down in the muffler as AJ said. Wish i would have know this as i wouldn't have bought them. They were loud and really sounded like corsa extremes and with little resonance. Now i have the lg big and its just the right amount of everything for me. I cant find any videos that give the true sound of these mufflers. But if you want to cut the tub and use C6 systems (c6 cans comparable in weight to the lg 3"), there is someone on here that did it with good results. I may have done that but that is where my lingenfelter battery relocation is.

So now I'm modifying the lg 3" to fit a new 2012 z06 diff and MH3 tr6060. I had to add 3" over the axle on the driver side, not sure about the pass side yet but it will probably be the same. I am taking the time to get it aligned perfectly and going to change those spring hangers to something that is more secure.

Here are some pics:



Pass side tack welded

Driver side in, still need to tack mid pipe flange and modify hangers to keep it here.

redcycle13

That looks good so far. I seems like there is plenty of room in that area, but I guess it gets used up quickly after the larger diff Is installed. I would like to quiet this car down some from the stingers, but I don't want to cut off its *****, then have to listen to the blower howling away. It needs to be a wonderful balance of noise between exhaust and blower.

slow ride

Not a lot of wiggle room in a C5 with C6Z+ guts. I have a big 3 and kept the factory coolers, now that was a pain.

LedfootLarry

see if you might like this:
https://www.corvetteforum.com/forums...my-c5-z06.html

o1Z0sick

That's my next step, do you have pics of the cooler and exhaust clearance?

Turbo-Geist

Did you re-clock the rear cover on the differential? Any information on the fittings you are using in the picture and how you are planning to plumb for the trans and diff coolers?

slow ride

I had to cut and mod the upper oil discharge pipe out of the diff pump and make it turn 90 HARD right out of the pump outlet to not hit the tub. Also had to move the drivers side 3" exhaust pipe up and over to clear the fixed diff cooler. You can see my small trans cooler that came with the parts I bought, it works for now, but might go bigger some time. My big 3 was already tig welded from my NA setup so it really sucked cutting it all up to make these changes. As you know a little change up front throws off the back big time. I sort of wish I would have sold the exhaust with my headers as I could have probably built my own exhaust using c6z parts and aftermarket mufflers, etc for less cash.

redcycle13

I've seen that before. Its an option, but Id rather not cut the floor out, since I use it for a subwoofer. I do like the idea of being able to use stock C6 Z06 mufflers.

o1Z0sick

Diff and trans coolers will be two 12" long 2 pass tube and fin like slow rides pic. Using 2 and the diff will be just behind the diff cover on the cradle and trans cooler either under the trans or in the space where the transverse spring is because I have coil-overs.

All fittings and hoses will be -6AN either braided or push on barbed, will see what I have the most of. The OEM cooler fitting threads in the diff and trans use 9/16-18 straight thread o-rings.

I did rotate the diff cover 90* clockwise. The are two alignment dowels in the top left and bottom left and the cover holes are slightly larger there. So you can either not use the alignment dowels or drill out the two bolt holes in the cover.

Turbo-Geist

Thanks for the info. Did you remove the dowels? Any idea why the factory had the arrangement vertical vs horizontal?

o1Z0sick

Kept the dowels and enlarged the two holes in the cover. No idea why it was done that way. Maybe fit better with the C6 config.

Seeing your in Houston, you can come check it out if you want.

Turbo-Geist

May have to take you up on the offer this weekend.