I would never have thought you guys would get your cars that light. So, there’s hope for me! lol

 

Late to the party, here, but I'm just wondering why anyone does this? The IRS setup has been into the 8 second bracket, and IIRC, Mark Carlyle has been into the 7s, maybe high 6s, with his C6, so the 'beef' is there.

 

Cheaper. Stronger. Lighter. More gear options. Easier to set up for differences in track conditions. More wheel options.

And, most of all, because it’s our cars and we can do what we want to them…

 

Running IRS cars at the 9,8,7,6 second levels takes increasingly long pockets, some guys do it but the maintenance is tiring and expensive. Mark had lots of help and spent a small fortune getting his C6 to those levels and rebuilt it many times. The rear trans options for the vette that hold any power are pretty pricy on their own and even those don't last all that long. I've been down that road and it gets old breaking the car every single time it goes out, even with all the fancy aftermarket parts. So the "beef" you see on one pass is very short lived. Last time I took my car out with the IRS I broke the entire drivetrain, and that was just after replacing it all from the last breakage. Its frustrating when you get two passes out of some $15k in parts.



Absolutely agree! If my car was still IRS it would no longer be mine.

 

Amazing build and i absolutely love it...but what she run?? i see pics at the strip so i know she been down!!

 

Thanks for elaborating. I shouldve known it was about money. What surprised me was the fact the IRS can't be built to hold together long at huge power levels.....

 

Finally got around to giving the front end some love. Swapped in longer 200lb springs and worked on dropping weight. Dropped about 100lbs between the Strange 4 piston drag brakes and two piece rotors, deleting headlights (used replacement lenses painted black to fill the holes), and fabbed up a .083 wall 1.25" chromoly tube front end, fender/bumper supports are .065 wall 3/4" chromoly tubing.

Front end bolts on like stock with the OEM fender/bumper brackets, bumper sits on the two nubs sticking out for extra support below the grill. LED lights shine through the lower grill and are way brighter than stock!

 

Is yours a Z06 or base model?

 

Just a base with wide body, makes welding to the frame much easier. I need to weigh it again soon, should be well into the 2,3xx lb range now. I also swapped to lighter turbos so probably 10lbs savings or so there as well. Debating if I can get it down to 2,1xx or so over the winter it might be worth going NA or do something silly like a K swap Ditching the twins would be like 40lbs, pretty sure a chromoly cage would save 50lbs or so, do a lexan rear window, and redo my back half in chromoly, it might be close.

 

 

Oh okay, i was tripping out there. Some reason i thought I had seen you say it was a Z, somewhere. That's nuts. I can't imagine a 700-800whp NA setup in that thing at 21-2200lbs.

 

It just looks like one, has OEM Z body panels so most people just assume it is. After seeing the hassle many go thru to get a cage and frame mods done on an aluminum car I'm glad I have this one, can easily make up the difference in frame materials elsewhere.

This engine has been together for awhile now, might be worth going thru it to give it a little bore and stroke increase either way.

 

My guess on weight savings turned out to be pretty close. Car came in at 2,383 lbs with R888 street tires. Bolted on my front runners and dropped to 2,352 lbs. Then put my slicks on and final weight with full tank of fuel, skinnies and slicks is 2,324 lbs!

That gives me hope it’ll be about 2,280 lbs with a half tank. Looks like a goal of 2,1xx without the turbos is a real possibility! Weight distribution isn’t too bad either.

 

Header build: Purchased 304 stainless from Stainless Headers MFG/Experimental Aircraft Exhaust INC.
One thing to note on flanges (some prolly know this) not all flanges are created equal (hell, not all stainless is created equal). When they are laser cut they are very raw. Some companies will sell them straight off the laser others will clean them up 1st. Mine where ready to install. I did have to shave a little off the bottom (around spark plugs) to give the boot protectors some room (dip stick mount also needed some attention cause the flange covered half the mounting hole). The flanges are 3/8 thick with 2" primaries. I didn't take any pics of all the stainless as is was all individually wrapped so I took a pic of a few pieces as I was using it.

I ordered a kit which included: 2 Flanges 2" round Port, 12 2" Mandrel Bent J Bends, 2 Merge Collectors (2" Primary 3" Merge 3 1/2" transitional Exit), 2 O2 sensor bungs, 4 Pack collector tabs, Purge Caps, and Tig filler rod 1/8lbs each of 0.045 and 1/16, 2 3/12" VBands

I took one of the JBends and traced it out on cardboard for a pattern. Then marked out 90* 45* 22* angles on the J. I wanted to stay as close as possible to these angles to keep it unified and somewhat symmetrical (no weird angles was my thinking). Plus the card board pattern made it easy to draw the cut line and keep the pipe at a 2" circumference. It worked for 85% of the project.

One of the reasons I went down this road is I had quotes for custom headers from $4300 - $6000 and 8-10 weeks of my car sitting in somebody else garage. Thats not me. I do 99.9% of the work on this car and I didn't have 8-10 weeks. The total bill for all the stainless was $1400. So I was either going to have a $1400 pile of cutup stainless or two headers..


Every piece was cut and ground flat on the end so there was absolutely no gap between joints. This allowed not using a filler rod 90 % of the time and fusing the pieces together with a pulse setting on the Miller. If I had a rotisserie the weld would have been prettier. But you can see where I had to stop turn the pipe and start again.




I started on the passenger side as i knew it would be the most complicated as I had to go around the starter. But I did pick the easiest hole after getting and idea of how they would all lay out and some simple mock ups. I also spot welded the 1st one. But looked for a different method as spot welding took more hands then I had. The new method was blue tape. I found that if I wrapped the blue tape tight it would hold all the pieces together (I was trying to make each leg with as few pieces as possible, 3 was my goal). I cut slits in the tape when I was ready to weld and spot welded each side (180* out) and then peeled the rest of the tape off and continued welding. Worked like a charm.

Also found that I could wrap each end and cram it in the flange and it would hold the weight..

Passenger side mock complete

The only thing I had to worry about on the driver side was clearing the steering shaft. But it was just a complicated as the passenger.

Passenger side

Well I thought I had the passenger and driver side ... but this looks like the passenger again..

Yeah baby ... your underside looks so sexy and pretty..

All taped and and final mockup. Believe it or not, they are not the lowest part of the car... My initial thought had them coming out in front of the wheels. But when I laid some Jbends in place it was just too much stainless and would generate too much heat in the bay for me.

Here is a pic of the merge collectors. The headers is the 1 7/8 Kooks I was running vs the new race collector...

Polishing them up on a bench grinder with a fine wire wheel, individually before final Assembly. I could have mirror finished them but I just wanted to matte them cause I knew they would turn after a few runs.. besides I hate polishing ...

More polishing lots of polishing....

I'll post up more on making the exhaust pipes.

 

Thats awesome! Thank you for the details! Do you think they would clear a stock subframe or does the TRZ clear up a good bit of room in that area?

 

Thanks again S'man.

I can't give a good answer to your question as I've had the TRZ for about a year and half now and really can't remember or picture where the stock cradle ends back where I have them merged on both sides. I would think though it would be tight especially the front cylinders (1,2) on each bank. I struggled a bit with those runners cause the were basically straight and turn hard into the merge. I have them snug around the TRZ and under the OEM frame rail. I think that would be the only place where there could be an issue. I have them pretty tight in all places but I did keep in mind, that I didn't want to hear them vibrating or rubbing against anything. I run solid mtr mounts so I didn't think they would when the mtr was running and loping on the cam at idle. Of course (not to me) the car is loud so I prolly couldn't hear it if it was.. but they don't appear to be!

 

Thanks! I could always notch the frame rail if needed, a lot has been cut already. I run a motor plate so mounts aren't in the way on my setup perhaps making it a little easier.

 

Ya, for sure! I forgot you run a mtr plate. While I laid cyc's 1&2 primaries between the mount and the TRZ, the mount being gone along with the pedestal would open up lots of room. I don't think you would have to notch the OEM frame maybe the back of the cradle just a tad. I'm still going to throw up some pics of the exhaust pipes later this evening.

 

That looks awesome. Threw me off in the other thread because you don't see that much on vette's, and if you do, 9/10 its a turbo setup.

 

Decided to build a new turbo kit, dropped some weight off the front end in the process. Not exactly symmetrical given the offset of the heads, but close enough. Still need to clean things up, but it works.