RebekahsZ

The biggest issue I see with how most 8.8 or R230 IRS conversion kits is mounting of the pinion end of the pumpkin. This is the end that lifts like a traction bar under power. I have torn the floor (separated a lap joint between two floor panels, really) and I find the associated bushing broken everytime I swap diffs. Try to integrate the pinion mounting into either your roll cage or some sort of fabricated crossmember. If you look at the drivetrain forum you will find an active thread titled something like "Ultimate IRS". The guy doing it is a great guy, an engineering student who your team should look at hiring when he graduates. Pinion mounting is the only aspect of his design that I think is borderline. The rest of his set up looks good, though his kit hasn't been tested at this point. I haven't been successful in getting a really good V8 racers forum going to share "no-BS" experiences with high traction, high shock, high horsepower cars. You kinda have to learn the different personalities in this community, and sometimes we just can't seem to play well together, each of us thinking we are the only smart guy on the planet. The really big hp guys gradually drift toward 4-links, auto trans and solid rears. Probably also depends on if you are going to try to race EVERY weekend or just a few times a year. At some point, the repairing to racing ratio gets a bit tedious. I drag race about 10-15 times more often than I autocross/HPDE. May eventually develop a (2) Z-car stable with one car for turns and another for straights. And I would consider all my stuff non-competitive time trialing. No trophies on the shelf other than a couple of 20-year-old FTOD autocross trophies from a club with no Corvettes or Miatas. Ha!-I guess the Miata wasn't even out back when I won those, and the Corvette of that era was a heavy, unsophisticated, low horsepower dog!

That's the tranny (the last option that you show in your spreadsheet) that I will be buying if the one I have ever craps out on me. I managed to find a rare 3.36 R200 and have it on my shelf, but I haven't tried it out. I definitely get out of 1st and 2nd really fast, but I don't know if I have enough power to pull the higher 1st gear out of the hole at the strip when the track is really sticky. Plus, I knew I wouldn't be at 115mph in the 1/8-mile, nor 150 in the 1/4-mile with only 400hp, so the 3.36 was kinda out of the question. You definitely have much more LS know-how than I do and I am a big-time noob with them. In 1-2-3, things are happening too violently for me to be able to sense what is happening in the timing and cam, but once I get into 4th gear and have a whole 1/8-7/8 of a mile to sit and feel the engine management working, it really is cool to feel the surge that happens around 5000rpm. I am willing to consider that the poor low-speed driveability in my truck is due to the leaf springs, helper springs and air shocks (for the trailer) and Caltracs. The Caltracs were added at the same time as the LQ4, so I can't intellectually separate them from each other. I just knew that without some traction adders (the gov-loc GM LSD was also tossed in favor of an Eaton helical LSD), I was just going to spin in place. Probably the smartest thing you are planning is the straight axle. Otherwise, you will be reliability limited rather than power limited. I have had pretty good R200 surviveability, but potential breakage is always at the forefront of my mind.

When looking at the gear calculator programs, i found the 3.70 gears fell in between any of my useable ranges. Same with 3.36. It pretty much came down to either 3.90 or 3.54. While talking about cams: I hate the cam that's in my LQ4-swapped truck. While at WOT the cam makes about 60hp more than stock, it makes lots of fumes at idle and really surges at parking lot speeds making it really hard to drive smoothly. I rarely drive the truck at WOT; it's a daily driver and a tow vehicle. Conversely, my LS2 Z makes more horsepower than the truck even with a factory cam and is smooth as silk from idle to WOT. My Z spends a lot of time at WOT. I may at some point put a stock cam back in my truck. I don't know the specs on the cams. I REALLY like how driveable my Z is. I may never want to trade its driveability for the cheap power a cam can provide-will likely add nitrous instead. The truck sure as hell sounds better at idle, but few people in my daily life would even know what that wicked idle means. And on a road course, I'm not a good enough driver to use all the power that she currently makes (400hp).

Savage42-I would be happy to contribute to such a data base, but I'm not willing to start one. One field in the database should be for a link to a photo of a car with the referenced wheels and tires mounted. I think that there should be columns for both advertised offset and measured back spacing, since it is kinda hard to measure offset.

Depends on the tire diameter. I built my car with a 2006 GTO LS2 and MN12 version T56. I started with 26" slicks and a 3.90 diff. I needed to shift to 4th before 600' (needed 4th to finish the 1/8-mile). But it was great for 1/4-mile (right on the 6000rpm shift light in 4th at finish line). But I don't get a chance to run 1/4-mile very often. So I went to 3.54. That moved my 1/8-mile rpm limit in 3rd from less than 600' out to about 640' and for a year I just rode the rev limiter thru the timers. Went to 28" slicks and after 6 passes, I'm not sure what rpm I am at when I cross the beams in the 660' but it's less than 6000. With 3.54 and 26" slicks at 6200 rpm in 3rd I'm at 100mph. In 4th with 28" slicks and a 3.54, at 6000 I'm at 148. With 26" tires and 3.90 at 6000 in 4th, I'm at 126. I have found the gear-to-rpm modeling programs on-line to be pretty accurate.

It needs stacks out the hood!

Since my Z is now required day to take me to work, I can't get started on winter mods yet. Argh! Just booked a week at Sandals St Lucia with the wife: investing a little so that as soon as I have something to drive, the all- weekend thrashing can begin.

Make us a good smoky burn-out video before you fool with all that trivial stuff!

Roger.

I vote for option #1. Go with a 3.54-ish diff ratio. I have option #2 in my car. I wish 1st was taller and I wish 6th was lower (so I could use it). Also, with option 2, I am out of both 1st and 2nd gears so fast that I really have to concentrate to keep from hitting the rev-limiter.

I wonder how much it would cost to ship my car to Finland so you could re-wire it and put all new gauges in it? I love what you are doing!

I have both a V8 240z and a V8 S10, both LS-equipped. Except for the lack of heat and airconditioning, the only thing I would rather do with my S10 instead of the Z is haul cow manure. The Z drives SO much better with the suspension system that God put in it. I may back-half a Z someday to improve the durability of the rearend, but there is no reason at all to change the front suspension, unless you plan to use a 4X4 chassis for the 4-wheel drive. And, the V8 fits between my Z's strut towers so much better than the V8 fits between my upper A-frames on the S10. Now, if you just want to do it cause you want to, go for it!

I don't know how that could look ANY better. I wish I had done my harness bar like you did-it gives additional room for shoulder belt adjustment. Beware, that door bar configuration is great for drag racing but you will smack your elbow frequently if sawing away on the steering wheel at autocross or road race. I did mine the same way to be NHRA compliant, and my elbow is really crowded.

Goodness knows you deserve a break. After my last session with Matt (and my inability to turn my steering wheel in turn 6 when the left front tire was fully loaded), I joined Cross Fit. I was really convicted by how out of shape I've let myself get. After squats the first week, I couldn't stand up from the potty without help. After last week's abs, I couldn't sit up on the side of the bed. My arthritis in my wrist is killing me, and my back is a little unstable, but so far the knees (which are keeping me from jogging) have been behaving. And once I start on the Z for the winter, I don't know if I still have many all-nighters left in me. Hope you feel better fast. It sucks being hurt.

I've been watching this thread since the beginning and have always been in awe of Will and his resourcefulness. Jealous of you guys, but I'm tired of working on drivetrain and just needed to work on other aspects of my car for a change. But I AM jealous.

Your Z is so wonderfully understated. A real sleeper. Cold up there?

Just found the limits of the AutoZone clutch the LS conversion guy installed in my truck. Tried a second gear burn out on dry pavement. That's a no-go: slipped like a mother. That will be the first project when I get the lift installed in the new garage: performance aftermarket clutch kit.

Ah, I see it (the way the door bar contours) now, and I can see that the door is gutted. You must have some long legs! You have an amazing machine. The wear and tear of drag racing is what is pushing me toward paved landspeed racing. It's just a matter of limited opportunities annually to limit the amount of carnage.

Isn't it aluminum? No coating saves weight.

McCormack Racing has 26x8.5 ET Drag slicks on sale for $170 today and today only. This is the largest drag slick that will fit INSIDE stock S30 fenders. I have 60'-ed 1.43 on this tire. Getchew some!

Looks good. A couple thoughts/questions. Is PP paved or gravel? Paved I hope, cause gravel will likely tear the hell out of your car (?). Your harness bar looks a lot like mine and I wish I had "relaxed" the harness bar all the way across, including the passenger side, to allow the passenger seat to come back more and for shoulder harness adjustment space. Not an issue if no passenger seat. Do you have any trouble with your left elbow having enough clearance for steering? Your steering wheel adapter looks pretty long, and I am trying to shorten my column to give me more elbow room.

Pump up the air pressure in the front tires and wipe them down with baby oil daily so that you can turn the steering wheel. Also, cut away half your airdam/front valance and you should be fine.

Yeah, I saw that. Looks great. I figured that gave some support in tension/compression but not torsional. Hey, if it works, I'm in!

Approximately how much have you spent? Once you have this figured out, you are going to have an awesome machine! There have been very few solid conversions that have provided such great photos. Where are you from, and are you going to ZCON2015 in Memphis this summer? Send me a PM or something to tell me more about the car!

My neighbors are hating me for building a garage with 13' ceilings in the subdivision. It's TALL.