JMortensen

Yep, more coils on top = less unsprung weight since the top half of the spring is sprung weight and the bottom half is unsprung weight. How much that really affects things is up for debate, but that's the "proper" way to do it.

Try that and see how it works out. It works if you have 3/16" and 1/8" stuff that you had to stick together, but when you're working with paper thin sheet metal and thicker stuff like .095" you're just going to blow holes in it IME.

Actually it was a digital. I looked for an analog and couldn't find one anywhere. That means that you have to deal with the refresh rate on the display, but if you do a whole bunch of pulls you'll get it right.

I had good luck with Bosch, as did a couple friends of mine. One used a heated O2, but like I said, just takes a couple minutes and then it reads fine. I think it cost me about $35 for the sensor, and then I seem to remember $6 for the voltmeter. Prices may be up a bit, I think I bought that sensor more than 5 years ago...

It was a one wire Bosch sensor off of a mid 90s GM V6 FWD car. A friend of mine used the heated Bosch sensor too (not sure what app), both worked well.

You got me with that one. That's funny stuff!

Don't know what to tell you, but I haven't had those problems when welding the thicker and thinner stuff. Like I said, I run the welder about as hot as the sheet will stand, I turn the wire speed down (don't think I mentioned that before), then I pull the pool into the sheet. If I had to guess I'd say that maybe your wire speed is too high if you can't get a lower heat setting to stick to the tube, or your heat is too high if you're burning the sheet. The only time I've had to do anything like you're describing is when I was welding sheet metal to sheet metal and there was big gap. Then I'd lay a bead on one side and the other and then fill the gap. I did that one a lot when I was stitch welding and when I was stitching the rusty cowl.

Also make sure that the big 24mm (15/16") bolts on the ends of the control arms aren't loosening up. That's happened to a couple of V8 guys now...

I thought he had an RX8. Maybe I was wrong...

I'd suspect rear control arm bushings first. If they're rubber or they're old, replace them. You can go for G Machine bushings on the inners to get less deflection. Poly on the outers, or if you're feeling racey you could get AZC arms or similar which have rod ends and no deflection at all. I don't think that the springs are going to do you any good at all. I just don't think that the IRS (properly maintained) does that rear steer thing like the solid axles do.

That begs the question: Are they limited to stock valvesprings in T1?

No, he's talking about anti roll bars. I think it's more of a straight axle thing, but I've heard of this before. You can see on some drag videos how the car leans to the right under power. With a straight axle when the suspension compresses the wheelbase gets shorter on that side of the car, kind of like a skateboard. So then the car steers right. So they use a normal anti-roll bar and they preload it by putting a big stack of washers in and tightening the end links down so that the sway bar gives a little extra resistance to the right side compressing, and this helps it track straighter. I believe this is a non-issue with our IRS. EDIT--I'm thinking I may have that backwards. It may be that the wheelbase gets longer on the side that compresses. I can't remember. The jist is right though: Prevent the body roll and get the car to go straight down the lane.

I'd go with the VLSD if it were my car. Keep in mind my own Z has about 250 whp and I've never installed or used either the Quaife or the VLSD, so I'm basing that on the info that I've read here.

For road racers you want to ride ride at the peak of the hp curve, so that when you shift you just have to pull the car over the hp crest, then shift again. I would figure a drag racer would be faster doing the same, but I am not a drag racer. The "problem" if you want to call it that, is that he redlines right at peak hp. If he could just get a little further, then with a relatively close ratio trans he could stay between say 375 and 403 hp even between shifts. If he shifts right at 403 hp then he might drop down to 330 or 350 hp when he hits the next gear. At least that's what I seem to remember in a thread from about 2 or 3 years ago that was all about gearing and hp curves, etc.

VLSD doesn't have clutches. It seems that the VLSD is damn near bulletproof. I'd suggest you go that way. R230 should be the strongest, so if strength is your priority, then you just have to deal with making a mount for it. The Quaife on the other hand is guaranteed for life even if you race, no matter what engine you put in front of it.

Just MHO, but I'd say clean it farther back on the ends. Use sandpaper or a wire wheel on an angle grinder. I've got this one piece of plate and I have to use a sanding flap disk to cut through the scale on it. When I first started to weld that stuff I was thinking "I cleaned it. WTF is going on here???" But I had not cut all the way through the mill scale though, and the welds looked really bird poopy. I'm sure that on the sheetmetal stuff it will make a big difference. That's such a large weld that you're doing there, and to try and do the whole thing through the scale is just not good. I don't think that weld needs a huge amount of strength because it is the tubing, the strut tower, and the frame rail that's providing the strength, the sheet metal is just along for the ride, but you can make it LOOK better. As far as the welder settings go I wouldn't go higher than the thinner of the base materials can handle. I'd go right to that point, but not beyond. On my Miller that's probably around 3.5 or 4 on the voltage. Then I'd start by welding to the tubing, and kind of "pull" the puddle into the sheet metal.

You gotta start cleaning your tubing before you weld it.

I'm not going to make the whole argument AGAIN, but if you search you'll probably find old threads where I had friends compare their NB to WB on the dyno and they were RIGHT ON. Not the best for the really high strung engine that has to run exactly perfect to prevent it from exploding, but a hell of a lot better than what most carbed NA guys do, which is read plugs (badly).

My buddy took his cover down to the autoparts store and found a freeze plug that fit just right. Just a little bit easier solution.

What do you have in store? Fiberglass or CF roof panel? That would be BADASS!!!

No doubt it's easier to cut through the pillars. Then you don't have to worry about the curve in the roof.

Unless its a very high strung engine, you're not likely to detonate a NA engine to death in a short period of time that it takes to get the thing in the ballpark. If it's turbo or supercharged or has 14:1 compression, then I agree, WB is the way to go.

My 70 didn't have this thing, FWIW. I've seen it in pictures and always thought "Well THAT would be the first thing to go in the trash can."

I think it would be less stiff than a straight bar. It's just not the best load path. Think about getting hit from the side with that dash bar. Instead of the dash bar sending the load from the driver's side of the cage to the passenger's side directly through a straight bar, it instead transmits the load to the cowl. The cowl itself is a structural member of the car, but it isn't as sturdy as the cage on the other side I don't think. You can still run the brace down to the trans tunnel with a straight across dash bar. 2) Those two buggers will support the new rear IRS/cradle. Not so needless : ) That sound interesting. Any pics of that?

BSR did that on their CP cars. IIRC there is a picture in How to Hotrod your Datsun. It's not very hard to do. Just run a diagonal from the top of the rocker tip to the upper frame rail as far forward as you can without causing interference issues with the front tire. I don't recall if the BRE team did that too, but I'm 99% sure it was the BSR car in the book. I remember that the BSR car had a HUGE brace, it looked like the same size bar as the roll cage. I think the rules at the time said that all the bars in the cage had to be the same size though, and I don't think that the brace needs to be that size to get the job done. I think of it like a strut tower bar on a different plane.