tube80z

Can't you simply cut the top of the 240 and use the 280 bottom? If you ever do any compliance testing you will rethink the idea of using the smaller 240 diameter tubes. Cary

I'm about the last person you want to talk to for carb advice. I found the 750 from researching a few books and magazine articles and those had dyno curves showing annular versus dog leg boosters. We've ran three carbs, all demons. 750 vacuum secondaries (not so hot), 650 mechanical secondaries (dog legs) much better, and the 750 sportsman with road race floats (the best). You don't want vacuum secondaries for performance apps. A custom carb may be even better but when you have enough power to burn the rear tires off it gets to be sorta moot. Cary

Go over to ebay and search for the GMPP manifold by part number. Wegner is selling some for $259 and had 24 the last time I checked. This is what I have. I can't say if this will be better or worse. I'm putting this on an LS1 with a HOT cam. There's a guy on ebay that's doing LS cams for $100 from time to time. Dave built his motor more for mid-range power rather than top end. I can't recall his cam but he reads these threads and hopefully will chime in. It's supposed to stop at 65/6600 hundred but it will pull to 7200 if you're not careful. The single plane may be easier to drive because it won't have such a large amount of torque down low. It pulls from about 1800 on up with the performer manifold. His LS2 has the 26x reluctor but you're right they normally need the 6012. On the carbs we've found that you want the annular boosters. They do a much better job at atomizing the fuel down low and you get a lot more low end this way. We've tried a 650 demon DP and it seemed strong but the 750 annular feels like we have a nitrous button. In a car setup to turn with a poor launch he did a 12 flat at 120 in the quarter.

Yes, it has this effect on me. It's also the first car I've ever seen to shake it's tires.

Viperredls1 has a similar car. LS2 with edelbrock performer RPM manifold, MSD 6010 (better than the distributor option), cam, LS6 heads, and a 750 sportsman demon. It's making the power levels you're looking for. I can tell you that even with 14 inches of rubber in the back this car is able to spin the tires at will in second and for a good part of third. It's a handful to try and use that much power at an autox. It's a time machine. All the 40 and 50 year old guys that drive it suddenly act like they're 16 again and just snagged dad's keys Cary

I see that you have AZ racing brakes, which I believe are wilwood superlites up front. You need to clean the pistons on these periodically or the brake dust can cause them to hang up. Also check the pads for taper wear. One trick we use to get longer pad life is to flip the pads up/down/in/out after a few events. You have a number of options if you don't find a caster issue. Swap tires, then swap pads side to side. Those are all easy. My guess is one of these would solve the issue before you need to look into anything more sinister. Cary

I'm sorry for the sideways hijack but I have to say I don't agree with the above statement. I've had the opportunity to drive a 240SX all last year with slicks and R-compound radials and I found the car to work extremely well. It was better balanced than any Z I've driven. The car was very easy for many to drive and ended up being used as a spare over the year by a lot of people. Back to thread. The Lexus stuff looks cool. I'm really liking the front stuff from these cars too. Cary

Not a good plan. They will most likely fail. Cary

I had pictures of this car from a few years back when it first came out. The wings are because it doesn't fit into DM because of the MC engine and now needs to run in AM.

The low tech version is called lofting. Most CAD systems will give you the cross sections you need to do that. It would be a more affordable way to get a one off made. Cary

You're assuming I make any two items the same Since that hasn't happened yet I can only show you what the mockup looked like, which is attached. I did add some info to the picture that may help. I will be building a couple more that may be a little different but will try and take a few more pictures. These were made reusing as many items as I had around the shop. We needed a longer arm to fix CV binding and something stronger than the AZ arms we were starting to have a number of issues with. And this allowed us to test out this idea to make sure it held no nasty surprises. The end goal is to make tubing versions of these arms and a diff cradle that lets us move the inner points too. This is the first step and so far has been a success. More testing is needed. Cary

Certainly. We didn't do that yet but it was in the back of our minds as something we'd want to be able to experiment with.

Yep, I first saw this on a 60's FF that raced locally many, many years ago.

Attached are some pics or our interpretation of the new rear control arm. These were built out pf parts recycled from the previous control arm thread that Jon started where rod ends replaced the outer rubber bushings. Two things were immediately apparent when putting these on. It was much easier to get them bolted up and the strut aligned with the camber plate with no fuss. It was one of those why didn't we do this a long time ago moments. And I should also mention that aligning for rear toe is now very simple. These are mounted on the back of Dave Kipperman's LS2 powered autox car. We gave them a bunch of abuse this past weekend with no issues attributed to the arms. We had a record heat wave move through our area so any plans for a back to back comparison were thrown out and at this point we're probably not motivated enough to revisit. Cary

How much did you get that setup for?

We spray tires at an autox to get the tread temp down to a range that produces grip. If they get too hot they get greasy and your lap times get much worse. I haven't ran on recent kumhos but they used to be worthless much over 110 degrees of temp measured in the pits. Unlike road racing the generates core temperature in a tire autox heats from the outside in. If you read a lot of tire data they'll tell you that you should see temps in the 190 to 200 range, which leads to this confusion. If you ever see a temp like that on an autox tire bits of rubber would probably be flying off.

When you figure 1.5/1.6 Gs for transients you'd be close to 2.5 degrees and that doesn't take into account tire deflection. So that's about what I'd expect to see. It does look like more camber could be used but I'd check temps to see how they look first. More camber will help in turns but you may lose too much braking for it to translate to a laptime decrease. Your picture is good but it's hard to tell how much the inside is jacking up (if at all). I've found in the past that sometimes I can't control roll as much as I'd like with bars and spring when the inside of the car lifts up. This is where a droop limiter can help to reduce roll. While it will reduce the lateral contribution of the tire that's limited keeping the outside tire flatter do to reduced roll may give you a net gain. And limiters are a lot quicker to add then longer lower control arms. It will also make the car change direction quicker in transitions. Just a thought, Cary

The slicks will last a lot longer if you flip them on the wheels and rotate often. I do two events (Fri, Sat, Sun) on a set before flipping. I use two sets of wheels to do this. Friday I will run in the Sunday tires. Saturday I will run the practice set. If done right I get a new set of used tires that are added to this each year and the 4 worst tires are removed. For the bias ply slicks I match them by diameter. Tires are bagged after each event and treated with formula V following the directions.

The new B compound is supposed to be the same as the what the A6 uses and I've been told negates this advantage. You still have the radial versus bias ply thing and so far I've found radials quicker. How long it will take Hoosier to get radials into all the slick sizes has yet to be seen. Given your soft spring rates you will probably be better with A6 hoosiers or using the kumho 710s. The slicks need to be worked pretty hard to get heat into them and make them function. The Atlantic tires even more so. So keep that in mind when you read "our" tire advice.

How far forward do you sit in the car? My attachment points are under the seat. Cary

A friend had a car similar to yours but LS-1 powered. It was probably 350 WHP and similar torque. 17x12 kumhos in back with 425 front spring, 400 rear, and similar bars. Very neutral and it's strength was how it could squirt out of corners. The one issue this car had was it worked the rear tires pretty hard and this was from the rear roll center being too high in my opinion. I think if that was fixed it would have been much better. The FP and XP cars we running all are currently at least 550 all round or higher. We're using FA tires rather than cantilevers. We have two cars currently running V8s with over 300 WTQ and they put the power down in corners and have excellent straight line traction. There are others on this forum with big HP/TQ and similar setups (Clifton comes to mind). It seems from an earlier thread you mentioned you had 250 springs in the back. When I first got my car it was setup like this all the stiffness in the front and very soft in the back (PO stated what you describe). The car was very adept at three wheeling on corners. Running a more balanced setup fixed this and the car was much faster. If you know you're corner weights try springs that give a wheel rate of about 0.8 times the corner weight. That seems a good rule of thumb for the street radials. On slicks we're trying to be closer to 1 and I hope to experiment with higher rates this summer. Hope this helps, I'm happy to tell you all the settings on our cars. Cary

Technically yes, practically no. What I mean by that is you can jack up one side of the car and the spring will come completely unseated. With the limiters this isn't allowed and there's a small amount of pre-load still left on it.

Maybe they'll chime in but my experience was a ten inch rim gave up too much on these tires. And watching one of the locals run them you could see the tread move before the car would ever start to turn. Are you sure they aren't running the GT-2 radials that are a similar size?

You have something else wrong with your car. We run stiffer than what you're talking about and have no issues with straight line traction or oversteer. And this is with cars with big torque too. Cary

We're using them all. Jeff (white and blue) and myself are on 13 inch bias ply hoosiers, the Chandlers (light blue custom bodywork are running 15 inch hoosier bias plies), Morgan (red and yellow cars) is mostly on 15 inch GY radials, and Dave (grey and black) is running yoko radials. Past testing on a L6 powered car indicated the GY radials were quickest. The yokos are a medium compound and take a while to heat up and may work better in the heat we'll get this summer. We plan to do a big tire test this summer and see how it works between a few cars. We chose the slicks because they are easy to find used and cheap. The atlantic tires are very light and heat up quick, which is good for autox. The new hoosiers are now all using compounds similar to the A6 radial street cars (designated B compound). Supposedly in response to crappy performance on the nationals "dune" course. You can run the fronts all round but can't do the same with the rears. And when buying used you need to be careful to get fronts and not rears in similar sizes as they won't turn very well. By going with the same size tire all round you'll lose half to three quarters a second on a 45 to 50 second course. At least that's been our experience. The larger rears allow much earlier throttle application while still maintaining a lot of cornering force. Gives a whole new meaning to point and squirt. We have a tire management routine for the slicks that lets us run them to the cords with decent performance. We use formula V tire treatment and bag the tires between events. The performance drop we see is a lot less than our buddies running the kumhos and hoosier radial street tires, of which hoosier seems to fair worse. The yellow car above is my old car and ran front and rear limiters. Currently it only has rear installed. You'll find using the limiters will make the car react quicker. It will be similar to when you jumped spring rates. Also keep in mind you need to go stiffer to make the atlantics work if you chose to o down the route. All our cars are running at least 500 lb-in springs. And a few of the heavier V8 cars will probably be going up to the 650 to 700 range this year. Cary