Gsxr600 micro sprint with h&m chassis? Maybe a kiwi chassis? Need help!!

[Sprintcarkid600]

Well I'll start off with a little background. Last year I got a 270 and a pmp chassis. I traded my 2001 yamaha yz125 and I started in the 270. The whole year I had troubles getting the car to clear out and when it did my setup was so wacky the car was difficult to handle. It would dart and turn real hard whatever direction i would turn the wheel. This season I had my motor ironed out and hit some play days and the car was great. Was fast pulling really hard. It was a 1/4 high bank track and I was on the track with 1000cc dwarf cars and I was smoking them. Gaining half a track on them every lap, and then flying past them like they were standing still. It was blast. The first race of the season the car won't run right. Won't clear out, handled fine but never could get it to hit the power band because it was like I was running to high of a gear and to fat of a jet but my plug was never fouled and looked perfect, that nice coffee color your looking for. I could slam it into 3rd and the thing would wake up for a moment then fall on its face. Sometimes if I shifted back up when she was alive it would stay alive through the gear and haul ass and if I kept my foot to the floor it would keep clear and scream down the straight but as soon as I feather the throttle for the turn it falls on its face. I'd downshift and sometimes it woke up but most times it didn't. I went through 3 races this season dealing with that frustration trying different jets, trying leaner and richer fuel mixtures, trying different premix, new cdi, new pulse pump just throwing parts at it until I gave up. I said no more, stripped it down the the chassis, put it in my shop, with all the parts boxed up and found a 600 roller chassis with an 05gsxr600 engine that had a bad cylinder for 800 dollars. Then I found a crashed 04 gsxr600 and I bought that motor for 250 bucks. Took the methanol setup off the 05 and put that on the 04 and slapped it in the car. It all started back in March. I'm finally ready for my first race this Saturday. I found out the 3rd cylinder injector was stuck open so I took those off and put the stock injectors on it just to get it running for now while I'm waiting for my autotune wideband setup from dynojet for my power commander 5. Now I can focus more on setting up the corners of the car but I don't know where to start. It's a coil front torsion rear 4 link car. Wide chassis, panhard. Idk what coils I should be running or what bars or what shocks or what changing any of that will even do. I'd you could point me in the right direction I'd much appreciate it

 

[flattop1]

Outrider
Member
Nov 21, 2020
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#4
For a sprint car, that is not an abnormal weight bias (we run a 600 micro, so there aren't a lot of differences); that rear weight percentage is within the range usually encountered. To change it, you can move the seat, or change the length of the links that locate the rear axle. One important thing about scaling a sprint car, as scales are not usually used in sprint car setup, except as a reference to see if something has changed, as after a crash; whether it is a real setup that you use at any specific track or no track at all, develop ONE setup, including the exact amount of fuel in the tank, that you use for scaling. Without the same setup each time you put it on the scales, the info the scales give you, especially with regard to whether or not the car has been tweaked in a wreck, is not particularly useful. So set the suspension up with the blocks in the usual manner, with some specific amount of turns on each torsion bar (or coil spring) at each corner, the same air pressure in each tire, and the same amount of fuel in the tank, as used the very first time you scaled it. This scaling is done without the driver in the car, and is done ONLY to tell you what the chassis numbers are. After you have that, you can put the driver in the car and see what changes and record that, too, if you wish. A good scaling setup is whatever baseline setup the chassis manufacturer recommends, but that is not not necessary, it just needs to be a setup that you have recorded somewhere, so that you can duplicate it each time you scale the car. Unless we had some sort of prang, we put the "scaling setup" on the car before each season to see where we were at, then repeated the scaling a couple of times during the season, and again after the last race, just to make sure there were no changes going on that we had missed. Scaling is not a tool for setting up a sprint car, it's a tool for checking the chassis and locating any changes that may require attention/repair.
...64%was the rear% in question .

 

[Sprintcarkid600]

I put the 270 in storage then pulled out my wallet and built a 600. I'm 150lbs in gear and the car is 550lbs without me in it. What weight bars should I have in the back? I have coils in the front so what would you recommend for my springs? I have about 10 shocks but i don't know what valving any of them are or if they are any good so I was going to have them redone, what valving should I have done? I know nothing about suspension and setup. I made a fast motor that I chewed up last weekend at my buddy's track but I luckily had a backup in the shop and had that one built up and swapped in the next day. Saturday is my first race in the 600 and we're supposed to have 20 cars on race night. The largest car count I've ever had was 7 micro 270s so I'm a little bit nervous. I just want the car to hold up and run well. If I can make it to the end of the main I'll be happy with myself

 

[Sprintcarkid600]

This is my 600