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Author Topic:   How Much Is To Much?
Walt328
Dirt Roller

Total posts: 8
posted July 16, 2003 07:30 PM  
When we put a new rearend in our 87 Monte purestock we were told to tip it down for more bite we must use stock upper and lower control arms. How are we to do this? Do we cut the tops or do we lengthin the lowers
and how much?


racer17j
Dirt Forum Champ
Total posts: 5390
posted July 16, 2003 09:22 PM  
Thanks Racer17j. I have read alot of your posts and they all seem make sence. I have also seen posts about the having the lr ahead of the rr can this be done by doing just one of the arms.

racer17j
Dirt Forum Champ
Total posts: 5390
posted July 17, 2003 06:03 PM  
I'm in no way trying to disagree with racer17j, but regarding leading the left rear...

I had been running mine pretty much straight, but last week I was doing some "re-engineering" of the rear upper control arms. I was kind of in a hurry as our track was having a practice that night. Once I finished I thought I would check the wheelbase on each side just to make sure I hadn't screwed anything up. When I measured it I found that my LR was now 1 1/2" in front of my RR. There wasn't a thing I could do about it at that point before practice so I figured I'd try it.

My assumption was that it MIGHT be ok in the middle of the corner, but coming off the corner and down the straights the rear of the car would likely be coming around to where I'd be driving it almost sideways and not be able to stand on the throttle at all.

To my suprise, the car handled better than it had when I had it almost square. The thing came out of the corners and down the straight-aways straighter than before and it really let me get into the throttle much earlier and harder than before.

Just wanted to throw that out there. Sometimes a screw-up can be beneficial... I'd oughta know as it seems I'm always making screw-ups.

racer17j
Dirt Forum Champ
Total posts: 5390
posted July 21, 2003 07:19 PM  
might be a little help to someone but if you loosen the bolts on the control arms a little or use a smaller bolt so during body roll the arms don't pinch the rearend and pick up the lr tire going around the corner. it seemed to help me a little

blanep
Dirt Maniac

Total posts: 105
posted July 21, 2003 09:32 PM  
Car was actually tight in and through the corner and loose off. Like I said, I really figured that leading the LR that much would take away my tight in and through but would be so friggin loose out of the corner and down the straight that it simply wouldn't be drivable.

I'm in no way saying that leading the LR this much on any other car would work and especially not recommending it for someone building their first car or who are in their first few races, but it somehow worked with this particular car.

As for shutting off the right front, I can't seem to use it either. I have a shut-off as well as a prop on the RF so that I can have something other than all or nothing. But the very few times I tried shutting it off I pretty much couldn't stand it.

blanep
Dirt Maniac

Total posts: 105
posted July 21, 2003 10:03 PM  
I apologize for taking over this thread, but I wanted to let you know about something else that seems to be working on this car which in theory makes no sense at all.

My uncle is pretty much a chassis and engine guru, but he doesn't care a whole lot for anything other than late models, so I get precious little of his input and wisdom. However, he suggested that I put a tie-down shock on the RF of the car. Now I of course had heard of using tie-downs on the LR and an easy-up on the RF, but never the other way around.

I really didn't see how it could work on a stock-type car even though the late models guys around here are using it with alot of success. They suck that car down on the RF and try to keep it sucked down. They way I saw it though, a late model's rear squats as it enters the corner and they don't have to worry about trying to get weight transferred back to the LR for forward bite coming out. Well, a factory stock in no way squats the rear entering the corner and the goal with stock supsensions is to keep the weight off of the RF and keep it on the LR or at least be able to transfer the weight easily from the RF to the LR as you accelerate out of the corner so that you can get bite with that LR.

It seemed to me that if I put a tie-down on the RF, the weight would go there and not be able to transfer back to the LR coming out. At the time I had normal stock mount Bilsteins on. I figured I'd try it though so I bought 2 new QA1 shocks, both of them being 7-3 easy-ups. Since they are rebuildable and revalveable I figured I could just switch one of them to a 3-7 tie-down and be able to try both at a test session. Well, I put the 7-3 easy-up (the one most other factory stock guys use) on the RF and tried it first. The car stunk. I haven't got to try the 3-7 yet though as I broke a major part in it while rebuilding it and am awaiting a replacement.

Since the easy-up didn't work, I put the Bilstein back on, but then something interesting happened. My RF upper spring cup gave way and collapsed during a heat race. I was unaware of it at the time, but knew that I was diving alot further down on my RF than normal and the car was driving the best it ever had... it was super fast. During the feature it continued to drive extremely awesome and again was super fast.... until my left side engine bolt lost it's nut and backed out, allowing my engine to move enough while cornering that it bound up my throttle linkage and essentially made a stuck throttle in the corners. Obviously I had to pull out of the race. But I learned something... that my car indeed was needing to lay down as far as possible onto the RF in the corners and it wouldn't sacrifice my forward bite. I of course had to repair the spring cup, but have now reversed my front springs in hopes of duplicating the effect. I'll be putting that tie-down on the RF just as soon as it's fixed as well.

Sorry for the length of the post, just wanted to expand on how backwards things work sometimes.

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