How bad is this.......
12-05-2007, 02:39 AM
#1
How bad is this....... I never really noticed this until yesterday. I'm kicking around the idea of running some 325/50/15 MT radials, and was wondering how centered my rear wheels were.
Turns out, they are WAY off. I don't know if the BMR boxed LCA's are too long, if the Moser brackets are on wrong, or if we welded the LCA relocation brackets on a bit wrong, but the tires are definitely off by quite a bit. I guess this finally explains why my diff cover was hitting the upper PHR.
I've got an adjustable T/A, and it started to hit the upper PHR a LOT worse after I installed it, to the point where I had to take off the upper PHR. I set it to -2*, with crankshaft being 0*, but I may have done it wrong. Beforehand it had rubbed on the cover a bit (where the preload bolts are), but nothing major like afterwards.
Do you guys think adjustable LCA's can fix this problem? Could it be blamed on a possible wrong setup on the pinion angle? I'm going to put it on a drive on lift tomorrow and see if I can't get it perfectly 2* down bubble, then see what I'm working with.
***********UPDATE! See post #6***********
Passenger side:
Driver side:
My whole goal was to 10's on these tires N/A, and deep 10's on gas, also on these tires. I've gone 11.18 n/a w/ a 1.78 60', standing on the rev limiter over the last 200', so I know I'm close. This is with a raceweight of 3850lbs.
Turns out, they are WAY off. I don't know if the BMR boxed LCA's are too long, if the Moser brackets are on wrong, or if we welded the LCA relocation brackets on a bit wrong, but the tires are definitely off by quite a bit. I guess this finally explains why my diff cover was hitting the upper PHR.
I've got an adjustable T/A, and it started to hit the upper PHR a LOT worse after I installed it, to the point where I had to take off the upper PHR. I set it to -2*, with crankshaft being 0*, but I may have done it wrong. Beforehand it had rubbed on the cover a bit (where the preload bolts are), but nothing major like afterwards.
Do you guys think adjustable LCA's can fix this problem? Could it be blamed on a possible wrong setup on the pinion angle? I'm going to put it on a drive on lift tomorrow and see if I can't get it perfectly 2* down bubble, then see what I'm working with.
***********UPDATE! See post #6***********
Passenger side:
Driver side:
My whole goal was to 10's on these tires N/A, and deep 10's on gas, also on these tires. I've gone 11.18 n/a w/ a 1.78 60', standing on the rev limiter over the last 200', so I know I'm close. This is with a raceweight of 3850lbs.
Last edited by TheBlurLS1; 01-13-2008 at 11:55 AM.
12-05-2007, 01:19 PM
#5
don't blindly set them both the same and leave them that way. Since everything is off that far, don't bet on anything being exactly the same side to side on the rear.
get them close, and measure front wheel center to rear wheel center, both sides. square the car up that way, or it will drive itself when you put most of or all the weight on the rear tires only.
assume nothing
get them close, and measure front wheel center to rear wheel center, both sides. square the car up that way, or it will drive itself when you put most of or all the weight on the rear tires only.
assume nothing
01-12-2008, 08:56 AM
#6
Update....
The more I thought about it, the more I thought I may have set the pinion wrong. Turns out I was right........ I mean wrong...... I mean.......ehhhh
I had previously set the pinion from the crank angle, which I found out a few nights ago was about 4* up lol. This means I have been running +2* for over 6 months! I got the car sitting normal on the ground, jacked it up maintaining the same angle, and set the pinion 2* DOWN.
Doing this rotated the rear forward pivoting on the LCA's and magically CENTERED the the tires in the fenders.
The tires were still a TINY bit off from center (like 1/4" on driver side, 1/8" on passenger), so I got them exact with my shiny new Spohn LCA's that I was installing to fix the problem (didn't really need them lol). The car hooks nuts now. I can roll it out at 2500 on the street and stab it in 1st, as long as I stand on it down low in the RPMs and dont shock the tires too high in the powerband, they won't spin. This is on WORN OUT 315 MT's with no burnout and 50* weather. Car is running a 530-550rwhp 408.
I cut a 1.75 with +2* in the car, which I'm pretty proud of lol, but now I can't wait to see what it will do at the track. I want to yank tire(s) on 17's!
Lesson learned: If the tires aren't centered, check the pinion angle first.
The more I thought about it, the more I thought I may have set the pinion wrong. Turns out I was right........ I mean wrong...... I mean.......ehhhh
I had previously set the pinion from the crank angle, which I found out a few nights ago was about 4* up lol. This means I have been running +2* for over 6 months! I got the car sitting normal on the ground, jacked it up maintaining the same angle, and set the pinion 2* DOWN.
Doing this rotated the rear forward pivoting on the LCA's and magically CENTERED the the tires in the fenders.
The tires were still a TINY bit off from center (like 1/4" on driver side, 1/8" on passenger), so I got them exact with my shiny new Spohn LCA's that I was installing to fix the problem (didn't really need them lol). The car hooks nuts now. I can roll it out at 2500 on the street and stab it in 1st, as long as I stand on it down low in the RPMs and dont shock the tires too high in the powerband, they won't spin. This is on WORN OUT 315 MT's with no burnout and 50* weather. Car is running a 530-550rwhp 408.
I cut a 1.75 with +2* in the car, which I'm pretty proud of lol, but now I can't wait to see what it will do at the track. I want to yank tire(s) on 17's!
Lesson learned: If the tires aren't centered, check the pinion angle first.
Last edited by TheBlurLS1; 01-12-2008 at 09:05 AM.
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01-12-2008, 10:51 AM
#8
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how did the car react when you launched it like that? a guy i know had the same problem but his car would head straight towards the wall when he launched. it was pretty scary
01-12-2008, 07:27 PM
#11
My car is lowered but my panhard rod is level, but this won't happen unless you relocate the mounting hole.
Adjustable panhard will fix it but when you have it lowered and at an angle it will move even more side to side with travel than at stock ride hight because you're starting with it at an angle and it'll move to the drivers side the more you lower it.
If you go over a bump and the rear drops 1" you'd be surprised how much that will move the rear end.
Adjustable panhard will fix it but when you have it lowered and at an angle it will move even more side to side with travel than at stock ride hight because you're starting with it at an angle and it'll move to the drivers side the more you lower it.
If you go over a bump and the rear drops 1" you'd be surprised how much that will move the rear end.
01-13-2008, 11:54 AM
#12
Car is FIXED guys.
The left/right was always dead on. With a lowered car it's pretty crucial to get it right when you're running 315's. The front/back in the fenders was jacked up due to the pinion angle being tilted WAY up.
Thinking back, I had a horrible slamming noise after install, and traced it to the diff. cover hitting the upper PHR, which I removed. If the pinion had been set right, it would have never hit it.