Subscrinbing also. All i need are rear shocks and mine is fully done also. Whats the deal with weighing each corner seperate?

 

Koni's are one of the most used quality shocks in drag racing, a lot of friends I have used their coil overs.

Point of weighing the car on each corner is to get the weigh distribution front to back side to side and on each tire.

Then you can know where to start setting up things like intersection points, adjusting anti roll bars, shock and spring rates.

Plus it is nice to just know what the car weighs

 

Sounds like your giving a description on hydros on some old impala, lol. But i know what your saying.

 

Yeah, having the vehicle scaled and the suspension tuned while on the scales involves setting the suspension preload and ride height...By adjusting and re-weighing the car you can effectively "move" weight from front to back to side to side...PAF did it with my car and it takes about 3-4 hours, but well worth it...I sent the numbers to PAF to see if he can see what you should do...He's very busy now, but I'm sure he'll chime in...

--Alan

 

hummm... didnt know it was that tech. So then what numbers weight wise do you wanna shoot for? You want the car 50/50, 30/70 or what? So basically you want to set up the weight part of it first then adjust your preload/rebound, pinion angle AFTER you set the weight and ride height?

And what kind of scales are they using? They expensive considering you need 4?

 

I wish I could get one of the local sponsors to do this with my car. The last one I called never returned phone calls/emails..And Im clueless when it comes to adjusting all that jazz..

 

The scales come in a kit, I think, all connected to a head unit that reads individual weights, total vehicle weight, etc...I don't really know what numbers you're supposed to shoot for, but Tyson from PAF does and I sent him a link to this thread...He's been pretty busy, but he said he'd look at it...

When PAF tuned my car first he squared and centered the rear under the car, set the pinion angle at 1.5 degrees negative with a digital angle finder with the suspension loaded, then had me sit in the car with the amount of gas I use to race with and scaled the car...Then it was adjustment after adjustment and back on the scale...by adjusting the front ride height and tweaking the rear sway bar end links he was able to "move" weight around the car...I'm not sure the number you are looking for, but it takes awhile and is much harder when you have a stock style rear bar with poly bushings (I'm switching to a Spohn drag bar shortly)...Then he set the shock settings to a good base line and we were done....The cool thing was that he came to the track on his own time and helped me stage the car in the groove and monitored each run continuing to tweak the shock settings and tire pressures...It was quite an eye opening experience for a fool who has been racing for 20 years...The end result was a very consistent easy to drive car that was going 1.52 60's with ease...

--Alan

 

WEll I got it hooking better, I let a buddy drive it at the track so I could watch it and fiddled with it. We only got 4 passes in before the fog got so bad we left, huge amounts of water in the air and on the track.

Best 60 ft 1.56 leaving at 2000 rpm flashing the converter. We were gonna go for broke and stall it to 3500 and leave but the car spun as did the slick tired car next to us from moisture on the track, so we packed up and went home.


I put the same setup in and tried it on the street and it is MUCH better, on a concrete bridge it left like a damn rocket!


SO you guys were right, I will keep fiddling with it and learning the car.

My only concern is I had to drop the tires to 11.5 psi, but it damn sure worked! Drove fine also.

David

 

Sounds like you're getting it to work more now, but 11.5 psi is a bit low imho...Guys around here with 325s run almost 20 psi...What are your back shocks set at again? I run 18 psi with rear shocks on 8, fronts on 2...

--Alan

 

Fronts on full loose, rear double adjustable Koni's are set on full loose on compression, one full turn from full loose on re bound.

I checked pinion angle today and it is at -1 degree.


I called a buddy of mine who crews on Jeff Cooners limited street car and builds alot of cars also....he said most guys with heavier cars like mine with that tire have to go that low on psi.


David

 

i have seen 2-3 negative on street F-bodies and many 3-4 neg. on race and it worked with 18psi in DR's

 

When I scaled my car I adjusted the pinion angle, softened the rear shock and moved my 4 link which was off a bit.

Needless to say I got a lot of tuning and setup info for free.

The effects were my car going from a 1.40 to a 1.31 60 ft on the very first pass out. Nothing other than chassis tuning.

My car was a little light on the rear end at 47%, car was 2750 and the weight left to right difference was less than 10 pounds, but what was weird was with me getting in the car only caused my side to weigh 5 or 6 more pounds.

 

All my suspension is heim ended, nothing moves on acceleration.

The reason people put 3 and 4 degrees of pinion angle is to be at zero on accel when the rubber or poly bushings move and compress on acceleration.


David

 

if you are talking a real street race. things you need are 1 gallon of VHT and use it moderatly during your burnout place a little patch in front ofeither of you tires and burnem down like you would at the track. back up into your rubber and run from a stop.

 

I am not familiar with the Konis, am I reading that they are set on the loose side on compression and rebound? You want those rear shocks tight on compression to drill the tires into the pavement, which is where the higher tire pressure works well...On my QA1s (single adjustable) I run the rears on 8 (out of 12 with 12 being the tightest on compression)...You dont want your rears loose at all or the car will squat allowing your wheels to go up into the wheel well and not forcing them into the track/street, and you'll be using the lower tire pressure to make up for the suspension squat...I had the same problem last year before going with the new shocks/springs..I had to lower the tire pressure to make up for my lack of suspension parts/tuning...

As far as using lower tire pressures there's some pretty fast 8-9 second local guys in the 3800 lb range who run 20 psi with your same tires and are hitting high 1.2 to low 1.3 60's...

--Alan

 

http://www.1320video.com/BigStreetWheelie.php

 

well this post is sure tells people that even if the car is close to the same it's very different also........I have a totally stock suspension 99t/a when at the track I come out the whole on 150shot and always have 1.50 to 157 60' and thats with a 4000 stall and it dead hooks on m/t drag radials with 18lbs. cold.........now on the street it will not really spin but haze the tires out around 20'......... and the only thing I do to my car is when I come back from the track I jack my front end up ands let the front tires just hang.And leave the back tires setting solid on the ground. Thats to keep the suspesion from keeping the same memory of ride height.