8 second OEM 4 link drag race chassis setup
- Thread starter Alky V6
- Start date
- Joined
- Jun 18, 2001
That is what we had at the time. What doesn't seem right? I know we ended up setting the HR rear bar offset based on the wheel weights and later rescaled the car to set it up. Which we also spent time squaring the rearend setting the front end alignment and checking pinion angle.
Car is 100# lighter now and we went back to a 28" tire that fits the car better. I did this when we put the Wolfe Racecraft UCA and LCA on with end links. Since we bent both UCA's and trashed every rod end in the set. I switched to Paul's new insane UCA and LCA with the teflon 7/8" rod ends VERY nice stuff and should hold up to what we are doing now.
I've also switched all of my front suspension to the TRZ stuff. Right now I have the front control arms with stock spindles and steering. After I hit the wall at Norwalk in 2007 I also had all the QA1 shocks rebuilt and re-valved. The valving on the QA1's is not ideal for our cars and it seemed to be a worth while investment. IMO the front suspension as important if not more important than the rear suspension in getting a car like this down the track. We by chance found the messed up Wolfe suspension pieces and were having no issues with the 60' or car handling. I wrecked the car over a bad right front shock and if you change my front shock settings one click either way the 60' will go to hell fast. My car has always been VERY sensitive to front shock and suspension settings.
Car is 100# lighter now and we went back to a 28" tire that fits the car better. I did this when we put the Wolfe Racecraft UCA and LCA on with end links. Since we bent both UCA's and trashed every rod end in the set. I switched to Paul's new insane UCA and LCA with the teflon 7/8" rod ends VERY nice stuff and should hold up to what we are doing now.
I've also switched all of my front suspension to the TRZ stuff. Right now I have the front control arms with stock spindles and steering. After I hit the wall at Norwalk in 2007 I also had all the QA1 shocks rebuilt and re-valved. The valving on the QA1's is not ideal for our cars and it seemed to be a worth while investment. IMO the front suspension as important if not more important than the rear suspension in getting a car like this down the track. We by chance found the messed up Wolfe suspension pieces and were having no issues with the 60' or car handling. I wrecked the car over a bad right front shock and if you change my front shock settings one click either way the 60' will go to hell fast. My car has always been VERY sensitive to front shock and suspension settings.
- Joined
- Jun 18, 2001
The Ford 9" housing really raises the UCA shortening the IC length quite a bit. As a result my car can hit the tire really hard and at the weight and power we are at it will KILL tire sidewalls. I run a 28x10.5 stiff sidewall WITH tubes. Lowering the car and tucking the 28's in under the body also helped take some "hit" off the tires to keep the front end down.
- Joined
- Jun 18, 2001
- Joined
- Jun 18, 2001
In my car we were thinking that 42" was to short. In lowering the car we were trying to get the LCA more parallel with the ground which I believe they are now. This would've increased the IC arm's length? I know it definitely helped keep the front end down.
Lowering the car will shorten the IC and will usually make the car handle a lot better so what you said is what I would expect to happen. A lot of people think that going 35" seems too short (compared to 50" and longer) but it can make a big difference on how the car feels and launches but this all depends on the car and is figured out by trial and error.
KS
What end of the scale is your front shock set at? It was recommended to me to start out on the soft or loose end of the extension adjustment range. I'm using single adjustable QA1s in the front.
What I feel is off is the more weight being on the right front and left rear corners. My research, so far, suggests you'll get better equal loading on the rear tires at launch by setting up static with more weight on the left front and right rear corners.
That's good news to me. Then depending on how hard my car launches, my long IC might be the ticket. My rear tire setup is the same as yours except for the diameter. I'm trying out the 29.5" in an effort to get better traction. Also, in the quarter mile, I was running way too high on the tach by the finish with the 28s.
With the old suspension I was also killing the sidewalls on the 28s on a hard launch tuneup. The front end was liking to get too high also. The IC before the suspension upgrades was probably very close to what it is now, so I would have to figure that going shorter with the IC is not what I want???
I was shooting for around 1.5" too. I didn't realize that oem bumper compressed and allowed so much more additional travel. Depending on how things turn out, I may still change that and lessen the travel more.I have 1.5-2" of travel in the front end
One thing I'm trying, don't know if it has any merit, I have the left front run out of travel just a tad before the right front. My thinking was, hey, it's an adjustment. Why does the front end travel have to stop at the same time for both sides? Maybe there's an advantage somehow to let one side or the other run out of travel before the other. I thought, if the left front gave up travel before the right front, then overloading of the right rear could be controlled. Is this a valid assumption?
- Joined
- Jun 18, 2001
I would start at 2 or 3 clicks tight. Settings 6-12 are so tight you can't even pull the shock out and are pretty useless for what we do.
We set the Hr bar preload to compensate for this. BUT after all the measuring weighing etc most of the initial settings ended getting changed once we got it on the track and saw what the car liked.
- Joined
- Jun 18, 2001
If you have to jack up the rearend to fit the 29.5 you may be better off with the 28's at least I was. To get them to fit you have to tuck them in under the body and lower the rear. With a stiff sidewall MT I could throw everything at it and they would dead hook but the car would wheelie. With the 28's I can throw 90% at them and sixty in the low 1.30's and never lift the tire. We started playing with the MT 325/50 DR. Last time out we went 8.68@163 with them and a 1.37 60' on a mild launch. With some tuning I think I can get them in the low 1.30's. I think Dave Fiscus pulled a 1.27 with them at Norwalk!
- Joined
- Jun 18, 2001
I wouldn't start there. Leave it where it is and take it out as you need it.
- Joined
- Jun 18, 2001
Who knows try it? IMO once you get it all together and everything plotted out real nice and take to the track you will likely still have to make adjustments and changes to get it right. The nice thing about a plot is you at least have a baseline of where you were at. What looks good on paper doesn't always work out on the track.
The ride height in the rear is very close to what it was with the 28s. There was room to fit the 29.5s in there without having to raise the rear. It's tight, but there's room. The rear may be higher now by about 1/4", if that. So the IC hasn't been messed with much with the tire and suspension changes.
I understand. Good advice.
Went to the track last night and made some mild launches. Tuning issues ruined the majority of the runs. By the last run we got some boost going (300 kPa). Car stuck really good. The new tires definitely made a difference. The launches were on the nitrous, but with a lot of retard, and a wildly varying mixture throughout the shot (one of the tuning issues), so they were mild. 1.6s 60 foot. No issues so far. Car ran as straight as a bullet, and left flat and very stable. A little boring for me after dealing with the last suspension setup. The transition from accelerating to braking was uneventful. Brakes? I guess they worked so good I didn't even give them a thought. Unless harder launches at the line bring out some problems, she's good to go.
One thing that was very noticeable was the amount of g force felt when she got up on boost. I'm used to wrestling with the steering wheel while she skates around until the finish. It felt like the tires were geared to the track. Very impressive. Can't wait until the next test and tune.
One thing that was very noticeable was the amount of g force felt when she got up on boost. I'm used to wrestling with the steering wheel while she skates around until the finish. It felt like the tires were geared to the track. Very impressive. Can't wait until the next test and tune.
Pit note
Rear tire pressures set at 9 1/4 for last nights racing.
There won't be much more to post until I can really load the chassis more at the launch. Next track event, I think, is in two weeks. The fastest street car challenge is that weekend, so I've been told.
Rear tire pressures set at 9 1/4 for last nights racing.
There won't be much more to post until I can really load the chassis more at the launch. Next track event, I think, is in two weeks. The fastest street car challenge is that weekend, so I've been told.
Dusty Bradford
Well-Known Member
- Joined
- May 24, 2001
I'd say it's valid. Although I control all loading of the rear tires with the anti-roll bar.
On the subject of front end travel. I have found anything under 1.5 or so can make the car inconsistent. If I still have wheelie issues at 1.5 of travel, I'll add weight to the nose. When the travel gets down to that low point, each 1/4 turn on the adjuster becomes a large change and that's just too fine of a range to control in. The other issue is the spring rate becomes much more important. Not enough spring rate and the car doesn't want to transfer, too much rate and the car will not settle away from the limiters. This causes you to have even less travel than you expected.
My car is not very sensative to front shock adjustments. I figure it's because there is so little travel. The biggest issue was the nose diving too hard when going from acceleration to braking. Stopping from 148 on some of the short 1/8 mile tracks, you get on the brakes hard right at the lights. I have to run compression full tight.
