Launching ????

[David Schwarz]

I don't want to make to many changes yet.

I see you are a man of great wisdom! Keep us posted on the progress, it helps me understand the suspension world better as well.

[BLOWNBY]

I am making some more test runs tonight if the weather holds. I will update you all.

[BLOWNBY]

The phototguy got a picture of one of my passes! ????? No wrinkle to the sidewall at all? Maybee still a little stiff since brand new??


http://motorcitynationals.com/v-web/...lbum49/YOK6545

[David Schwarz]

How was the 60' and other incrementals?

[Bobalos]

Are the tires dead hooking? if they are, I would try travel limiters on the front end.

Not sure if those shocks up front only adjust extension or if it does both, but if you can slow down the bump, that would slow the front end coming down. not sure how much that will help though, as its likely unloading the tires as the front wheels come down.

when the front end comes up, does the rear hit the air bag & then start raising the rear end? if it does try taking some air out of the bag. if it just squats & then the front end just falls, then I would think that the travel limiters would be your best bet.

Bob

[BLOWNBY]

How was the 60' and other incrementals?

Not sure which pass that was for nut my best 60' that night was 1.6x's

[BLOWNBY]

Are the tires dead hooking?
Bob

Does this answer it? Only 1.53 60' though?

http://motorcitynationals.com/v-web/...lbum55/YOK9016

[BLOWNBY]

So far the best last night was 10.34 @ 134mph with a 1.53 60'. The setup was no front sway bar, added about 1.5" of travel to front end, MT's at 13.5 psi (seems they like a little more air than normal), air bag at 20psi, front struts at 1 and rears at 3. Launching of the transbrake at 4300rpm's. I was also short shifting at 6,000 and crossing the line at ~6600+. I pullled the front an good 8-10" off the ground.

I did change the timing a little and made two more passes with my mph going up! 138.5 and 137mph. So that is good news. The bad the 60 ft fell off due to spinning, but no worse than before, but an increase in mph.

Now I just have to leave the timing and BTM where they are as the motor seems to be making a little more power and now retune the suspension from here again.

[Bobalos]

It looks like it, but if the front end is still coming up & then it looses traction when the tire starts to spin, then its gonna nose over.

but if its coming up & hitting the air bag & thats causing seperation of the rear shocks it could also unload the tires. I see you lowered the Bag pressure, did that seem to help any with where/how much it spun?

A buddy of mine had the same issue with his 68 Chevelle & he ended up putting an anti roll bar on the rear of his car & that helped to straighten out the car on the launch. It was rotating pretty hard, hitting the airbag & unloading the drivers side & compressing the pass side, this sent the car into wheel spin.

Bob

[Bobalos]

Another GREAT resource is Monty's site @ http://yellowbullet.com/v-web/bullet...5b3e1301a79c84

There some Pro's that are mod'ing his board. you might try seeing what they have to say about it. there are some DARN fast dudes there!!!!!!

Bob

[BLOWNBY]

Well for this Fun Ford weekend I made a pass friday afternoon but I put on my old 27 x11.5 Hoosier QTP's to see how those would work. I left every thing else the same from last times best run. I launched and it felt like it pulled harder and better than before. FInish the pass and hear a loud whinning noise. Pull off the track and shut the car off and open the hood! When what do I see??? A broken vortech strut support and a destroyed idler pulley for the SC as well. The bolt that holds the tensioner plate backed out some how and hit the idler pulley and then must have backed itslef all the way out (considering I just tightened them up before that pass). It was pinched between the plate and the pulley and chewed about an 1/2" off the idler. My 10 rib belts is now also an 8 rib belt. However that pass neted me a 10.27 @133 and a 1.51 60'

I did manage to get it fixed and run again Sat, but was only able to run a 8 rib belt and no strut bar as I couldn't get a 10 rib belt same day. I managed a 10.6x, 10.5x, and a 10.4x pass in that order all back to back. I was also making about 3-4 psi less as the belt was new and once the street cruise starts you can not open the hood or make any changes other than air pressure, so the belt was a little loose as well. Also was unable to get a good 60' as I ran True street and there were a lot of "Street Tires" and no traction compound down at the start.

[fanglemeister]

Reading this thread the first time, I can suggest a few things:

1) move the HPM lift bars up to the 80% anti-squat position - the lower more aggressive (120%?) setting is letting the rear axle unload too soon after launch,

2) I see you already did this - lower airbag from 30psi to 18-22 psi. This will need to be checked again after changing control arms,

3) check that pinion angle - the HPMs are longer than stock and usually give you too much negative pinion angle, then when the tires start to slip the pinion angle snaps back down to static (too much negative) position which helps unload the rear tires.

I'm running silent upper adjustables from JD's in addition to the HPMs -- http://www.jdsperformance.com/index....tem&inmake=all
these helped get my pinion angle back to where I wanted it. I also have BBK poly bushings in the upper arm diff ears, and I'm running the airbag drag spring setup from Laurel Mountain Mustang, which iirc is slightly different than your Eibach setup, but can't recall how exactly.

[BLOWNBY]

My next change this week is to move the mounting location of the Mega Bite Jr's as you just mentioned. I will have to try those adjustable uppers as you mentioned. But that will be later. I don't want to spend more $ or throw parts at it yet.

Thanks

[fanglemeister]

I agree, one change at a time is plenty. I think you will like the 80% position alot better.

On the adjustable length uppers: you can get fancy with the settings and introduce some suspension preload, but actually, you will need them to correct the bad pinion angle induced by the MB Jr arms you are running now. My pinion angle right after I installed the Jrs on my '90 at 80%, with stock length police/taxi upper arms ended up at -5.25 degrees! - a bit too much even for sloppy rubber bushings. With fresh poly bushings top and bottom, you would want the angle at -2.5 to -3 degrees or so, and half that if you install spherical bushings at the upper arm locations.

You can probably find a cheap magnetic angle finder at the local hardware store for less than $20 if you are curious about where your pinion angle is as of right now.

[stevieturbo]

Whats this airbag thing I see you mention ?