69 mach 408w build

[superduty69 11]

Here is a simple test, jack the car up and let the rear hang down. Measure the extended length of the shock vs the total extended length. If they are very close the shock is topping out under power.

 

My guess that roughness you felt was the shocks topped out.

 

I ran the 44130's on mine, on the street for a bit and track with the stock springs. The stock springs are just not ideal for this application.

 

You are encountering the same issues I did when I started taking mine to the track. I didn't have as much fun street driving, car shows as I did racing so I went that way.

[BuckeyeDemon 211]

Here is a simple test, jack the car up and let the rear hang down. Measure the extended length of the shock vs the total extended length. If they are very close the shock is topping out under power.

 

My guess that roughness you felt was the shocks topped out.

 

I ran the 44130's on mine, on the street for a bit and track with the stock springs. The stock springs are just not ideal for this application.

 

You are encountering the same issues I did when I started taking mine to the track. I didn't have as much fun street driving, car shows as I did racing so I went that way.

 

the shocks were the limiting factor. i always have had to remove the shocks to let the rear drop all the way down when adjust the pinion angle.

 

of course there ar compromises when trying to make a show car, drag car, street car, etc. along with trying to make it look stock. that's the challenge.

[superduty69 11]

of course there ar compromises when trying to make a show car, drag car, street car, etc. along with trying to make it look stock. that's the challenge.

 

This is as true as it gets.

 

You have done an amazing job with your car, and it is good to see you enjoying what all the work got you.

[BuckeyeDemon 211]

i mounted a camera to the underside to see what the suspension was doing (first time on the way to a cruise in).

 

[BuckeyeDemon 211]

and i finally got the software to slow down the drag video from the still photo below.

 

[Powershift 19]

Cool videos. Always interesting getting perspectives from points you can't normally see.

[bnickel 10,004]

pretty cool to see how far you were carrying the front tire. it still looks to me like the car is hitting the limit of the shock on the top. also definitely looks it might could use some more air pressure in the tires too, sometimes going the other way with air pressure actually works better, so maybe instead of going down from 20 psi, try going up. sounds counterintuitive I know, but a lot of guys get better results with more air pressure. it's a definite balancing act between suspension, tire pressure, launch rpm and clutch release to get a car to go down the car right and hook up well.

 

as side note, I'd bet if had marked the slicks on that run you'd see that the tire was spinning some on the rim too. you may need to try some rim screws as well... maybe.

[stangnet33 88]

Great video!! Good eye on the front tire bnickel :biggrin: I learnt about the screwing the tires down the hard and expensive way early on when I started racing. :001_rolleyes: Agree with the adding a little more air in the rears.

[BuckeyeDemon 211]

i'm already running rim screws to prevent rotation and damage to the tube (conservative decision from the start). 8 per side.

 

in a perfect world i would watch the video right after making a run. given the circumstances i wasn't able to do that on my previous trips. maybe this camera can help give a little immediate feedback for myself when i go to the track the next time.

 

i have installed a set of double adjustable shocks (two small knobs) for the front (i have a full set of koni classics with 1600 miles for anyone interested). i'll also have the ability to throw in an easy 1" offset to the front for a couple more inches of travel when going to the strip the next time. it will be a few more weeks before i can get back.

 

[bnickel 10,004]

good job on the screws!!! when I do the cougar I'm gonna have a set of 15" cougar rally's made that look stock and are totally painted so I can use trim rings and I'll hide some rim screw under trim rings. :sleep1::yes:

 

also looking for a set of old school Gabriel striders and some AR 200s daisy wheels too, if anyone know of someone stashing a set of either....

 

If I can't find a set of daisy mags for it I may just end up getting a set of the new US Indy slot mags instead, would rather have the daisy's though

 

 

I just bought an NOS vintage set of Air Lift helper bags for the rear and I already have an NOS air shock compressor with dash controller so I can run the setup from the driver seat.:thumbup1:

[stangme428 33]

so when you lift the tires like this... do you install straps to control the length of travel? seems that when the straps are hit then the tires may start back down... :sweatdrop:

[BuckeyeDemon 211]

i took it to the dragstrip again.

 

i cut up the main leaf from the old original springs and added it to the front of the spring pack (forward of the axle) along with adding one additional band on the front and another band in the back. these are different shocks (double adjustable) as well, so i took a guess at a setting.

 

the car felt a lot better. my friend took more video from the side at the launch, so i'll get that tuesday. the spare tire/jack is still in the car and the 1 1/8" front sway bar is still connected. although i don't think those items will have a big impact at this point anyways.

 

it wreaks of clutch, although i can't really tell if it's slipping or not.

 

i did manage to improve to 11.89 @ 117 and get a 1.68 60'.

 

here is a short video from underneath with the camera (and one with slow motion). i may need to try taping it to reduce the vibration.

 

 

[Bossed 10]

The ole girl sounds healthy

[BuckeyeDemon 211]

video from my friend who has been kind enough to do this for me every time.

 

there is still some bouncing (could see it from the undercarriage shots), but nothing like before.

 

i'll probably try firming up the rear shocks some more first (was on setting 12 of 16).

 

i have a set of 2" shock extensions for the front and rear but i'm trying to avoid the need to use them (preference is to simply change tires and shock settings and hit the track). the shock extensions would probably take less than 10 minutes to install though.

 

 

[superduty69 11]

Ok, a few questions,

Leave rpm

Tire pressure

What traction bars are they?

 

I watched both slow speed videos multiple times. I see several issues but I know your reluctance to change the car as it sits.

 

Here is a video of mine. Ran a 7.44 @ 95.

Stock springs, slide-a-link traction bars and Calvert shocks.

Leave rpm was 5000 and tire psi was 15.

 

[BuckeyeDemon 211]

3500 rpm

17psi

caltrac, upper hole, just touching leaf

 

7.65 @ 92.3

 

i'm open to suggestions.

[superduty69 11]

Move the bar to the lower hole in the front. In the vid it looked like Calverts rear bracket but the bar was at such an angle I was unsure.

 

Do not use the upper hole, in a stick app. It will hit the tire to violently, as you are seeing.

 

I would lower bar in the front. I set mine with a 1/16" gap with me in the seat. This soften the hit even more.

 

Install the shock extensions also.

 

Take it and run it. See what it does, you may not need the extensions but I would put them on and see how it reacts. If it doesn't do the bounce, take them off and see if it comes back.

 

 

I would leave everything else as is till you make a pass.

If it bogs raise the leave rpm.

If it spins lower the rear psi. My Hoosiers liked 12.5-13.5 the best but I never used M/T so you will have to experiment with that.

If it still seems to have a lot of body separation tighten the shock extension 2 clicks and if still spinning after lowering the rear psi loosen the shock extension 2 clicks. This is also experiment area.

 

The traction bar setting is most likely your biggest issue in the vids. In the second slow vid you see it try to crush the tire and it never moves. The bars put that much leverage on the tire that it raises the body till it takes the weight off of it. Or the shock tops out. The tire snaps loose for one turn and the car goes forward.

Having the tire stick like that on the hit is extremely hard on parts.

 

Try it and see how it works and let us know.

Edited September 19, 2014 by superduty69
Missed something

[BuckeyeDemon 211]

i don't have any other hole for the caltrac. i've been toying with the idea of making another set of brackets and at most lowering that hole 1/2" (will put the bracket level with my frame rails). I won't go any farther than that. That won't happen till this winter though.

 

As previously mentioned, I toyed around on the street with the caltrac's loosend a lot and it seemed to let the car rock back instead of lift (before i reworked the rear springs). I think the less preload (or more gap) delays the hit (and hopefully gets the car rocking back).

[superduty69 11]

Yes, opening the gap will help to a point,but too much could be a problem at the track with sticky tires.

 

If you only have one hole in the front you could raise the rear of the bar. I did this with mine. It was still hitting the tire too hard with it in the bottom front hole. Drilled another hole maybe 1" up. Any amount of lowering of the front hole you can do, would help.

 

I can take a pic of that in the morning if you want.

[BuckeyeDemon 211]

Yes, opening the gap will help to a point,but too much could be a problem at the track with sticky tires.

 

If you only have one hole in the front you could raise the rear of the bar. I did this with mine. It was still hitting the tire too hard with it in the bottom front hole. Drilled another hole maybe 1" up. Any amount of lowering of the front hole you can do, would help.

 

I can take a pic of that in the morning if you want.

 

i think i understand what you are talking about a different hole in the back. a picture would be nice (no rush because i absolutely won't be drilling that hole any time soon till i'm sure that's what i need). with how high the front hole is, i would be a little concerned about the leaf springs hitting the bar though if i relocated the back.

[sportsroof69 13]

I think you really need the lower hole. When I had the stick, I could never get mine to work in the top hole.

[BuckeyeDemon 211]

I think you really need the lower hole. When I had the stick, I could never get mine to work in the top hole.

 

that's just not going to happen.

[BuckeyeDemon 211]

i had picked up another flywheel and pp/clutch setup and had them both balanced last friday in preparation for a clutch replacement. so i met up with someone else at the dragstrip. it was pretty warm evening but not bad.

 

i did add the rear shock extensions. my intent was to set the rear shocks at setting 14 (of 16) as well.

 

the car bounced again severely. so i was scratching my head on how that could be. it turns out when i got home and was adjusting the rear shocks back to the setting i had on the street, i realized i had forget to turn them up after taking them to full soft (which is really, really soft) for verifying the setting and installation of the shock extensions. i was really kicking myself at a wasted opportunity.

 

here is an in car video of how it was kicking me around.

 

 

i pulled the flywheel/pressure/plate etc and replaced it this weekend. here is a picture of it. it appears to be blistered with a bunch of high spots. i'm pretty sure i'm the reason it looks like this.

 

 

[1969mustang 10]

Have you had problems with your pressure plate being out of balance? I have a vibration at 2500 rpm and the pressure plate is the only thing I can think of that could be causing it (that is if my machinist did everything he said he did).

[BuckeyeDemon 211]

Have you had problems with your pressure plate being out of balance? I have a vibration at 2500 rpm and the pressure plate is the only thing I can think of that could be causing it (that is if my machinist did everything he said he did).

 

i had the centerforce balanced along with this new one before ever using them. both shops took a little weight out of both of them. a lot more was removed from this mcleod unit.