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Discussion Starter #1
Having some issues getting the car to the 60' these days. I'm not going to throw a whole bunch of parts at it just yet but am looking for shock input. Tires were 4 runs old on this pass, hoosier QTP's. 26x11.50's. I'm newer to the trans brake thing and think I may have been up too high all weekend on the pill. This launch was at 4,600rpm. Next time out I'll lower it and see if flashing the converter helps or not. Does the suspension look like it's doing what it's supposed too though?

14/130lb coilovers up front. PA Racing cromoly member and arms.
Strange single struts set on #2 from full loose.
Team Z rear springs & lower arms. Baseline uppers.
Strange single shocks set at #4 from full loose.
2940lbs with me in the car.

Track was EXTREMELY good.

1.478
4.272
6.601 @ 105.08
8.624
10.341 @ 131.00

Video is a bit long, there isn't much too see after the launch.
Thanks.

https://www.youtube.com/watch?v=6kUGhl2ASa4
 

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How much air was in the tires ?

Awesome video by the way, I watched the launch to many times. I'm taking off work and going to the track tonight lol.
 

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How much adjustment does the rear shock have? 4 clicks from full loose. How far is that from full tight? If you have 10 clicks from full loose to full tight that is one thing, if you have 20 clicks then that is something entirely different. So saying 4 clicks from full loose does not mean much without the rest of the context. I saw near 1 full revolution of the rear tire before the car even moved.
 

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Discussion Starter #4
How much adjustment does the rear shock have? 4 clicks from full loose. How far is that from full tight? If you have 10 clicks from full loose to full tight that is one thing, if you have 20 clicks then that is something entirely different. So saying 4 clicks from full loose does not mean much without the rest of the context. I saw near 1 full revolution of the rear tire before the car even moved.
The rear shock has 10 clicks of adjustment total. We can do it this way. If #1 is full loose and #10 is full tight, I was at #4 on this pass so 6 clicks from full tight. I tried tightening the rears up through out the weekend and didn't see anything change in the 60'.

I started at 15lbs of pressure in the tires and ended up at 12lbs. That's where I got the best short time out of the car. Still spinning more than I think it should be.
 

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Great video! It looks like the sidewall is deforming right at the hit and begins to spin. The instant center appears to be short and fast acting. The suspension appears to hit the tire hard and then it immediately bounces back into the fender like a basket ball. If you had double adjustables I would try going tighter on rebound to slow the hit and tighter on compression to hold the tire there. I bet it would respond to a stiffer sidewall like the MT 3053S. Just my two cents! Car looks really nice!
 

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Discussion Starter #6
Great video! It looks like the sidewall is deforming right at the hit and begins to spin. The instant center appears to be short and fast acting. The suspension appears to hit the tire hard and then it immediately bounces back into the fender like a basket ball. If you had double adjustables I would try going tighter on rebound to slow the hit and tighter on compression to hold the tire there. I bet it would respond to a stiffer sidewall like the MT 3053S. Just my two cents! Car looks really nice!
Thank you for the input! I'm stuck using a DOT this year for the class I'm running so choices are a bit limited. I'd love to run a radial but I haven't had a chance to narrow the rear end on the car and with the Aerospace brakes it's pushed the wheel out more than I like. I'm pretty sure if I go to one it's going to look like dumbo and I'm going to have major clearance issues with the 6.5" back space wheel. I've had my eyes on those Viking's, I guess it's time.
 

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Love my Vikings!

I was down at Norwalk watching the stock eliminator cars. I filmed a bunch from the side - like your video. In slow motion they all dead hook the tire out of the hole. I would keep taking film and watching slow motion. Tweak the setup until the tire dead hooks. That will be the most consistent and I imagine the tire will last longer too.

You may want to mock up a larger tire before you go to the trouble of narrowing the rear end. I have to run a 1/4" spacer on my car with a 28x10.5 stiff sidewall Hoosier mounted on a 10" rim. I beat the snot out of the inner fenders and rolled the wheel well but I have trouble with the spring pocket area (cant be moved). The width of those aerospace brakes just might put you in a happy place!
 

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what's the converter stall supposed to be? Are you running tubes? what does it do footbraking?
 

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Discussion Starter #9
what's the converter stall supposed to be? Are you running tubes? what does it do footbraking?
I don't really know what it's supposed to be. It's an UCC 8" that came out of a bigger inch N/A car. I called Lenny when I got the converter and he recommended trying it before changes were made as he thought it'd be pretty close. On the trans brake with no pill in the 2 step it goes up to 5900 or so. I'm not running a tube. I've only foot braked it a couple of times and I get too anxious and give it too much rpm. It seems to do the same thing spin wise except it tries to push the car through the beams before hand.
Here's an in car clip from the same weekend. It doesn't seem like it's spinning but this is actually an even worse 1.54 60'.

https://www.youtube.com/watch?v=DuR0Q3-SsHs
 

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I would think that the converter would be too tight if it came off a bigger cube motor, but I can see it was worth a shot before you spend any money on it. Lenny is awesome, he got my converter spot on, great customer service to. It may need a lower launch, maybe a "run" at the converter, or may need a higher launch, would be worth trying both. You don't list any measurements or anti squat, instant center values, but from the video it appears like the IC is short and the AS is near neutral (guessing around 100%). I'm guessing the AS is near 100% due to the lack of body separation at the rear tire, above 100% there would be separation and at less than 100% the car would squat or suck the tire up into wheelwell on launch. the front struts may be too loose, coming up too fast. most I've dealt with in the rear 10-ways needed to be in the 6-7 ( on 1-10 scale) sometimes more. I also think you will benefit from tubes or stiff sidewalls or even both, and more air pressure. You may also want to call Lenny back and tell him what the car is doing and how the converter is acting. What transmission?
 

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I threw away all the AS measurements and stuff, and just tuned by watching a video. One thing I found is the upper arms did very little at the hit. The lower arm's angle between rear end bolt holes and front end bolt holes had a large effect.

I believe plotting arms is a waste of time, because the upper arms do not push on the chassis like a suspension that has close body connection points for the upper and low to the chassis. The Fox has a very wide spread with short upper arms that are angled. All they do is pull back on the chassis way up high.

On my car the upper arm positions mostly seem to control the longer term lift of the front.

By angle through the bolt holes of the lowers, I have a lot of separation dialed in. Using a real stiff sidewall MT SS 295/55R15 tire at 14 psi, I get hard hit without any sidewall distortion. I managed a much faster 60 with a Hoosier slick than a MT 3055S, but my 3055S might have been worn out. The Hoosier was much stiffer, and that lets me run less air and more hit. That helps with high power launches, and got me well into the 1.1 sixty times. This is almost .1 better than any MT tire got me, but in fairness the MT's might have been shot before I had the suspension right. I have to buy and try brand new MT's to be fair.

With the street DOT legal full treaded radials, I have only done 1.2 sixty foot times. This might improve. I have Strange ten ways, and I run the second click from full loose with the street tires at 10 psi boost (ramping up after release) and 4100 RPM launch on a 6300 stall converter, and with slicks I run 5 clicks out of ten and launch at 5200 with trans brake boost at 20 psi. The rear arm angle hits the tires pretty hard, then I apply more boost.
 

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That slow motion video is great, Jesse. I could see you getting a lot out of something like that. Hope you get it sorted out. Car looks great.

Ed
 

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Looking at the video, I hear a bog or hesitation sound to the exhaust in the 60 ft area. It sounds like it needs more converter or something wrong with mixture or timing at the start.

Listen close to 1st gear sound as the car is rolling.

https://www.youtube.com/watch?v=DuR0Q3-SsHs
 

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The more I listen the more it sounds like the converter is too tight. Is there a data log??
 

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Discussion Starter #15
The more I listen the more it sounds like the converter is too tight. Is there a data log??
No, unfortunately I don't have a way to data log at this point. I'm still running on a factory A9l with a crystal mod and an old SVO Extender. When the car was dyno'd it was almost creepy how well it did in the A/F range with no real tuning device. It started out a little lean but by adding pressure at the rail we were able to hold low 13:1 through out the curve. The in car doesn't really show it but in the seat it feels like it's just spinning through the 1st half of the gear until it grabs. I wonder if when the tire actually does hook makes it seem like its pulling back on the motor which might indicate too tight of a converter? I don't know.... It'd be nice to see it "dead hook" just once to see what happens there. Thanks for all the help, I appreciate it!!
 

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Discussion Starter #16
That slow motion video is great, Jesse. I could see you getting a lot out of something like that. Hope you get it sorted out. Car looks great.

Ed
Thanks Ed!
 

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It would be nice if you had a log of RPM in low gear, but I looked at the first slow motion video and you are spinning like crazy. No point in worrying about the converter with all that spinning.
 

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Discussion Starter #18
It would be nice if you had a log of RPM in low gear, but I looked at the first slow motion video and you are spinning like crazy. No point in worrying about the converter with all that spinning.
Agreed. Trying to fix that 1st.
 

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Discussion Starter #19
Well... I said I wasn't going to throw a bunch of stuff at it so I made a quick run down to the local parts store to see what they had. Low and behold they had these on the shelf! I guess it helps when Vikings shop is 4 miles from my house! Cant wait to try them out.



 

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In to see how the vikings do. That video is nothing short of technically amazing. In my opinion, you need to loosen up the front struts and raise the tire pressure to around 15-16 psi. You appear to be distorting the tires right on launch and the front end needs to come up faster to transfer more weight on the hit. My car does the opposite - also QTPs - hooks, then spins. You can see how my front end comes up too fast:

https://youtu.be/tgMk44_lnBc

It kind of pops up, then spins. Your front rises slowly by comparison (I'm about 450 lbs heavier than you).

Also, I'd double check the upper torque boxes to make sure there's no damage. The rear seems to moves around on launch. But at this framerate, it's hard to know exactly what normal is.
 
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