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Discussion Starter · #1 · (Edited)
I finally made it to the track yesterday with the new motor combo. Before launching into the problem, let me just point out that the car is radically different since I last drove it – not only is the HP and torque almost twice what it once was, but I have switched to Weld rims and MT ET Streets (28 x 11.5) out back (previously using 235/15 BFG DR on AR Neptune rims). My best ¼ on the old motor was a 14.1. So I was somewhat disappointed yesterday when the fastest I could go was 13.38. Here is a breakdown of that timeslip:

RT = 0.795
60ft = 2.239
330ft = 5.960
1/8 = 8.90 @ 85.04
¼ = 13.383 @ 113.53

On this particular run, my reaction time was pretty poor (I routinely cut in the 0.65 range now), but as you can see, my real problem is getting out of the hole. It took me over 2.2 seconds!! I have done better than that on street tires. In fact, with the same suspension set-up, I cut routine 2.0s with the drag radials.

I already know that traction is the main problem – the tires spun in the first three gears on that particular run. But varying my launch technique seemed to have no effect. Whether feathering from idle, or launching at up to 3,500 rpm, the 60ft times were the same. In fact, the five runs I made were: 2.26; 2.23; 2.24; 2.32; and 2.26. If nothing else, I consistently sucked. Note – because these are new tires, the first burn-out was a really good John Force style smoker. The others I tried just hazing the tires to really smoking them again.

The ET Streets are run with tubes, and all the runs were made with 16 psi (per MT recommendation). I have H&R springs with Tokico Lumina adjustable shocks (set to 4 left and 5 right). The rear lower CA is from Maximum Motorsports, and the upper is a Ford heavy-duty. Up front I also have H&R springs with Tokico drag struts set to 1. The front tires are Moroso DS2 4.5” skinnies. Finally, I’m running 3.83 gears.

I firmly believe this car can make easy low 12 passes if I can eliminate the tire spin. I know I can lower the tire pressure, but how low should I go and still be safe? As for suspension, I know this will need to be improved eventually, but do you think I can make at least a mid-12 pass with what I currently have?

One last thing - at the track, I notice that other racers slicks crinkle when they drive, and flex dramatically at launch. There was none of this in mine. They looked like normal street tires. Now I know this is due to the pressure, but why does MT recommend 16 psi? Is the lack of any flex due to the tubes? Should I loose them as early as now?

Thanks for bearing with the long thread.
 

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one thing to check for is if the outer or inner fender are hitting the tires.my stang with 285/60/15 mcreary dot's would hit the tire on the outer edge and unload the tires, i switched to the same size et street that you have and i have plenty of room, but my backspace is 5 1/4 not the usual 5 1/2 on weld wheels. you may also want to play with the rear shock adjustments. i have the avo adj. and i have mine set at 2 clicks from full - and i was able to get 1.80 60ft even with the mcreary's. hope this helps.
 

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I run 12 in mine with tubes
I have run them down to 9 with no problems
This is with a stick letting the clutch out at 6400
1.57 were the norm.
The next thing to do is baseline the suspension.
I would read www.Baiselinesuspensions.com and see where you are at.

Tim
 

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Discussion Starter · #4 · (Edited)
Thanks for the link Tim, I'll give it a read tonight. You might want to edit the address for other users, it should be www.Baselinesuspensions.com you added an extra "i" by accident :)

See - I had to edit my "adit". Sometimes I think I need a second brain.
 

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Discussion Starter · #5 ·
iceman5426 said:
one thing to check for is if the outer or inner fender are hitting the tires.my stang with 285/60/15 mcreary dot's would hit the tire on the outer edge and unload the tires, i switched to the same size et street that you have and i have plenty of room, but my backspace is 5 1/4 not the usual 5 1/2 on weld wheels. you may also want to play with the rear shock adjustments. i have the avo adj. and i have mine set at 2 clicks from full - and i was able to get 1.80 60ft even with the mcreary's. hope this helps.
Thanks Iceman - I've banged, bashed, and cut to the point where the tires fit nicely with no rubbing issues (that wasn't the case when I first put them on).
 

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David Schwarz said:
Thanks Iceman - I've banged, bashed, and cut to the point where the tires fit nicely with no rubbing issues (that wasn't the case when I first put them on).
Ive got a very similar suspension setup (without the HP though im sure).. I think i can help! You should be easily hittin 1.7 60's dude.. Its your suspension setup & PSI thats way off.. First the Adj. struts & shocks, Wow! try #2 or 3 up front & 4 in the rear.. mine are at 2 up front (real soft may even go to 1 with my ET Streets) and 4 in rears (Real stiff, No squating) Squat is not needed till you get to about Pro-Stock.. I tried softer, lower springs in rear & it completely threw my car off 2.0 60's & i couldnt adjust it back in line.. If im turning 2.0 60's i go home or try & fix it fast cause im way off! Next is your tire pressure.. if your spinning @ 16PSI & think your suspension is kinda close DROP PSI if your at 16 especially.. you can take it down to 10 or 12 no problemmo just to "see".. If ET falls off but your not spinning move it back up a tad till you get it spinnin again.. Nose of car should be coming way up pretty quick & come back down slower.. My tires come off ground with D/R's & im well under 300 HP SAE... Im hoping to get both tires to lift better with weight changes & ET Streets i have now.. Unless youve lost HP somewhere or your car weighs 4000 lbs. youve got to find the problem somewhere.. My Lowers are also Adj. so i can lift my rear springs up a tad to "tighten" them more.. This alone has helped almost .15 in the 60 believe it or not! :D
 

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i just re-read your first post & noticed ALL runs were made at 16 PSI.. thats bad in that its the easiest quickie change to make between passes to "dial car in" for that particular day.. this 1 thing could account for most of your 60' problem right there.. it may very well have been a 11 PSI kinda track day but now you will never know.. Im betting this is at least .2 tenths of your problem with Shocks/Struts adjustments being .15 more.. these 2 things would have gotten you into at least mid to upper 12's.. Good Luck next time either way! :cool:
 

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Discussion Starter · #8 ·
Thanks for the ideas AV8R. I'm already looking into adjustable control arms. I think this is going to be the biggest help, although using less air should help as well. As for tire pressure, the tires were originally at 16 psi cold. After a couple of runs, they had gone up to nearly 18 so I lowered them back to 16. So in fact I did lower the pressure a little, just not enough :)

P.S. That's a mighty impressive Mach I you have there. I didn't want to modify mine yet (I have an extended warranty) - that's why I bought the '88 to play with. The year old Mach I only has 9K on it.
 

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David Schwarz said:
Thanks for the ideas AV8R. I'm already looking into adjustable control arms. I think this is going to be the biggest help, although using less air should help as well. As for tire pressure, the tires were originally at 16 psi cold. After a couple of runs, they had gone up to nearly 18 so I lowered them back to 16. So in fact I did lower the pressure a little, just not enough :)

P.S. That's a mighty impressive Mach I you have there. I didn't want to modify mine yet (I have an extended warranty) - that's why I bought the '88 to play with. The year old Mach I only has 9K on it.
Hey Cool, my mach is barely 6 mos. old & 2800 miles only.. :D
 

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Your 330' and 1/8 mile time and speed are way off for a 460+ hp car. This tells me either you are spinning all the way through the eigth or you have a slipping clutch that isn't catching up until some point after mid-track where it starts to charge giving you the 113mph trap speed.

Yes, 16psi is too much pressure but there is much more to this story than a bad short time.

Hope this helps.
 

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Discussion Starter · #11 ·
JB - you're right, I'm spinning all the way through the 1/8th. You may have noticed buried in my novelette that I spun the tires in the first three gears. In fact, I cannot get all the way on the throttle until i get past the third gear shift, otherwise my tires do in fact spin. So I agree that tire pressure won't be the whole story, it's also going to be the suspnsion.

As an afternote, I watched a video taken of one of my runs, and noticed that the front of the car was lifted and settled back down all within the first 10 feet. This tells me that there are adjustments to the shocks that I need to make as well. The fronts were set to "1", so I may try a stiffer setting for my next time out.
 

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You want looser on the front and stiff on the back as far as the shocks/struts go. It's allright for the front to come up a bit as that usually transfers some of the weight to the rear tires. It sounds like you have some pretty basic stuff you need to tweak. The tire pressure is a big one too, I've seen guys run 8-9 lbs on ET Streets. Definitely look at Kevin Slaby's site baselinesuspensions.com. You might try emailing him or PMing him on here for some advice if searches and research doesn't answer your questions.
 

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Discussion Starter · #13 ·
Chris91LX said:
You want looser on the front and stiff on the back as far as the shocks/struts go. It's allright for the front to come up a bit as that usually transfers some of the weight to the rear tires. It sounds like you have some pretty basic stuff you need to tweak. The tire pressure is a big one too, I've seen guys run 8-9 lbs on ET Streets. Definitely look at Kevin Slaby's site baselinesuspensions.com. You might try emailing him or PMing him on here for some advice if searches and research doesn't answer your questions.
Thanks Chris - I wasn't concerned about the fact that the front end rose, but rather that it settled back down within 10 feet. That's why I was thinking that a stiffer setting in front might slow down the rise and settle, giving me a longer duration weight transfer.
 

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What is your burn out procedure? Do other racers complain about your track surface? Are you racing on a "street" night with a lot of cars on radials? (they tend to take water down the track)

DO YOU SMELL CLUTCH?

Something is really fugged up with your car.
 

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Discussion Starter · #15 ·
351 stang said:
What is your burn out procedure? Do other racers complain about your track surface? Are you racing on a "street" night with a lot of cars on radials? (they tend to take water down the track)

DO YOU SMELL CLUTCH?

Something is really fugged up with your car.
Nope, don't smell any clutch. It's low mileage, and holds fine. Both tracks that I race at may have "traction" issues according to some racers, particularly up at Carlsbad. Yet there are those that do cut 1.5 - 1.6 launches. Unfortunately, I don't have any other tracks to compare to, so it's difficult to troubleshoot. KevinS suggested an interesting possibility, namely that my "new" ET Streets might be older than I think. I'll look into this to see if that's a possibility. It may just take some time, practice, and patience to get it all sorted out.
 

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Discussion Starter · #17 ·
silver_lite_nin said:
Carlsbad wasn't bad today. The traction was actually pretty good.
9.30 - you're smoking. I have the red GT, we talked briefly earlier this fall. Maybe next trip up to Cbad I should let you take the car down the track once. Then at least I would know if it's car or driver.
 
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