1985 GT - Test your mustang knowledge, guess how fast i'll run 1/4 mile

[tireburner163]

Originally Posted by nitrousboy

i would say 13.00 with out the bottle on a good day with the bottle 12.50 ish.

I think nitrous is going to add a lot more than 1/2 a second. My old car ran 13.5's on motor and 12.1 on a 150 shot. My coupe ran high 12's on motor and 11.60's on a 150 hp shot.

[bigred90gt]

Originally Posted by tireburner163

You want to keep the V-8 rear springs.


The 4 banger rear springs are too soft, the suspension ends up having too much travel. It absorbs all your launch energy instead of planting the tires.

I have heard the opposite. The 4 cyl rear springs help the ass end squat, allowing for greater weight distribution to the rear of the car, giving better traction and a harder launch. I'm no expert, but this is common practice.

[Unit 5302]

If your springs allow for "too much" squat, you waste energy lifting wheels off the ground rather than applying it to forward acceleration.

[RBatson]

Originally Posted by bigred90gt

I have heard the opposite. The 4 cyl rear springs help the ass end squat, allowing for greater weight distribution to the rear of the car, giving better traction and a harder launch. I'm no expert, but this is common practice.

Exactly what I was thinking when I read it.

[RBatson]

Originally Posted by Unit 5302

If your springs allow for "too much" squat, you waste energy lifting wheels off the ground rather than applying it to forward acceleration.

I'm just curious, how much time have you spent at the drag strip?

[tireburner163]

Rear springs should be a little stiffer for a drag car but many people think that the car should "squat" during the launch so they install softer rear springs on the car to accomplish this. The only cars that should be squatting during the launch are those cars that shock the tires very hard (5-speed cars) and with enough power where the car will overpower the tires. Prostock cars actually squat during launch because they develop enough torque and hit the tires so hard that the squatting helps absorb some of the shock and keeps from overpowering the tires. But, setting up the car to squat is not a function of the springs. It is the position of the Instant Center (IC) that determines how the car squats. The STOCK mounting points for the control arms already cause the car to squat which can unload the tires. So in order to compensate for this squatting the springs need to be stiff to transfer the force to the tires.
If the rear end squats that means that the rear springs/shocks are not pushing the rear tires into the ground. They are just compressing. For the most part you don't want the rear to squat because you want some resistance from the springs/shocks to transfer the force/weight to the tires.

Example:
Make a coil spring out of a coat hanger and place it on a bathroom scale. Push on the spring. The scale is not going to read much because you are not transferring any force to the scale through the softer spring. Now take the spring out of your car and place it on the scale and do the same thing. The scale will read more pressure because it IS transferring more force through the spring.

[tireburner163]

Originally Posted by RBatson

I'm just curious, how much time have you spent at the drag strip?

I ask the same question to you, sir.

[RBatson]

I used to go a few times a year. The first time I went you probably weren't too far out of diapers. I do have a good friend that ran Pro 5.0 though and it seems to me he said the cars should have 4 cyl springs all around. Any other questions? I'm about to get the 89 running again.. I guess you might wanna run it.

[tireburner163]

Originally Posted by RBatson

I used to go a few times a year. The first time I went you probably weren't too far out of diapers. I do have a good friend that ran Pro 5.0 though and it seems to me he said the cars should have 4 cyl springs all around. Any other questions? I'm about to get the 89 running again.. I guess you might wanna run it.

So what your saying is that you USED to go a couple times a year.......but now you don't. So basicly you spend little time at the drag strip. Just because I didn't even have a drivers license when you first started drag racing, doesn't mean you know any more than me. Times change, GT-40 intakes and E-303 cams used to be the shit.........not anymore.

Who was your buddy that ran Pro 5.0?

I'm just going buy what a few people say about how to set up a suspension. I mean really...what do a couple of people like David Wolfe know about suspension stuff anyway.

Glad do see your getting the 89 running again.

I'd be glad to run you, I'm always up for a little fun.

[RBatson]

Originally Posted by tireburner163

So what your saying is that you USED to go a couple times a year.......but now you don't. So basicly you spend little time at the drag strip. Just because I didn't even have a drivers license when you first started drag racing, doesn't mean you know any more than me. Times change, GT-40 intakes and E-303 cams used to be the shit.........not anymore.

I know things change quickly when it comes to racing. Actually I USED to go quite a bit. Life changes and so does interests.. I changed job description, got a new car and got into the stock market and so on.. I'm not saying I know anymore than you, I'm not a mechanic and never really got deep into an engine but.. 4 cyl springs on the back is almost a given.

Originally Posted by tireburner163

Who was your buddy that ran Pro 5.0?

My friend was sponsered by Holcomb. He drove the car in their ad. I don't even know if they still use that picture but he is still working on mustangs.

Originally Posted by tireburner163

I'm just going buy what a few people say about how to set up a suspension. I mean really...what do a couple of people like David Wolfe know about suspension stuff anyway.

Names don't really impress me much anymore. I thought I was being smart by ordering a chip off a well known guy by the name of Chris Johnson. The Diablo had just came out but I thought I would go ahead and get a custom chip by the legendary Chris Johnson. The chip never did work and he really didn't seem to care. Though he said he would look at it if I drove many hours out of my way for $75 an hour.

Originally Posted by tireburner163

Glad do see your getting the 89 running again.

I do miss it.

Originally Posted by tireburner163

I'd be glad to run you, I'm always up for a little fun.

When I get it going again I'll let you know.

[84LX89GT]

Originally Posted by 87 heartbreaker

hey man let me know when u race, i live in puyallup would love too see ya, maybe me take a few tries myself.......p.s. anyone here have the mac short tube headers? i just tried to install and the passenger side is lodged ontop of the engine mount any suggestions or concerns? please hurry i need to drive to monmtana next week, in a WORKING car

Sorry i missed your post the first time through and just now read it. Sorry i didn't reply, now i feel bad. What i would do (you probably figured it out) would be to loosen the mount bolt, take a jack with a block of wood and jack up that side of the engine.
Yeah, send me some contact information (email or phone # and i'll contact you before i head out.) It's really fun and doesn't cost that much (compared to other stuff you can do all day). There's usually a few mustang guys there at the track and they are more than happy to b.s. and help out when you need it. I should be heading out there soon.

[tireburner163]

You got a chip from JMS and it didn't work? For the mach 1? If you would have called and talked to Monte he probably would have fixed it for you. JMS does all my tune work and does a good job of it as well. Doesn't really seem like them to be screwing people around?




But back to my main point.

Jump over to any place that has some REAL tech such as www.hardcore50.com or www.nmraracing.com and see what those guys are doing. Not what they THINK will work or what is SUPOSE to work, but what IS working in their race cars.

I did a V-8 conversion several years ago on a 92 LX. It was cutting 1.79 60 foots with 70/30's and otherwise stock 4 banger supension. I swaped in a set of 95 GT rear springs and added a rear-sway bar. The next week at the tack 60 foots dropped to a 1.71

The 4 banger rear springs don't work unless you are shocking the tires very hard. You want the front end to come up, but the rear-end to say level and plan the power. Not just waste all your launch energy.

Either 1) the springs will absorb a lot of your launch energy and/or 2) the springs are so soft that when you do hook, the car will unload about 30-40 feet out and spin.

Take a look at the spring rates on Eibach's drag launch kit. Much softer front springs and rear springs that are about the same as stock.

[andy669]

Every stock suspensioned drag racing Mustang I have been associated with has had stock V-8 springs in the rear. 4 cylinder springs up front are the most common for guys not using coil overs.

Andy

[Unit 5302]

Originally Posted by RBatson

I'm just curious, how much time have you spent at the drag strip?

I don't go to the drag strip at all. It's not really part of my interest anymore, and when it was somewhat, there were still other things I was more interested in.

That being said, I wasn't indicating 4 banger springs are better/worse/the same. I'm explaining tireburner163's logic using some rudimentary physics.

I find the conceptual side of automotive engineering less expensive than the direct application.

[Dark_5.0]

I have 4 banger springs up front and V8 springs in the back and I yanked a 1.59 60ft on 8 inch slicks last night.

I prefer to walk the walk rather than talk the talk.

[84LX89GT]

Cool, i'll probably just run the 1st time with the 3.73 rear axle (allegedly 3.73) with stock control arms and lowering springs, then for the next time out i'll swap the 4.10 8.8" rear out of my LX and install the granatelli arms i got with GT rear springs and see what happens.
---update, the car is running and driving and i drove about 100 miles to start breaking the clutch in----
currently needs fixing: high idle, probably vacuum leak or carburetor - won't spend too much time doesn't affect 1/4 mile. I need to swap the stock shifter in - the summit shifter SUCKS!!!!! - all gauges are erratic or just don't plain work, i'm going to make an aluminum plate for the dash and install gauges in that. - Shake at freeway speeds, probably (hopefully) just unbalanced tires.
I have phone dial wheels for the slicks and i'll mount those up soon.
Also found out (found ID on carb) that carb is a 3310 Holley 750 cfm vacuum secondary....that explains the stumble/bog at part throttle or at mid-rpm.
I pulled out the MSD distributor and found that when i got it the timing was retarted to 6* initial so it would idle at 900 rpm, the distributor curve was the slowest possible (comes w/dist) heaviest springs (advance full @ 5500 rpm) and the total advance bushing was 21* (27* total advance w/initial). I changed the curve to hit full @3000 rpm, 36* total advance with 11* initial, made a huge difference in torque and power in general.
-things are progressing but i've had to start almost from the ground up with this stupid thing

[RBatson]

Originally Posted by andy669

Every stock suspensioned drag racing Mustang I have been associated with has had stock V-8 springs in the rear. 4 cylinder springs up front are the most common for guys not using coil overs.

Andy

I must be remembering wrong then, too bad you didn't reply earlier. You definitely have credibility friend, that may have been what he said now that I think about it but.. for some reason I remember someone using 4 cyl springs all around.

[RBatson]

Originally Posted by tireburner163

You got a chip from JMS and it didn't work? For the mach 1? If you would have called and talked to Monte he probably would have fixed it for you. JMS does all my tune work and does a good job of it as well. Doesn't really seem like them to be screwing people around?

I hate to be redundant but.. No, not for the Mach. I said when the Diablo chip first came out which was in the spring of 2000, I think. I paid $302 for a chip to go in the 89 stroked and blown mustang, the one that currently needs main bearings. I actually met Chris in 1999, nice guy . I talked with him a couple times on the phone and we talked for quite a bit, great guy. I talked to him about upgrading my Vortech and ordering a chip. A few months later, when I was ready to order the chip I ended up talking to someone that sounded like they were eating their lunch, which I hate. Anyhow, when I got the spec sheet, which was supposed to list my mods, it said long tubes(which I don't have) and a few other minor things that I can't remember didn't match up. I called and they said it was no big deal, didn't speak to Chris. In the meantime I ended up having some cooling and charging problems that set me back a bit and by the time I got around to dealing with the chip again.. I called and told them the car was running way rich, I couldn't tune it and the chip wasn't doing anything. I asked if they could look at it in Bradenton and figure out why it wasn't working, they said they would be busy with their car at the spring break shootout, I can understand that. Then I asked if I could come by earlier in the week, on my way down to Bradenton, and Chris said he would but he got $75 an hour. I said I bought a chip that doesn't work, he said he doesn't work for free. The more I thought about it the madder I got. I'm not a rich man, I paid $302 for a chip and I expect it to do what it was supposed to do. It did absolutely nothing and I have no idea why. I don't think I should have to pay $75 an hour for someone to figure out why their product doesn't work.. maybe I caught him on a bad day, I don't know. I do know that I wish I had ordered the new Diablo chip instead of going with someone that impressed me. You have to remember, I first read about Chris Johnson and his little white coupe back around 1991(I believe), I was quite impressed that someone could get an extra 100hp out of tuning the ecm.

[84LX89GT]

well i injured myself at work so the now almost done Gray GT may not run for awhile....crap.....things were going to good, lol

[fordmustang]

hi , i hope that you get 13.low , good luck