Building new ITB Mustang

1

13GT3

New member
There seems to be many opinions about parts, set-ups, tires, etc, and at this point, I'm open to most any suggestions. I have a very clean 93 coupe which is ready for the cage. I have already selected the builder for that, and will be doing the optional 8 point attachment, with NASCAR-style bars. The only question I have on the cage, is the location of the rear main hoop braces. I also have a very low mileage 87 engine, new Ford Motorsport 3.73 and 4.10 gears, and 1 new and 1 rebuilt posi diffs, and a 4 pt front crossmember brace. I am not totally unfamiliar with what is available, but I am looking for help, ideas, and sources.

[This message has been edited by 13GT3 (edited March 27, 2004).]

[This message has been edited by 13GT3 (edited March 27, 2004).]
 
To answer your question about rear main hoop braces: We experienced favorable results by locating them at the point of the rear floor above the rear spring perches. Our first car had them located by the rear shock mounts...but the second had them over the spring perches and we felt that it significantly helped things (we replaced the shell and used the same components, so it was a pretty accurate comparison).

As for other car issues: Brakes are marginal (at best) on these cars and finding decent pads is difficult and costly, plus without cooling ducts, you'll cook everything--I mean everything! Synthetic wheel bearing grease is a must! Without ducts at a track with moderate braking requirements, our tire pressures were unpredictably high, the backing plates melted (conforming to the piston), and without the synthetic grease, we would have certainly cooked the wheel bearings!

You'll always be down on power compared to other cars in the class, or you'll be illegal. The cars are tanks, aren't too horrible on tires (even considering their high weight for the class) and spare parts are cheap. Plus, assembled correctly they'll take all kinds of abuse! We ran one in a 24 hour race in 96 and it never skipped a beat...wasn't the fastest thing, but was quick enough and was dead consistent.

Contrary to popular opinion, it is possible to get the car down to minimum weight legally (2640 lbs.). But, consider that our shell was a 1987 Hatchback...I'm not sure about the 93 chassis.

Good luck!
 
Watch your brakes! The 4:10 rear end might be a little too short depending on the track. I don't see how you can get the car down to weight. Our new car is non-power steering, non-brake booster, light weight griffin radiator, the lightest of four different front K-members etc.... This is the problem, we have a very safe cage that adds 56 added pounds to the car.
There are a great amount of books on the car. Get them all and read them over and over. You can pick up little facts even when they Talk about the V-8 stuff.
The double adjustable Koni's are great. The Steeda rear end set up is our set up. Heim joints in the front and rear work wonders.
We are lucky to have dyno time on the motors and the power is there, not Volvo power, but close. The heads on the flow bench are OK, oval or port D-port does not matter. The twin plug flows the worst but the roller cam is the best. Ford put quite a few cams in the motor, you just have to find the one that works with your set-up. We found that the carb and F.I. flow and power about the same. We run the carb for the simplicity. It just takes a lot of time to figure all that out. Play with header size and lenght, carb placement and filter placement. I could go on and on, were not even done yet with our car. Every motor we build comes out quite often for checking and new set up options and then back to the dyno. There is a reason why sunbelt builds great motors for Mazda's, they do there home work. For me, my dads motor man from racing years ago helps us. He still had volumes of engine notes from the past. We also hooked up with some circle track boys that run the 2.3 in stock classes and they have been great. Do not worry about all the power stuff until you get the car handling well. Call me and I can tell you more.
My typing sucks and I am so slow. I will tell you this, I want more Fords out there and I am willing to help you get 90% of the way there, the last 10% is up to you.

Ron
770-218-9967 Home
770-757-1447 Work
 
As Kazoo (we're partners) mentioned, we built an '87 ITB Mustang from the ground up. Every, repeat, Every unneccessary item was eliminated, and we carefully selected the pieces that were to go on the car. It was a hatch, so there was about 50lb that could not be eliminated.

The cage was fabricated from scratch by a professional to our design, 8 points, well cross braced, with the rear bars attached to the SPRING purches, not the shock towers. We used an 8 gal cell, electric pump, and as much aluminum as we could to fabricate anything that was needed. It had a legal, complete dash, with the original heater box in the original position. Hoses too!!

To major items: T-5 transmissions are heavier than the earlier Cologne 4 speed boxes, and if you are very clever and resourceful, you can find a '79-'80 6 3/4 inch differential which is substantially lighter than the 7 1/2. Gears are problamatical as they come from the earlier application (Pinto), but solvable legally...machining of the gears is required. We ran with a 3.45. We know people using 3.73 in a 7 1/2, but I'd think the 4.10 is a bit high with a 1:1 fourth. Could be wrong, though.

13X6 inch wheels in steel, very light are available, and the tire sizes are compatible, and lighter also. They are also cheeper than 14 inch tires. Inexpensive 14X6 wheels were not available, so we went with the 13's. They do clear the larger legal brakes, incidentally. We had offset of 3 inches. Plenty of room around the brakes.

We were heading in the direction of the rear that I mentioned, and had already purchased the wheels when the opportunity to sell the car came along. It was done only because I couldn't race last year, and a new house was consuming all the time. An interested party approached me, and the deal was struck.

Don't think that a Mustang can't be built to the listed weight. We were about60-70 lb over, and the lighter rear and wheels were not on it yet. With a Hatch.

I'd be glad to offer information at [email protected]

Good racing.

Bill
 
Just to add a little more fuel to the fire...if memory serves, we weighed the car last at Daytona:
With 230 lb. driver, 3 1/2 gallons of fuel in the cell, and wheels that weighed 23 lbs. a piece + Kumho tires (not the lightest)... we came in at about 2658 lbs. (if my horrible memory serves me correctly). With no ballast.

Note: the steel 13X6 wheels that never made it onto the car weighed about 12 lbs a piece!!!!
...so the car could have been lighter (not to mention the driver!
smile.gif
by 44 lbs of wheels, and about 20 or so pounds with the smaller rear end...not to mention about 50 fewer pounds if it was a notchback.

Email Bill F...it can be done (legally)!
 
Ron,

You stated that your rear end set up is the steeda. How did you do that without using an 8.8 axle? where do you have your roll center set at? What sway bar do you run? What spring rates do you run? I am asking because I would like to see how it compares to mine. I just installed a custom 5-link and am looking for a good starting point.
Thanks for any help
 
Sorry about posting late, I was out of town.
The only thing I had to change to mate it to the 7.5 was to build the mount that goes on the rear end cover. The holes did not line up by about 3/8 of an inch. The roll center is dictated by the rear panard bar setting and of course we are playing with spring rates and sway bars then trying to get the car even. We are going to 400 pound in the rear with a .750 sway bar. That is subject to change with further testing, but that is where we are now. We started off with 750 fronts and 325 in the rear with large sway bars front and rear, however we were having issues with camber gain in the front and bump steer issues. We are moving up to 900/400 and smaller sway bars and see what happens in Savannah.
 
Ron,

The Engineer that is assisting me in my set up reccomended 750s front and 275s rear. We will be tunning using rear sway bars and panhard adjustments. I was asking you about your set up just looking for a starting point for the panhard rod. How did the attitude of the car change from before the 5-link? I have not yet driven my car with it installed , but I can not wait! As far as bumpsteer there is not much any of us in ITB can do about that. The AS cars are allowed to adjust for it.
 
With 750 in the front we were getting 3.5 inches of compression. In setting up the car we were hoping for 2.5 inches. We set our bump steer using different steering rack offsets and caster settings. What off set wheels are you running? We are at 3.5 positive and that might be one reason why our spring rates are going up.
On the set-up the car is totally different. There is no sudden snap oversteer. The amount of adjustments to improve the car are great. We need to build a better rear sway bar that mounts to the body that is adjustable. The one between the LCAs just does not do enough. That is one reason why we are going to the higher rear rates. We have a race in a few weeks and the new brake ducting to pump all the air through vaines is killing my time. The motor is going back to the dyno for a days worth of pulls. We have a couple of different crank scrapers we are playing with with a few other things to try. I just want to be ready a week ahead of time so if something comes up I can get the back up motor in the car.
Good luck with your new set up. Where do you race out of?

Ron
 
My home track is Waterford Hills. I plan on visiting Mid-O, Grattan, and Gingerman this season. What area of the country are you in?
 
We run out of Atlanta. Tracks like Road Atlanta, VIR, Roebling Road, Barber. I don't get down to Florida much. I need to.
 
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