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Discussion Starter #1 (Edited)
Today was the day. I finally got to run the car at an autocross event held by the local SCCA chapter.

It was a great day and learning experience. It started off rough with the serpentine belt getting shredded on the way to the track. The stupid power steering pulley (which has been a problem) ended up walking off the pump mostly and that caused the belt to lose alignment and get shredded. I was able to fix it on the side of the road after a quick trip home to retrieve some parts and a spare belt (dumb luck to have one).

I learned how to drive the car a lot better since I've done so many suspension mods. I've learned that in the mid 40's that I have way too much gearing and power overall to expect to be able to get on the throttle in any of the turns. However, I also learned that the Nexen Nfera tires I bought stick like glue as long as I'm off the throttle. I managed to be faster than all of the modern Mustangs by a couple of seconds (44-45 seconds vs. their 47-48 seconds). The car is an absolute beast for sure though. Unfortunately it's a bit too much of a beast for autocross but it's still some of the most fun you can have on four wheels.

Here's a grainy video of one of the runs: <iframe width="560" height="315" src="https://www.youtube.com/embed/VioYhtvoY30" frameborder="0" allowfullscreen></iframe>
 

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Hey Randy,

Looks like you had alot of fun today..
The car looks and sounds great!

How many runs did you make?

Congrats,

Tim
 

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Discussion Starter #3
Hey Randy,

Looks like you had alot of fun today..
The car looks and sounds great!

How many runs did you make?

Congrats,

Tim
It was a test and tune event and it was also cold so there wasn't a huge crowd. That equated to a total of 7 runs. I think that if it had warmed up a little more in the afternoon that we might have gotten more runs in but it stayed right around 43-45F all day.
 

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Where exactly was the event located? Car looks good rolling tho!
 

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Discussion Starter #5
Where exactly was the event located? Car looks good rolling tho!
The event was held at National Trail Raceway in Hebron, Ohio. It sounds like that's going to be the course they use for Ohio Valley Racing (OVR) this year. The parking lot is a little rough but the whole thing is gigantic and wide open.
 

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It looks like your Bird wants to fly.:nerd:

Be careful.
 
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Looks good, and sounds good!

Al
 
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Iv been there before but never for auto cross. Drag week and import face off. I'd love to do some auto cross tho!
 

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I was chatting last night with my machinist buddy who has been racing in Lemons for quite a few more years/track-hours than me.
I explained exactly where I had spun out at Sears Point and what i was felt trying to catch the slide twice before doing a 180.
Since you and I have similar suspension setups now, these tidbits might help you:

He says that it's not surprising what had happened given the track conditions and he believes it's because we stiffened up the rear a hair too much.
By doing so, as our car went through the carousel, it's going down hill at a fast clip and weighs down the car (down to the bumpstops).
Then, as you transition to the "drag strip" (which is really where the drag strip surface is at Sears Point), weight on the car shifts forward and cars with a light rear end (I think my tbird is probably more 60/40 now ) frind their back end breaking free and the whole thing destabilizes. If this happens in traffic ass puckering ensues.
Example: I think I lost it maybe 50 yards after this car as I was a littler wider at the point where he lost it.

Mike's First Suggestion:
* Soften the rear dampener slightly by going to a lighter weight oil. - Not worth it since the Bilstein's aren't easily drainable/refillable.
* Next Suggestion: If I move to a fuel cell, I'll mount it in the trunk so the weight distribution will shift rearwards and the CG will go slightly higher. While raising CG is not optimal, the wonkiness of the fuel shifting should help us reign things in before things break abruptly. IIRC, that's how the car felt before when it was much more "tossable."

* BEST SUGGESTION (esp if we don't go fuel cell): raise the front end slightly -- maybe 3/8" max by putting some rubber between the spring and the perch. That much lift shouldn't be noticable but it will mean the weight will take more time to shift forward. I know with our cut springs we are probably 1/4" too low already since the LCAs are NOT horizontal (heigher on the outside than inside). I've been told that our ackerman angle is probably slightly messed up because of this.

This should also if I understand things stiffen up the front end ever so slightly. See an exxagerated ver of this engr from a bunch of Mazda engr (literally):
FrankenMiata - Handling with a Hacksaw > MotoIQ - Automotive Tech, Project Cars, Performance & Motorsports


Bottom line MaddMartigan: you might want to think about what Mike suggested and it might be worth an experiment. I'll think about materials but I'm sure this could easily be done with everything from rubber to a cutting board.
 

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Discussion Starter #11
I was chatting last night ......

....Bottom line MaddMartigan: you might want to think about what Mike suggested and it might be worth an experiment. I'll think about materials but I'm sure this could easily be done with everything from rubber to a cutting board.
That's pretty good information but I think the challenge I have is slightly different. Basically, I could take just about any of the turns at significant speed without any slip/slide at all. It was only when I gave the car significant throttle that I had the rear end break lose. I think that it was a combination of the temperature and humidity and my power combination. The one problem that one of the Mustang guys mentioned is that since I'm running a 3000rpm non-locking converter that I would end up having more power available to me than I had traction to put down on the course. While this may not hurt me on a longer road course, it will definitely hurt under the conditions I was in for the day.

I went into most of the turns with as much speed as I could get but I had to be careful on the exit because too much throttle caused me to lose grip. In fact, my usage of brakes was actually fairly limited for the day.
 

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That's pretty good information but I think the challenge I have is slightly different. Basically, I could take just about any of the turns at significant speed without any slip/slide at all. It was only when I gave the car significant throttle that I had the rear end break lose. I think that it was a combination of the temperature and humidity and my power combination. The one problem that one of the Mustang guys mentioned is that since I'm running a 3000rpm non-locking converter that I would end up having more power available to me than I had traction to put down on the course. While this may not hurt me on a longer road course, it will definitely hurt under the conditions I was in for the day.

I went into most of the turns with as much speed as I could get but I had to be careful on the exit because too much throttle caused me to lose grip. In fact, my usage of brakes was actually fairly limited for the day.
I think we are on the same page here -- how do you continue accelerate out of a turn without breaking the rear end loose?
* I haven't dyno'd our tbird but it probably makes an honest 250HP now and a good deal of torque.
* In 3rd gear on a damp surface, you would have to be extra careful around a corner (aka: gently roll onto the throttle vs. just stabbing down like we used to do with the poor v6) or the back end would break free in almost every corner. I believe we are going a bit faster than you through our corners since it's a road course vs autocross but it seems like in the short clip you did a bit of unexpected throttle steering through some of these turns, right?

Q: What kind of gearing do you have in this car and what RPMs does your engine seem to make the most power? Also, on this autocross course, what gear was your car mostly in?

For our car, we have slightly shorter than 3.73:1 gearing b/c of the slightly smaller OD rear tires.
This makes 1st and pretty much 2nd gear fairly useless on the track; Sears Point is quite twisty and we spend most of the time in 3-4-5 (you could drive most of the course in 4th with only a few forays into 5th and a few into 3rd to really launch out of a corner -- when dry)..

Our 302 really seems to pull hardest from 3K-5K RPM. You don't really need to go higher than 5.5K RPM unless you are trying to wring the most out of the gear before the next turn.


-g
 

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Are both of you running trac-loc, diffs?

Do you think a geared diff would help?
 

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Discussion Starter #14
I think we are on the same page here -- how do you continue accelerate out of a turn without breaking the rear end loose?
* I haven't dyno'd our tbird but it probably makes an honest 250HP now and a good deal of torque.
* In 3rd gear on a damp surface, you would have to be extra careful around a corner (aka: gently roll onto the throttle vs. just stabbing down like we used to do with the poor v6) or the back end would break free in almost every corner. I believe we are going a bit faster than you through our corners since it's a road course vs autocross but it seems like in the short clip you did a bit of unexpected throttle steering through some of these turns, right?
Maybe we're seeing something similar. I'm running an engine setup that is probably in the neighborhood of 360rwhp and 400rwtq. I'm also running a AOD with the 4R70W gearset, 3000 stall non-locking converter and a 3.73 rear end that's an honest 3.73 due to correct tire size. Not much throttle steering through the corners that I could tell. Just too much power in the temperatures is what it felt like. Others were having similar problems.

Q: What kind of gearing do you have in this car and what RPMs does your engine seem to make the most power? Also, on this autocross course, what gear was your car mostly in?

For our car, we have slightly shorter than 3.73:1 gearing b/c of the slightly smaller OD rear tires.
This makes 1st and pretty much 2nd gear fairly useless on the track; Sears Point is quite twisty and we spend most of the time in 3-4-5 (you could drive most of the course in 4th with only a few forays into 5th and a few into 3rd to really launch out of a corner -- when dry)..

Our 302 really seems to pull hardest from 3K-5K RPM. You don't really need to go higher than 5.5K RPM unless you are trying to wring the most out of the gear before the next turn.


-g
My torque peak is between 3500 and 4000 rpm with HP peak being around 5200-5400rpm. I have an automatic and I stayed in second gear for the most part. The first time I ran and spun out was partly because I kept the car in first gear. I rarely got up to the 5000+rpm range as far as I recall. In fairness, I didn't do much looking at the gauges because I was focused on driving the course.
 

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Discussion Starter #15
Are both of you running trac-loc, diffs?

Do you think a geared diff would help?
Mine is definitely a trac-loc. If anything, I have too much gear for this setup but I'm not worried about it just yet.
 

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Now THIS! THIS is the kind of driving / setup I want to do in my T-Bird!!! In time, in time.

How many runs did you do?
 

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Now THIS! THIS is the kind of driving / setup I want to do in my T-Bird!!! In time, in time.

How many runs did you do?
Since it was test and tune I got a total of 7 runs in. It sounds like it will be more like 6 runs for a normal SCCA day.
 

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Discussion Starter #19
When I said Geared Diff, I meant like a Eaton Truetrac, or similar.

Detroit Trutrac Differential, Helical Gear Limited Slip Differential - Vehicle - Eaton
OK, I see. I'm not 100% certain but I don't think my traction is an issue of the differential. I think it's more of a case where I have too much torque and not enough rubber on the pavement in cool temperatures. There was no ability to "pre-heat" the tires before the run so I had to run with 200TW tires in 45F. I'm going to go again on the 15th this month so we'll see if the situation changes with warmer weather (I hope).
 

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I'm going to go again on the 15th this month so we'll see if the situation changes with warmer weather (I hope).
April in Ohio? You know better. :D

Pretty neat stuff! Great to see all the work you've done finally paying off in the wild.
 
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