TRUE TRAC ON DIRT

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turtle
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TRUE TRAC ON DIRT

Post by turtle » Tue Sep 30, 2014 7:57 pm

A buddy and I have been kicking the idea around about trying a True Trac or a in our dirt circle track car. Has anyone here had any success with one? What are the advantages or disadvantages of running one? What kind of car would see the best results?? Heavy or light car with small hard tires? High power small tires? Heavy or light car with big tires? Heavy track, slick track??
I really don't want to hear a sales pitch from a sales rep. I want to hear from somebody that has had success with it and their application.

Thanks to all that share.
Tod
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Re: TRUE TRAC ON DIRT

Post by ZIGGY » Wed Oct 01, 2014 3:43 pm

turtle wrote:I want to hear from somebody that has had success with it and their application.
Never ran one so don't qualify per above. FWIW, two items of somewhat related experience from long ago with two link claimer engine mods and small hard IMCA tires on dirt. A main point is that the limited slip will allow use of less stagger and supposedly therefore increase forward bite. We briefly experimented with a Detroit Locker but didn't find an advantage, maybe because of the very limited stagger we usually ran with the IMCA tires of the time. The other experience was racing against
a Gold Trac. Never thought it did much for him except one night on a poorly prepared race track where he was able to drive through wet slop at the extreme bottom of the track to pass. That made track officials aware & he was told to take it out. I later saw the differential in pieces at the competitor's shop. He said it was high maintenance.

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Re: TRUE TRAC ON DIRT

Post by SLPRACINGENGINES » Thu Oct 02, 2014 5:05 pm

i know we run them all the time on asphalt...i never have know of anyone that ran one on dirt.i guess in theroy they would work the same.we find on asphalt they work better for us ..because we have to run less roll out..some of the track get lazy and dont like to order short and tall tires..so this was a solution to one of or problems..also found that the right rear tire runs much cooler running it..because your not dragging it threw the corner.ive got a couple of good friend that are big time super model drivers..ill se if i can get ahold of them..and get you some info

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Re: TRUE TRAC ON DIRT

Post by turtle » Sun Oct 05, 2014 9:22 pm

SLPRACINGENGINES wrote:i know we run them all the time on asphalt...i never have know of anyone that ran one on dirt.i guess in theroy they would work the same.we find on asphalt they work better for us ..because we have to run less roll out..some of the track get lazy and dont like to order short and tall tires..so this was a solution to one of or problems..also found that the right rear tire runs much cooler running it..because your not dragging it threw the corner.ive got a couple of good friend that are big time super model drivers..ill se if i can get ahold of them..and get you some info

That would be great to have some feedback from dirt drivers!

We like to set up, and drive, the car as if it were on asphalt. Keeping the rear of the car from sliding. I can see the advantage of running a locker or a true trac with the limited stagger, letting it free up the rear, through the center of the corner. We can get stagger but we usually try to run as little as we can and still make the car turn through the middle.
Another question is about the LR bite in the car. Would you need to add or subtract bite from your original setup, when installing a true trac??
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Re: TRUE TRAC ON DIRT

Post by governor » Mon Oct 06, 2014 8:10 am

I have a True Track for a Quick Change, have had it 2 years and never used it, it was used when I bought it but like new.

250.00 PM me if interested

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Re: TRUE TRAC ON DIRT

Post by rklessdriver » Mon Oct 13, 2014 1:05 pm

The Franklin QC my dad had in his Rayburn Late Model (in the late 1980's) had a Tru Trac diff in it... but you could lock it up with a "plug" and make it like a spool.

The car wasn't anything odd that I remember.... Typical Late Model for the time with 2X3 frame rails, dual A-Arms/Coil Overs front and Rear Mono Leafs and a "5th Coil Over Bar" (basically a sprung TQ arm).

We bought the car 1yr old in 1986 from Brad Sorenson (his son runs NASCAR now).... The well known Billy Clanton drove the car for my dad in the 1987 and most of the 1988 season. Dad drove it some in 1986 and some of 1988 before he retired the car and bought a new Larry Shaw chassis in 1989 (we should have kept runnig the Rayburn). Dad was always a better engine builder than driver and he knew it.... He prefered to have good people at the wheel most of the time in his stuff and only drove when he felt the urge.

I'm orginally from Georgia and the car was raced at Dixie Speedway, Rome, Senoia, Douglasville, Phenix City AL, Talladega Short Track, Greer SC.... he's a pic of the car.

Image

I remember that the Tru Trac diff made for some interesting set ups.....

With the plug in and the diff locked up like a spool the car needed 3.5"to 6" of roll out/stagger (depending on the track and driver).

With the plug out and the Tru Trac working as intended the car needed 0 to 1.5" NEGATIVE roll out/stagger.

We always ran the car with the rear end locked up except when we went to Talladega ST... Billy liked the car to push a little at that track (he always ran the top groove there) so he ran it with the pug out and a "ZERO" stagger set up.... it worked well for him. He came from 29th to 4th in 75 laps in the 1987 Tommy Dobblin Memorial 100 lap race race and would have won it except they called it a race at 75 laps when rain came.... Sucks becasue Billy had done the same thing (come from the back) and won that race the year before in 1986 driving in his own designed "Frisbee Chassis".

Anyway thats what I remember about running a Tru Track in a Late Model on dirt.
Will

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Re: TRUE TRAC ON DIRT

Post by turtle » Wed Oct 15, 2014 1:53 pm

Well from the replies that I am getting, the main advantage to the True Trac, is that it has the ability to remove stagger from the tuning of a set-up.

I think that if we get one, we will leave the bite in the car alone and try running it with our normal 1-1/2" to 2-1/2" of stagger, then go to straight up and see how it performs. I am also curious about the lower RR tire temperature, as mentioned by SLPRACINGENGINES on the asphalt car.....

I am interested to see how it performs across the mud at the bottom of the track! I can't tell you how many times we were faster than the car in front of us and could not pass because the bottom of the track had wet spots that had to be avoided!
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Re: TRUE TRAC ON DIRT

Post by SLPRACINGENGINES » Wed Oct 15, 2014 2:05 pm

TURTLE.im also a chasis builder.one of the biggest things i always preach to people who buy my cars is tire temps..they will tell you so much about your set up and what the car is doing..if your not real good at picking them aprt ..there are several good books out there that will help you..but most tire manf..will tell you the lower you can run the air pressure in a tire the better you are.to a certain point..

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Re: TRUE TRAC ON DIRT

Post by governor » Wed Oct 15, 2014 5:52 pm

I have sold the True Track I mentioned earlier in this thread.

Thanks,

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Re: TRUE TRAC ON DIRT

Post by turtle » Tue Oct 21, 2014 7:33 am

governor wrote:I have sold the True Track I mentioned earlier in this thread.

Thanks,

Gov
Gov, We are running a nine inch is why I didn't PM you. Thanks for the offer. :)
SLPRACINGENGINES wrote:TURTLE.im also a chasis builder.one of the biggest things i always preach to people who buy my cars is tire temps..they will tell you so much about your set up and what the car is doing..if your not real good at picking them aprt ..there are several good books out there that will help you..but most tire manf..will tell you the lower you can run the air pressure in a tire the better you are.to a certain point..
I do use the tire temps. as a tuning tool. I recently have been running/experimenting with higher than average Left Side weight percentages. I have actually gotten the LF tire temps higher than the RF. I was going to post on that subject in the very near future.
Using the higher LS % and trying to mimic an asphalt style of driving, (in certain conditions) has brought up the subject of a Tru-Trac on dirt, between my buddy and I. I think we are going to try it.
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Re: TRUE TRAC ON DIRT

Post by Bubstr » Wed Oct 22, 2014 12:48 am

I think your going to find out that the LS weight over 55% is going to be self defeating. Most everyone is using a soft RF with a lot of hike in the left rear, to promote rear steer to rotate the car and get bite on the LR for forward bite. Once you get your Percentages right, you fine tune with raising or lowering ballast and adjusting the J bar. Even the limited late models, with leaf springs, use a form of rear steer from hike to rotate.

In the old days, they used ratchet to get in the corners, now they just roll the car over and pick up part throttle a lot earlier. I think most are using a spool and carbon fiber drive shafts for durability now.

A lot has changed in the last 5 years. Be prepared to spend $12.000 on shocks. There are some very knowledgeable guys on 4m.net tech forum that can give you chassis specific info.
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Re: TRUE TRAC ON DIRT

Post by rklessdriver » Wed Oct 22, 2014 4:40 pm

Bubstr wrote:I think your going to find out that the LS weight over 55% is going to be self defeating. Most everyone is using a soft RF with a lot of hike in the left rear, to promote rear steer to rotate the car and get bite on the LR for forward bite. Once you get your Percentages right, you fine tune with raising or lowering ballast and adjusting the J bar. Even the limited late models, with leaf springs, use a form of rear steer from hike to rotate.

In the old days, they used ratchet to get in the corners, now they just roll the car over and pick up part throttle a lot earlier. I think most are using a spool and carbon fiber drive shafts for durability now.

A lot has changed in the last 5 years. Be prepared to spend $12.000 on shocks. There are some very knowledgeable guys on 4m.net tech forum that can give you chassis specific info.
I agree about running over 55% LS.... Billy Clanton was obsessed on maximizing LS weight in his chassis designs for a few yrs and I personally never saw any benifit over the typical 52-50% other chassis like our Rayburn and Shaw cars of that time frame had.

Later on in the mid 90's we had a guy named Eric Evans from Griffin GA driving our stuff and it was a Bullet (4 bar with a pull down bar) and later an American Made Chassis (swing arm). Both really didn't set up much different weight wise from our old leaf spring sets ups.... Althou the Bullet always like a shit load of rear bit and always had a ton of rear suspension seperation on acceleration.... the American Made was the first chassis we ever had that hiked the left front up off the ground. After that we had a suscession of GRT's and combo (Z bar/Swing arm) Rayburn's... things were really changing quickly in Late Models during the mid 90's to early 2000's. Heck just in engines we went from 23* 362" 585HP to 15* 421" 715HP engines.... from 2spd converted Muncie's to Brinn's and Berts....

I have some of my own knowlege to add to your comparison between how cars are set up today v/s yesterday.

Back in the 80's and 90's we 99.9% of the time ran the rear locked up like a spool and used brake bias, throttle and stagger to turn the car. Leaf spring cars had very little to no rear steer built into the chassis - Up until the time they were obsolete in Late Model.... You had to turn them with stagger or be happy driving a car that pushed like a dump truck. The only time I can remember we eve ran the rear unlocked was at Talledega ST and that was specifically so Billy could run the top groove around that place and let everybody else burn their soft tires up fighting for the bottom while he cruised around the top on brick hard GF-5's.....

On rear steer specifically, I can remember Billy talking with Keith Masters in 88 or 89 about "rear steer" because Billy had just finished updating a leaf spring car he had bought by eliminating the leafspring on the right rear (keeping it on left rear) and installing a 4 bar on the right side to gain rear steer and help turn the car going in the corner when it rolled over on the RR..... it never really was very consistant. The next car Billy built for himself was a straight up 4 bar rear suspension with floaters and a pull down bar.... it was a much better working Chassis.

I personally don't think that these new style hiked up suspension set ups are worth anything speed wise.... I know everybody runs that way and these days we do it as well because.... well everybody else does it and theres no set up info for driving a "flat car" on dirt..... But just from comparison I looked up some old info from Dixie Speedway to compare to info as recent as this season.... the HP between the cars is comparable as back then (1987) our 2X3 Rayburn Leafspring car had 580HP. Today we have a customer that runs Dixie with a 4 bar GRT Limited Late Model that has 562HP.. of course the new car has way better tranny and suposedly better round tube, "hiked up" super rear steer suspension.... hell even new tires are better than they were in 87....

The proof is in the lap times and our old 1987 leaf spring Late Model ran 15.60's around Dixie and was a top 5 car every week. The new GRT with it's uber cool looking hiked up left front tire only runs 15.70's..... and it too is a the top 5 car.

Now with a Super Late Model and it's 900HP it must make a big difference... probally because of the way drivers drive the car with the throttle.

But with less power.. epsc a Limited Car or Crate Model (which has NO POWER at all) I think they'd be faster running the car calmed down on all 4 tires.
Will

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Re: TRUE TRAC ON DIRT

Post by SLPRACINGENGINES » Thu Oct 23, 2014 5:41 pm

we still run mot of the time those same percentage.my son races a warrior chassis in super late models and create late models..run a little different in the street stock cars..im a warrior and lefthander dealer.build my own designed street stocks..mostly for the nesmith seris and mississippi street stocks..back to the dirt thing on a true trac..i think honestly i would stick with a straight up spool setup.the dirt side has got to be more of a shock and spring package battle on set up .we have a small fortune in shocks.

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Re: TRUE TRAC ON DIRT

Post by Bubstr » Thu Oct 23, 2014 11:02 pm

You can get rear steer from leaf springs, but it is a little undependable. The trick is re-arch left spring and turn some of the leafs around and re-drill center hole on some, beef up the front of left spring. Then make a very solid saddle with around 2 inches of lowering block welded on. Can't stress to make that tough enough. Then clamp the front about every 3 inches and double the length on that shackle and make quite a few upper mounting holes fpr adjustment.That will hike your LR but won;t steer. the trick come from the right side. A Mono leaf on a floater and a coil over mounted solid to rear of axle, Slider on the rear of that mono. This steers from the right side axle going to the rear, under power,

This was a late 70s early 80s combo and you had to drive it like you stole it. All breaking before you rotated. You could trail brake a little as you picked up go pedal. These had gobs of forward bite for no 5th coil.
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Re: TRUE TRAC ON DIRT

Post by ZIGGY » Fri Oct 24, 2014 8:29 am

Similar to Scooter May's "Fast Boys" leaf setup. IIRC he had success with it on a national level into the late 90's.
The induced roll steer tightened the car both under acceleration and under braking.

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