Took some Data at the track at the SLP days in Ennis this weekend, With my new motor combination,

I've been trying to tune to get off the line with out going up in smoke.
I followed Grumpy's sugestions of reducing timing bellow TC stall.

Good news I lanched at full throttle from idle and no tire spin and I acheived a 1.9 60ft time, on street tires.(BFG 285x40x17ZR)

The bad news is as soon as the motor climbed to 3000rpm the tires broke loose, the tach went to 5700rpm, and the car went side ways, I got out of the throttle and back in it in secound gear, the car hooked up and pulled hard to 4300 rpm and broke loose again, shifted into third and pulled hard but it felt a little loose.

End results:
More HP & TQ = poooor tracktion & slooow 1/4 mile times,
13.20 @ 109mph.
Looks like some 17x11's with 315x35x17 G-Forces are next before any more runs or tuning.

 

nothing like breaking loose and going sideways at the track, LOL Suggestion try the nittos drags they hook up extremely well, also relocation braket worked wonders for hooking up, it a must have if your lower you car.

PS my three car garage is looking more like yours everyday, just waiting for a warmer temp to apply the gray sealer on the floor.

 

It will take ALOT of tire to hook that up.
OR
A clever patch to the code your running.
OR
some suspension work.

Cheap and EZ would be some Nittos, IMO.
The patch will cost you some HP, but allow for better top end fun.

 

if this is a drag only car check into southside machins and there lift bars. they work very well and can be easily removed and applied for the track. also try airing down the tires 5-10psi. im not real big on cutting timing. i always worry that egt's will creep up.but then a bit more fuel could kewl it down. also how are you launching line loc etc ? ? are you oveheating the tire on burnout ? radials dont need to really be smoked up. it actually hurts traction. just things to think about.

 

Having actually run the Southsides, I think they are junk.
They don't allow for any roll in the rear suspension. I/C center is too short. At least for a street car, where you have to go around corners. Not to mention how the short I/C screws up braking.
Feel free to get a copy of DoorSlammers by Dave Morgan. Also Herb Adams book about Race car Engineering show the Reese bar Rear Suspension for the 3rd Gens that does work.

A high EGT from afterburning isn't a big deal, in the realm of the original posting. And it's momentary.

 

funstick,
Thanks for the Info.
Its mainly a street car / Cruiser / show car.
I was runing 24psi in the rear tires at the track .
No line lock, just launched from idle.
I'm doing a short burnout just to clean the tires, very little smoke.
I think better tires and some suspension work will be next.

As far as backing out the timing at WOT before the TCC stall,
that seemed to really help a bunch, before you could not launch the car at all with these tires, it would just sit and spin.

I read somewhere that Grumpy sugested this type of tuning for launches and 60 ft times.
seems to make alot of sense, and I went from a 2.xx down to a 1.9 60ft.

what do you think about the Lower control arm relocation brackets, I heard they help alot in the traction department.

Hmmmmm, Sticky street tires, I'll try that next month.

 

I've had the same problem. Sideways after the shift into 2nd gear, lift, get back on it while keeping the car straight and not lifting completely to a 13.8 @ 102mph. I had 2.2 60' times next to nill as far as tuning (a lot of base timing), and lowered with no relocation brackets on 245/50-16 tires. It was a great for burn-outs but after a few wet and snow drives it gets old. Pulling out timing seems to be the best solution to traction/suspension problems. Taking away some of the torque if you don't have the tread is the best way to eliminate driver consistancy (throttle rate). There are lots of ways to make the "right" torque for your tire, some include changing rear gears, trans with lower 1st ratio, stuff like that helps until you've got the rubber.
Relocation brackets and good LCAs seem to be the best thing you can do for the suspension on a lowered car. I just took a bunch of welding sessions given to the members of student car related projects. Finally got the hange of TIG welding aluminum joints (not easy). Hopefully I can get these brackets welded in before I hit the track this spring.

 

Many of peeps are running low 1.6's on stock third gen suspension including my self,You want a street tire that hooks?
ET STREETS hook phenomial. wear is a little on the weak side though,BFG's in between,NITTO's good wear and traction but least of the three.

 

I wish I had been there to have seen your make that run.

 

You can hang alot of tire on a car to get traction dispite a poor suspesnion design. And you can get a good 60'er, which is some ways neat. ie if all you do is drag race.
While a 1.6 is by no means bad, on a similiar note, a G Body can do 1.4s with just bushings, and boxing the lower arms.

But, with every good thing there is some what of a trade off. In using that bigger tire, it slows the cars accleration down at the higher speeds.

The simple easy answers usually have bigger downsides then the more involved answers.

If you have the ability to datalog, then you want to really look at what's happening as the engine recovers from a shift.

Flash speed and stall while important at launch are critical for engine recover after a shift in gettting back to peak torque.
And while running a locked coverter on some apps might seem like a good deal, that's really hard on tranny parts.
There is a fair amount of sense in the later code for the abuse mode strategies.

 

Well I was just giving an example of my own,and thats with just a little 26 x 10 x 15 ET street with only a 9.1 tread width.Not really even as big as what the car comes with.
Yeah the g-bodies have a great design ,I have also heard of third gens w/stock suspension running in the 1.4 range,I myself when
running nitrous as opposed to my charger have gotten 1.501 best 60 ft w/28 x 10 ET drags.
But the biggest problem with the stock suspension at that kind of launch is the torque arm lifting the tranny into the well,causing very bad pinion angle and mount breakage.

 

With the oem torque arm hinging at almost the front u-joint, how do you figure there is much of a pinion angle change?. The *shortness* of the LCA is for roll steer, and have little to nothing to do with actually transmitting any torque to the frame of the car, as I see it.

Going thru the math in Doorslammers is very interesting in seeing how the loads are generated, and the leverage actually applied to the various frame locations.

 

With the tires being rotated clockwise the axle is trying to twist oposite forcing the torque arm in an upward motion picking the trans up.. as in a leafspring car -tracion bars limit that movement or torsional force ,the torque arm is to stop that twist ,but being that all that is stopping it from raising is a weak trans mount you figure the rest.
Or better yet take of your trans mount and punch it,see where the tail shaft goes. right into the floor board.

 

well as you improve your hook get the timming back in there. abosolutly no reason to kill off TQ for traction. id think it would be worthwhile to really work on teh chassis dynamics. get some air bladders to help evenly plant the tires. get poly bushings. replace that tranny mount. get and iproved TQ arm. put in a rear sway bar. these are things i would do to get traction. then after all methods are exhuast pull timming.