Torque Steer, Control Arms or Just Life with a GT500?

[Imatk]

So after doing some research, I'm not really sure if I have an issue or if it's just the way it is.

I have a 2007 with an FRPP TVS at 605 hp.

Stock control arms, SVTPP suspension (shocks springs) from the 2012 GT500, 2013 OEM GT500 wheels with MPSS tires... approx 27k miles on the car and have had it since almost new (2k miles).

I find it very difficult to launch on the street without the car pulling to the left. Basically it feels like the passenger wheel is doing most of the work, and pushing the car over to the left.

Steering wheel remains straight and I have no wheel hop, but there have been more than a couple times where I nearly crapped my pants because it almost spun around on me. Mostly when I'm not paying attention and for whatever reason forget to feather the throttle.

My question is... would lower control arms MAKE the car track straight? Is this the reason for the pulling... deflection off of the stock pieces?

Or is this just simply the nature of the car and I have to continue to be vigilant and not matte the throttle?

Thanks for any insight.

 

[Sonic 03 Cobra]

The control arms will help. I have upper, lower and a watts and still have some of what you are calling torque steer in the rear.

 

[MastaAce03]

I have a set of steeda billet lower control arms and relocation brackets for sale, let me know if you'd like to upgrade.

Sent from my SAMSUNG-SM-G925A using Tapatalk

 

[03 DSG Snake]

You can grab the stock LCAs and twist them by hand.

I have the Steeda UCA, billet LCA with relocation brackets and a MM panhard bar. Sitting on the FRPP springs and shocks. With just 652rwhp and 3.73s it will spin like crazy, but the car stays dead straight on me if the road is decent quality.

 

[Black Cobra '99]

The control arms will help. I have upper, lower and a watts and still have some of what you are calling torque steer in the rear.

This.

I used to crap my pants when I first got my 09, now I have LCA, UCA, whattslink and coilovers. The car feels and behave a million time better. Although I still have some of that torque steer, I know where the car is going and how to handle it.

 

[BMR Tech 2]

Addressing deflection in the suspension will definitely make the car track straighter and more predictably, but you likely won't be able to get rid of the sideways shuffle that these cars like to do. There are so many things that cause it, that just addressing suspension is unlikely to complete cure it. Differential bias and how power is applied to the wheels (is the diff splitting power equally?), are your tires exactly the same circumference, road surface, etc....

 

[geoffmt]

^ as Dylan is saying is all correct. I had my trac loc double stacked when I changed rear gears. New carbon clutches removed some of the steel discs and replaced with friction. car spun both wheels about equally and kept it straight. MMR lower control arms and panhard bar helps also

 

[RedVenom48]

Almost makes me want to say F-it and just run a spool. ^^^^

Put some LCA relo brackets on my car. The RR wheel is sitting about 3/4 back from the LR wheel. Definitely made the thrust angle unhappy even though laterally the housing is centered under the car.

Will be getting some adjustable rod end LCAs to correct the issue soon hopefully.

 

[BMR Tech 2]

Almost makes me want to say F-it and just run a spool. ^^^^

Put some LCA relo brackets on my car. The RR wheel is sitting about 3/4 back from the LR wheel. Definitely made the thrust angle unhappy even though laterally the housing is centered under the car.

Will be getting some adjustable rod end LCAs to correct the issue soon hopefully.

Have you measured the wheel base on both sides, or are you just eyeballing it? Sometimes you can shorten the wheelbase a touch by loosening the bolts on the relocation bracket, pushing it back with a prybar, and then torquing the bolts back to spec. It helps to have a friend when you're doing this.

 

[RedVenom48]

See below

 

[RedVenom48]

Have you measured the wheel base on both sides, or are you just eyeballing it? Sometimes you can shorten the wheelbase a touch by loosening the bolts on the relocation bracket, pushing it back with a prybar, and then torquing the bolts back to spec. It helps to have a friend when you're doing this.

No scientific measurement, but a quick check from the tread of the tire to the front of the rear wheel arch with a tape measure.

Is there a specification and method to check for the housing alignment in the wheel well? (Wheel base)

 

[Catmonkey]

I don't think you can really eliminate the back end kicking out. While poly or rod ends can help unwanted movement and take a lot of the unpredictability out of over powering the tires, if you have a lot of wheel spin it's a crap shoot whether it will go straight or not. At least that's been my experience. I think to some degree uneven tire pressure and traction control can influence the side step movement.

Lexustech, the easiest way to check the thrust angle is to put it on a 4 wheel alignment machine just to see if it's out of spec and by how much. Wheel base measurements will get you in the ball park.

 

[RedVenom48]

That was the first thing i did after i got the brackets in. I had .14° of thrust angle. I found equal distance between my rear quarter panel lip and wheel on both sides. Lol thats when i checked wheel well alignment.

 

[Imatk]

Awesome information here guys thank you very much.

Is there a way to tell (other than doing a burnout ) if both wheels are turning the same with the dif / traction loc?

Also interesting is the thrust angle, I'm going to break out the tape measure tonight and see if the wheels are in the same position.

 

[BMR Tech 2]

No scientific measurement, but a quick check from the tread of the tire to the front of the rear wheel arch with a tape measure.

Is there a specification and method to check for the housing alignment in the wheel well? (Wheel base)

You can measure the wheel base by measuring the center of the front wheel to the center of the rear wheel. Your wheel base should be between 106.9" and 107.2". The thrust angle is basically just the difference between the two. Factory spec is up to .5", but anything under .25" is good. The closer you can get to 0, the better!

Using the wheel wells arches is not accurate because the sheet metal can be off, and it doesn't tell you where the rear wheel is in relation to the front wheel.

 

[RedVenom48]

Ok cool, ill take a measure when i get home tonight. Ill end up just getting a set of adjustable LCAs. My original set of BMR LCAs have served me well... time to upgrade it looks like.

 

[fmylife]

Weird...I was just about to start looking for some posts about this exact problem because when my '08 rear was mostly stock (FRPP springs and BMR panhard adjusted to mostly even) it would still spin completely straight.....once we added the BMR LCAs and adjusted the panhard a little more left to get it lined a bit closer is when mine really started throwing it out left, badly! It was a tense pucker moment the first time it happened because I expected it to grip and handle a little better off the line, not try spinning around on me.

Guess we need to get back under there and measure things better and readjust!

 

[1st usa car]

mine curves to the right

 

[RedVenom48]

Yeah, i knew something was off. As we start messing with arms and angles and mounting points, its inevitable that something will get thrown off.

Lol, when I first started modding my rear suspension, i was quite content with non adjustable arms and poly bushings. As i learned of the violent nature of drag racing on rear end suspension stuffs, ive quickly gained an appreciation for rod ends, adjustsble everything, and set of rear gears that arent worn lol

 

[1st usa car]

So - if my car is pushing the rearend to the passenger side under hard throttle... which way do i need to adjust my panhard bar?