Husker973

Wondering ways I can get better traction on the street. I have new tires but at a launch it spins a lot before it can catch. Its a stock auto 2.73. Any recommendations for tire pressure or any suspension parts that may help? Thanks

Injuneer

Lots of questions……

Is the vehicle stock ride height, or lowered? Stock or aftermarket shocks? Stock rear LCA’s, torque arm, panhard rod?

What size and brand/model tires are you running? How old are they? Stock wheels, or aftermarket?

Is the engine relatively stock, or modified? If modified, what's been done, and estimated HP? Stock stall torque converter?

Any sign of wear on the limited slip differential - e,g 1-wheel burnouts?

Husker973

The tires are bf good rich 245/50/ZR16 they are about 6 months old. The suspension is completely stock with 100k miles on the car. Only mods on it are flowtech afterburner muffler and a k and n cai. Stock torque converter. No signs of wear on the diff. Stock ride height and wheels

Injuneer

Is the BFG tire the G-Force Comp-2 All Season Plus? That's the only BFG tire in that size I see on Tire Rack. They have a comparison test, and the BFG seems to be best available, with good dry traction.

https://www.tirerack.com/tires/tests...y.jsp?ttid=253

The consumer feedback ratings put the BFG at the top of the ratings with regard to “dry traction”.

Problem with 16” wheels is limited tire size selection. That's why most people (and the WS6 and SS coupes from the factory) opt for 17” wheels and look at 275/40-17 tires. But I don’t see any tires in that size on Tire Rack. Nitto does offer them though. The solution used to be “drag radials”, but they can be dangerous in the wet. I ran BFG 315/35-17 drag radials on my Formula, and even with those I could do a John Force style burnout with minimal effort (but the was 490 flywheel HP, no nitrous).

I always ran my tires at the recommended pressures on the vehicles tire label. Think is was 32 PSI. Cars been gone for 2 years.

Short of swapping wheels/tires, the rear suspension is the only hope. I found significant improvement with tubular lower control arms, LCA relocation brackets, and an adjustable torque arm. All of those came from Spohn Performance. Maybe start with the LCA’s and the relocation brackets. Dropping the axle end of the LCA causes the forces on the LCA to push up on the chassis, while the “equal and opposite” reaction force pushes down on the rear axle assembly. Use of polyurethane bushings, or spherical rod ends (or a combination of both) removes the deflection and “slop” from the system. Generally used to prevent “wheel hop” on launch, but does offer some improvement at speed. Might be enough to calm down the wheel spin given the limited mechanical thrust of the 2.73:1 rear axle ratio.

The torque arm upgrade is probably more beneficial for hard launches, not so much for wheel spin at speed. Primary function is to control the pinion angle, and distribute the lifting force of the front end of the arm under hard acceleration more effectively. Not sure it would help in your situation. My focus was always improving the 60-ft times on the drag strip. The new owner of my Formula has made a lot of changes to the engine, but has left the suspension alone, in view of the fact the car pulls 1.2xx 60-ft times.

Be nice if we could get some input from the auto-x/road race folks. They're into thing like the Watts linkage rear suspension mod, tricky torque arms. My focus was always drag racing. Unfortunately there aren’t a lot of enthusiasts left on this site.

@JakeRobb

dlinger

I swapped my BFG for new Firestone's. I noticed a dramatic improvement, but then the BFG's were on the car when I purchased it in 2004. They still had tread left, but I slid it sideways a couple times and I decided they needed to be replaced.

Injuneer

Obviously replacing 20+ year old tires will improve a lot of things, even if the new tires aren’t top rated. Anything over 10 years old is consider a safety risk.

JakeRobb

Yep. Most tire shops draw the line at seven years, after which they will not service the car or repair the tire except to replace them.

If you’re happy with the Firestones, cool — but if you want more traction, I’d encourage finding a set of 17x9” wheels from an SS or WS6. I have 2002 WS6 wheels on my Z28 and I think they look great! The tire selection at this size (275/40R17) is much better, especially in the high performance summer tire area. The Michelin Pilot Sport PS2s I have now have been really great, but they were super expensive, and to my knowledge nobody has introduced a better tire in this size in several years. Michelin has three generations of newer, higher-performing tires in other sizes.

That being the case, I find myself still limited by the selection these days, and am pretty seriously considering going to an 18” wheel. Depending on just how much performance you’re after, you might want to do the same.

Husker973

Yes they are the all season ones and I didnt make the post about the firestones.

Injuneer

My mistake, I've got to stop spending so much time on this site.

Sorry about that.

JakeRobb

Ah, and I read Fred's mistake and assumed he was correct.

Okay, so can you tell us exactly which BFGoodrich tires you have? BFG currently only makes one tire in this size: the G-FORCE™ COMP-2 A/S PLUS. It's a "high performance all-season." Is that what you have? I'd think that would be enough for a 2.73 auto LT1.

Just to rule out the obvious: in these situations where you're getting wheelspin, has the pavement been warm and dry, and the tire tread surface free of debris? I'm guessing from your username that you're in Nebraska; what's the weather been like there?

Does your car have a limited-slip differential? Look for the code "G80" on your RPO code sticker, which you should find on the back of the driver-side door, below the latch (visible only when the door is open). If not, we might be dealing with a "one-wheel peel" situation. That would make more sense.

If you can find the DOT date code on the sidewall, I'd like to see that as well. Looks like this, and it will tell us when the tires were manufactured (which is the only thing that's important; how long you've had them is irrelevant). The tire shown here was manufactured in the 27th week (early July) of 2018.

Chimera96

So a stock LT1 with 265 HP breaks the tires lose when you floor it at 40 mph with 2:78 gears......yeah right....maybe in the rain but so will a volkswagon

Injuneer

All V8's left the factory with the G80 limited slip diff.

JakeRobb

Wow dude, just... wow. All that in one line?!

JakeRobb

Ah, okay. I wasn't sure about LT1s, especially without the performance pack.

It's also possible that it's worn out after 28 years (!!) and isn't exactly limiting the slip anymore.

... which Fred already asked.

Injuneer

Mentioned that specific BFG tire in post #4,

Kinda pointed that out in post #4, just not so bluntly.



Sorry for confusing the author of post #5, but it was so pointless to point out that new Firestones produced better traction than 20 year old BFG’s of some unknown type. Probably would have gotten better traction with new wheelbarrow tires from Harbor Freight……. I just don’t get it, and lost my focus.

And to be accurate, 275 HP.