Beretta.net

Okay, so a lot of us here have powerful enough cars to have wheel-spin, in fact, even my basically stock 3.1 MPFI automatic Yellow Indy can do a lot more than just bark the tires if I lay into it hard off the line. But I have noticed a couple of odd things with some of these cars... My '95 Z-26, even with the 3400 big-port intake and throttle-body never really had enough oomph through the 4T-SlushBoxE to loose traction on dry roads with the relatively sticky tires I had on it, and at the 9,000 feet-above-sea-level altitude I drove that car at (anyone who attended last year's b-fest in Colorado should have an idea of what I am talking about there). My 3800 SC-powered GTU has so much torque that I can simply over-power the front-wheels' traction even through third gear (with the old five-speed 282, I have not been rough with the six-speed yet, as it is still 'new'), but I am still not seeing a whole lot of torque-steer with that car. The engine is a little heavier than the 60-degree aluminum-head engines, but the Muncie five-speed is a lot lighter than the TH125C that originally inhabited the car's engine-bay, so I think that evens out well. But my '90 'T-Type' Turbo 'Retta was a torque-steer monster, even with the 3.1 LG5 turbo in it before, and still very much so with the semi-built 3.4 turbo engine in it now.

I am still just getting re-acquainted with the car after it being mostly down over the last few years, but the other day when I took it out for a drive I decided to put it through the paces a little. After shifting into second gear, pushing the accelerator down results in at first a good pull forward followed a second or two later by a sudden increase in acceleration as the over-sized T-4 starts to spool-up to the current maximum boost setting of 5psi. Right after that, the car looses traction in first one wheel, then the other, and back again. Basically, it becomes a challenge just to keep the car in one lane at that point. This as opposed to the GTU, who just violently starts roasting rubber and pulls straight forward with a little effort on the controls, so I have to wonder if something else is going on with the Turbo car's steering or suspension...

Here is how they compare:
Both cars have Z51 front sway-bars, but the GTU also has a front tower-brace and FE3 springs, whereas the 'T' is running with the 'Heavy Duty' F41 suspension.
The GTU also has FE3 rear springs and sway-bar with a piggy-backed Z51 rear sway, while the 'T' is making due with the F41 suspension until I get around to making new supports for the Z51 rear sway it will also be receiving. Both cars are slotted for rear shock-braces once I get around to making some.
The GTU is running on 16" GTZ wheels with (IIRC) 205/55's, while the Turbo 'T' has 15" GT cross-laces with probably 195/60's (guessing here) with a little taller (probably 65-series) tires in the back. The tires on the turbo car are coming due for a change sooner than later just due to age, but have served me pretty well so far and provide excellent lateral traction.
The GTU's 3800 is solid-mounted in the bay, and has virtually no movement at the mounts. The '90 'T' has a more conventional mounting setup, except that the trans mount is on the bottom and it has my custom 3X00 mount on the front. With old, worn mounts, the car was much more docile, and the first time I took it out with fresh stiff mounts (with the old LG5 turbo), it surprised me and got away from me, pulling dramatically out of one lane and back in before I could get the torque-steer back under control.
The GTU's five-speed 282 had the older-style CV on the right-side, with the extended jack-shaft housing and oil-seal, while the 'T-Type's original five-speed was of the newer variety with the oil-seal at the transaxle. Both cars have a carrier-bearing at the end of the jack-shaft and a short CV plugged into it, not the low-power Isuzu-style with the longer CV shaft on the right, so I can't see where this makes a difference in function.

If the differences I am getting here are not simply the results of the different tires, I would love some insight while I am still working on the V-8 Indy, in case there is something I am missing here. The V-8 car should have almost as much torque as the 3800 GTU, and more than the '90 Turbo 'Retta does, so if it has something more to do with the suspension or other structural add-ons I've done on the GTU, I would love to hear about it now while I am still re-designing the mounts and other architecture inside the bay (it is already getting the same strut-tower brace that the GTU has, and solid mounts for the engine as well, but will have the same under-side transmission-mount that the 'T-Type' is using for its' five-speed, and is different again with stock FE7 suspension front and rear).

Edit: Unfortunately, none of my FWD cars have been blessed with LSDs, and I don't foresee myself having time or funds anytime soon to change that. But considering how differently these two Berettas of mine behave, I am still thinking that something else could be done for enhanced performance even before investing in limited-slip...
Anyone else with fun-to-drive torque-steer monsters?

I had every suspension/steering upgrade you could have pretty much including sway bars, strep bars, all poly bushings, KYB suspension, lowering springs, and with my supercharger at 7 psi on my 3450 it would spend until I let off the gas, I usually always waited until like 15 to 20 mph to smash the gas and it would still spend a little but then catch after a couple seconds, I had really bad torque steer with my automatic it would pull to the right like crazy, I bought an EP LSD hopefully that should fix it

I'm guessing and five speeds the same thing that causes torque steer in the automatics is that the one driveshaft in the transmission is longer than the other creating more power going to one wheel

And i run 225-45-17 rims/tires

I am quite certain you are putting down more power than my turbo 3.4 is, and you definitely have a better-built suspension. I am used to the higher-horse FWD cars pulling one way or another, although my turbo 2.4 Z-24 tends to light-up both tires if I am too aggressive on the gas, despite it not having an LSD. What my Turbo 'Retta does is pull left, then right, then left again until I let off or shift to the next higher gear. I have had this in this car with two different Muncie 282s, and two very different turbo engines. BTW, the other day I was at maybe ~30 MPH (tough to say for sure since the GPS is a little slow, and I am still working on the digital speedometer I have in the car) when it started its' side-to-side jog, it stopped because I had to up-shift.

My GTZ (2.3/stick obviously) torque steers pretty badly. Don't know about you but I get wheel hop on occasion too especially when you hit second hard. Don't recall having either issue with the GTU (2.8/Auto)

Suspension and crap is all low Miles on the Z so that can be ruled out. Have the options list for the Z if that helps but I think all 90 GTZs have the same suspension right?

GTU89 wrote:My GTZ (2.3/stick obviously) torque steers pretty badly. Don't know about you but I get wheel hop on occasion too especially when you hit second hard. Don't recall having either issue with the GTU (2.8/Auto)

Suspension and crap is all low Miles on the Z so that can be ruled out. Have the options list for the Z if that helps but I think all 90 GTZs have the same suspension right?

Yes, FE7. Yeah, I get some wheel-hop on that car too, now that I think about it. I think my 3800 GTU has had wheel-hop issues too...

In my car (2.8L Auto) torque steer = bad engine mount.

I have bad torque steer but that's cause many things were bad on my car( ball joints, tie rods, struts n mounts) u name it but all is replaced now n will have to see if it's any better

Styluss wrote:In my car (2.8L Auto) torque steer = bad engine mount.

Interesting... I actually had fairly limited torque-steer on this car (with the LG5 3.1 turbo) until I replaced the old worn mounts, and with the new mounts it was almost uncontrollable at WOT in first or second gear. It isn't quite as bad with the new engine, which makes sense to me since I had the undersized T-25 that spooled-up so quickly, as opposed to the over-sized 60-trim T-4, particularly since I am only running ~5 psi right now (new turbo and engine bearings still being broken-in, and stock tune on the Venture ECM for the moment).

MY91GT(Z) wrote:I have bad torque steer but that's cause many things were bad on my car( ball joints, tie rods, struts n mounts) u name it but all is replaced now n will have to see if it's any better

All of this car's suspension and steering is original (to my knowledge), with I think something like 135k miles on them, but I don't think anything is actually 'bad' in that regard, because the car handles just fine, and stops the way it should in a straight-line... But I will keep my eyes open for problems on that front, thanks.

For clarification, the car handles fine until I am pushing enough throttle on it that it breaks traction -that is as expected with the build I did on this car. But the weird part is how it keeps shifting traction from one side to the other -as I said, my 3800 SC GTU does not behave that way at all.