The problem with awd is that it does weight transfer. Sow you have more weight over the read wheels less over the front making it harder for the front to get traction and in some cases to much for the reaer wheels. There are many other reasons AWD isnt best for drag racing.

 

To be honest with you, i've never really seen an AWD car with its front tires off the ground. All 4 wheels just grip for the most part since you don't have 100% of the power/tq routed to the back 2 wheels. I don't think their front to rear weight tranfer is as great or dramatic as RWD cars.

I do know that the STi is nose heavy with 58-60% of the weight distribution being in the front. That may help in keeping the front tires planted down during weight transfer.

 

I have no arguement here, and again, I'm neither taking up for AWD nor do I prefer it.

That said, just like you can setup a suspension to transfer weight, you can also set up a suspension to NOT transfer weight.

 

Then you get 4 wheels that want to spin not just the front 2. Setting up the suspention this way makes it like a rigid frame. Thats not good for accel.

 

LOL. Uh.....there is only so much weight a car can put on 1, 2, 3, or 4 wheels. And let me assure you - the vast majority of drag racers want a VERY rigid frame (hence the reason for subframe connectors, solid-bushing control arms, extensive rollbars, etc). Regardless, in reference to weight transfer, you're thinking RWD only. With AWD, all the cars weight is always on the driven wheels. The ONLY time all of a car's weight is on the driven wheels with RWD is when the front wheels are off the ground. No exceptions. As such, the AWD has that inherent advantage. It can be overcome on the track, but almost never on the street.

Setting up an AWD suspension to NOT transfer excessive weight to the rear wheels - likely by making the suspension stiff and rigid - will allow all the cars weight to stay on all 4 driven wheels.

 

Rigid - as in no suspention.

Drag racers then put shocks/springs that transfer weight. Suspentions that handle well ususally dont do so well in drag racing.

Just the G's caused by accel. creates weight transfer. AWD is not a good thing for drag cars.

 

Been seeing that chevy commercial alot...those cobalts look nice w/ chrome wheels....pulley change to the blower and open up some air it'll be a runner.

 

Yeah, that is really amazing. No complaints coming from anyone in Canada.

 

Most cars that lift up their front end noticeably are the ones running drag slicks in the back, many of them with modified wheel wells to accommodate really wide tires. Those tires really hook up. However, if you go to street tires (even Lingenfelter's C5 running 9's has street tires), there is no real danger of the front lifting for any more than a fraction of a second, and often not even both front wheels lift up but only one. AWD, I would think, would still have advantage in this case. Even if some of the front loses traction, it instantly transfers power to the wheels that grip, removing just enough from the front to stop wheel spin. You will not see AWD car lift up its front end for long enough period of time where steering would be a problem, not anymore than the C5 running 9's. The moment the front wheels get some traction, more power will be transferred back to them.

If you compare AWD and RWD cars that run the same MPH, AWD will usually run a few tenths faster.

AWD has advantage in 1st gear, where RWD cars can have trouble with traction. AWD also has advantage during shifts, where RWD cars can spin wheels after power shifting.

The problem with AWD is that it robs the driveline of more power. And is AWD for drag racing? I don't think so, otherwise NHRA would have some variations of it.

 

Uncle.

Have a nice day.
Bob

 

Forgive me here, and I really do appreciate the theoretical discussion, but methinks the number of cars that are ever going to have to worry about lifting the front tires is pretty small.

Cobalt SS.... hmmm... might make a nice replacement for my beater Crapalier in 3 years or so...

 

All 4 wheels that want to spin, not just 2? So which will be easier, to spin only 2 wheels, or to spin all 4 wheels?

Soft suspension can rob power because it takes energy to compress it. When it's rigid, there is no less power loss. With RWD, though, you do want drag suspension, precisely because only 2 wheels grip and you want all the weight on them you can get so that they actually grip and not spin. AWD is a different beast.

 

To be fair, Motor Trend's numbers were better than R/T (gee, what a surprise).

Motor Trend's numbers for the SRT-4 are as follows:

0-60 5.5
1/4 mile 14.0@102.7
60-0 112
Slalom 68.3

Even the slalom difference isn't that big as originally presented here. Aw hole .7mph. Add in the standard Quaiffe limited slip differential, and the SRT-4 will clobber a Cobalt around an autocross course.

GM missed the ball here. A day late and a buck short. They really had a chance to take the bar that PVO set and move it higher with the 2 years extra development time. IMO, they didn't.

 

If I remember right, that SRT-4 DID have the LSD in that article. That's how they got such good times out of it. It's not going to CLOBBER the cobalt in autox. They look fairly well matched to me. The SRT-4 has the Cobalt for acceleration though. Do you have the SRT-4's skidpad #'s?

Dan

 

That's my point.
No it's not. The 04 with LSD isn't really any quicker in the 1/4 mile than the 03s because of the LSD. They're quicker from a slight power increase. Even a non-LSD SRT-4 will light both tires up in a straight line because of the equal length halfshafts.

An LSD is not going to improve skidpad numbers (which tests solely lateral grip) or slalom numbers (which only tests transition). Where it helps a FWD car on a course is putting power down coming out of a corner. And Quaiffe is the best in the business.

Yes it will. As a matter of fact, I'm going to find out first hand this year if any Cobalts make it out to Gingerman or Blackhawk. No LSD in the Cobalt means it's going to light up the inside tire leaving every corner, while the SRT-4 gets busy putting its power down. If I were to bet on which car is going to be quicker around a road course, my money is on the SRT-4.

Sport Compact got a .85, I'm trying to find my Motor Trend where they tested the '04, it may take a while. I'm kinda messy

Edit: I'm aware that you can option an LSD for the Cobalt....but why should that be an option when it's standard on the SRT-4. It already starts out as more expensive. Which is why I again say that GM missed the ball with this one.