Question on 1g FWD

[its_hey_ma]

If I had the rear just welded solid at its highest point, what would that do for my 60'ers? Wouldn't that cause the wieght distro to be mostly on the front helping my launch? I've got everything stripped off it for wieght reduction and a set of 195/50 Eagle #1's (old school )
Just FYI: Its a track only car so I don't care about the ride.

 

[jtmcinder]

If I had the rear just welded solid at its highest point, what would that do for my 60'ers?

Increase them.

- Jtoby

 

[mavisky]

why in the hell are you running smaller than stock tires?? get something sticky and a decent suspension and you'll notice the big changes then. hell i'm on 205-16 azenis, eibach sportlines with agx's (not a good suspension really, but it works) and i'm in the low 2.1-2.2 at the strip with an open diff. what sort of 60' times are you running right now?

 

[jtmcinder]

Old school. The "195/50" refers only to the rears.

To be clear: On a FWD, you run skinny rear tires, since they are only there to keep the rear bumper from dragging. Think about RWD drag cars pointing backwards, only even more extreme since you don't brake or steer with the rear tires.

Heck, he should just run a set of spare-saver spares in the rear, like some Honduh Boyz do.

- Jtoby

 

[rebuilt65]

Old school. The "195/50" refers only to the rears.

To be clear: On a FWD, you run skinny rear tires, since they are only there to keep the rear bumper from dragging. Think about RWD drag cars pointing backwards, only even more extreme since you don't brake or steer with the rear tires.

Heck, he should just run a set of spare-saver spares in the rear, like some Honduh Boyz do.

- Jtoby

The only problem with that is the speed rating of the spare tires. While he won't sustain high speeds for long on the 1/4, it is still a little dangerous maybe?

 

[jtmcinder]

Good point. Maybe that's why it's a Honduh Boyz thing....

- Jtoby

 

[boostin1g]

haha thats funny my talon is siting with the spars on the back as i type i toke my rims off to put on a dif car and only got 2 jack stands .

what would happen if you did run with spares on the back. would this help at all they are kinda unstable i would think. i was going to put them on the front and see what would happen or how long it would take to blow them up

 

[mavisky]

Old school. The "195/50" refers only to the rears.

To be clear: On a FWD, you run skinny rear tires, since they are only there to keep the rear bumper from dragging. Think about RWD drag cars pointing backwards, only even more extreme since you don't brake or steer with the rear tires.

Heck, he should just run a set of spare-saver spares in the rear, like some Honduh Boyz do.

- Jtoby

Well since he didn't mention where the tires were I figured that he had 195/50's all around the car. Don't worry I understand the meaning of running smaller rear tires, although I'd think that a set of 175/70's would work better or something of that nature. If you cranked the pressure in them they would be a little squirrely, but by being taller they'd also rake the car and help a small amount with weight transfer. The 195/50's are actually shorter than stock which is helping to put a small amount MORE weight on the rear tires by tilting the car backwards from what its position would be with 205/55's on it. This would hurt his 60' times actually. The real question is whether or not the skinnier tires and subsequent less aerodynamic drag and rolling friction offset what he lost in weight transfer by going to shorter tires. I'm sure we could calculate out the change in rolling friction if we considered the same mu for both tires and assumed a perfectly rectangular contact patch, same with the aerodynamics since we could probably make a good guesstimate at each tires frontal area. The problem comes in calculating just what his car's corner weights would be with each different tire on the car since the weight of each tire would change as well as the distribution of load across each contact patch.

In reality it probably doesn't matter much, i'm sure if he was running within .001 of his best time on every single run we might be able to see a difference, but with all the other variables (wind, direction, temperature, humidity, fuel level, driver weight, launch, missed shifts) i'm guessing we'd never even see a noticeable change if we wasted all of our time and found the best option and then had him run the car 100times. Now if he was running 13" wheels on the rear severely offsetting the weight distribution or if he was running some mickey front runners (under 4" across) we might see some negligible gains or losses, but with tires only 5% off on sidewall ratio and only 10mm skinnier i'm guessing he's not gaining or losing anything worthwhile.

 

[its_hey_ma]

Well since he didn't mention where the tires were I figured that he had 195/50's all around the car. Don't worry I understand the meaning of running smaller rear tires, although I'd think that a set of 175/70's would work better or something of that nature. If you cranked the pressure in them they would be a little squirrely, but by being taller they'd also rake the car and help a small amount with weight transfer. The 195/50's are actually shorter than stock which is helping to put a small amount MORE weight on the rear tires by tilting the car backwards from what its position would be with 205/55's on it. This would hurt his 60' times actually. The real question is whether or not the skinnier tires and subsequent less aerodynamic drag and rolling friction offset what he lost in weight transfer by going to shorter tires. I'm sure we could calculate out the change in rolling friction if we considered the same mu for both tires and assumed a perfectly rectangular contact patch, same with the aerodynamics since we could probably make a good guesstimate at each tires frontal area. The problem comes in calculating just what his car's corner weights would be with each different tire on the car since the weight of each tire would change as well as the distribution of load across each contact patch.

In reality it probably doesn't matter much, i'm sure if he was running within .001 of his best time on every single run we might be able to see a difference, but with all the other variables (wind, direction, temperature, humidity, fuel level, driver weight, launch, missed shifts) i'm guessing we'd never even see a noticeable change if we wasted all of our time and found the best option and then had him run the car 100times. Now if he was running 13" wheels on the rear severely offsetting the weight distribution or if he was running some mickey front runners (under 4" across) we might see some negligible gains or losses, but with tires only 5% off on sidewall ratio and only 10mm skinnier i'm guessing he's not gaining or losing anything worthwhile.

Although only one person answered my question (sort of) and everyone else just b!tched about the tires, this was an awsome reply. I was thoroughly impressed at the detail about tires.

 

[mavisky]

Although only one person answered my question (sort of) and everyone else just b!tched about the tires, this was an awsome reply. I was thoroughly impressed at the detail about tires.

everynow and then the inner engineer come out in me and i go off on a random tangent to a level that's usually useless given the circumstances

 

[danl]

Your really not going to want to put solid rear links in. Even though this is a track only drag car you still have to get stopped. I don't know how fast your trapping but I trap 110mph plus and on one of the local tracks I visit the rear end gets awfully light when I come to a stop. On a cold day with skinnies out back and slicks up front it would be interesting trying to come down from 120 plus mph. I think a better comprimise would be coilovers in the rear with very stiff springs and high dampening rate shocks. I cut a 2.1 sixtey on a cold track on winter tires with no track prep in my fwd. I was about 0.3 tenths off my awd friends sixteys, they were spinning as well. I have coilovers and adjustable shocks.

 

[defrag010]

I used to have a friend with a turbo lebaron, and he made solid "shock bars". He took two pieces of metal, drilled a hole in each end, and he would bolt the "shock bars" in place of his shocks when he'd run at the track. He had them measured out so with his shock bars in, the car sat at stock height. He was cutting 1.9 60' times with DR's on an open diff and his "shock bars".