Well here a chassis for a chevelle - Lateral-g Forums

R67Chevelle · #1 09-23-2007, 01:05 AM

This may be the route I will go if finances get better here soon....

http://roadstershop.com

What have any of you all think about this?

Blessings,

ProdigyCustoms · #2 09-23-2007, 05:50 AM

I saw the orange car autocross pretty hard at the Run thru the hills event last week, It made it into the top 5 shootout. The car looked like it had a push in it, but that is probably more a tire stagger issue (too big on back) then anything. I could not say it is the best thing since sliced bread or not, but I have to say to perform like it did, it was not bad. Only based on what I saw, it looked like smaller rar tires may make a better balance, assuming you cannot put more front tire on it which I only ASSUME you cannot or it would seem they would have it on the test car.

**XcYZ** · #3 09-23-2007, 08:45 AM

If the car is tight, regardless of tire sizes, basic chassis changes like a lower front spring rate, higher rear spring rate, less sway bar and raising the panhard bar would help, if not correct the problem. These are basic principles of race car chassis setups (not counting tire pressures, shock settings, etc), but they should also be the basics when setting up a street car.

I know this post doesn't add much to what the original thread was about, but the topic of tire sizes and understeer comes up from time to time and I wanted to add my two cents.

**Steve1968LS2** · #4 09-23-2007, 10:04 AM

Thier test car, running the subframe, was out a the Run Through The Hills autocross event and did VERY well. I think it was in the top 3, maybe even top two, times for cars on street tires (non-R-compound)

They also tested the car out here in CA at the El Toro Marine base. I can't release the numbers but the car did very good. I think it almost got a 1g on the skidpad. Again, on non-r-compound tires.

Their chassis uses a lot of DSE parts including chuncks of thier hydoformed subframe.

Anyways, it's a cool car and beat the snot out of it. lol

mazspeed · #5 09-23-2007, 03:15 PM

Quote:

Originally Posted by Steve1968LS2

Thier test car, running the subframe, was out a the Run Through The Hills autocross event and did VERY well. I think it was in the top 3, maybe even top two, times for cars on street tires (non-R-compound)

They also tested the car out here in CA at the El Toro Marine base. I can't release the numbers but the car did very good. I think it almost got a 1g on the skidpad. Again, on non-r-compound tires.

Their chassis uses a lot of DSE parts including chuncks of thier hydoformed subframe.

Anyways, it's a cool car and beat the snot out of it. lol

I saw that car at the last goodguys event here in Aug. They had a display of chassis and the quality looked killer. Yeah, that has a big block merlin right? It was nice, and had bugs on it, which means they drive it.

R67Chevelle · #6 09-23-2007, 04:01 PM

Reason for my interest is that the rear tires on a stock chassis is max 10" on the rear. On my chevelle the chassis is not rigid at all and want a firmer handling and more stable ride. The weight difference would be a interesting issue. Also the time is consuming in redoing the stock frame. It would be nice to roll a new chassis and be ready to finish the paint and body. The price after all the options are definately going to be over 20k and not too pleased about this, but you camaro guys have some awesome chassis options out there.

With the orange 66 chevelle the RS concerts has is a neat car. I do not like any wheel over 18" on a chevelle.. It does not to me look any good. I would like a 18X12 wheel in the rear and a 18X9 in the front. Cornering is not the biggest factor but I want something with 700-850hp and need a stable chassis and rear tire to handle the power on the street.

Thanks for all the input. This decission helps. My project is now a complete redo. Not going to cut coners this time, Had the velle for 22 years now and I want to do the build like I have always wanted.

Blessings,

Derek69SS · #7 09-23-2007, 10:06 AM

In all honesty, you can get equal geometry improvements with bolt-on parts on your stock chassis for a LOT less money. The only real benefit I see over the right combination of bolt-ons is the added chassis rigidity.

The big rear tires are cool if you're not serious about road-racing/track days (which most of us aren't but if you are...), they will come up to temp much slower than the smaller fronts, effecting the balance of the car differently throughout the run... if it starts neutral, when the fronts get sticky it will go loose, then the fronts get too hot as the rears just start to get sticky and it goes tight. They also require running the springs/shocks further inboard negatively effecting the motion-ratios.

Edit: ...should add the big tires may help on a tight course such as an autocross, but likely a hinderance on a big course.

**XcYZ** · #8 09-23-2007, 02:38 PM

Quote:

Originally Posted by Derek69SS

The big rear tires are cool if you're not serious about road-racing/track days (which most of us aren't but if you are...), they will come up to temp much slower than the smaller fronts, effecting the balance of the car differently throughout the run... if it starts neutral, when the fronts get sticky it will go loose, then the fronts get too hot as the rears just
start to get sticky and it goes tight.

I will agree with that, but if you're going to look at how the tire temp changes are different with different size tires, then you might as well start looking at everything, such as fuel load. As you use fuel your balance is going to change, just like it will with tire temps. I know some guys that used to race using methanol but have switched to race gas because you don't use nearly as much over the course of the race, which means the change in balance isn't as drastic.

Of course, with street tires, this is just about pointless. lol But if you're serious about competing (in sanctioned racing), nothing is left out of the equation.

I still say that tire sizes differences from front to rear can be dialed in with the right chassis setup.

68protouring454 · #9 09-23-2007, 03:09 PM

they were out of the top 5 until they got to hot lap it 4-5 extra laps to knock the last 2-3 10ths off, at the end before the top 5, the car is cool and did well for a boat..
cool chassis, and they were nice guys too.

PTAddict · #10 09-29-2007, 10:42 AM

Quote:

Originally Posted by Derek69SS

The big rear tires are cool if you're not serious about road-racing/track days (which most of us aren't but if you are...), they will come up to temp much slower than the smaller fronts, effecting the balance of the car differently throughout the run... if it starts neutral, when the fronts get sticky it will go loose, then the fronts get too hot as the rears just start to get sticky and it goes tight. They also require running the springs/shocks further inboard negatively effecting the motion-ratios.

FWIW, my '71 Camaro with a modified LS1 uses 265 front and 295 rear Pilot Sport Cup tires on the track (Portland Raceway). After a 20 min session, the pyrometer shows the rear tires 5-10 degrees hotter than the fronts, even with 4 PSI greater hot pressure.

I notice that high-powered RWD cars with near 50/50 weight balance (Viper, Z06) are often running 50mm or more rear stagger, even in full-race setups. You want that kind of car to keep the rear end stuck down when hard on the throttle exiting turns. Something like, say, a spec Miata is a somewhat different story ...

Finally, keep in mind that a solid axle car provides no provision for negative camber in the rear. Personally, I will run the biggest tires that will fit on both ends, then tune with camber, shocks, and tire pressures.