Ride height question

[kevins2]

The ERA manual states: ERA recommends that the main chassis rails be raked about 1/4" to 1/2" from front to rear.

I assume this means "positive" rake. In other words, the rear would be higher than the front. Am I interpreting this correctly?

Thanks,

Kevin

[DanEC]

Kevin - that is how I interpret it. I think that matches the ride heigth measurements in the manual that shows clearances from ground to frame - with the rear about 1/4 to 1/2 inch greater than the front.

[ERA Chas]

I set the height as measured at the flat of the lower edge of the frame, measured right in front of the brake box and at the aft edge, before the rear kick-up. I set mine at 4 7/8, F & R and I think the manual wants 5". Remember, the wider rear tires add rake by their larger diameters.
Try 5" as a baseline and readjust to taste. The lower the better.

[DanEC]

I'm considering setting mine close to flat - mostly just because in appearance a lot of the originals seemed to sit just a little low in the rear and not raked. Also a forward rake only drops that oil cooler scoop a little closer to the ground and top of speed bumps.

[kevins2]

The manual calls for 5 1/4" at the front of the main rails and a rake to the rear of 1/4 to 1/2". It also says to drive at least 50 miles first. I have about 80 miles, so hopefully it has settled as much as it's going to. Not a big deal if it needs multiple adjustments.

Thanks for the help.

Kevin

[ERA Chas]

FWIW-my chin scoop is 3 5/8" from the ground. Avoid speed bumps (and the malls they're in) and you're fine. If you must traverse one, approach at an angle and the raised wheel is enough to clear a bump.
Also 'helicopter tape' is your friend; I only had light scuffs in it and untouched fiber glass. A patch cut to the shape of the bottom of the scoop is unseen from standing above.

[kevins2]

Helicoptor tape comes in 8 mil and 14mil. I assume the thicker the better for this purpose. I'll check the scoop height - haven't measured that yet.

Thanks again.

Kevin

[ERA 778]

OK, I'll bite..What is helicopter tape? Never heard of it !!!

[vatdevil]

Originally Posted by ERA 778

OK, I'll bite..What is helicopter tape? Never heard of it !!!

Polyurethane tape....often called Racers Tape.

[Bobcat]

Kevin ... my manual says 5 1/4" in front and 5 3/4" in rear for ride hgt . measured from frame rails as ERA Charles says . Mine is a bunch lower and I sometimes run more rake than the 1/4 to 1/2 " as it seems to help the front end to not be so squirrely at high speed on the track ( 130 + ) as I don`t have a front spoiler/air dam . My suggestion is until you get some miles on the car ... several hundred , don`t worry about ride hgt . Just get it close and once everything settles in , then start lowering until you`re happy .
FWIW , I set my ride hgt with a little over 1/2 tank of fuel and my weight in the driver`s seat . I also make sure the front and rear antisway bars are disconnected while setting the ride hgts and reconnected with no preload while the weight is still in the driver`s seat .... but then I`m anal on things like this .

Bob

[patrickt]

Originally Posted by Bobcat

FWIW , I set my ride hgt with a little over 1/2 tank of fuel and my weight in the driver`s seat . I also make sure the front and rear antisway bars are disconnected while setting the ride hgts and reconnected with no preload while the weight is still in the driver`s seat .... but then I`m anal on things like this .

Of course he will need to set the corner weights when he does the final ride height. Nothing makes as big a difference.

[Bernica]

Originally Posted by patrickt

Of course he will need to set the corner weights when he does the final ride height. Nothing makes as big a difference.

PatrickT, you beat me to it! I second Patrick's comments about the importance of corner-balancing the car, keeping in mind that your weight in the driver's seat is a factor used as well to get proper corner-weights for the car. Then you need to decide how much fuel to have in the tank, especially if you are running a big tank.

[ERA Chas]

Yes, polyurethane but not 'racers tape'.
3M aerospace and aircraft product catalog
Literally used for leading edge protection on fixed and rotary winged aircraft.
Mine is black but now clears are available.

[lippy]

Originally Posted by ERA Chas

Yes, polyurethane but not 'racers tape'.
3M aerospace and aircraft product catalog
Literally used for leading edge protection on fixed and rotary winged aircraft.
Mine is black but now clears are available.

Anyone have a good source for this - especially the clear? I checked the web and only found 0.75" x 36 yd, at a price of about $3k (!).

[scottj]

Originally Posted by lippy

Anyone have a good source for this - especially the clear? I checked the web and only found 0.75" x 36 yd, at a price of about $3k (!).

ISC RACERS TAPE

[ERA2076]

Interesting the concern over corner weight on an assumed street car. Unless ERA missed the manufacturing completely, I don't see how corner weighting is really going to matter much. There are lot's of other assembly tolerances that are taken for granted and are possibly not correct e.g. suspension pickup point alignment, chassis squaring, etc. all of which academically affect corner weight and all should be optimized before corner weighting. Isn't that how Shelby made his living i.e. Cobra, GT 350?

On ride height - The slight rake in chassis is just good setup. We get some component of aero working to push it down (at least at the speeds we can legally drive) and also help with squat.

If we consider track - take a look at this software and consider RC and IC and check the resultant ride height against the manual. Depending on tire height (as an example) things will change.

Circle Track Analyzer Racing Simulation Chassis Setup Software Program

I wish we could find some 1 to 1.5" dropped spindles. We could drop the CG and maintain a great RC.

Except for the entertainment value, not sure any of it pertains much to a street car. Very much applies to a track car - (especially if you build an under powered motor )

I think ERA has much balance built into their cars as designed, manufactured, and delivered. If you did not purchase a roller, then suspension blue printing makes sense. If not, other than a very good educational exercise, why bother corner weighting a street bound ERA? I doubt we could tell the difference between one that was, and one that was not, if testing were done legally on the street (that means clover leaves at legal speed).

My 3500lb mustang has not been corner weighted and for what it is and what I do with it (intermediate HPDE) it runs like stink. I would c-weight it, but I have spent a lot of time making it track-able and that is time (and $) stolen from the FIA. (much forgiving to learn in though )

We'll corner weight the FIA, but we are setting it up for track use. We have taken the time to square the sus pick up points, the steering, bump steer it, square wheel base, etc. IMHO - none of which makes much difference for a street car built to ERA standards following their manual.

Go Stanford - 3:06 to go

drop spindles?



chr

[ERA2076]

grats to State - great game - 2 great heavy weights.

chr

[ERA Chas]

Originally Posted by ERA2076

I think ERA has much balance built into their cars as designed, manufactured, and delivered. If you did not purchase a roller, then suspension blue printing makes sense. If not, other than a very good educational exercise, why bother corner weighting a street bound ERA?

Everything Cliff said in his post is exactly my experience with mine-in the '90's. Mine was a pallet car, not a factory roller. It has no add-on's but does have magnesium wheels. It's a very elemental car like S/C's were.
I did c/w it and here were the results with 1/2 tank of fuel, batt in trunk and me in it:
CORNER WEIGHT W/DRIVER: LF: 682 / RF: 648 / LR:755 / RR: 748
WEIGHT DISTRIBUTION W/DRIVER: F: 1330- 46.9% / R: 1503 – 53.1%
I made no changes and found it perfect for autox, track days and street.
Those that claim a remarkable transformation in street driving after corner adjustments are deceived by lack of force input of a racetrack. Unless the car is saddled with amenities, sound-deadner, fake aluminum and such, it will be very close right from ERA-and they will all be similar. A good alignment with a performance bias will be much more beneficial to improved 'feel'.
So the improvement after c/w is largely psychological-unless you plan what Cliff does on track.

[kevins2]

Lots of little details to tend to. It's been said that you're never really done with these cars, which makes them a perfect hobby. I appreciate all the helpful advice. I won't completely obsess over the ride height just yet but will tinker with it to get it close. The driver's side rear is just shy of 1/4" lower than the passenger side. I'll at least get things close and then get some miles on it.

As for corner weighting, I'll have to ask around locally to find someone to help with that.

It's supposed to rain hard tonight and tomorrow, so hopefully it will and wash all the salt off the roads so I can get it out for a drive. That would be a great Christmas.

Kevin

[patrickt]

Originally Posted by kevins2

As for corner weighting, I'll have to ask around locally to find someone to help with that.

It's not hard. The hardest part is just finding the scales, but usually someone in your local club has them. You can even do it by cleverly cantilevering on to bathroom scales to reduce the apparent weight. But you've got to do it. The world will come to an end and you will never be happy if you don't.