Build Diary - RCR Lola T70 Spider

[Ron Earp]

Doing some more setup and prep work on the T70 for the UTCC. We've lowered the rear a bit, ditto on the front, and set everything back up again. We've also done extensive camber curves for the front throughout the suspension range of motion and spent quite a bit of time getting everything just so. We were in pretty good shape last time out but this time I think we're in very excellent shape as far as setup goes.

If other T70 owners are interested I'll post up our final suspension settings but off the top of my head we're about:

-0.5 camber rear
-1.2 camber front
6.7 caster on both sides rear
5.5 caster on both sides front
About 3/32" toe in front
About 1/16" toe in rear
Front springs at 6" tall and 1000 lbs
Rear springs at 8" tall and 850 lbs

Rear ride height is right at 4" and the front ride height is a bit less than that. Ride height and spring changes were our big ones this time around.

We've also added more weight to the car in the form of the DR COOL in the passenger side of the car. The DR COOL will be needed though as July at VIR is damn hot. Scale setup is shown with everything installed and we ballasted up for a 200 lbs driver this time around using cinder blocks and dumbbells. 9 gallons of gas, so about 5/12ths load of fuel.

OH! And the dang ol half shaft angles are way down. When we set the rear up again at the lower height these were very much improved - down to 11 degrees from essentially 17-18 degrees. Much more tolerable. I think I've banished all thoughts of flipping the transaxle because if we did that we'd end up with basically the same thing, about 8-9 degrees, but more problems if we wanted to RAISE the car.

Since out last track outing back in September it hasn't done any more track work, but, it has been driven 728 miles on the street without any issues. Starts, runs, shifts, drives - works as it should. A lot to be said for simplicity of a V8 with a carb, simple electrics, and no fancy bits beyond what is needed to make the car run.

 

[Howard Jones]

V8, carb, simple electrics, no fancy bits................a man of my heart. Good luck buddy. Can't wait to see how the enduro goes.

 

[flatchat(Chris)]

Best 'O luck bro. We'll be watching with much interest --of course we'll expect a full report after the event :thumbsup:

 

[Ron Earp]

V8, carb, simple electrics, no fancy bits................a man of my heart. Good luck buddy. Can't wait to see how the enduro goes.

Yeah, makes you wonder how we can make the car run without ISIS and a Motec doesn't it?

I hope we get to race it. I am pretty sure we'll make the UTCC but I'm fighting a bit of a time issue with home/family, and work. My dad's taken ill recently and we're still trying to sort through what's going on with that. Overall though, since the sale of the Z car back in April I've had a bit more time for the T70 project and without racing every other weekend more time for home life as well as more money in my pocket. Having a "year off" from points racing is a good thing but there is another SCCA IT car being drawn up in spare minutes on the computer.

Chris, you guys dry sumped your Chebby motor didn't you? I suppose you never had any problems with half shaft angles out of the 930?

R

 

[flatchat(Chris)]

Nope and no -- Poor mans dry sump, ("accusump") remote cooler and filter.
Don't worry about the drive shaft angles ! We run approx 3° for / aft and 8°-12° @ ride to droop --just make sure you have QUALITY CVs and boots

 

[Johan]

Regarding your settings, here is what we do differently.
We run toe out in the front and toe in for the rear.
We run stiffer springs in the rear than the front but with lighter rates than you propose.
We keep the suspension supple and control roll with the bar.
We run 1 1/2 " of chassis rake.

 

[Ron Earp]

You guys are running vintage tires though, correct? Besides that difference, there are surely suspension geometry differences between that two cars that would probably prevent a direct comparison. We're going to start with the settings I wrote but we'll see what we end up with. We do have a method to our madness and reasons for picking these starting points.

We've got the best axles, CVs, boots, grease, cages etc as we could find (detailed on other threads) so I think we're going to be fine with these half shaft angles. Probably would have been fine with the 17-18 degree angles too.

This morning I discovered that my battery had "exploded". I went to wire up the DR COOL and the inside of the battery box was all covered with acid an the battery was expanded. Not good. Heat, vibration, or over-voltage? Not sure but I suspect the internal regulator in the alternator has failed. So putting in an AGM battery and will check the charging system with the o-scope to see what is going on.

R

 

[Chris M]

Regarding your settings, here is what we do differently.
We run toe out in the front and toe in for the rear.
We run stiffer springs in the rear than the front but with lighter rates than you propose.
We keep the suspension supple and control roll with the bar.
We run 1 1/2 " of chassis rake.

very interesting johan, mine also is set up with stronger front than rears and about an 1" of rake, must be to do with us all having different types of suspension arrangements to the original.

 

[Darren]

Been reading with interest lately, and Johan's post has prompted me to add my own thought's as to settings we use on the 3b's both orig and continuation. Similar to Johan's we run 3/4 deg neg camber fr 1/4 pos rr, 5 1/2 deg castor f+r, 3/4 deg toe in on front, 1/2 deg on rear, 500lbs f / 600lbs springs, 3" fr 4"r ride height (1" rake). I'm assuming the great variation in spring rates has something to do with susp geo/ damper angle. We tried upto 800lbs on the rear but it made the car very skittish.
Anyway, great thread, and just my views from the pit lane...

Darren.

 

[Ron Earp]

If you guys are going to post suspension settings you'll need to mention tires. Vintage type tires are going to want a different setup than modern racing rubber. I'm using Hoosier R6s, not slicks, but the R6 is a stiff sidewall and low profile radial tire with a lot of stick.

I figure my effective rate (will calculate it exactly) of springs due to the suspension is in the 750 lb front and 575 lb rear range, or thereabouts. I'll measure and determine it more precisely.

 

[Chris M]

If you guys are going to post suspension settings you'll need to mention tires. Vintage type tires are going to want a different setup than modern racing rubber. I'm using Hoosier R6s, not slicks, but the R6 is a stiff sidewall and low profile radial tire with a lot of stick.

I figure my effective rate (will calculate it exactly) of springs due to the suspension is in the 750 lb front and 575 lb rear range, or thereabouts. I'll measure and determine it more precisely.

mine runs 335-30-18 toyo 888s or pirelli Pzeros, with 245 or 255mm fronts.
ride height is 3 3/4" front and 4 3/4" rear, springs are 550ish front and 750 rear.

i could drop the ride height a little but it was based on a compromise of Gd road type settings and the fact that 3" was too low to get the car out of the garage and onto the trailer without catching the underside of the nose all the time! :cheesy:

 

[Jas Camillo]

Hi Ron! Beautiful looking car! What is the wheelbase/track on your RCR T70? I guess it`s the same as the GDT70 since the same body mould was used?

 

[Ron Earp]

I don't know precisely, I never measured it. The body work is the Lola Heritage style nose and if that is what GTD has then they are the same style. However, from what I can tell they appear to be a bit different and you'd need to check with RCR for details on their particular molds, I know they don't source them from GD though.

I sold the car on after the racing season ended in 2011. Final pictures of how the car looked can be seen here.

http://www.gt40s.com/forum/gt40-cars-sale/36155-rcr-t70-spyder-sale-sold.html

 

[Johan]

Not to nit pick, but it is not a Lola Heritage nose or body. It is a Heritage Engineering nose and body. There is of course an entity named Lola Heritage but it is different than the Heritage T70 that was produced long ago and which was copied by both GTD and RCR and I am not saying there is anything wrong with that whatsoever. The Lola Heritage T70 is the current T70 continuation car and is exact in most every detail to an original. Only 5 spyders were produced by Lola Heritage. Only 3 spyders or chassis were produced by Heritage engineering . I do not know how many GTD or RCR cars have been produced. All are cool cars though, of that I am sure.

 

[Fran Hall RCR]

GTD did not make this type of car...only myself and GD ...

The moulds I own are the original style ones from Heritage engineering in the UK...the ones GD have started life as the same shape but have since been modified to create their GDT70.

The RCR ones are the same as originally used by Heritage engineering with zero changes....I purchased them long ago from the guy that bought a Heritage car and spares...including moulds.
He eventually sold the Heritage Engineering car

 

[Johan]

Oops, my bad, I meant GD and not GTD... thanks Fran.

 

[Fran Hall RCR]

Not to nit pick of course....:lipsrsealed:

 

[mark b.]

if you don't mind me asking and i don't want to get the thread off track, but that seems quite a bit of caster at the rear, what are the benefits and how is it measured? thanks.

 

[Jas Camillo]

GTD did not make this type of car...only myself and GD ...

The moulds I own are the original style ones from Heritage engineering in the UK...the ones GD have started life as the same shape but have since been modified to create their GDT70.

The RCR ones are the same as originally used by Heritage engineering with zero changes....I purchased them long ago from the guy that bought a Heritage car and spares...including moulds.
He eventually sold the Heritage Engineering car

Hi Fran,
So I guess the wheelbase of the RCR 70 is about 95 inches?

 

[Fran Hall RCR]

RCR70's are the same...Coupe or spyders...either version...why?

Do you mean the SL-C when you refer to the Coupe...as thats a different animal altogether.