RCR T70 Spyder Lightness

Ron Earp

Admin
The team finally broke down and bought some scales for the 2010 racing season. First thing I did was weight the T70 Spyder and it is pretty light. Now, before I put out the weight rememeber this thing has a full SCCA legal roll cage that is overbuilt, two 10 lbs fire extingushers plus one hand held extingusher (I am scairt of fire), iron block, 11 gallons of gas, 930 transaxle, STEEL wheels at 22 lbs each, full road lighting, eleven gauges, two MSD boxes, and some other redundant stuff.

Weight - 2094 lbs as it sits.

I was expecting around 2300 lbs as the bodywork is not the light weight option and we have a lot of stuff in there.

We have not adjusted cross weights yet but things look pretty good for a base:

459 481

577 579

Easily done. F/R is 45% 55%, not too bad out of the box.

I think this thing is going to put some serious hurt on a track.

R
 

Randy V

Admin
Lifetime Supporter
Re: RCR T70 Spyder Lightness.....not bad

Sounds really good Ron!

Make sure you dummy the driver's weight into the car and disconnect the anti-sway bars when you scale it out..

That car is gonna go like a bat out of hell!!!
 

Ron Earp

Admin
Re: RCR T70 Spyder Lightness.....not bad

I don't suspect we have a lot of hp compared to most motors on this board. We have a standard 302 inch motor, about 10.5:1 compression, a low duration cam that has a very smooth idle, stock smooth, Air Gap intake, 650 Demon carb, and run of the mill Eldelbrock heads. I'd estimate that it is in the 260-280hp range but in a few weeks the dyno will let us know.

What I'm thinking about is how light this thing could be:


  • Ally block could shave 75-80 lbs if memory serves
  • The battery in the car is a BIG one, a Walmart special and is very heavy. A lighter battery, even picked with a bathroom scale at an auto parts store could knock off 15-20 lbs. Go "race" battery and lose more.
  • 40 lbs could be saved with some ally wheels that were selected for lightness
  • Drop one fire system, 11 lbs
  • Fuel cell/NASCAR fueling - drop another 45 lbs (use sponson tanks that are built in)
  • Use one MSD, one coil, drop another 9 lbs
  • Ditch the tranny cooler, pump, lines, fittings, drop another 14 lbs
So even with keeping the cage you could drop about 200 lbs relatively easily. Ditch the cage and that'd probably knock out another 60-70 lbs.

I dunno much fellows but light makes right!
 
Re: RCR T70 Spyder Lightness.....not bad

As Colin Chapman apparently said:-

Add more power and it will make you faster down the straights.

Make the car lighter and you will be faster everywhere.

Chris
 
Re: RCR T70 Spyder Lightness.....not bad

If you want a really light and tiny battery, try an optima group 51 - it's able to start my 408w, even in -20* temps.
 
Re: RCR T70 Spyder Lightness.....not bad

Ron, you'll get to purchase that lightweight bodywork in almost exactly a year if you run that 13 hour next year. :)


--Donnie
 
Re: RCR T70 Spyder Lightness.....not bad

The original Lola T70 weighed (dry)1625 with Chevy and 1580 with Ford....
We added 175 lbs for driver and filled the tank 1/2 full (100 lbs).
The car has a dry sump oil system that adds another 30 lbs and a 20 lb fire system.
The alternator and coolant add another 50 lbs.
We also added door bars that weigh 15 lbs each and headlights that weigh 8 lbs.
This adds to 2038 so I have 19 lbs unaccounted for ! It is probably paint because the cars were delivered in gelcoat.
 

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Ron Earp

Admin
Re: RCR T70 Spyder Lightness.....not bad

This adds to 2038 so I have 19 lbs unaccounted for ! It is probably paint because the cars were delivered in gelcoat.
Hey Johan,

I like those mirrors, great picture! Are those fabbed up by the Lola crew for the T70s?

Now you know dry weights are like someone telling you cup size in a Wonderbra. I looks like we're not doing too badly then it would seem. We've probably got heavier wheels than you guys, our chassis is surely heavier, and we've definitely got lot more cage. We're still wet sump though, so a bit lighter in that respect.

1/2 tank is 100lbs for your car, what size cell does it have? With gas coming in at 6.6 lbs per gallon seem you'd have a 30 gallon cell - that is nice. We can only do 25 gallon max and even then I don't think I'd call that all usable, probably only 22-23 usable. Sort of like flying, I know my fuel load out is 24.5 gallons but I'll be damned if I'll try and fly all of that. 19 lbs unaccounted for huh? Lucas smoke or English ghosts?

So if we're around 2094 lbs now, add in 180 lbs driver, that would put us up around 2300 lbs, certainly heavier than the real deal. I think I could get weight out of it to knock it back down another 180 lbs to negate the driver, putting us around your weight BUT, we won't have the horsepower you do. Still, it'd be interesting to see how they would run on track together. Based on power I think we'd get stomped.

Ron, you'll get to purchase that lightweight bodywork in almost exactly a year if you run that 13 hour next year. :)
--Donnie
We won't as long as you don't hit us! :cheesy:

Seriously, we've had mixed results over the years on the 13 hr. Some of our cars have come through unhurt, other times with a lot of damage. One year when we were fielding four cars as a sort to team effort two of our cars hit each other, that was the shits. Definitely a risk, that is for sure, but if we want safe I suppose we need to stay home, play golf, cut the grass, watch football, or hold down the couch.
 
Re: RCR T70 Spyder Lightness.....not bad

Ron it holds close to 30 gallons per side but only the left side has a bladder. For a short race like 1/2 hour we run 15 gallons and burn almost 10. It gets around 4.5mpg at 100 mph average speed.
The mirrors are the original mirrors and are a bit crusty with the lenses siliconed in place so they are no longer adjustable but the good news is that they do not slip out of place while driving.
The transmission is very heavy.
The wheels/tires are very light.
 

Ron Earp

Admin
Re: RCR T70 Spyder Lightness.....not bad

Ron it holds close to 30 gallons per side but only the left side has a bladder.
That is a lot of fuel and you'd have quite the endurance racer with that load.

What are the specifics on the motor in your Lola? Iron block I reckon, but ally heads?
 
Re: RCR T70 Spyder Lightness.....not bad

After Swede Savage's fatal accident at Indy in I think 1969 the maximum fuel capacity of race cars was changed from 50-60 gallons to 25-30.
The motor is a Traco 364 SBC with an Iron block and aluminum heads with the original (to the car) set of 58mm Webers. It produces 550 hp. It is dry sump and run with a fat body, wide tires and vented brakes in the USA. In the UK it is run wet sump with a narrow body,narrow tires and non-vented rotors.
 

Ron Earp

Admin
Re: RCR T70 Spyder Lightness.....not bad

Hi Johan,

I think you could help quite a bit on set and I appreciate the offer. I'll get our starting specs out tonight and post them and you can maybe guide us.

I feel that we got the rear of the car very close. We have the caster adjusted well, toe was good, about 1/16th in if I recall, and camber was a little much at -1.6 degrees. Tire temps showed we need less camber in the rear. Toe change just about non-existent in the rear over a few inches of travel so I don't think that will be a problem.

Again, I'll get the specs but our rear felt very planted and hooked up. I did spin it giving in the boot in a tight low speed corner as I got cocky with the feeling. Still, it was good overall and in the high speed corners the rear was solid, and gave confidence.

Now the front, well, that is a different story and we know we have a lot of setup tuning to do there.

There are similarities and differences in the rear end pictures of the RCR T70 in comparison with the Lola you have. I do notice one thing right away that I have to do - get that engine oil cooler elevated so it can take advantage of the air flow. Does your rear clip have any ducting around the intake to further help air hit the cooler? Does your engine run a magneto ignition?
 

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Re: RCR T70 Spyder Lightness.....not bad

Your car is darty and does not provide the right "feel" in high speed corners, right ?
1/8" toe out in the front
1 /16" toe in in the rear.
The rears stand straight up.
3/4 degree negative camber in the front.
2" chassis rake
5 degrees castor front
3 way shocks all set to medium settings.
450 springs front set on the snubbers (2" chassis clearance}
550 springs rear
both bars hooked up
9" front wheels 10" tread Avon grooved slicks
12" rear wheels 14" tread Avon grooved slicks

ftp 16 BIAS PKY
rtp 18 BIAS PLY
yes
yes

makes her drive like a 962 (almost)!
took 4 track events to come up with this
this message shall self destruct in 24 hours
 
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Randy V

Admin
Lifetime Supporter
Re: RCR T70 Spyder Lightness.....not bad

I do notice one thing right away that I have to do - get that engine oil cooler elevated so it can take advantage of the air flow.
Ron - Where is the sending unit for the oil temp? If in the pan is it close to the top of the oil level?
 
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