Toms RCR 40 Trackracer

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Hello to all
If you are interested I can give you some test result we had in years 1996 to 1998 when doing similar test on track and on wind tunnel on VBM cars ( as you know very very close to GT 40 technics !)
We had lot of problem with heat on air coolers installed on rear engine bay and we tried to do similar scoops you are doing
We noticed that no best results where found with temp level and we had the opportunity to have wind tunnel session offered to understand what was happening : until rear engine compartment was not closed on behind there was flow under the car( velocity but not pressure) and due to wheels air movment this flow was not enought in compression to reach air scoops and go enouth in pression to puch onto radiators and result was poor !!
As soon as we built a floor with sides ( something like a diffusor with quite no angle) airscoop pressure intake was better but inside temp engine compartment increased ! so the effort into scoops was just enought to compensate that difference and track comportment of the chassis was changed and sometimes dangerous ( sudden oversteering on large curves !!
We understood taking various datas of air depression in various areas under the engine bay and under the gearbox ( trying to lower or lift the car ) that flow on these volumes what too much submit to variation and if not ducted from the forward part of the front floor it was very luky if we obtained good improvment on cooler efficiency
So we decided to go into top air scoop ( strangly on same time some famous GT 1 did same devlopment so we copy them !! and had good result)
Some years after working on modern LPM1 with big and efficient diffusor and very low ground clearance I tested to do some naca opening to ducts like yours and had very good result but infortunatly Le mans ACO rules do not allowed us to do so and I closed these holes!!
Hope this experiences will give you some info of what is happening to underflow air :shy:
THanks for this informations. Did install this already last year and achieved in average a 15degree lower oiltemp. Will see how it works on the track

Also building a Turkey pan for my Holley setup. Will be not the Cobra Holley style, rather will be the weber style pan, covering the whole opening.

Milled down the intake by 13mm first, to achieve the need clearance for using heat insulation gaskets between intake/pan/carb.


Turkey pan is done in one piece



the walls are fitting exactly behind the fiberglass side walls of the opening with a 5 - 7mm gap all around. THinking about a push-on gasket to seal it of.


Randy V

Staff member
Lifetime Supporter
Nice job Tom.. I've been contemplating a Turkey Pan and how to seal it also. Not sure if sealing will really do much good. But. If you were to add metal to the opening on the rear clip that would intersect with the turkey pan, I think you might be able to deflect more heat -which is what the turkey pan is all about anyway.

Like the oil cooler scoops too!
Nice. No more Webers?

I have the weber intake portmatched now and put it on my workbench. I will set up the weber system completly of the engine first until it is just a day of changing from one system to the other.

Before putting the webers on, i will max out my holley to have a benchmark.

Also i´m planning on running my ducati racebike in september. to do so i have to finish the build of it first


All my efforts to get a better heatmanagement work out like intended:

- 180° Robert Shaw high flow thermostat, works great, improved cooling significantly; Temperature is fluctuating between 175° (non load, due to modified thermostat version with 3 bypass holes) and 185° ( load situation). Also the cooler fans switch on much less due to this.
- Heat insualation gasket and Turkeypan. Car restarts immediately even after sitting for a while when hot. No stalling anymore when very hot ( doesn´t get so hot anymore due to thermostat change).
-FUel Pumps used to get louder in idle in the past when engine got hot. Probably due to difficult pressure situation in hot fuel lines. Now this is is not the case anymore. It seems that the turkey pan is effeciently shielding the carb fuel lines from radiant heat.
- Oil cooling ducting: Works great. In the past i had oiltemps in heavy load up to 280° , now the max i reach in heavy load with 23°C outside temp is 230°F. As soon i back out to low to mid load, oil temp returns back to 200°F.
- On trans cooling. in the past the oil pump was always runing when i stopped the car after some ambitous drive (pump is thermostat controlled). Now it does not run when the car is stopped. Means that cooling during the drive is much more efficient.

Over all good success with all this measures.

Semi rigid engine mounts: Also this works out great. No sensible increase of vibration or engine noise in the car. If any, than the gear whine in second ( race gears) is a bit louder. but thats it.
Car feels much more in control in heavy acceleration and in coming down from high RPM there is no resonance vibration anymore.

updated pictures to come

Tom, just read the complete build, and i agree with all of your other readers: great work, clean, professional, and damn sexy. Thank you for all of the information, i look forward to your SLC build as that is probably the car i'll be building.

Thank you,
David, sadly, our good friend Tom was seriously hurt in a car accident involving his gorgeous GT 40. Last we heard he remains in a coma his passenger in the car was killed.
Jimmy, I'm so sorry to hear that. Obviously that's horrible news, my condolences to the family. Let us know if the forum family will be doing anything to support Tom's family.

Randy V

Staff member
Lifetime Supporter
I sent a letter to his son about 6 weeks ago with my email address and phone number. I've heard nothing back. :(

Edit ---- I am locking this thread until I hear back from either Tom or a family member...
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