Toms RCR 40 Trackracer

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HALLO

Beeing a big fan of classic race cars i initially planned to built a FFR DAYTONA COUPE. By searching the FFR FORUM for months i one day stumbled over a thread with the title "my new GT 40 Kit". Curious about i clicked on the link provided and landed on BILL D´s Bill's GT40 Build Site .
Waht i saw there impressed me very much, so it doesn´t took long and the Daytona Coupe was past.
Beeing a fan of the GT 40 since my youth i checked for available kits a few years ago, but at this time the only one i liked (RF 40) was out of reach. Time has changed and new players came up ( an info which i missed because i didn´t follow up activly anymore).
THANKS BILL D for your threat on FFR. Without that i wouldn´t know about RCR and FRANS great products.
After spending another 4 months on this great forum, i knew i´m going to have a GT40 Kit. The information provided on this forum helped me a lot to learn about the available products and there pros and cons.
The concept and quality of RCR was so impressive, that for me it has to be one of FRANS kits.
In January i got the chance to purchase the UK DEMO KIT. I picked it up personally at CHRIS MELIAS home. All of the people i met there where very helpful ( see also : http://www.gt40s.com/forum/rcr-forum-rcr40-rcr70-p4-mkiv/24131-first-rcr-40-germany.html ).

In this thread you will get an regular update about the build process of my car.
The car will be a purposebuilt trackracer with the following spec:
  • RCR 40 De luxe plus kit RHD
  • 6 Point rollcage
  • +2" suspension package
  • 12x15 widened BRMs with 345/35/15 rear wheels
  • 8x15 BRMs with 225/50/15 front wheels
  • modified gulf flares
  • Gordon Levy built high rpm 331 ( 7500 rpm - redline)
  • G50 Transmission with LSD
Actually the built will start end of April, because i have to finish a SOS Racebike first for the upcoming classic bike racing season.
Right now i´m collecting parts and working on the concept.

I would like to encourage all of you, to provide information, comments
and help during the built process.
Whenever you like, dislike, have ideas to improve things you see on this thread, please post your opinion.

Thank you all

TOM
 
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Thanks for the nice compliments Tom. You will really enjoy your RCR. Fran makes a great car and his customer support is second to none
 
TIRES:

Because i like the look of it, i decided to widen the car in the rear.

To scope with the highspeed expected, i was looking around for the different alternative tires. As the trackevents i want to attend ask for street legal tires, going to race tires was no option.
By searching for approbriate tires i created the onby tirelist to have an overview about the different options and their sizing.
Finally it came down to choose between AVON CR6zz or PIRELLI PZERO. Although the AVONS would give a more period correct look i was more up to achieve a look provided by DUNLOPS CR 82 racing tires. So i decided for the PIRELLIS PZEROS.
In 345/35/15 for the rear, their total diameter is just 3/4" smaller than the DUNLOPS. They will be mounted on +2" widened BRM´s (the beautifull vintage wheels provided by RCR).
In 225/50/15 for the front, their total diameter is just 1/4" taller than the DUNLOPS.
Additionally to this, they are ZR rated and have a modern silica compound which will work ok in wet conditions.
The wide look in the back will be even wider, due to the use of RCR´s +2" suspension parts.

The pictures show how far the tires stick out of the standard width body. This will be covered by adapted +4" flares.





The flares will be modified to look like this ( i like the curled lip)



TRANSAXLE:

The transaxle i use is a PORSCHE G50/05 ( US version with a 3,33 final drive ratio). I purchased it out from a 964 with 45.000mls on it.
It will be modfied with a 2.5 Ratio 1st gear and a 1,84 Ratio 2nd ( which i already have, but still looking for the 1st).
3rd to 5th fits pretty good. With the modification the RPM drops are from1850 RPM( 1st to 2nd) down to 1400 RPM (4th to 5 th) calculated at a shiftpoint of 7000 RPM.
Topspeed @ 7000 RPM will be 176 mph. So its rather short, but on the track i don´t look for nice crusing RPM´s. I rather focused on small rpm drops and short ratios, to achieve good acceleration out of the turns.

Would be interested to get some feedback from the racerfraction on this ratios ( see chart onby).
Additional modifications will be a billet differential side plate, oil cooling and
a LSD ( 45/65 or 45/80 -100).
I´m still looking for a LSD, so if anyone knows one, please PM me.
Onby some picks after cleaning it.


Next week i will get a pan big enough to lay it in, Than it will be washed regularely with BIODIESEL, which cleans aluminium pretty perfect, without the need for blasting. Will be interesting to see how it turns out finally. Don´t want to paint it.
 

Attachments

JUst realised that the picture server don´t provide the pictures anymore.
Have to check it a soon i will get home ( on the road for business as usual)

Any reco for a good picture hosting site ( decent file size, folder organising and for free would be the best)

Thanks
TOM
 
I'm interested to see the final weight of this car, so far, it seems that the few RCR's out their are 'street cars' that have A/C systems and other interior luxuries. If I ever get one of these, its going to be a dedicated track car as well. I wonder how light you can keep things.
 
I'm interested to see the final weight of this car, so far, it seems that the few RCR's out their are 'street cars' that have A/C systems and other interior luxuries. If I ever get one of these, its going to be a dedicated track car as well. I wonder how light you can keep things.
Hallo,

Just check and get in contact with Ron Mc Call RCR #14. As far i know he has no AC, No Carpet, just pure racing.
I will built mine with AC, because part of beiing fast, is feeling comfortable in the car.

TOM
 
Mine is 2450lbs. That is with A/C and carpet, full cage, drysump, fire system, and aluminum everything. Minus the A/C and Carpet you are close to 2400lbs. My car is a good street car with plates and registration but it is a great track car!
 
Although i haven´t started to realy work on the car ( will reorganise my workshop within the next two weeks and than get going) i ´m still in collecting parts.
This time i drew up my fuel system.
please see sketch onby and feel free to post suggestions


Thanks TOM
 
This weekend i started to reorganise my workshop in order to get enough space for building the car. You know like it is, the number o toys is growing but space not.
When i started i was not quite sure if it will work out. Too much stuff for this small space.



But finally i managed it somehow and i´m pleased wit the result. I just have to keep it organised and than it will be ok.


Enough space to work comfortably around the car.
Before placing the car on stands i measured the workshopfloor with a laser-level. The result was very pleasing. It is level on +-1mm, so i can use it as reference measure to align all the body parts in terms of height.


Jay: thanks for the hint
accumulated work hours (awh): 13
 
CHASSIS SETUP:
I decided to do the bodywork first.
First thing i did was to put the car on stands, so that the floorpan-level is app 350 mm above the floor. As a result the car is perfect in level without "kippling" ( i just don´t know the english experssion) over one of the diagonal axes.
Next i adjusted the right hand side front suspension like recommended. Lower wishbone shimmed to the very front of the car with 1 shim as reserve, top wishbone shimmed in mid position, This will give you a basic caster of app 5°. Top wishbone universal joints full in and lower wishbone joints equaly threaded out to achieve the desired negative camber of app 1,5°. I also took the spring of from the shock and adjusted the front suspension to the correct ride height (4,5")
Until know i measured it with my standard level which i had calibrated ( marked) before on the desired angles, but i ordered a digital eletronic level which enables me to do it on 0,1° exact.
LEFT SIDE SUSPENSION:

Caster app 5°

right hand side camber app -1,5°
in order to be able to measure it the wheel has to point straight forward parallel to the car longitudenal axxis. I achieved this with a second simple setup.
An aluminium bar along the front bulkhead. I referenced this with several measurements . The chassis is very true, so if the bar leans on the front bulkhead it is exact rectangular versus the car axxis.
Using this as a basis i used a long straight edge to reference the front wheel direction.

alu-bar with straight edge

right hand side toe in adjustment
Than i repeated exact the same shimming and universal joint and height adjustments on the left hand side front suspension and measured it.
The result was very impressive exact the same as on the right hand side, showing how true this chassis is.

Left hand side camber app -1,5°

I also adjusted the toe out to 0.5°.
With the front suspension adjusted to the correct height and angles i did the same with the rear suspension.
Ride height was adjusted to 5.25". Caster as a result according to the reco that the control arm axxis´s should run parallel with the chassis 90° cross brace.
Toe in was adjusted (neutral) by measuring along a long straight bar running along the chassis longitudenal axxis.
Also here i started with one side and repeated the exact same adjustments( radius rod lenghts´, control arm lenghts and universal joint adjustments) on the other side. The result was as impressive as on the front suspension. Both sides have exact the same resulting measurements.

rear left hand side camber app -1,5°

left hand side caster

right hand side caster

right hand side camber app -1.5°
After finishing that, i measured the dimension from front to rear wheel center. The result is exact the same (diviation less than 1mm) on both sides.
Next i established 2 longitudenal and one vertical reference lines for all future body allignement work.
I started with a alu-ruler accross the chassis and measured the dimension from there to the wheel centers, to put it exact in the middle and 90° to them.

alu-ruler

This line i marked with a pen and checked vs the fuel tank edge. which are exact 90° to this cross reference line.

Left hand side cross reference line fit


Right hand side cross reference line fit
Knowing that the fuelcells running exact parallel to the cars longitudenal axxis i drew a parallel reference line 100 mm inside the outer edge on both sides.

drawing the longitudenal reference line

Right hand side reference line

left hand side reference line
I than checked the dimension from on to the other reference line

rear reference line distance

front reference line distance
The exact the same dimension confirmed the chassis straightness.

As last step i measured
the left to rigth centering of the front and rear suspension, by running the long alu-bar along the chassis edges and measuring to the brakedisc surface ( always on the same spot).

right hand side left to right dimension ( 210 mm)

left hand side left to right dimension ( 210mm)
The same result also on the measurement fo the front suspension.


rear suspension with strap to adjust ride height

I knew that this chassis is of high dimensional quality, but i didn´t expect it to be on that level.
IMHO that´s very impressive and i´m very happy with my desicion to go with RCR.

Now as i have this done i will move on to the body parts alignement. The adjusted suspension will give me good reference points and with the weels on also allows me to check all kind of suspension movements and resulting tire clearances.
TOM

awh: 20 h
 
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This weekend i started to reorganise my workshop in order to get enough space for building the car. You know like it is, the number o toys is growing but space not.
When i started i was not quite sure if it will work out. Too much stuff for this small space.




But finally i managed it somehow and i´m pleased wit the result. I just have to keep it organised and than it will be ok.


Enough space to work comfortably around the car.
Before placing the car on stands i measured the workshopfloor with a laser-level. The result was very pleasing. It is level on +-1mm, so i can use it as reference measure to align all the body parts in terms of height.


Jay: thanks for the hint, Changed to photobucket, seems to work fine
post in disorder due to edit rules
accumulated work hours (awh): 13
 
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Chuck

Supporter
Tom:

Excellent summary of static chassis alignment. Your post will prove helpful when I tackle that project.

Question: Have you made any effort to check the bump steer?

The precision with which you approached the chassis dimensions / alignment is impressive. Keep the posts coming!
 
Chuck:
Thanks, your build is always a benchmark for me.
I have not checked the bump steer yet, mainly because i have not heard of any issues on that topic with RCR´s. Also by reviewing Deans datas it seems to be ok, i just trust Frans engineering skills and check it with the final alignement ( somewhen in the future:)).

Just started the body alignement. will post as soon it is done.

TOM
 
I finally got my RCR40 to the alignment shop about two weeks ago. The road test shows no signs of bump steer, and the roads in Tennessee are a pretty harsh test for bump steer.
 

Randy V

Admin
Lifetime Supporter
Very nice Tom!

Would you be so kind as to post some more detail pictures and measurements of the rear suspension?

In particular - I'm interested in how you got all the toe-out dialed back in to acceptable levels.

On my car, with the lower control arms level to the ground, I have about 3/4" of Toe Out on the rears.
I have shortened both the trailing arms as short as they will go.
The Camber is set to Zero
Lower control arm outer heims are centered (depth wise)
Lower control arm inner heim is centered (depth)
I know that I will need to adjust some of the toe with the outer heims, but I also need to lengthen the trailing arms to get back to a 95" wheelbase.

What it looks like I will have to do is to shim the lower control arm "Inner heim" toward the rear of the car by 3/8" or more.

Thoughts?

And THANKS! :)
 
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