Vintage Racing

[nashvet]

I am new to this forum and have just recently purchased an 85 Mark IV.  I hope that I do not offend the purists, but my plan is to vintage race this car. I will rmove most of the interrior trim and put it away for the time when it will be put back in street trim.  i would really like to hear from anyone else that races their car, either in Europe or here in the US.  What other modifications are typically helpful for handling purposes, etc.  Any hepl would be appreciated.
   
   John

[Mark IV]

What events do you plan to enter? The Mk IV is not eligible for most US events as it is is neither "fish nor fowl" to most sanctioning bodies.
   
   Still good luck and post some pictures!

[Johan]

Actually, the MKIV is perfect for many US events. HSR and SVRA allow them as do big events like the KIC or HAWK.
   What region of the country are you in ? I could suggest some events.
   Can you put 15" wheels on the car and still clear the brakes ?
   This would allow the use of Goodyear Blue Streaks which is sort of the common race tire.
   Lots of fun to be had vintage racing...

[Gus Meyjes]

So will I see you at the Hawk with Brian Redman at Road America this year?
   
   Gus

[nashvet]

Johan,
   
   that is actually my plan.  Not sure if I will do any events this season, but definately next, maybe in the fall.  It really depends on how much I decide to do to the car.  Will have to put in fuel cell and do some gutting of the interrior.  I haven't taken delivery of the car yet, but that will probably happen in the next 30 days.  I do plan to go to 15" wels if the brake calipers will clear.  I use the Goodyear Blue Streaks on my csx4000 car and really like how they grip.  Do yoou go to the Mitty at Road Atlanta?  Do you by chance race a Lola?
   
   Mac

[shep]

Hi John,
   Welcome to the select band of Mk IV racers. Back in the late 80s and 90s we had several Mk IV Cobras racing in the AMOC Intermarque Series.  The cars ran Hoosier Tyres on 15 and 16 inch rims. The quicker cars used a 302 Motorsport Block, bored and stroked to about 322 cubes (5.3 litres over here) and tuned tubular headers. Transmission was via a 4 speed top loader gearbox. They produced just over 500 real dyno horses and 420 lbs ft of torque. Strangely no one stripped the interiors, as the few pounds it would save made no difference at all. Brakes were AP 4 pot calipers on AP ventilated discs with Neverfade Pads. Springs were 50% stiffer and we fitted adjustable shocks to lower the ground clearance, and front and rear anti roll (sway) bars. Radiators were changed to aluminium and oil coolers made bigger. The windscreen was removed and a plastic fly screen fitted for driver only which gave you a huge advantage at the top end. You are right to get a fuel cell, but mount it as low as possible. If you are really serious and need any help, just ask. Andy.

[nashvet]

Thanks for your input Andy.  I will probably do modifications required for safety and justm meet requirements for HSR and / or SVRA for starters.  Then other things as they become evident.  I will be glad to hear input from anyone's prior experiences.
   
   Mac

[Johan]

Hey Mac, yep, one and the same. Sounds like a fun deal to me. Let me know if I can help.

[C9OBY]

quote:Originally posted by shep
   
.... Brakes were AP 4 pot calipers on AP ventilated discs with Neverfade Pads... Andy.
   

   
   Hi Andy,
   
   Can you give us any guidance on which size AP calipers and disk should be used on a MKIV to fit within the 15-inch rims?  Their 4-pot range of sizes are shown below, but with clearance within the 15-inch rims being quite critical I'm assuming that the disk diameter is the biggest deciding factor. I expect that there is no point keeping the disks originally fitted to the car.
   
   Option/No Of Pistons/Suitable Disc Ø/Disc TH/Piston Sizes/Inlet Thread/Mtg Centres/Mtg Offset/Mtg Hole Ø/PL
   Caliper 2 / 4 / 280-295 / 25.4 / 38.1 Ø / M10 x 1 / 130.0 / 43.2 / 10.2 / 53.0
   Caliper 3 / 4 / 315-330 / 28.0 / 38.1 Ø / M10 x 1 / 152.0 / 44.1 / 12.2 / 57.8
   Caliper 4 / 4 / 330-356 / 32.0 / 38.1 Ø / M10 x 1 / 180.0 / 42.0 / 12.15 / 57.74
   Caliper 5 / 4 / 330-356 / 36.0 / 38.1 Ø / 3/8 UNF / 180.0 / 42.0 / 12.15 / 73.6
   
   (Taken from Demon Tweeks website in case the text spacing above is difficult to read : http://www.demon-tweeks.co.uk/motorsport/brake-calipers/a-p-racing-pro-5000-plus-brake-calipers)
   
   I'll shortly be making the switch to my cars brakes.
   
   Thanks
   Bruce

[C9OBY]

Oh dear.  The sizes above are from their Pro 5000 range.  The sizes for their 'standard' racing brakes are shown below.  Even more choices = even more confusing!
   
   No. of Pistons/Option/Piston Ø (mm)/Disc Size (mm)/Disc Th. (mm)/Mount Type/Mtg Hole Ø (mm)/Mtg Offset (mm)/Mtg Centres (mm)
   4 / Option 3 / 2x 28.6, 2x 34.9   / 330-355 / 28-32 / Radial / 12.15 / 44.1 / 152
   4 / Option 4 / 2x 28.1, 2x 44.5   / 330-355 / 26 / Radial  /12.1 / 42 / 180
   4 / Option 5 / 2x 28.6, 2x 36.0   / 356 / 32 / Radial / 12.15 / 42 / 180
   4 / Option 6 / 2x 28.6, 2x 36.0   / 356 / 32 / Radial / 12.15 / 62 / 130
   4 / Option 7 / 2x 36.0, 2x 44.5   / 295-355 / 28-30   Radial / 12 / 44 / 152
   4 / Option 8 / 2x 27.0, 2x 34.0   / 310 / 27 / Radial / 10.15 / 45 / 130
   4 / Option 9 / 2x 28.6, 2x 36.0   / 356 / 32 / Radial / 12.15 / 40 / 210
   4 / Option 10 / 2x 34.9, 2x 41.3 / 285-355 / 28 / Radial / 12.15 / 35 / 180
   4 / Option 11 / 31.8 / 285-355 / 28  /Radial / 12.15 / 35 / 180
   4 / Option 12 / 31.8 / 285-355 / 28 / Radial / 12.15 / 35 / 180
   4 / Option 13 / 2x 27.0, 2x 34.0 / 300 / 28 / Radial / 10.15 / 35 / 180
   4 / Option 14 / 2x 34.9, 2x 41.3 / 280 / 28 / Radial / 9.7 / 44.1 / 152
   4 / Option 15 / 2x 34.9, 2x 41.3 / 280 / 11.5-25.4 / Radial / 10.2 / 22.0 - 30.0 / 152
   4 / Option 16 / 2x 38.1, 2x 44.5 / 280 / 30 / Radial / 10.2 / 48 / 152
   4 / Option 17 / 2x 34.9, 2x 41.3 / 278 / 16-17 / Radial / 10.2 / 40 / 120
   4 / Option 18 / 2x 26.0, 2x 31.8 / 278 / 16-18 / Radial / 10.15 / 40 / 120
   4 / Option 19 / 38.1 / 267-295 / 16-18 / Radial   10.2 / 37.25 / 130
   4 / Option 20 / 31.8 / 267-295 / 16-18 / Radial   10.2 / 37.25 / 130
   4 / Option 21 / 2x 38.1, 2x 44.5 / 295-356 / 32 / Radial / 12.1 / 42 / 180
   4 / Option 22 / 2x 38.1, 2x 44.5 / 332   32 / Radial / 12.2 / 42 / 180
   4 / Option 23 / 2x 38.1, 2x 44.5 / 332   32 / Radial / 12.15 / 42 / 180
   
   Again, courtest of Demon Tweeks
   http://www.demon-tweeks.co.uk/motorsport/brake-calipers/a-p-racing-brake-calipers

[SB7019]

Bruce.
   
   Do you have 4 pot AP's fitted to your CRS?  If so the dimensions of these (assuming their size is still produced) should just fit.   I have them on my Superblower and apart from having to slightly shave the balance weights fitted to the inside of the 15" rims they fitted perfectly.   If you don't have them on the CRS let me know and I'll get the ruler out.
   If this size is no longer available would love to know the dimensions of the closest alternative in case I ever have to replace mine.    From the photos on the Demon Tweeks site mine look like the Pro5000 ones rather than the 'standard' ones.

[shep]

Hi Bruce,
   
   I was helping Graham today with some info on your old springs and shocks. I told him how beautifully it handled on those Avons you ran at Castle Combe. I was really impressed. Were they on 16" rims? Regarding AP 4 pots, the ones I had fitted to the Orange Mk 2 I used to race, came from a Metro 6R4 but with "bridged backs". I don't have a record of the part numbers, but I would suggest calling Bob Green at BG Developments, as he is most likely to be able to supply some which will fit inside the 15" rims. If that doesn't work, let me know, and I'll put down my Easter Egg and look some more. I'm at Donington this Sunday 8th April, racing David Emmans' Ace Bristol in the Fiscar 50s sportscar race with 4 other Aces! Should be a good race. Speak soon, Andy.

[SB7015]

Bob Green has retired. May I suggest you contact John Freeth at Performance Braking. Tel: 01600 713117 Email: JFreeth@PerformanceBraking.com
   
   Malcolm

[shep]

Thanks Malcolm, and I thought it was just me who was getting older! Andy.

[C9OBY]

quote:Originally posted by SB7019
   
Do you have 4 pot AP's fitted to your CRS?

   
   Hi Peter, my CRS did have 4 pots on it, but as it's moved on to a new owner I no longer have in downstairs to measure.  If you could get under yours with a ruler that would be much appreciated!
   
   Andy, thanks for your advice and yes, the CRS did handle very well, hence why I definitely need to upgrade the MKIV if I'm going to enjoy it as much!  I was running on the 15-inch rims when we went around Castle Coombe - I found them to give a much improved handling over the original 16-inch wheels (although to be fair the Avon CR6ZZ tyres on the 15's were also vastly superior to the ageing rubber that was on the 16's when I bought the car.  Big Al and Alec did a great job recommending teh uprated springs and setting up the overall suspension geometry.  Once I've done the brakes and springs I'll most likely take it back to them to do the final setup.  Good luck at Donnington - any chance you'll be able to get some in-car footage and post it on youtube for us to enjoy?  I have a digital "HD Hero" camera with mount that you're welcome to borrow - I could always drop it off on Friday/Saturday if you're around.
   
   Malcolm, thanks, I've just spoken to Johnathan at Performance Braking - John F will call me back on Wednesday next week when he's back from holiday.
   
   Bruce