Dreadnought Track evening - Thurs 27 August

[tvrolet]

TVrolet, It was good to see you on track. I am sure I've seen you at KH a number of times before. What's the spec?

It's based on a retired TVR Tuscan Challenge racer. The chassis and running gear remain original. The body started off as the racer's too, but I 're-created' quite a bit of it, beefed it up, made it a two-seater and changed it here and there to make it road legal (the Tuscan Challange cars were never built as road cars and were never type approved). Now the important bit, the motor is a Small Block Chevrolet 383 stroker (so 6.3L), BPL/Holley 750 race carb (no choke so mucho revving to get it fired up and running), Dart heads, roller cam etc. McLeod multi-plate clutch and a Tremek TKO600 box.

It's a far bigger and heavier lump of iron up-front than the original race cars ever had to lug around; the motor and box are probably over half the weight of the car! No power steering, no ABS, no traction control, no servo on the brakes, no electronics (bar the data logger), no fuel injection; just good old fashioned fun Appeals to my love of real simple cars and big American V8s. The motor was bench dyno'd when it was built and made just under 500BHP and 485Ft/Lb. The car was weighed for the SVA with all fluids and a full tank at just over 1000Kg. No shortage of power then, but it comes in pretty early and there's no real point in revving it so I do notice that loads of cars that rev higher and have a bundle of gears to play with are just as fast if not faster out the slower corners, particularly the hairpin. On the other hand I only need 5 gear changes per lap and just use 3 gears. Biggest problem has just been developing it to get it reliable; it'll run all day at the 'wet' pace, but I'm still trying to bottom-out heat/reliability issues when it's running harder.

Feel free to jump in for a pax session; although the result is the same - fun on track and on the road, the way it goes about it is very different to the Lotus.

[Modena Scotland]

500bhp/ton sounds

Look forward to the pax laps. You are welcome to jump into mine to compare notes

[gdr]

On the other hand I only need 5 gear changes per lap and just use 3 gears.

Don't you need even number of gear changes so you get back to same one you started lap with? Didn't think about it before, but I believe I'm only on 6 gear changes per lap with exige, perhaps why I'm so slow!

Your car was certainly quick at last SIDC regardless of gear though

[Modena Scotland]

The gears I use at KH on a dry day.

Starting at the main straight:

In the CR, 4-3-4-3-4-3-2-3 back to 4 again.
In the SLR, 5-4-3-4-3-4-5-4-3-2-3-4 back to 5 again.

[David]

Here's a some video clips from Thursday. Due to the bad weather, much of the night's footage was useless, but here's some shots from the helmet cam with the hood off. It was that 'dry' half hour

http://www.youtube.com/watch?v=PGHGgV7H2FA

By the way, my gear changes are:

I also use just 3 gears: 5-4-3-4-5-3-4-5 with a 3.62 final drive. I sometimes use 3rd at the Chicane and Clarks but find the extra gear change spoils any advantage - the same with hairpin and 2nd gear. But then the Duratec does have good low down torque too. What diff have you got Mass?

[Modena Scotland]

I have the LSD. Don't know the gearbox ratio. I think the 2nd at the hairpin is a must. Just before I get to the chicane, I hit the rev limiter in 3rd so I need to back off a little. Tried using 4th through there but it doesn't give me a good drive out.

[tvrolet]

http://www.youtube.com/watch?v=PGHGgV7H2FA

By the way, my gear changes are:

I also use just 3 gears: 5-4-3-4-5-3-4-5 with a 3.62 final drive. I sometimes use 3rd at the Chicane and Clarks but find the extra gear change spoils any advantage - the same with hairpin and 2nd gear. But then the Duratec does have good low down torque too. What diff have you got Mass?

Wow, looks real twitchy in there! Brings back memories of the Megablade I used to have.

Big motor without a close ratio box, wet or dry does:

[jason]

I have the LSD. Don't know the gearbox ratio.

You will almost definitely have the same 3.62:1 diff * ratio as David, Mass (99.99% chance - since unlikely an SLR owner will have converted to shorter 3.92:1). You both have the the 6 speed box (the ratios of which are same), so the only speed:revs:gear difference will be your rear tyres.



* Diffs same ratios but not the same mechanically - yours (99.99%) will be ZF plate, David's AP Suretrac (David?)

[Modena Scotland]

Thanks Jason

[VXJON]

David whats the car you pass about 50secs in ?


Looks like an old toyota

[David]

Big motor without a close ratio box, wet or dry does:

Yes, these 'sectors' looks much the same as me but I'm one gear higher all the way round - except maybe McIntyre (3rd). I've discussed with Jason my gear changes and I do seem to loose more time than I should - I think it's my technique that is the problem. . I can get away with less changes in the Duratec as it pulls well at anything over 3k. But Mass has probably got it right for the ultimate lap.

My 195/45 R15 rear tyres are not up to the job on the track and they are about 3% lower geared (smaller diameter) than the 245/50 R13 - if that is what Mass is using on the SLR. The need for 13 inch wheel is becoming more obvious as my experience builds and a professional geo set-up might be worth it too.

It does have the ATB quaife (which is not ideal for the track).

Not sure what the green car was, but it did seem to get quite quick at times.

David

[tut]

I am exactly one gear up on the diagram, with changes at the same points.

tut

[gdr]

Tvrolet, I stand corrected on no changes as you go down 4-2 before hairpin so 5 it is! Diagram OK for me too although I go 4-3-2 at hairpin and can reach limiter in 3rd on short back straight before Clarks so sometimes take 4th there briefly to show some mechanical sympathy....

[Modena Scotland]

Dave, I think my tyres are 195 front and 215 rear (Toyo 888 13inch).