New Knockhill "Time Attack lite" series for trackdayers

[Stu160]

If I map my Elise down to 240bhp it should give around 200 at the wheels. Car with me and a tank of fuel should be around the 1000kg mark hopefully. So would fit nicely in Class D.

Will it be as heavy as that Mike???

When did you fit the Honda in it ???

Stu

[Mikie711]

I'll make it that heavy

TBH it probably won't be that far away, Book weight for a 111R is 916kg with option,which I'm guessing is AC and touring pack. Some guys on Seloc have weighed their cars at around 870kg with a half tank of fuel. Add to that the supercharger, intercooler, oil coolers , hoses, harness bar, rear spoiler and heavier wheels and I'll probably top 1000kg with driver easily. I recon somewhere around 1040kg all up. I weigh 84kg on a good day.

240bhp at wheels less 15% for trans loss = 204bhp
1040kg car and driver gives 197bhp/ton
1020kg car and driver is bang on 200bhp/ton

[robin]

Hmm. That makes entering in n/a K-series mildly tuned elise a waste of time, I suspect. Even if you could get close to 200BHP/ton you would only be "equal" at the red line. Everywhere else the s/c engine will be making a lot more power (to weight) than the n/a K. Of course the lighter elise will be faster in the corners, but probably not that much different (800kg va 1000kg is not THAT significant I suspect).

But rules is rules and they cannot cater for all types of cars. Just a couple more excuses

Cheers,
Robin

[r10crw]

Hmm. That makes entering in n/a K-series mildly tuned elise a waste of time, I suspect. Even if you could get close to 200BHP/ton you would only be "equal" at the red line. Everywhere else the s/c engine will be making a lot more power (to weight) than the n/a K. Of course the lighter elise will be faster in the corners, but probably not that much different (800kg va 1000kg is not THAT significant I suspect).

But rules is rules and they cannot cater for all types of cars. Just a couple more excuses

Cheers,
Robin

Exactly, all about under the curve. Mike could have his 265 hp (I'm guessing) at 8k which makes 240 by 6k. Map it so the last 2k remains at 240 hp and hes laughing, will be crap to drive but quick.
If they insist that they make peak power at or close to max rpm then fair enough but really difficult to police.

[Shug]

Yep, the way I'm reading it, it's all good intentions. A lower entry level for people looking to take their trackday toy and go into competitive motorsport. As happens everywhere though, the chequebook will inevitably rule - especially with something as general as a P2W ratio. Just as Craig says, map a big-money forced induction engine to a power, have it make that power for 60% of it's rev range and you've got an incredibly flexible delivery which will piss on everything - no money saved. Not in the spirit of the rules, but if motorsport ever proves anything, it proves rules have no spirit...

[BiggestNizzy]

Yep, the way I'm reading it, it's all good intentions. A lower entry level for people looking to take their trackday toy and go into competitive motorsport. As happens everywhere though, the chequebook will inevitably rule - especially with something as general as a P2W ratio. Just as Craig says, map a big-money forced induction engine to a power, have it make that power for 60% of it's rev range and you've got an incredibly flexible delivery which will piss on everything - no money saved. Not in the spirit of the rules, but if motorsport ever proves anything, it proves rules have no spirit...

I always liked the (I think it comes from Finland) where if another competitor asks to buy your car you have to sell it to them for no more than 'x' amount. I don't think anyone ever uses it but it stops the chequebook winning.

[TrackScotland]

There is talk of a class E (sub 150bhp per tonne) but it would only (if at all) be added if there was a clear need for it. At the moment there doesnt seem to be.

Mikie - You dont want to be OVER stating your cars weight - If you finish top 3 you will be checked on the scales, and stating your cars weight on the heavy side with a full tank is likely to end in you being measured under weight and removed from results/reclassified.

If anything I'll be taking off 10kg or so for my weight to allow a little margin of error. Also stating my cars weight with minimal fuel. As if you state with FULL TANK you will be cheating.... you are using fuel out on track!

In reality Class C is where your car should be... lapping high 58s? Isnt 15% drive train loss pretty high for RWD too? Normally more like 10-12% isnt it? Giving you a 1020kg car, 240bhp, 210-215whp = 210bhp per tonne. Just re-read and your running 265bhp or so, so about 235whp with 1020kg = 230bhp per tonne. Why not just go for winning class C instead of 'sand bagging' into D? LOL

If you add ballast it needs to be done correctly, and pass scruitineering. You cant simply lob a bag of sand somewhere

[BigD]

Isnt 15% drive train loss pretty high for RWD too? Normally more like 10-12% isnt it? Giving you a 1020kg car, 240bhp, 210-215whp = 210bhp per tonne.

That's what I was thinking re the transmission losses.

Very little room for error in that and you could end up adding more ballast than you need just to ensure you aren't reclassified at the weigh in. Not worth all the hassle if you ask me.

Just go up a class and have a bit of competition. The best thing about time attack for me was giant killing, I knew I had no chance of winning but was happy scalping higher powered cars.

I reckon a couple of hunded kilos makes a fair difference in an Elise Robin, not that I've ever owned one but I notice a passenger in a 1450kg car and I know folk talk about the difference with a pax in an elise and the effect on top speeds etc.

I also think a well driven elise if at exactly 200bhp/ton would have a fighting chance against a detuned overweight supercharged 111R. But try it it will be interesting to see.

[alicrozier]

especially the 2-11 which is designed as a track car, and will almost certainly win Class C comfortably.

I wouldn't be so sure, there is going to be some pretty handy machinery in class C and a 2-11 will be 260-270 BHP/ton with a 80-90kg driver if it is the full 260bhp at the flywheel. 40bhp is a lot to give away at KH.

R400 should be a bit quicker.
As I mentioned before a standard GT3 RS would be competitive or Nissan GTR could be tuned and still fit Class C.

There is always potential for someone to map a car to the regs, flat power 'curve' but not really in the spirit of the event.

Then again someone might go out and buy a new Radical SR3 SL...sneak into class C and beat all but the very quickest Class A cars...

[r10crw]

As its WHP it doesnt really matter but also worth noting that the drive losses are not exactly proportional to power increase. So a car with 150fhp and 30hp losses does not have 90hp losses when tuned to 450. Extreme I know but worth factoring in when estimating your class, guess it would be best to use software like dynolicous to get things in the ball park. Anyone who needs use of the scales, there not super accurate but alledgedly within 0.1%, just let me know and we can organise the SE Pony express.
Ali, I know what you mean but "spirit of the event" wont count when your effectively racing? Winning is winning as they say....
Craig.

[alicrozier]

So what would be the ultimate class D car?

And why is there not a budget class E?

Ultimate class D probably Caterham RSA or bike engined caterfield?

[Mikie711]

I won't be adding weight or running a full tank or cheating or sand bagging. BTW 38l of fuel in an elise only weighs 28kg so assuming you use almost all of it you won't loose that much weight, SG of petrol is 0.737.
By swapping the factory ecu and injectors (which I have) it's easier to drop the car back to 240bhp spec or indeed 220bhp, and the car will be that heavy. S2 111R were never renowned for their lightness, they always were a heavy elise and I have added all the above mentioned weight to an already heavy elise. So it'll be very close to the standard weight of an S2 Exige S before you put the driver in it.

So where's better, the top end of one class or the bottom of another?.

No point in C class, it simply wont be as quick as a 2-11 which it's based on never mind an R400 or what ever else appears in the mean time and it's much easier and cheaper to map down rather than up. If 240bhp is to much and it's lighter than I think then there is always the original Exige S 220bhp map.

I'll bet you that if this series catches on I certainly won't be the only one think this way.
And just for clarity, I doubt I will do any of the above as I haven't even finished the car yet, never mind found out how it drives.

[TrackScotland]

I know what you are on about, I just think it would be better to have a challenge than potentially walk it.

We have moved both of our cars up a class.

I should (going by known figures) be in C but I thought my car and experience would be a bit much for that class.

To take part you dont need to be 199bhp per tonne or 299bhp per tonne you can win from somwhere in the middle

[GBOBM]

There is talk of a class E (sub 150bhp per tonne) but it would only (if at all) be added if there was a clear need for it. At the moment there doesnt seem to be.

Hmmmm.... a sheddy Mx5 with decent suspension, and decent tyres might do ok in this class.

[tut]

Interested on the fuel side. I never take fuel to the track, so would expect that I could fill up at the Drum with what I needed with no chance of running out on track.

An Elise driving to the track can not take 5 gallon jerrys with it, you will not know how many laps you will be doing in the day with run offs, so how would that work?

tut