Super Lap Scotland 2015 - Interest

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Mikie711
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Re: Super Lap Scotland 2015 - Interest

Post by Mikie711 » Fri Jul 24, 2015 4:40 pm

A V6 Exige has a quoted dry weight of 1176kg. Add in the options on an LF-1 say another 50kg (air con is heavy), add fuel 40kg approx and then add the driver 80kg at a guess. That gives an all up weight of 1346kg. 345bhp quoted less 12% transmission loss of 41.5bhp leaves 303.5bhp. 1000/1346 x 303.5 = 225 bhp/ton. Doesn't need much change in weight or measured power to swing it into the lower class.
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Re: Super Lap Scotland 2015 - Interest

Post by Dominic » Fri Jul 24, 2015 8:02 pm

Mikie711 wrote:A V6 Exige has a quoted dry weight of 1176kg. Add in the options on an LF-1 say another 50kg (air con is heavy), add fuel 40kg approx and then add the driver 80kg at a guess. That gives an all up weight of 1346kg. 345bhp quoted less 12% transmission loss of 41.5bhp leaves 303.5bhp. 1000/1346 x 303.5 = 225 bhp/ton. Doesn't need much change in weight or measured power to swing it into the lower class.
Thanks for the explanation!
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Re: Super Lap Scotland 2015 - Interest

Post by B12ANR » Wed Jul 29, 2015 1:20 pm

Dominic wrote:
Looks like a decent entry.

Slightly confused how Brian's V6 Exige S LF1 is in the 161 - 210 BHP / ton class. :scratch - would have thought it had a better power to weigh ratio than that.
Have a gander at my power curve in the initial post... then look at the one I just posted (from the Lotus RR session in Hillington)...

http://forums.seloc.org/viewthread.php? ... pid6857338

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Re: Super Lap Scotland 2015 - Interest

Post by BigD » Wed Jul 29, 2015 2:14 pm

So 340bhp giving 290bhp at the wheels and weight of 1157kgs (inc driver and fuel) is around 250bhp/ton is it not? Certainly more than 210bhp/ton. :thumbsup

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Re: Super Lap Scotland 2015 - Interest

Post by B12ANR » Wed Jul 29, 2015 3:08 pm

BigD wrote:So 340bhp giving 290bhp at the wheels and weight of 1157kgs (inc driver and fuel) is around 250bhp/ton is it not? Certainly more than 210bhp/ton. :thumbsup
That's actually why I questioned the results. All the competitors used the same rolling road which made me doubt every entry.

What I need is a big turbo with various maps - that seems to be the way to do it :cheers

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Re: Super Lap Scotland 2015 - Interest

Post by David » Wed Jul 29, 2015 3:27 pm

I slipped from A to B this year for no obvious reason with the results going from 240 WHP to 210 WHP. A session at my mapping dyno last month suggested very little change. I also suspect 4WD and 2WD sessions are not matching very well. But as we are all are using the same RR this year, it probably doesn't matter that much. But it may explain why Class E is so busy and Class A is empty.
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Re: Super Lap Scotland 2015 - Interest

Post by Mikie711 » Wed Jul 29, 2015 3:57 pm

David, who's RR are they using now, thought there were a few you could go to.

B12ANR the fuelling on your dyno plot is all over the place. Super rich all the way from 2500rpm till 5500rpm when it leans off dramatically. If you look at Bloke 79's post on SELOC his runs rich to about 10AFR where it stays, completely different to yours.
Summit not right there.

And, damn these engines need some fuelling to make the power :?
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Re: Super Lap Scotland 2015 - Interest

Post by David » Wed Jul 29, 2015 5:38 pm

Mikie711 wrote:David, who's RR are they using now, thought there were a few you could go to.
All cars had to go to HQ in Dalgety Bay
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Re: Super Lap Scotland 2015 - Interest

Post by TrackScotland » Fri Jul 31, 2015 3:48 pm

My 2p worth....

Yes, all cars do seem to have low WHEEL hp readings at HQ, but they are all tested at the same location, and all seem to match up on the day (times/speeds).

We would normally see ~15% on our cars at a Dastek type rolling road, but get about 25% at HQ. It would be a similar story with DynoDnamics for example.... all different... and thats the reason for using ONE single testing station this year.

Have a look at the data below...

REPORTS -

Round 4 - http://superlapscotland.co.uk/2015_round4.htm

Round 5 - http://superlapscotland.co.uk/2015_round5.htm


Both sets of speed trap data online now.

Round 4 - http://superlapscotland.co.uk/SLS2015_R ... edtrap.JPG

Image

Round 5 - http://superlapscotland.co.uk/SLS2015_R ... edtrap.JPG

Image
Last edited by TrackScotland on Fri Jul 31, 2015 3:54 pm, edited 1 time in total.

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Re: Super Lap Scotland 2015 - Interest

Post by TrackScotland » Fri Jul 31, 2015 3:53 pm

BigD wrote:So 340bhp giving 290bhp at the wheels and weight of 1157kgs (inc driver and fuel) is around 250bhp/ton is it not? Certainly more than 210bhp/ton. :thumbsup

Donald.... you need to add in driver, fluids etc etc. I'm sure Brians car tested over 1300kg. I was there on the day getting mine checked and was surprised at just how heavy it was.

HQ are seeing about 22% losses for RWD so that 340bhp would be ~265whp. 265/1.3t = 204hp/tonne. (these are from memory, and what is stated above)

:)

Thats why Brian was/is in Class D.

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Re: Super Lap Scotland 2015 - Interest

Post by BigD » Fri Jul 31, 2015 3:56 pm

TrackScotland wrote:
BigD wrote:So 340bhp giving 290bhp at the wheels and weight of 1157kgs (inc driver and fuel) is around 250bhp/ton is it not? Certainly more than 210bhp/ton. :thumbsup

Donald.... you need to add in driver, fluids etc etc. I'm sure Brians car tested over 1300kg. I was there on the day getting mine checked and was surprised at just how heavy it was.

HQ are seeing about 22% losses for RWD so that 340bhp would be ~265whp. 265/1.3t = 204hp/tonne. (these are from memory, and what is stated above)

:)

Thats why Brian was/is in Class D.
Brian stated weight of 1157kgs including driver and fuel. I was using his measured weight from earlier in this thread.

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Re: Super Lap Scotland 2015 - Interest

Post by TrackScotland » Fri Jul 31, 2015 4:00 pm

ok, there is some confusion there then :) :|

Book figures put the LF1 at 1175 dry. Brian needs to factor in the full weight of the car as it would compete... and as tested at HQ.

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Re: Super Lap Scotland 2015 - Interest

Post by Mikie711 » Fri Jul 31, 2015 4:27 pm

by using the same dyno and scales (i am assuming they weigh the cars at the same time) you do mitigate the power to weight argument and level the playing field for all. It makes no difference what the use for transmission loss as the power is measured at the wheels so is, in effect, actual power there and then. Not all cars will exhibit the same transmission losses anyway so as long as you use wheel HP then you remove the doubt and confusion.
D, there is no way his car is 1175 dry. Lotus quote 1176kg for a bog standard Exige S which doesn't have aircon as standard so his car, like mine would be heavier by at least the weight of all the zircon gubbins. AFAIK Lotus do quote weights with full and fluids so it won't be massively heavier. Not unless Brian is a big loon :)
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Re: Super Lap Scotland 2015 - Interest

Post by TrackScotland » Fri Jul 31, 2015 4:31 pm

Yup, all cars run on same dyno, and weighed on the same day... giving 'certified' power/weight for SLS series.

Weights are also checked at the circuit (parc ferme after sessions)..... checking for any dodgy business.

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Re: Super Lap Scotland 2015 - Interest

Post by BigD » Fri Jul 31, 2015 4:32 pm

B12ANR wrote:I was first on the queue on Saturday and got the LF1 weighed for SLS. 1157.5kg with me on board. I must be about 300kg of that... :oops:
Now to get it power tested!

Looking forward to the first round (unless it's wet).
I agree, something isn't right which is why I mentioned it. :wink: So 265/1.1575 = 228bhp/ton still over but all you need is a big breakfast and you'd be under 225.

I also agree that it matters not a jot which dyno you use as long as it's the same one. Brian's power figures are another issue, looks to me like the TC cutting the power high in the revs. :scratch

Mike, I was only going on what Brian said, aside from that, I know nothing. Does the LF1 not have weight saving over a bog standard Exige?

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