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BEC weight distribution
Echidna - 24/4/08 at 05:55 PM

What is the fore/aft weight distribution of a typical BEC 7even clone? Thanks!


hobbsy - 24/4/08 at 06:06 PM

Depends if one of two passengers, how heavy they are and how much fuel!

Also if a dry sumped Busa (~85Kg plus another 10Kg or so(?) for dry sump kit or a 62Kg Blade engine).

I know mine seems to handle quite differently when I've got 2 up (especially if they weigh ~100Kg).

I don't have any firm figures though, if you do a search for corner weighting that may give you some figures.


Jon Ison - 24/4/08 at 06:08 PM

50/50 with driver is achievable without to much difficulty.


hobbsy - 24/4/08 at 06:10 PM

I'd say mine feel quite neutral when only one up but when 2 up I notice the rearward weight bias and that the front seems lighter at speed.


Echidna - 24/4/08 at 06:21 PM

50/50 is not the best configuration!
Is it possible to get 40/60?


Puk - 24/4/08 at 08:18 PM

Hi Echidna - I asked a similar questiona few months back:

http://locostbuilders.co.uk/viewthread.php?tid=81003

http://www.locostusa.com/forums/viewtopic.php?t=3157&highlight=

The bike engined cars seem to be achieving 60% over the rear.


rotax78 - 24/4/08 at 08:19 PM

i've just been senting my indy up at the weekend and here are the results the first is without driver ballast the second is with driver ballat. A basic description of the car is, Mk indy, 5vy r1 engine, fibreglass seats, basic interior, full cage, wilwood fronts, sierra lsd and discs rear, 13" alloys.

Sorry if the pictures are massive, i wont know until i upload them


unballasted corner weights
unballasted corner weights



ballasted corner weights
ballasted corner weights

cheers Simon


smart51 - 24/4/08 at 09:07 PM

Mine is just slightly rear heavy, about 51%

You want 60% to the front? Lead bars? Concrete slabs? A pinto engine?

[Edited on 24-4-2008 by smart51]


Echidna - 25/4/08 at 06:39 AM

quote:
Originally posted by smart51
Mine is just slightly rear heavy, about 51%

You want 60% to the front? Lead bars? Concrete slabs? A pinto engine?

[Edited on 24-4-2008 by smart51]


60% to the rear of course!


progers - 25/4/08 at 07:54 AM

My race Phoenix is around 55/45 split. Thats using an R1 engine. It would be closer to 50/50 if you had a bigger lump and dry sump.

In a BEC 60/40 would be too much rear bias I think, you would struggle with front end grip.

- Paul


hobbsy - 25/4/08 at 10:54 AM

I do seem recall someone saying something about STM / Ian Gray moving the bike engines forwards to increase the front bias and therefore front end grip.

I'd imagine when I've got a heavy passenger its definitely rear biased and as well as being slower I don't like the handling as much (less front end grip and more lightness at speed).


Bob C - 25/4/08 at 11:57 AM

mine was 210/220 fr/rear without driver at SVA. So will only get more rear bias with me in ;^)


sucksqueezebangblow - 25/4/08 at 01:42 PM

That's a pretty damn good spreadsheet you've got there rotax78! Any chance of a copy? Clive.


rotax78 - 25/4/08 at 07:59 PM

Here's a copy of the excel file, it's not my work, i originaly downloaded it from lcb, ifi've done wrong by reposting it let me know. Cheers Simon