raver
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| posted on 12/2/05 at 02:23 PM |
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troubleshooting on newly built 750 mc locost
Hello all,
just been testing a newly built locost for the 750mc championship at pembrey in the wet, and have discovered some problems...
1. slight misfire/hestiation when getting back on throttle during cornering. ok at full thottle, acceleration. Im suspecting the float levels in the
carb? any advice? -seems to be only under high 'g corners.
2. heavy inside-left wheel spin only during left handers, as the driver's wieght is on the right i appriciate that this may casue some wheel
spin, but seems excessive. Im using poly (pretty hard) rear tailing arm bushes - could this cause the suspenson to lock up? Where can you find some
softer equivilents?
Any ideas, pointers would be appriciated...
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britishtrident
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| posted on 12/2/05 at 07:01 PM |
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For the wheels spin check the corner weights could be front left and rear right are supporting most of the cars weight.
For the hesitation it might be worth check the the accelerator pump is working ok or it could be you need to look at the carb jetting to match the
airfilter/intake you are using.
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raver
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| posted on 13/2/05 at 11:30 AM |
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Thanks will check the carb components.
the corner wieghts on the day were, n/s/f - 154, o/s/f - 149, n/s/r - 141, o/s/r - 182 (all in kg), so is heavy as you say on the front left and rear
right, with a heavy driver how can you equise these weights?
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I.S.M
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| posted on 13/2/05 at 07:15 PM |
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Those CW's are very good. Nice and close accross the front axle - just what you want.
This might sound a little patronising, but are the shocks of known valving? AVO inparticular are known for rubbish/inconsistant valving. Also, spring
rates/tyre tread/wear?
Also......you were in the wet
Jamie Robinson
ARDS Circuit Driving Instruction
www.jamie-robinson.com
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Chunkie
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| posted on 13/2/05 at 07:43 PM |
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From what I've only just learned about suspension it's opposing corners that matter for weight distribution. If I learned correctly, Your
N/s/f and o/s/r are 28Kg out - I wouldn't have thought that excessive but would have an effect in corners.
Stiffer spring/ preload would help on n/s/f IIRC - remember I only just learned all this so someone else may dispute it.
cheers
chunkielad
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I.S.M
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| posted on 13/2/05 at 07:47 PM |
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Sorry misread in my haste - difficult to know without knowing CW's with you in car.
Jamie Robinson
ARDS Circuit Driving Instruction
www.jamie-robinson.com
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raver
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| posted on 13/2/05 at 09:39 PM |
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Those corner wieghts are including driver.
driver is 93kg (heavy!)
Do you think it is best to equalise rear wieghts as they are the driving wheels, and may be sensitive due to the solid axle?
Not sure about the dampers....
Is inside wheelspin common in the wet usually?
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Chunkie
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| posted on 13/2/05 at 09:55 PM |
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Again, this is recently learned but...
INSIDE wheelspin could be - diagonal corners weights are not similar and also the suspension setup may not be keeping the wheel level and true to the
floor in the turn.
Remember that it's DIAGONALLY OPPOSITE corners that are important not accross the car or front to back.
So, N/S/F should be similar to O/S/R and O/S/F should be similar to N/S/R.
Again, only just learning this stuff but that's how I've read it in Des Hammill's 'How to build and modify Sportscar and
Kitcar suspension and brakes'.
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blackie
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| posted on 13/2/05 at 10:23 PM |
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Talk to Ivan / Matt at Procomp (0121 350 3258) about bushes for your trailing links - they do nice compliant ones that are ideal.
DB
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Locost82
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 posted on 16/2/05 at 04:58 PM |
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Well that's me confused then!!
My understanding was that the ideal situation is 25% weight in each corner, and failing that try to equalise across the axle.
Does anybody have a definitive guide to corner weights/weight balance etc?
I have always been confused over the benefit of a perfectly balanced car and a car that will go around a fast right-handed circuit (Mallory for
example). I would have thought heavy inside wheels would reduce the weight transfer outwards and increase grip accordingly, or again am I confused
and speaking out of my @rse?
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