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Heh... like even a standard one of these things is never unsafe...
At least you ET guys got a rear swaybar, but that's still a bit of a token attempt to cure the understeer, I gather.
My Exa's convinced me there's no way oversteer's more dangerous than understeer - if you can drive, that is. Most RWD cars with a halfway decent chassis give you all the time in the world to catch and modulate a slide, and any trouble you find yourself in is down to the loose nut behind the wheel, but a FWD like ours is another story...
For a start, there's the hideous weight distribution... I'd hazard a guess around 60/40... then consider how all that mass cantilevered off the front there affects the polar moment of inertia. (If you don't know what I mean, imagine the situation of adding a considerable amount of ballast front and rear to a car so as to maintain the weight balance. Now consider adding the same amount of weight to an identical car, only all at the center of gravity. Which one will handle better?) Then there's the power delivery... you try to have some fun on some twisty stuff in my car, and it's nothing but hairy moments, I tell ya... even just flooring it in a straight line is a challenge; as soon as it hits this massive boost spike at 3500, I'm just sliding down the camber... and it's almost stock.
The turbs is a brand spanking KKR280, not sure whether it's closer to a T25, T25G or even T28, with a shitty dump pipe half as bad as the stockie. That's all for mods so far, runs a supposed 8PSI on a freshly run-in reco donk. It was the cheapest and smallest new turbo I could find with a T25 flange.
So yeah. I reckon you could easily wrap one of these around a pole without trying too hard...
At least you ET guys got a rear swaybar, but that's still a bit of a token attempt to cure the understeer, I gather.
My Exa's convinced me there's no way oversteer's more dangerous than understeer - if you can drive, that is. Most RWD cars with a halfway decent chassis give you all the time in the world to catch and modulate a slide, and any trouble you find yourself in is down to the loose nut behind the wheel, but a FWD like ours is another story...
For a start, there's the hideous weight distribution... I'd hazard a guess around 60/40... then consider how all that mass cantilevered off the front there affects the polar moment of inertia. (If you don't know what I mean, imagine the situation of adding a considerable amount of ballast front and rear to a car so as to maintain the weight balance. Now consider adding the same amount of weight to an identical car, only all at the center of gravity. Which one will handle better?) Then there's the power delivery... you try to have some fun on some twisty stuff in my car, and it's nothing but hairy moments, I tell ya... even just flooring it in a straight line is a challenge; as soon as it hits this massive boost spike at 3500, I'm just sliding down the camber... and it's almost stock.
The turbs is a brand spanking KKR280, not sure whether it's closer to a T25, T25G or even T28, with a shitty dump pipe half as bad as the stockie. That's all for mods so far, runs a supposed 8PSI on a freshly run-in reco donk. It was the cheapest and smallest new turbo I could find with a T25 flange.
So yeah. I reckon you could easily wrap one of these around a pole without trying too hard...
Gees, Kimmo!, The polar moment of inertia of a FWD make it oustanding for Motorkhana, as does the drive from the front wheels with the hand brake on the back. You should get out and give it a go, won't damage the car . . . if you can drive . . . . because all you'll hit is little plastic sticks.
Thats said oversteer is more dangerous than understeer, mainy because of how it puts you into the scenery - SIDEWAYS!. Cars at better at front impacts than side impacts.
C
Thats said oversteer is more dangerous than understeer, mainy because of how it puts you into the scenery - SIDEWAYS!. Cars at better at front impacts than side impacts.
C
I can't see how a high a high polar moment of inertia is good for any kind of turning, rather than just straight-line stability... maybe it could help give the Scandinavian flick a bit of momentum, but I reckon you must be talking about the overall weight balance, not the actual distribution.
Anyway, messing around on grass is one thing, but I'm thinking of the more usual scenario of booting it around a tarmac corner... RWD cars have no trouble getting around; sometimes it's a bit of strife stopping em getting around too far, but as I say - managing that is a breeze next to the sudden and not entirely predictable appearance of another 50 or so horses at front tyres which have their which have their work cut out just changing direction, with all that weight poking out the front.
Anyway, messing around on grass is one thing, but I'm thinking of the more usual scenario of booting it around a tarmac corner... RWD cars have no trouble getting around; sometimes it's a bit of strife stopping em getting around too far, but as I say - managing that is a breeze next to the sudden and not entirely predictable appearance of another 50 or so horses at front tyres which have their which have their work cut out just changing direction, with all that weight poking out the front.
Kimmo, no offence mate, but FWD cars have a lower polar moment of inertia and it is about a forward axis. There is no rear axle, longitudinal gearbox, drive lines.... so a FWd has a lower polar moment of inertia, that is more of the mass is in a tighter area. Moments of inertia are about mass distribution, which sets the weight balance, so I'm not sure what your on about.
Now ordinarily you'd want a balanced weight distribution to near the centre of the wheel base and you want it to change as little as possible, so things like fuels tanks are put at the centroid. But motorkana is different, it all about hand brake turns and maximum power. So a forward PMI is good, as is a light rear end and drive occuring at the wheels that don't lock for the turn. This way you can keep the power on all the wa through the bend, using the back to turn.... Its great fun. Dirt, grass, tarmac and concrete it's all great. Just like legal hooning!
C
Now ordinarily you'd want a balanced weight distribution to near the centre of the wheel base and you want it to change as little as possible, so things like fuels tanks are put at the centroid. But motorkana is different, it all about hand brake turns and maximum power. So a forward PMI is good, as is a light rear end and drive occuring at the wheels that don't lock for the turn. This way you can keep the power on all the wa through the bend, using the back to turn.... Its great fun. Dirt, grass, tarmac and concrete it's all great. Just like legal hooning!
C
Ok, I see what you're saying here... the 'poles' are closer together, basically... so I stand corrected re PMI. But no matter how hard I look at it, all that weight outside the wheelbase looks like a bad thing.Callumgw wrote:so a FWd has a lower polar moment of inertia, that is more of the mass is in a tighter area.
I dunno, maybe I just need to get my head around FWD handling still, but it seems like I've already adjusted to the situation, yet I'm still not comfortable with it...
Yeah it is generally considered a bad thing. Purpose built cars just won't do it. But well sorted FWDs can lap a smooth dry track as well as RWDs, remember the old Super Tourers or the BTCC? However reduce the surface friction and things swing in favour of RWDs and 4WDs....
Motorkhanas are different because they are tight and relatively low in speed. They favour small light weight vehicles that turn on their nose...
C
Motorkhanas are different because they are tight and relatively low in speed. They favour small light weight vehicles that turn on their nose...
C
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The Renegade
- Administrator
- Posts: 3002
- Joined: Tue Jul 04, 2006 7:22 pm
- Location: Telegraph Point - N.S.W. Mid North Coast
I'll let yaz know next time I'm down there, I'd love to see both ya cars. Then we can go have some beers n talk shit about cars.
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Trust no-one but yourself.
The beast:
http://forum.n12turbo.com/viewtopic.php?t=3982
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Mid North Coast Member.
=====================
Trust no-one but yourself.
The beast:
http://forum.n12turbo.com/viewtopic.php?t=3982
=====================
Mid North Coast Member.
=====================
Update!!!
just a lil update
i had a boost leak.i have fixed most of it,i think
(two bolts in the front housing of the turbo where mising or never there but was leaking air out of them anyways)
i had a a misfire up high which i think is also long gone by changing plug gaps from either 7-8mm to 6 mm
i also broke a clutch cable and then the next day the alternator had enough ,which was fun (NOT)
i need to plug my bov and redo the ends of my cooler pipes as they are bell ends.i want to change them to straight pipe with reducer flexy hose.
and last but not least ,last fri nite really pissed me off cause it rained in sydney and therefore didnt get to run at wsid
(but i think it was a god sent cause the clutch cable would have given out down there
)
anyways thats all for now
more another day
i had a boost leak.i have fixed most of it,i think
(two bolts in the front housing of the turbo where mising or never there but was leaking air out of them anyways)
i had a a misfire up high which i think is also long gone by changing plug gaps from either 7-8mm to 6 mm
i also broke a clutch cable and then the next day the alternator had enough ,which was fun (NOT)
i need to plug my bov and redo the ends of my cooler pipes as they are bell ends.i want to change them to straight pipe with reducer flexy hose.
and last but not least ,last fri nite really pissed me off cause it rained in sydney and therefore didnt get to run at wsid
(but i think it was a god sent cause the clutch cable would have given out down there
)anyways thats all for now
more another day