Front End Lifting Badly Under Full Throttle

[dorifticon]

Hey all

Have finished running in the 3.0 motor and it's all good, except the extra torque has exposed some limitations with the chassis/suspension setup.

So I'm not getting anywhere near full throttle on corners, it's lighting up all four at around half throttle or 2/3.

We took it for a run today and came out of a corner in second, then floored it til the posted highway speed limit, and the steering got really, really light and the nose started lifting. Not just the rear end squatting under power, but like the nose of the car really coming up. Kind of relying on the back diff locking up to keep it in roughly a straight line.

Now I know in the absolute worst case (like in drag cars etc) the front wheels can actually come off the ground, but I've only ever seen that in cars with really light motors and really short wheel bases, like rx3's and the like. I would have thought that with a comparatively mild 3.0 motor I'd be pretty safe from all that, especially with a long wheelbase and a big lump of cast iron in the front.

now obviously we aren't allowed to go driving around with a wheely bar, just wanted to know if I have something obviously wrong with my suspension before I go upping the boost etc. Have other people experienced this and what are your solutions? My current suspension setup is nice for cornering but not much good for exploiting the straight line characteristics of the motor.

Cheers

Andrew

[PM-R33]

What suspension is in there? Spring rates?

What kind of power are we talking here?

Something doesn't seem right.

[dorifticon]

320kw, 600nm.

Suspension is what came with the car (i/e don't know the spring rate etc) - not coilovers, but towards the very firmest spring rate you could get. Definitely neither springs nor shocks are sagging or flogged.

Tires are 235 all round.

I agree, something is amiss, heaps of other people have posted power/torque figures well exceeding mine, I just need to get pointed in the right direction to start looking at suspension etc. or alternatively wondering if it's a common problem people have experienced.

What suspension is in there? Spring rates?

What kind of power are we talking here?

Something doesn't seem right.

[SargeRX8]

My old R33 gtst would lift on high boost and steering would be weightless to say the least. I found out I had adjustable suspension so I raised the back up a notch which firmed up the arse end and hopefully put the center of gravity further up the chassis. I was only making about 240rw and 580nm.

Firm up the rear and try get the COG forward.

[waxracing]

What an awesome problem to have, Up your dampening rate and it will help with anti squat. actually just realised you dont have coil overs so you cant easily

To much droop in the front suspension will cause you to have this issue as well. as the front lifts it gains momentum and this can make it go higher than it normally would. Reducing droop stops it doing this. But really if you have stock style suspension your going to find it hard

[tarmac]

Stiffen your suspension?

[dorifticon]

Thanks for all the replies, I'm a noob when it comes to suspension.

I thought the springs were about as hard as I could live with but then I thought about it and it's really the front springs that shake you around when you go over bumps etc so firming up the rear end shouldn't affect driveability and ride too badly.

I think I'll have to start looking into adjustable coilovers at this point rather than trying to experiment with the standard style setup.

[Duncan]

can you measure from the centre of the wheel to the guard for both front and rear? this will tell us more about the spring heights in there now. also have a good look underneath, or give us pics of the shocks and springs.

it is very possible that old, standard shocks and springs will allow heaps of squat

[HEKT1K]

What an awesome problem to have

+1

So you built a 30 but paid no attention to suspension etc?

[Plan-FAILURE]

+1

So you built a 30 but paid no attention to suspension etc?

Edited January 18, 2011 by plan-b

[Plan-FAILURE]

Hey all

Have finished running in the 3.0 motor and it's all good, except the extra torque has exposed some limitations with the chassis/suspension setup.

So I'm not getting anywhere near full throttle on corners, it's lighting up all four at around half throttle or 2/3.

We took it for a run today and came out of a corner in second, then floored it til the posted highway speed limit, and the steering got really, really light and the nose started lifting. Not just the rear end squatting under power, but like the nose of the car really coming up. Kind of relying on the back diff locking up to keep it in roughly a straight line.

Now I know in the absolute worst case (like in drag cars etc) the front wheels can actually come off the ground, but I've only ever seen that in cars with really light motors and really short wheel bases, like rx3's and the like. I would have thought that with a comparatively mild 3.0 motor I'd be pretty safe from all that, especially with a long wheelbase and a big lump of cast iron in the front.

now obviously we aren't allowed to go driving around with a wheely bar, just wanted to know if I have something obviously wrong with my suspension before I go upping the boost etc. Have other people experienced this and what are your solutions? My current suspension setup is nice for cornering but not much good for exploiting the straight line characteristics of the motor.

Cheers

Andrew

I know this doesn't help you but you can't say it was all displeasure!