[Mk2] [Turbo] Nervous front end at high speed.

[JP1]

As far as I'm aware, a nervous, vague and unstable front end is a bit of an mr2 trait. I assume its due to a lack of weight up front, over assisted power steering rack and possibly some poor aerodynamics creating a bit of lift at speed.

I was wondering if anyone has come up with a solution to it. On a day to day basis its not really a problem as the stabilty issues are only really evident from around 80-140 mph, obvously not speeds I am likey to see on the road. On a recent trip to the green hell it was very apparent, pretty scary over 100mph to be honest.

Also, is there a non power assisted steering rack available for the mr2, that would atleast remove the over assistance from the equation or any way of reducing the assistance to around 50% of standard.

This is the only real issue I have with my 2, its otherwise a very capable car.

[JohnnyC]

I wouldn't blame the power steering, I believe it switches off above a certain speed (it's variable in it's power too).

Could be a number of things, worn suspension and/or bushes, tyre pressures/balancing, lack of rev5 speed flaps etc etc

[JP1]

You're right, it prob isnt the power steering, just wanted to remove that to eliminate it from the list.

I should have also said that I have tein flex coilovers, new ball joints all round and new bushes. Pretty recent visit to Wheels in Motion to try to fix the prob too.

Is it possible that something is making the power steering stay on all the time, steering def feels light at speed and no feel around dead centre.

John.

[robwsurf]

think it ll be the aero to be honest on my mk1.5 at 100 to 130 on a track front end used to get light.

its from air coming through rads then gets forced down under the car lifting front end

on mine solved it by venting bonnet and bulkhead toallow air toflow through rads thenout over the bonnet

also decreased engine coolant temps massively

[HighwayStar]

Have you had a play with front tyre pressures yet? That's where I'd start along with ride height (a lower front compared to back should help reduce front end lift). I think I've read the p/s turns off over 60ish so that wont be a factor unless as you say it's broken but I'd think that would be unlikely... don't think I've ever read a post here with it stuck on.
You could try a vented bonnet but I think to get the effect robwsurf describes I think you'd need the radiator relocation kit as well. The rev5 speed flaps obviously do help but apparently are difficult to fix on as they require work to the inner arch guards so like the bonnet idea can become quite expensive.
If it were me I'd concentrate on tyre pressures and ride heights which in your case are both easy to adjust.

R.

[steve b]

Geometry.

Amazes me how people swap suspension about wheels etc and never take the car to specialists to align.

http://www.wheels-inmotion.co.uk/

Recognised the best in the south. I'm sure if you turned up and told Tony you thought the front end light, darty etc he'd sort it.

Opp's just read on that you've been already. Very weird, my MR2's have been planted at speed.

[JohnnyC]

He said he's already been to Wheels In Motion

[steve b]

Have you had a play with front tyre pressures yet? That's where I'd start along with ride height (a lower front compared to back should help reduce front end lift). I think I've read the p/s turns off over 60ish so that wont be a factor unless as you say it's broken but I'd think that would be unlikely... don't think I've ever read a post here with it stuck on.
R.

I've heard stories in the past that some importers bodge the speedo to read in miles & delimit. The bodge means the speed sensitive power steering is alway on full assistance, not heard of it for a while though as more delimiter / convertors have coem on the market in the last few years.

A car with full assistance on all the time would be dreadful.

[steve b]

He said he's already been to Wheels In Motion

As soon as I posted I read the rest of the thread......

[JP1]

The reason I'm a little suspicious of the power steering is that it really is very light. Having not driven any other 2's it may well be pefectly normal tho, just not what I would prefer.

With regards to tyre pressures, I've recently dropped the front to around 27psi, will see if that has helped the next time I get chance to to open her up a bit.

I've seen the vented border bonnet and wondered if that really made that much difference, from what I could see there is only a small vent which I assume passes over the front bulkhead? Would it be an idea to make a much larger one that possibly cuts through the bulkhead?

What about canards, not a fan of the look but those maybe coupled with that PP hood spoiler might help?

I've even considered chucking a couple of bags of cement in the front just to see if its a weight distribution issue.

Would love the 2 considerably more if I could get this sorted.

[steve b]

The reason I'm a little suspicious of the power steering is that it really is very light. Having not driven any other 2's it may well be pefectly normal tho, just not what I would prefer.

See my post above. MR2 powersteering is variable, at parking speeds its light when rolling it basically turns off, they are quite a heavy car in steering terms, much heavier than my MX5 or Honda Accord. My bet is there is a problem and yours isn't turning off.

Its not a weight distribution problem, I had my old turbo up to an indicated 155mph and it was solid, perfectly planted. My current rev3 n/a i've only had to about 120mph and thats perfectly solid. Both I threw out the spare wheel to save weight on as soon as I got the cars.

[JP1]

I'll take a look to see if the speed converter/delimiter has been bodged. What exactly am I looking for and where?

[benGT]

I visited WIM last week for new front tyres and a complete geometry setup.
The car feels completely different at 80mph now - no nervous, light, skitty handling - completely flat! i'm very impressed ......

[JohnnyC]

I've heard stories in the past that some importers bodge the speedo to read in miles & delimit. The bodge means the speed sensitive power steering is alway on full assistance

I thought the problem with some converters/delimiters is that say if the PAS is supposed to switch off at 60kmph - it will then just switch off at 60mph instead - which isn't correct.

Not sure that's the problem though as he claims it's too light at 80mph+, while I don't know what speed the PAS switches off, I'm sure it's not that high.

Could still be a problem of PAS still being active though, just doubt it'd be the converter.

[alanmr2turbo]

I wouldn't blame the power steering, I believe it switches off above a certain speed (it's variable in it's power too).

Could be a number of things, worn suspension and/or bushes, tyre pressures/balancing, lack of rev5 speed flaps etc etc

do these flaps make much of a difference?

[Tony.]

As far as I'm aware, a nervous, vague and unstable front end is a bit of an mr2 trait. I assume its due to a lack of weight up front, over assisted power steering rack and possibly some poor aerodynamics creating a bit of lift at speed.

I was wondering if anyone has come up with a solution to it. On a day to day basis its not really a problem as the stabilty issues are only really evident from around 80-140 mph, obvously not speeds I am likey to see on the road. On a recent trip to the green hell it was very apparent, pretty scary over 100mph to be honest.

Also, is there a non power assisted steering rack available for the mr2, that would atleast remove the over assistance from the equation or any way of reducing the assistance to around 50% of standard.

This is the only real issue I have with my 2, its otherwise a very capable car.

JPI... haven't you got a fixed castor?...... This meant we couldn't dial in straight line stability without adding aggressive camber.

You need to get some adjustable tie rods.

[JohnnyC]

I wouldn't blame the power steering, I believe it switches off above a certain speed (it's variable in it's power too).

Could be a number of things, worn suspension and/or bushes, tyre pressures/balancing, lack of rev5 speed flaps etc etc

do these flaps make much of a difference?

TBH I've no idea, but my car has never suffered a light frontend

I guess they do help - but whether or not that would solve any lightness problems is another matter...

[JP1]

We swapped out my tie rods for the Rev2 items with poly bushes, adjusted them up as far as they would go. Around 3 degrees if I remember right.

I'll look into getting some with a bit more adjustment if you think running more would benefit me.

Would be a pretty easy fic if adding another degree or 2 would sort it.

[ikarl]

indicated 150 on the clocks on the short 2.5m autobahn about 10 miles from the 'Hell.....no lift worries at all and very well handled on track too....poss a delimit issue that your p.s. ain't turning off.

where are you? surely someone can help this guy out.....? a wee shared test drive perhaps

[benGT]

the reason I mentioned having the geometry checked/setup is because I had exactly the same thing - I even started investigating possible power steering issues - i.e. not switching off when it should.

Thoroughly recommend going the geometry route before you shell out monies for parts....