high speed stability / top speed

[nas80]

When you hit three figures in these cars, its like going through the invisible barrier of "reason" how do I get rid of the feeling that the car isn't planted on the road?

It seems ok at anything under 100, I know its shaped like a brick so its not aero dynamic, do I really need a front and rear spoiler?

I suppose what I am after is advise from people who race really, what suspension geometry do you guys use?

If I fit a thin alloy flat tray underneath, would that help you think?

[murran]

mine feels planted at 95 (a side from i think theres a wheel out of balance somwhere as ive got a steering viabration about 70-80)...... not really been any faster than that.

edit..... was not on the queens highway, was on an airfield.

[e21-Mark]

I spoke to a couple of guys from TWR and they said they'd experienced problems with panels being literally torn from the bodyshell down to constant high speed running. They also said front and rear spoilers reduced lift ''substantially'' although I don't think they tried under trays. I maxed mine at about 130+ (satnav) on a private road obviously, and while I wasn't keen to do it again, it wasn't as bad as I expected. The TWR is supposed to be good for 145mph but I doubt I'll put that to the test.

[murran]

yeah, from the way mine pulls in 5th, and bein that 95 is just over 4000 rpm (just getting into the power band) id have thought it'd do 130. i wouldnt wana try it tho!!
does the bbs spoiler create any down force?

fastest ive ever driven is 135 in a toyota engined lotus elise.

[varden]

the fastest I've seen in my e21 was 110mph and it was like being in a tub in the high seas the wallow was so bad, it was a stock e21 with blown front shockies.

I was chasing a mate in a sorted e30 and he thought my car looked hilarious pitching and rolling behind him.

Then i ran out of oil pressure.

Much has been modded since then but I've never felt the desire to try it again.

[petroscf]

Ok, Saturday evening on the motorway outbound Athens towards Loutraki (a town by the sea) I saw 110 mph (177kph) as well on the GPS!!! It's the fastest I 've ever seen I iirc.
(The car was showing about 171 kph = 106 mph) but it's my 195/55/15 wheels I assume

My question is the following, though: how come I did max speed with the 5th gear and not with the 4th? (as my gearbox is overdrive)...Is that normal?

[drjim]

Slug hits about 100 on long straights on track and I can feel the front end lifting. I need a rear wing and a front splitter. Tidying up airflow underneath is a nice idea but there's all those exhaust bits sticking down and getting in the way. Low front spoiler to stop the air getting under the car in the first place is the best solution.

[e21-Mark]

I'm going to fit a Ronal front spoiler at the weekend. It looks quite a bit like a County Race item although not quite as deep. Has anyone seen a fibreglass front bumber? I want the look but not the weight of a metal one.

[petroscf]

However, I still have this question...:

how come I did max speed with the 5th gear and not with the 4th? (as my gearbox is overdrive)...Is that normal?

does this mean that, (in theory, at least) I should be able to achieve more on the 4th? or even more on the 5th?

[Jason_323i]

petroscf wrote:
how come I did max speed with the 5th gear and not with the 4th? (as my gearbox is overdrive)...Is that normal Yes


And I maxed my car when it was on the tripple carbs and a 3.15 diff speedo read 140 so more like 120 really (due to diff change) very bouncy, skitish lots of panel vibration.

I with Jim in needing a front spoiler and spliter, plus a rear spoiler. The other big issue is ariflow across the rad entering the engine bay so I have additional vents added to the bonnet at the front. Also if you can set the suspension up with a tad of rake towards the front.

Jason

[petroscf]

How much top speed is a front spoiler expected to cut?

[Alhogr]

i have done with my e21 something over 140. im running with a stock front and no wing an 13 inch rims with 175 tyres. dont trust the tail at speeds over 110 120 without a tail. and with small rims. if u are running on 15' the car gets a better felling even at high speeds.

[petroscf]

Alhogr 140 with what engine?
In general my feeling at 110 was not bad, maybe I am not a good driver(and cant understand my car -which I 've been driving for 20 years!!!), maybe its the 15"s, maybe its the strut+stress bars (but on straights??) maybe its the APEX springs that although stiff, however they keep the front quite low, so somewhat air helps???

Where are you based in Greece?

[nas80]

i solved most of my high speed stability problems by adjusting rear toe - one side was slightly more than the other and now they are the same it feels much much better now.

[Alhogr]

petro, i have a m20 b25 and im running on stock motronic. maybe in the summer when im back in greece we could meet and ill show u my car. τι λες αδερφε?