Scuttle shake - can it be reduced?

[Blitz]

Top speed of a 325i cabby.

http://www.evo.co.uk/videos/planetevovi ... t_one.html

[Rav335uk]

Top speed of a 325i cabby.

http://www.evo.co.uk/videos/planetevovi ... t_one.html

132mph with a M20b25, so really my claim to 140mph in mine doesn't need much more to be said then

[daimlerman]

Talking about scuttle shake,gents,not alleged top speed....
My cabbie shakes about a bit,but it is a whole lot better than the Morgan I ran back in the early '80's!
Front strut housings are already braced to the inner wings,so a strut brace will do little more than look pretty and get in the way when you need to adjust the tappets.
Cabbie's are all about cruisin' and looking good,if you want the things to go well around corners on poor surfaces you need a touring.....

[ImysE30]

Well next time i do it, i will video/photo it just to prove you all wrong

Cabby's are for cruising anyway, not for racing

[Dezzy]

Well next time i do it, i will video/photo it just to prove you all wrong

Cabby's are for cruising anyway, not for racing

What with the M30 turbo if it ever happens.

You are full of shit trying to tell people on here your M20B20 cab has shown 140 on the clock

Still keeping it up as well when everyone knows its bullshit

[Ian_M]

Even with an M30 Turbo it will only just go over 140mph on the longest stretch of straight road you could imagine.

Don't know why so many people have to talk crap on here yes E30s are nice but they've got the aerodynamics of Pat Butcher.

[ImysE30]

Well next time i do it, i will video/photo it just to prove you all wrong

Cabby's are for cruising anyway, not for racing

What with the M30 turbo if it ever happens.

You are full of shit trying to tell people on here your M20B20 cab has shown 140 on the clock

Still keeping it up as well when everyone knows its bullshit

It will mate and you'll be lagging behind

How do you know it didn't, were you a passenger, errmm no.

What ever you say

[djk]

How do you know it didn't, were you a passenger, errmm no.

What ever you say

Can I apply some maths?

5th gear in a 240 box is 0.81:1.

Final drive in a stock 320i manual cab is 4.27:1.

Stock 205/55 R15 circumference is around 1905mm (probably less taking into account contact patch deflection).

So...

140mph is about 224km/h
or, 3.73km in a minute
so the wheels would have to turn at 1958 rpm
the prop at 8361rpm
and the crank at 6772rpm

So you're telling me your b20 cab will pull well over 6.5k rpm in top? No, it won't.

I guess if your speedo overread by the usual, in my experience, e30 amount of about 10% on stock wheels and tyres, and you were also running a smaller wheel and tyre combo to make the gap even bigger, you might, might, see 140 on the speedo. But even then, your true speed would be closer to 110mph than 140mph, mmmmmmkay?

[Blitz]

I think Imy had 205/40/16 tyres.

[e30topless]

Also, convertible top speeds are lower so you'd have an ever tougher time getting to that point.

Not true.

Depends on what engine you have in the bay.

Steve (E30Topless) will back this up, we both were travelling in excess of 140mph a few months back.

on that private road it showed about 149-50 on the speedo and 141 on sat nav,

there were 3 of us, one was a standard 325i with a 3.73 diff, and 15" BBS on 55's


Imy I have ran a 320 as a daily for years, I know they won't do over 125 ,

I live on the highest summit motorway in the UK, with a steep downhill stretch for 20-30 miles, even that won't shove a b20 (with a tailwind ) over 125 !

[ImysE30]

I've definitely had it at over 125, on several occasions easily

[bss325i]

Front strut housings are already braced to the inner wings,so a strut brace will do little more than look pretty and get in the way when you need to adjust the tappets.
Cabbie's are all about cruisin' and looking good,if you want the things to go well around corners on poor surfaces you need a touring.....

There is still a void between the strut towers and despite the extra strengthening cabrios still flex.

I agree though, cabrios are for crusing about in and should be auto.

[bss325i]

With regards to the top speed thing.

My sport will easily pull an indicated 150mph but thats about 138mph on the sat nav.

As for no E30 being able to do 140+mph.

On the way to the ring in '08 there were several of us in convoy including Andrew aka demlotcrew in his S14B23 powered 318iS. He has a calibrated speedo in his car and whilst he was doing 140mph i passed him like he was standing still in my old touring. That touring had a 160mph M3 speedo and the needle was off the clock and nudging the MPH at the bottom!

Thats what just shy of 300bhp of S50B30 will do and anyone who disputes that just ask Ant or Oguz327 as they were my passengers at the time.

And another thing, Alpina quote 151mhp for the E30 B6 3.5 which "only" has 260bhp!

[Ian_M]

I've definitely had it at over 125, on several occasions easily

You haven't, your speedo is f*cked if you think you're going 140. Probably being overtaken by 150mph Daewoo Matiz's.

[bss325i]

As for an M20B20 powered cabrio doing 140mph?

Come on! They struggle to make 129bhp!

[mrLEE30]

sorry lads but i stand by what i say. No standard E30 will do 140. my current sport with minor exhaust mods oulls very strong and is 115000km old. it struggles toi reach 230 indicated even given a very long road in Saudi. thats indicated so realisatic around 210 - 215 at best, this is about 130 mph. to gain another 10 mph will require a lot more power. My arse dyno says my 325 runs at least as well as any i have been in here and in Germany/UK - but maybe i am wrong, but not wrong enough to make 10 mph difference. only down hill with favorable wind could a standard e30 see 140.

yes very high power modified cars may have the grunt to push on to perhaps the 150 mark, but these cars are few and far between.

[Blitz]

E30's very poor aerodynamically.

[bss325i]

Im not lying!

My speedo over read by approx 10% at all speeds.

Indicated 150mph is about 135mph. My sat nav was reading 138mph with just over 150mph on my speedo.

But then my sport is no shitter.

Are you trying to say not even an M3 sport evo will do 140mph?!

[bss325i]

E30's very poor aerodynamically.

M technic 2 body kit helps.

[Blitz]

Alpina B6 2.8 does 143 MPH.

[bss325i]

Alpina B6 2.8 does 143 MPH.

Alpina B6 3.5 does 151mph.

[Brianmoooore]

Top speed of a 325 E30 saloon is given as 137 MPH by BMW. This would show as well over 140MPH on most speedos.

[Rav335uk]

Alpina B6 2.8 does 143 MPH.

Alpina B6 3.5 does 151mph.

I agree with Barry, most speedos are out by about 10%, but if you have the gearing right with a M30/M52/S50 then there is no reason why you should not pull 140mph in an E30

[bss325i]

Alpina B6 2.8 does 143 MPH.

Alpina B6 3.5 does 151mph.

I agree with Barry, most speedos are out by about 10%, but if you have the gearing right with a M30/M52/S50 then there is no reason why you should not pull 140mph in an E30

I have pulled a guestimated 160mph in my old S50 touring.

[mrLEE30]

Alpina B6 3.5 does 151mph.

I agree with Barry, most speedos are out by about 10%, but if you have the gearing right with a M30/M52/S50 then there is no reason why you should not pull 140mph in an E30

I have pulled a guestimated 160mph in my old S50 touring.

which is exactly my point!!! standard E30's will not make 140. again back to my sport its running a 3.46 diff while i look for a 3.9, so in theory i should run out of puff before i run our of revs, it could not make 140, i doubt 130. In real life conditions on real life roads under real life conditions not many cars will hit 140. I am lucky enough to spend a great deal of time driving some very nice machinary around the F1 circuit here in Bahrain, which has a monster straight. few cars hit 140/150 exception of X6M, a GT3 and i forgot before to mention a Corvette ZR06 also hit about 150 on speedo. but these were in very optiumum conditions i.e. cold weather with favourable wind.

My E39 540 struggled to maintain 220-210km/h indicated whilst on a 400km trip back from Riyadh, this is a three lane straight road accorss what is basically flat desert scrub land for 400km. the reason this 300hp / 400Nm (rough) car with better areodynamics than any E30 could not maintain a decent speed - about a 15 mph head wind and hot temp.

My point is some E30's may have hit the 140 mark at some point in their life, but none will do it repeatedly with major modifications, such as big engines.

[gooner1]

Mine gets from A to B, that,s enough for me.

[PeteE30Tourer]

Is scuttle shake any better at 140mph????

[ImysE30]

It's more stable

[djk]

On topic, could excessive scuttle shake be caused by unnoticed grot/poor repairs in the bulkhead/inner arches? I'd have thought a strut brace would make a difference, as would a hardtop, though that won't exactly put the wind in your hair. TBH, speed isn't the issue, it's rough roads that have highlighted it in the cabbies I've driven. Stock suspension and tyres will be better than anything modded for 'performance', and bushes in good nick etc.

[PeteE30Tourer]

It's more stable

Phew - problem solved!

[PeteE30Tourer]

I'm pretty sure in my case, the suspension is the cause. I bounced the front end last night and a.) it was surprisingly easy to bounce and b.) it bounced back several times before coming to rest. As I said previously, the ride is very trashy (though i'm probably unfairly comparing it to the modern cars i've been driving for the past 4 years).

Time to jack it all up and see what's underneath me thinks.

Thanks for all your advice folks - and the added enjoyment of the maximum speed debate!

[pacerpete]

A FIXED strut brace and or a hardtop do make a noticeable difference in reducing scuttle shake in a convertible, the hardtop making a major difference. All E30 convertibles feel less than rigid, which is hardly suprising with no roof. What is suprising is how the degree of 'shake' can vary from car to car , even on standard unmolested cars

[djk]

(though i'm probably unfairly comparing it to the modern cars i've been driving for the past 4 years).

TBH, on stock suspension in good nick, I think e30s ride better than most more modern cars. My Dad's got a new Touran, so hardly a 'sporting' choice, and the ride is shocking.

As convertibles go, I don't think e30s are generally too bad for wobbly shakiness - ever been in a saab 900 cabrio?

[PeteE30Tourer]

(though i'm probably unfairly comparing it to the modern cars i've been driving for the past 4 years).

TBH, on stock suspension in good nick, I think e30s ride better than most more modern cars. My Dad's got a new Touran, so hardly a 'sporting' choice, and the ride is shocking.

As convertibles go, I don't think e30s are generally too bad for wobbly shakiness - ever been in a saab 900 cabrio?

Ironically, I've been driving brand new Tourans for the past 4 years and I'm still surprised how much I can throw them around - quite pokey too with the turbo diesel. I do appreciate a good ride, so i will be aiming to get my cab's suspension back to as-new standard.

[bss325i]

I'm pretty sure in my case, the suspension is the cause. I bounced the front end last night and a.) it was surprisingly easy to bounce and b.) it bounced back several times before coming to rest. As I said previously, the ride is very trashy (though i'm probably unfairly comparing it to the modern cars i've been driving for the past 4 years).

Time to jack it all up and see what's underneath me thinks.

Thanks for all your advice folks - and the added enjoyment of the maximum speed debate!

Sounds like your shocks have had it!