E30 Zone

just out of interest, does anyone know the top speed of a standard 325i?
would it hit 150?

I think the book says 130mph and mine pulls strongly through 120mph.

Dont think it would hit 150mph. You have to realise it has the aerodynamics of a brick

hmmm, never thought about aerodynamics, i can get 120 in my 1.8 and just assumed the 2.5 would've been much higher

your speedo will be well out, need to get a gps unit to confirm,

My 320 will show 130 on the speedo buy by gps its 119

I had a standard D plate Mtech 1 and it did 140 downhill....then had put the anchors on cos the back end was light as fcuk & i was very close to finding out whether there is life after death.

interesting theory with the gps, is that one of those gadgets that tell you exactly where on earth you are? are they expensive?

must admit, at "120" the car felt really light

i got a solid 200kmph on my 325i auto, but at those speeds things, you need to start concentrating, especially if you running 195/65R14

I think the book speed (owners manual) is 137, but would have to check. Been in mine years before I owned it and watched it go off the clock, but that means sod all really IMO

speedo will over read by atleast 10% at that speed, i've seen over 150 on a lightly modded 325i on the clock, that probably equals high 130's.

Took my 4dr 325i to Germany in July...3 up with loads of baggage the car cruised at an indicated 125-130mph with enough reserve for a bit of extra if needed....

I have no idea (not having GPS) how accuarate that is, but I'd assume a real 110-120mph
I would expect it to reach a real 130-135mph without too much bother (especially if it was just one-up) but I doubt a standard one would go past that and 150mph is certainly not on the cards....

Even a standard SportEvo M3 with 235bhp, higher (7250) rev limit, 3.15diff and better aero aids doesn't officially reach 150mph...(think the official figure was 147mph)

At those sort of speeds aerodynamics really does play a huge part...Along with power, of course...
Some fairly exotic motors with 300-400bhp (or more) and superlightweight bodywork don't get much past the 160mph mark cos the aerodynamics are crap...(Caterham R500, for example only reaches 145mph despite weighing 460Kg and boasting 230bhp...does 0-60 in 3.4 secs, though!).

The other side of that coin is that you don't necessarily need super power to get close to the 150mph mark...I had a Nissan S13 200sx with a stock 170bhp (roughly the same as the 325i), but that would reach a true 145mph given a long enough road....

when i boughtt a 325i mine hit 130 and i had a tiny
bit of oomph still left but on a car that old u gotta
expect it to be very slightly out at least!

probs 130 top end is reasonable

This is what Scott said about Delphin:
"Car goes like a rocketship! My best friend timed me 0-60 at 7seconds dead and she does the clock. not bad is it?!"

I'm not much of a speed freak and have nasty tyres so get scared at 90!

Ive done about 135 in my IS, with room still to go.So i recon you can do the same in a sport, (ive got a sport diff), although as people say, the clocks may be well out

Has anyone tried to use the OBC to confirm actual road speed?

Mine shows I over read 5mph @ 70 and I've checked it's out at higher speeds too

How does the OBC get it's speed readings? and are they more accurate?

But GPS is the only way to know for sure.

Cars generally overead a lot more than people imagine. I have a Garmin GPS, and most cars when showing 40mph on the clocks are only doing just over 35mph. For example, I have an 04 plate Audi A3 TDI which was showing 136mph on the clock. True speed? 121mph.

OllieB wrote:Cars generally overead a lot more than people imagine. I have a Garmin GPS, and most cars when showing 40mph on the clocks are only doing just over 35mph. For example, I have an 04 plate Audi A3 TDI which was showing 136mph on the clock. True speed? 121mph.

I had someone in my car with a GPS and 80mph worked out to be 71mph in the real world so now I cruise everywhere at 85mph

I hit 105 in my 318i on the way back from Brighton the other weekend and that feel horrid. Tramlining all over the place with the 17's, bouncing everywhere coz it's lowered. I must have sweated about 5 gallons. Never again - it's now a cruiser !!!

Had 140mph on the clock in my sport and it felt ok, didn't have GPS with me though so was probably a lot less in reality, (125mph?)

How's about off the clocks ? Been that fast in a 325iS Evo1, with Chip, exhuast Branches, Upped Fuel Pressure, Gasflowed head, and Big Throttle and AFM... was pretty cool...

my father-in-law said that when he was up north last week he went past a board displaying his speed and that it tally'd up with his speedo, are they designed to over read? didnt ask what speed he was doing though

My 325 has seen 145 on the clock on a cold morning on the M5 (thatÔš's the M5 in Germany, obviously), but was probably doing 130-135 I guess Ԛ—a and it is a well-maintained quick example with Viper II chip, BBTB, and K&N panel.

You have to remember that the faster you go, you need exponentially more power to go just a little bit faster, so the extra bhp needed to get from 140 to 150 is much more than that needed to get from 130 to 140.

You have to remember that the faster you go, you need exponentially more power to go just a little bit faster, so the extra bhp needed to get from 140 to 150 is much more than that needed to get from 130 to 140.

Very well put mate....

Its not all about power and aero though, at what speed would you be doing if you could hit the limiter in 5th???

My old S1 RS Turbo hit the rev limiter hard at 138 mph, that was dissapointing, wanted to get a longer box, or remove the limiter!!!!! no matter how much power or boost I had, I couldn't have gone any faster!

fozzymonster wrote:How does the OBC get it's speed readings? and are they more accurate?

I don't know how it gets its readings, but it is definitely more accurate.

We have a 320i with the OBC and if you set the maximum speed to 60mph it won't bleep (to say you've exceeded this speed obviously) until the speedo reads about 67 or 68mph.

stevo wrote:my father-in-law said that when he was up north last week he went past a board displaying his speed and that it tally'd up with his speedo, are they designed to over read? didnt ask what speed he was doing though

Yep, the ones that display your speed and the smiley face ones (that smile if you're within the limit and frown if you're over it) are designed to overread the same as the speedo. It's to stop you realising your speedo is overreading.

Obviously speed cameras are accurate!

Wilson wrote:what speed would you be doing if you could hit the limiter in 5th???

Check davetouring's sig for the answer I think

I'm not sure what box he has though; I think it's a Sport box.

Zayyan wrote:

fozzymonster wrote:How does the OBC get it's speed readings? and are they more accurate?

I don't know how it gets its readings, but it is definitely more accurate.

Don't know HOW accurate - in any 325 I've driven there is little relationship with reality on the OBC as far as petrol consumption is concerned... maybe with mph it's different?

hogweed wrote:

Zayyan wrote:

fozzymonster wrote:How does the OBC get it's speed readings? and are they more accurate?

I don't know how it gets its readings, but it is definitely more accurate.

Don't know HOW accurate - in any 325 I've driven there is little relationship with reality on the OBC as far as petrol consumption is concerned... maybe with mph it's different?

I'm 100% sure it is. I'm sure if someone compared the GPS readings to the OBC readings I don't think there'd be much difference at all to be honest.

ive had my speedo saying 150 but by the gps was saying 142. put the gps in my mates bosses 645ci and his speedo was spot on to the gps at 145 so im guessing the gps is very accurate though.

My 325i wouldn't do over indicated 145mph on an extended run on empty motorways across Europe, which when checked on a GPS was 132mph in reality
This was with a zone wild chip and 3.64 LSD, still plenty revs left, but had hit the aerodynamic wall

Of course downhill, or with a favorable wind it'd prob go a bit quicker, I got another 7mph indicated top speed out of my CRX with a good tailwind

low325icab wrote:ive had my speedo saying 150 but by the gps was saying 142. put the gps in my mates bosses 645ci and his speedo was spot on to the gps at 145 so im guessing the gps is very accurate though.

was that on the way back from silverstone dude?

OK so here's the figures from my owners manual

325i saloon
Top speed - 137mph (auto 132)
0-62 8.3 secs (9.8auto)

325i Cabby
Top speed - 135(auto 129)
0-62 8.6 (10.3 auto)

3251 Touring
Top Speed 135 (131 auto)
0-62 8.8 (10.1 auto)

Drag coefficents (lower is better)

BMW e30 (m-tec) : 0.32
BMW e30 M3 : 0.32
BMW e36 M3 : 0.32
BMW e46 M3 : 0.32
Ferrari Testarossa : 0.36
Ferrari F50 : 0.372
Ferrari F360 : 0.33

BMW 1 series : 0.29

Although some places say 0.36 for the e30, but that might be without mtec kit, it was designed in a wind tunnel after all and a brick with rounded corners is suprisingly aerodynamic...hard to belive it's better than an F360, mind you the F360 generates a lot more downforce and this increases drag

318is turbo it had gone up to 167mp/h on the pic is going 245kmh=153mph and look at the revs, e30 the best car in the world

It's frontal area multiplied by drag coefficient that matters though. So a small car with slightly higher Cd will be better off than a large car.
Pleased to see how good the E30 with Mtech kit is.

Back to speeds, you need nigh on 200BHP to reach a true 150mph.

Power required goes with speed cubed, so a small increase in speed requires a lot more power.