top speed of a 325i?

[Lordschleife]

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

Where did you get these figures?
I always thought the e30 was around 0.36 or 0.37
Dont forget the e30 m3 has a different angle rear window which helps aerodynamics a fair bit

My CRX was 0.29 and was very small, no wonder it flew for a 1.6

[Jos]

I think the 0.36 / 0.37 figure is for non-mtec based chassis. The numbers were just from searching, then correlating between various places to make sure the numbers were correct. Might still be wrong though

Didn't know about the front facing area thing, I though Cd was measured rather than calculated so it takes frontal S.Area into consideration.

the Toyota Prius (which is about as aerodynamic looking as a dead cow) has a Cd of 0.26

[stevo]

would something like this give an acurate speed?
http://www.demon-tweeks.co.uk/products/ ... =P/EHES114
a bit pricey if its just for curiosity but its kinda cool

[johnl320]

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.

Gps are extremely accurate and can tell you where you are in the world within about 3 square metres. so calculating speed is just one of their many functions . Prices start at about 50 notes ,but spend a shade over 100 notes and get a good Garmin .

great for p*ssing off chavs that think their ford escorts can go off the clock and you clock them at 110 ,then listen to them argue that their ford speedo is more accurate than the latest Satellite technology.

regards
john

[stevo]

this gps is interesting me, does it measure mph, or would you need to calculate the time at point A and point B then work out how long it took, kind of thing?

[johnl320]

On the better ones you can have mph or kph. Once it has aquired the satellites it needs (the more the better) it will have a speed reading,altitude, direction (compass) ,grid reference (for maps) .

Mainly used by mountaineers,climbers,hill walkers, armed forces, fisherman,divers etc.
Available from most good outdoor pursuit shops.

HTH
john

[tomstickland]

Didn't know about the front facing area thing, I though Cd was measured rather than calculated so it takes frontal S.Area into consideration.

Cd is measured. But the overall equation is:

F = p * A * Cd * v^2 / 2

where F is drag force, p is density of air, A is frontal area, Cd is drag coefficent and v is air speed.

So, yes they measure, but the frontal area is included in the maths to get to the Cd. The reasoning behind this is that the drag coefficient is a dimensionless number telling you how draggy an object is regardless of how big that thing is.

[OllieB]

Gps are extremely accurate and can tell you where you are in the world within about 3 square metres. so calculating speed is just one of their many functions . Prices start at about 50 notes ,but spend a shade over 100 notes and get a good Garmin .

I bought my Garmin streetpilot just over a year ago, middle of the road model. RRP was Ԛ£950, I paid Ԛ£700 direct off the salesman. They have come down a lot in price I agree, but even sh*te ones like the basic TomToms are nearly Ԛ£300. They are smart though, its quite astonishing how far off speedo's can be, fords are the worst, mercs the best. They also store your top speed, so you can show off a little!!!

[k9]

I've had 2 325i saloons and both have pulled to 130-135 mph on the clock in forth, 5th would drop the revs off a bit. The touring I have now is newer but heavier and gearing is different I belive and will only pull 125mph.

I'd say 130 in 4th is about stock.

K

[kingbreezer]

OK so here's the figures from my owners manual

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

I thought it was around 7.4? Or is this only with the M50 24v engine? If so, when did the M50 become standard?

[johnl320]

Gps are extremely accurate and can tell you where you are in the world within about 3 square metres. so calculating speed is just one of their many functions . Prices start at about 50 notes ,but spend a shade over 100 notes and get a good Garmin .

I bought my Garmin streetpilot just over a year ago, middle of the road model. RRP was Ԛ£950, I paid Ԛ£700 direct off the salesman. They have come down a lot in price I agree, but even sh*te ones like the basic TomToms are nearly Ԛ£300. They are smart though, its quite astonishing how far off speedo's can be, fords are the worst, mercs the best. They also store your top speed, so you can show off a little!!!

I think we are talking about different types of GPS mate, I'm talking about hand held ones about the same size as a early style mobile phone, My Garmin X12 cost me 126 quid , but is still very accurate but eats batteries for breakfast.

[OllieB]

Oh, I see. Mine runs off 12volts!

[andymn]

i thought i'd give my 318 is a blast......can feel the difference in any gear at about 4000rpm....(think its got the viper 2 chip in)...........anyway got to around 90mph and back end felt a bit lighter and really did feel as though it was going to take off

needless to say my arse went, as i was starting to feel a little unsafe at the LIGHT feeling....

[jordano]

i had 140 on the clock in 325 cab, also timed it at 7.2 0-60 on g-max thingy, they are really good

[SCOTT325SE]

My old 325i (currently Missy30's car) does/did the clock, with 1 other passenger. I passed my friend in his Scooby STi which has a GPS system in it. He said his GPS was saying 137 when i passed him and he was flat to the floor (sh1t gearing) but i passed him at a good running speed. I run at 12-14mph ish, so you do the maths, but my speedo said 150... maybe its the most accurate speedo known to man (and now woman) lol.

Get that car past 4000revs and by christ she flies! ... I want her back.

[Davenotouring]

The pic in my avatar was the second time that day that I hit over 140mph (indicated), first time I hit the limiter in fifth and was well chuffed, showing just over 150mph. Man that felt good!! Haha!!

Later demlotcrew snapped this picture.

This was on the way from Cambridge to Gaydon, via Germany.

[SCOTT325SE]

This was on the way from Cambridge to Gaydon, via Germany.

These Germany detours must really rack the miles up Dave!

[Davenotouring]

Yeah, it's a nightmare mate. Costs loads in fuel but it's well worth it.

[woodysjw]

I have a good pic on my phone need to get on here I had my speedo
ready over 150 but my gps says my speedo is about 7 mph out
I have hit the limiter in 5th on the way back from southend too.

[Davenotouring]

Woody, your car looks phat!!!!!

More pics!!!!

[woodysjw]

Dave there are some in the gallary bit with my old ones

[amaank]

Rockin the grey type-Cs, hell yeah!!

[bryang]

Just going back on what others have said re the power required to reach higher speeds rises disproportional to the speed you want to achieve, I read an article a little while back they stated, if all other things remained equal on a vehicle (IE drag, dimensions, tyre pressures etc etc) and that vehicle hit a true 100MPH, it would take an 8x power increase to raise that 100 to 200MPH

So your standard 70BHP 100MPH (for example Fiesta) with its BHP double to 140BHP will take you to the 120-130MPH bracket but to gain another 70MPH you would need over 550BHP!

Gives you some idea anyway!

150 Speedo readings alouÔš' they look good and lets be honest, 150MPH is a kind of benchmark, are generally wildly inaccurate, my Imprezza would drag its sorry ass up to 150MPH which equated to a genuine 136MPH..

Just over 135 was the best I had out of my 325, on a few occasions, I never quite managed to get it over 140 , I think it probably would have on a downhill attack and a few more RPM

[clinty]

Mate had his at 140 mph coing back from Portrush one night, he was coming into Belfast via the motor way and at 140 on a slight bend it started to slide at the back he keeked him self as it went into a powerslide accross 2 lanes on a sweeping right hander. He was jittering wreck...which I am not surprised as he thought he and the car were a gonner!!!

[tomstickland]

I read an article a little while back they stated, if all other things remained equal on a vehicle (IE drag, dimensions, tyre pressures etc etc) and that vehicle hit a true 100MPH, it would take an 8x power increase to raise that 100 to 200MPH

Yes, power rises with speed cubed, so doubling top speed would require 8 times as much power. Conversely, you can work out the new top speed from a power rise because it rises by the cubed root of the power increase.

ie: new speed = old speed * ( new power / old power ) ^(1/3)

So doubling power output would increase top speed by 2^(1/3) which is 26%.
Roughly, for small changes (10-20%) can say that each 1% increase in top speed requires 3% more power.

Talking about top speed, since I fitted the proper wheels back on the car, chaned diff and gearbox oil etc, the top speed has increased to just over 130 indicated, which I'm well pleased. Must be around 120-123mph true speed which is a respectable result. Thing is, it's so solid and planted that it doesn't feel any faster than 80. Big contrast to FWD hot hatches whoch get wobbly at high speeds.

Applying the math(s) to the above, where a 325 has 170BHP compared with 135 for the iS. That's a 26% power increase, so it'll give around 9% increase in top speed. Say a 318iS can do 122mph, then the 325 would manage 131mph.

[hogweed]

Mate had his at 140 mph coing back from Portrush one night, he was coming into Belfast via the motor way and at 140 on a slight bend it started to slide at the back he keeked him self as it went into a powerslide accross 2 lanes on a sweeping right hander. He was jittering wreck...which I am not surprised as he thought he and the car were a gonner!!!

Funny, but old Hogweed comes from Norn Irn himself, albeit a very long time ago, and my first ride in an E30 was my mateÔš's early 325i (sort of dark metallic silver). We had been to the disco in Kilwaughter House, and decided that he was so drunk I had to help him into the car, so IÔš'd better drive, even though I wasnÔš't much better.

Managed to get back to Glengormley, then decided that chips were in order, so best trot down the M2 to Belfast. This is a long steep hill, couple of miles, and I had her up to 135 on the clock in no time. What I was blissfully unaware of was that my reaction times had gone from picoseconds to minutes, and by the time I saw the dim tail-lights of whatever heap of shite was doing -30 in the middle lane I had already passed straight through it at warp speed.

Or at least thatÔš's how it seemed Ԛ—a one minute the lights were there, right in front of me, seemingly feet away, the next I had somehow swerved round them Ԛ—a at 135mph. We both howled with laughter and proceeded to do an impromptu Ԛ“MadnessԚâ€a impersonation, the speedo needle now bouncing off the clock stop, as I prepared to negotiate the "sweeping right hander" mentioned above, where the M2 turns west to follow the Shore Road into the City.

He wrote the car off shortly after that, pissed again, on the notorious Bellevue Bends just north of Belfast Ԛ—a a brave man would have attempted to negotiate them at 60, whilst he was doing the wrong side of 80, and roofed it comprehensively.

Remarkably, weÔš're both still alive, and thank fcuk age has taught us wisdom or weÔš'd both be dead for sure, and God knows who else who was unfortunate enough to live in the same country as usԚ…

RJF & GD, ex suicide pilots

[Adam318i]

great story.

I've only been through Belfast off the ferry but it seems a nice enough place. My nan lives in Portrush and thats real nice! Excellent surf on the North coast.

Adam

[Dan318-is]

fu*kin pshycos

respect for surviving

for drink driving

[hogweed]

fu*kin pshycos

respect for surviving

for drink driving

Must be nearly 30 years ago mate, and my days of drinking (whether driving or not!) are behind me. Shudder to think of what mad bastards we were then - now just a pair of sad old men. But now I have the E30 and my freedom, whereas he has a fcuking motorhome, big family, & big mortgage!!!

[tomstickland]

But now I have the E30 and my freedom, whereas he has a fcuking motorhome!!!

LOL

[clinty]

Where are the Bellevue bends Hogweed never heard of them!!

Big Davy who I was talking about did say he got some speed coming down that hill aka The Grand Canyon as he called it!! Class bit of road for gettnig a bit of speed!

[hogweed]

Where are the Bellevue bends Hogweed never heard of them!!

Big Davy who I was talking about did say he got some speed coming down that hill aka The Grand Canyon as he called it!! Class bit of road for gettnig a bit of speed!

Come out of Belfast on the Antrim Road heading north instead of the motorway - as the road cuts round the Cave Hill, it goes into a serious weave, due to slippage since it was originally built a million years ago! You end up going through Glengormley where I hail from - also a million years ago - then you can rejoin the M2.

Another mate and I wrote off his mother's Mini Clubman 1275GT there - also pissed I'm ashamed to say - back in about 1973...

Keep it between the hedges...

[clinty]

Will try keep it between the hedges lol.....gota give that road a go for a bit of craic!!!

Pity my car didnt stear rom the rear sounds like fun

[ady786]

i did 140mph in a standerd 325ise on the moterway

[ian332isport]

I managed a GPS verified 157mph at Bruntingthorpe. With a bit more tarmac it may have just managed 160, but I had to hit the brakes for the bottom corner

Ian.