E30 top speed providing you have the power?

[g57yle]

Hi everybody. i have a very intriguing question.


I have a project e30, currently under reconstruction due to failure of my chassis.

I am rebuilding the entire car from scratch.

Providing i have enough power to achieve this, what is the top speed acquirable in the e30 shell with m tech II (Widened) without me taking off? i know the car can do 160+ but at that point my added eyebrows snapped off so i slowed down. Also from around 145-160 i could hear wind coming in from the door seals. After that day i never tried again, but i would rather not kill myself YET and get some opinions from you guys to see what how aerodynamic this car is.

Thanks

[blingsta]

to solve this problem Gary, just sell me your engine and i will give you 1 that wont kill you !

[g57yle]

LOL im tryin to be serious, and even is i sold you my engine you would be asking the same question!

[blingsta]

i think any car after 140-150 needs a bit of downforce, like a spoiler or somin

[Turbo-Brown]

Be interested to see where this goes (preferably on a track!) Would imagine that keeping the underbonnet area and underside of the car from pressurisation would be a consideration (given my limited understanding of aerodynamics).

Also be interested to know just how cosmetic the E30 boot spoilers are

Sorry, that wasn't really a constructive post

[Ant]

Ians 3.2 beast has done 165 iirc ? Bruntingthorpe, sure its in a PBMW somewhere.....

I've driven E30s that shook so bad @ 130 I was gripping the seat with my ringpiece ! stability would be my concern

165+ scary stuff

[ShepsEvo3]

I have had my E30 M3 Evo2 on the limiter in 5th gear. Speedo was reading just over 160MPH and that car has 226BHP. But I question the accuracy of the speedo at those speeds, althoutgh the Evo2 is fitted with a 3.15 rear diff and the revs wound round to 7600RPM I guess its not too far off?

It was on a level piece of road with not much wind about. Also with me and another fat B'trd sitting next to me. It took a while to get there from 155 onwards, but it got there and onto the limiter.

I'd say you'd need alot more power to get a big increase over that. After 140MPH everything seemed to go quiet.

[candyman]

Hi i know nascar racers run large flat bottom sumps and all the petrol pipes brake lines gearbox running gear etc is recessed so floorpan is pretty much smoothed so that they can run faster as for the aerodynamics of the shells they are just as boxy as an e30 although they are longer

Think that the chro moly tube chassis plays the biggest part in these cars being able to hit 200 mph ish just so rigid and over engineered etc etc and that is where the e30 loses out no matter how much power you have car will only run to the capabilities of the chassis .

all the people i know who run drag cars know that to get more speed from their once standard car usually just take the body of build new box section and tubed chassis then put body back on with complete new floorpans etc etc

So in the interests of safety would say that once you get to the sort of speed your talking about it , next upgrade to your car (absolutely stunning bit of work by the way) is going to be very expensive mate

Stuart

[g57yle]

Thanks stuart. im not intending on changing to tubular chasis ever. LOL

Im now in the process of rebuilding/restoring and modifying the new shell from scratch.

Im not really bothered about top end speed, BUT i would like to know what ratio diff i should install and what speed i should stay below, i have satnav which can accuratly calculate speed.

I have a vid of a subaru take off at top speed and end up upside down, i wouldnt really like that to happen to me once its finished.

[DanThe]

I have a vid of a subaru take off at top speed and end up upside down, i wouldnt really like that to happen to me once its finished.

ABS dont help in that situation

Got a link? Know how fast he was going?

[jkarran]

I don't know at what speed you'll start to really need it but it wouldn't be too hard to design a totally flat underfloor with rear diffuser and some kind of front difuser arrangement venting out behind the front wheels especially if you're starting with a fresh bare shell and you can spend some time cleaning up the underside. It will of course affect cooling

A thoughtfully designed rear wing and front splitter should also help kill some more of the lift. Whether you'd generate much (any) downforce without creating huge drag I don't know. Letting some air out the sides of the engine bay and down the tunnel rather than all of it over the car should further help reduce lift.

Your other problem is the more you become reliant on the aerodynamics for stability the bigger the trouble you'll find yourself in when something like a pitch change, wind change or the splitter hitting the floor and stalling the airflow under the car upsets the airflow

Have a look for a decent book, I bet there's loads of simple tricks like using taped on strands of wool to view the airflow over the shell.

How fast... as fast as you like with enough work and power! It will at some pont stop looking much like an E30 and start looking more like a sports prototype... not a bad thing

jk

[g57yle]

I have a vid of a subaru take off at top speed and end up upside down, i wouldnt really like that to happen to me once its finished.

ABS dont help in that situation

Got a link? Know how fast he was going?

Sorry it was an rx7 at 215mph.

Here is the vid:

[bootyman]

Whoosh! Well with flared arches and massive wheels, i doubt how accurate your speedo reading will be. I got 9 points in 3 months in my Flared Msport cab cause the reading on the speedo was so off. I was running 17x11 rear and 17x10 fronts and the clock would show 40mph, but i was actually going faster

[jkarran]

Just spotted the pics above. What's going on with the boot, why's it all cut away?

And didn't the M3 have a different roofline and rear screen angle? You might get quite different results to those people are quoting for original M3s

jk

[ian332isport]

Ians 3.2 beast has done 165 iirc ? Bruntingthorpe, sure its in a PBMW somewhere.....

It actually got to 157 before I had to hit the brakes to get around the bottom corner. That was measured on a GPS device as well, so was accurate. With a bit more road, it would probably just have nudged 160, but not a lot more to be honest.

Apart from the wind noise around the door seals as mentioned above, it was very stable and not scary at all. I have read that the Tech2 kit does actually improve high speed stability, and adds a little down force. It's not purely decorative

Ian.

[Morat]

nasty crash - I bet he's glad he had a rollcage in there.
Was that a parachute escaping at the end?

[g57yle]

Hmmm so the m tech2 kit does do something then. Yes my car didnt feel unstable at all, also i dont have a spoiler fitted either. ill probably be going with m3 side skirts if i can modify them to fit with the widearches and m tec2 door moulds. and they should help out aerodynamics a bit. The gearing on my car should hiit around 205mph if my calculations are correct, but thats in theory, minus wind ect. i want this setup purely for crusing on motorways ect, as normal e30's are roughly @4k rpm at around 80mph in 5th gear with a 3.91:1 ratio diff, i would like mine to be doing around 120-130Mph @3k rpm in 6th for nice economical crusing. but i know you cant do that in a standard 325 cos it'll bog down, lol

[g57yle]

Just spotted the pics above. What's going on with the boot, why's it all cut away?

And didn't the M3 have a different roofline and rear screen angle? You might get quite different results to those people are quoting for original M3s

jk

Hi mate, during this rebuild ive been really fussy. if there is a bit of rust anywhere i would rather replace the pannel,i actually went to bmw's and asked for a new e30 shell, but to my dissapointment they no longer make or stock them anywhere in the world. In the top of this rear pannel there was a baby bit of rust which i knew would come through eventually, So i went to bmw's and bought a brand new one

Although installation is not yet compleated. i still need to cut out my second exhaust section, make some sort of diffuser setup and make a custom boot floor with added recess for other bits

[g57yle]

nasty crash - I bet he's glad he had a rollcage in there.
Was that a parachute escaping at the end?

yep that was a parachute, it didnt do much though!

[g57yle]

OH, im going to ask another question!!!

Can we source a speedo that goes up to 200mph+/- for our cars?

but i would like it to look original-ish, ??

Any ideas??

[g57yle]

Whoosh! Well with flared arches and massive wheels, i doubt how accurate your speedo reading will be. I got 9 points in 3 months in my Flared Msport cab cause the reading on the speedo was so off. I was running 17x11 rear and 17x10 fronts and the clock would show 40mph, but i was actually going faster

Unlucky for you, What tyres are you running front and back? i have always slowed down even more because of that reason. Just incase

[bootyman]

225/40/17 front and 255/40/17 rear

[Hyperion]

hi g57yle
just a 1 Q....what the hell happened to the blue e30, did you crash it? or did u buy it like that for parts…
PS: on a side note i have never driven my car faster than 190kph... its a auto and even for that speed i had to hit a down hill to get it there

[g57yle]

hi g57yle
just a 1 Q....what the hell happened to the blue e30, did you crash it? or did u buy it like that for parts…
PS: on a side note i have never driven my car faster than 190kph... its a auto and even for that speed i had to hit a down hill to get it there

LOL. The answer to your question is: i took it apart, but in the process of stripping it, we took an axe to it. the reason its being stripped in the first place is because i ripped off my rear crossmember where the diff bolted on to due to too much power and i didnt reinforce it.

[ian332isport]

OH, im going to ask another question!!!

Can we source a speedo that goes up to 200mph+/- for our cars?

but i would like it to look original-ish, ??

Any ideas??

UK spec E30 M3 clocks go up to 160MPH, and I think Hartge did a 300KPH speedo (approx 186MPH). Apart from that, you are into custom gauges.

Ian.

[g57yle]

Hmmmm the hartge seems more desirable, any idea of where to buy one from? and how much they are worth? would bmw sell them? or would you need to go direct to hartge?

[ian332isport]

Hmmmm the hartge seems more desirable, any idea of where to buy one from? and how much they are worth? would bmw sell them? or would you need to go direct to hartge?

Rare as rocking horse poo these days.

You could try Hartge, but don't hold your breath

Ian.

[e21Jason]

Hi

If you are getting a book Simon McBeath is okay but is more focused on single seaters, but Katz is more biased towards saloon cars.

Aerodynamics like all tuning is a compromise between downforce and drag. In come series downforce is easy to get as they have so much horse power they will accept a large amount of drag, other cars like le-mans minimise drag rather than maximise down force.

From my reading on saloon cars, front down force is easy to get with a splitter, easy to make/modify your own, but if look at the BTCC ones you will see they the are stepped in the middle this is to reduce their sensitivity to ride height (i.e. going over bumps, braking etc) Balancing the rear with a spoiler is more difficult, the nascar guys use a near vertical strip about 150mm tall good for down force but a killer for drag which will kill your top speed. An evo 3 m3 spoiler would be the easy option, possibly with a roof spoiler to direct the air flow down over the spoiler.

The next issue at that speed will be uncontrolled air flow in the engine bay, you really want to seal of the front grill except for the air flow into the rad, after that you want to get the air back out of the engine. There is no room for a ducted rad in an e30 so fit a few bonnet vent & louvres and possible lift the back edge of the bonnet up a few cm to get the air out.

After that look at cleaning the air flow up under the car smooth of the under side as much as possible and late over openings, remove the spare wheel well and run a diffuser out through the bumper, any side skits should drop below the level of the floor pan to help create a “tunnelâ€a under the car.

Jason

[jkarran]

OH, im going to ask another question!!!

Can we source a speedo that goes up to 200mph+/- for our cars?

but i would like it to look original-ish, ??

Any ideas??

Buy a euro one in Kph (should go to 300 ish 'units') and a SpeedoHealer to calibrate. That's what I did with my kitcar to get it reading Mph on a Kph bike dashboard. Make up a neat Mph sticker to cover the old units.

http://www.speedohealer.com/ - Excelent product available from uk dealers

Simple and factory look

jk

[schuey]

Another aerodynamic issue with high speed,is the speed squared rule.
i.e-its not the case that a (eg) 180bhp 325i sport that could probably just do 140,would do double the speed with double the power,its all a bit of a blag to work out,but even with some substancial aero work you would probably need somewhere in the region of 700-900 bhp norway style to get anywhere near 185mph for instance,and well over 1000bhp and plenty of aero mods to crack 200mph.Don't forget the amount of extra drag at high speed especially from any spoilers you would need for the stability issues

I reckon 350 BHP would get you somewhere near a true 160mph with no aero work,although you'll be losing bits of trim,and scuttle!

As a guide my previous IS which had 164bhp at the flywheel,did an indicated 150 after a long run up,however this was backed up by a GPS reading of 133mph-that was on the limiter!(private road of course )

[jkarran]

I reckon 350 BHP would get you somewhere near a true 160mph with no aero work,although you'll be losing bits of trim,and scuttle!

That seems about right 280ish bhp gets my E34 540 to 150mph (apparently ) that's probably a bit slipperier than a spoilered up E30.

jk

[g57yle]

OH, im going to ask another question!!!

Can we source a speedo that goes up to 200mph+/- for our cars?

but i would like it to look original-ish, ??

Any ideas??

Buy a euro one in Kph (should go to 300 ish 'units') and a SpeedoHealer to calibrate. That's what I did with my kitcar to get it reading Mph on a Kph bike dashboard. Make up a neat Mph sticker to cover the old units.

http://www.speedohealer.com/ - Excelent product available from uk dealers

Simple and factory look

jk

Excellent idea mate, i will look in to that.

[oldroydsr4]

I was watching hartge 300kph clocks on german ebay a while ago, think they went for about 186 euros.

[maxfield]

My dads done a few 150mph (autobahn ) plus in his car and mostly been stable not big rattles to worrie about. But once the side trim off the window came flying off.

After the engine was built he said the speedo was reading about 165mph using road angel i think so the GPS is probably pretty accurate.

I wouldn't want to be going anymore than 170 in 17year old car.

[g57yle]

my car will be like new when done, both my trims round the doors flew away! but now im going to glue them on!