Best engine conversion for light weight/power ratio

[aluntirlan]

My hillclimb sprint car is slowly taking shape. I'm tempted by the power available off the bat by sloting a 6 pot BMW engine in to the bay, but I want the car to be mega light weight well balanced E30. I'm obessed by the weight issue (I used to hillclimb a 700kg 200bhp Mi16 205 GTi) and I'd be very interested in you views. Currently I'm thinking...

Vauxhall Red Top

Cosworth YB

S/C M42 (Already have this motor sans supercharger in the car)

Or would the massive power of an E36 M3 motor make weight an irrelavance?

Cost is an issue, but this is a DIY long term project so I can save up before getting the work done.

Thanks -AJ

[Jhonno]

M52B28..

[chu346]

E36 M3 weighs ~150kgs

M42 weighs ~100kgs

Cosworth engine has great potential.

S/C or turbo M42 would be a cheap and easy option as you have the engine.

E36 M3 engine isn't a cheap swap

What do you fancy?

[dlatch]

would not like turbo lag for sprinting myself.
and as u have all ready done the 4 pot screemer with your 205
a tuned 6 pot sounds about right.
E36 m3 engine would indeed be plenty powerfull enough and reliable too.

[djivesp]

The vauxhall lump is quite heavy too at about 130kg's.

I'd look at something with an alloy block, thats an easy 10-15kg's to be saved, like the aluminium duratecs. Add an eaton m45 and you're looking at an NA sort of torque curve

Is it a rear wheel drive car? If it's rear-wheel drive there is also quite a bit of weight saving to be had by using aluminium bellhousing adapters.

[Alex]

M52B28..

+1

[Brianmoooore]

Use the M52B28 with the gearbox it comes with, and you'll have a good selection of readily available E30 diff ratios, suitable for your purposes.

[fuzzy]

i have a complete cosworth yb in my shed, i wonder how i could weigh it to find out exactly what ones weighs....
would an engine be over 100kg's?

[e21Jason]

Honda s2000

or s/c m10 would be less tgan 100kgs

merc v8 2 vales have a vey high bhp/kg

Jason

[daimlerman]

I would be wary of supercharging the M42,have a chat with Hoshy first!

[aluntirlan]

Thanks for your views. I'll keep you updated as to what I eventually go with. In the meantime, here's some pics of the car as the project stands today.







Alun

[Gunni]

What power/weigth ratio do you want?

[rix313]

I would be wary of supercharging the M42

Why?

[ShakeyC]

If lightness is the key i would use 1.4 or 1.6 zetec-se with type9 box some cams in 190-200bhp package that is well under 100kg dressed. Cheap, reliable very light and extremely revvy 9k on stock head with suitable cam profiles

If you want power for value chevy ls v8 with tremec t56 for 400bhp+ in a box ready to go. This combo i recall is lighter than most 4cylinder cast iron blocked turbo engines when fully dressed inc cosworth, red top, m10

don't forget the gearbox weighs a lot too

[nickso]

If you want power for value chevy ls v8 with tremec t56 for 400bhp+ in a box ready to go. This combo i recall is lighter than most 4cylinder cast iron blocked turbo engines when fully dressed inc cosworth, red top, m10

hardly good value, you will be around 8k for an LS1 and tremec straight out of a box and it probably wont make 400hp, more like 350 iirc.

certainly good power to weight ratio though.

[martinpallot]

I recently had the pleasure if driving an e30 rall car with a 2.4 n/a cosworth. 270bhp and a t5 dog box. was dry sumped and sat beautifully low and far back in the engine bay. Suppose it isnt an option though seeing as you have a tight budget. think its at least 10k to have a cossy built to that spec nowadays and another 3k for the box.

[aluntirlan]

Martin,

My father in law has a Jondell 2.3 n/a cosworth in a Mk1 Escort that he recently wrote off in a 50mph inteface with an oak tree. He paid £7500 for the engine alone. Great motor, though! My wife and I had it as our wedding car!





Ideally, I like to get the car down to around 900kgs (or less) and the more power (and torque) the better. I'd need at least 200bhp.

AJ

[All_Torque]

Depends on how much power you want I guess. The M52B28 has near enough 200BHP as standard, and with a few mods (M50 manifold, BBTB, air filter, remap) you should easily see 235ish plus. Benefit of these are they're very easy and cheap to maintain, lots of torque and pretty cheap to buy - just make sure you avoid an early Nikasil block.

The S50B30 or S50B32 have a lot more oomph - nearer 300BHP as standard, but cost a hell of a lot more to buy and maintain. That said, these are absolutely marvellous engines if your pockets are deep enough

O/T where did you get your arches from mate?

[gareth]

Martin,

My father in law has a Jondell 2.3 n/a cosworth in a Mk1 Escort that he recently wrote off in a 50mph inteface with an oak tree. He paid £7500 for the engine alone. Great motor, though! My wife and I had it as our wedding car!





Ideally, I like to get the car down to around 900kgs (or less) and the more power (and torque) the better. I'd need at least 200bhp.

AJ

that's lovely! I wish i could get a E30 down to mk1 / mk2 escort weights, alas it'll be a bloody hard task!

a local lad has a 240bhp+ n/a cossie powered, steel bubble arched, caged, mk1 escort alan mann replica

[martinpallot]

Interesting point about the weight. Just how much do people think a proper group4 escort weighs? its over a ton easily.
The guy who built the e30 cosworth has been building escorts for 20 years and has his own which he used to rally, he literally threw the e30 together in a couple of months using the engine and box out of the escort as a stop-gap while he was rebuilding it. Apart from custom gartrac suspension and wilwood six pots it was a totally standard caged 318i on manky 100,000 mile bushes all round and a standard 25% lock-up lsd. He came 10th overall in the Jersey rally beating a lot of escorts. anyone who knows about the event will be aware of what an achievement that is.
I think with more development and proper engines e30's could be beating escorts in the not too distant future.

[e21Jason]

About 3k for an s14 200bfp out of the box, and 2.5 s14's make about 340 bhp in the german hillclimb series, use an e36 subframe to get the engine back and chop teh bulkhead

Jason

[gareth]

Interesting point about the weight. Just how much do people think a proper group4 escort weighs? its over a ton easily.
The guy who built the e30 cosworth has been building escorts for 20 years and has his own which he used to rally, he literally threw the e30 together in a couple of months using the engine and box out of the escort as a stop-gap while he was rebuilding it. Apart from custom gartrac suspension and wilwood six pots it was a totally standard caged 318i on manky 100,000 mile bushes all round and a standard 25% lock-up lsd. He came 10th overall in the Jersey rally beating a lot of escorts. anyone who knows about the event will be aware of what an achievement that is.
I think with more development and proper engines e30's could be beating escorts in the not too distant future.

over a ton? really? wow! that's a lot of extra weight in the cage and beefed up components!

my E30 is on the top end of the fat bastard list as it's a touring, has a LPG kit and a 3.5 M30. tips the scales at 1400kg

My mk2 RS2000 must have been in the region of 2/3 that

in my eyes, the E30 is the only real sucessor to the mk1 / mk2 escort. they're cheap, plentiful, tunable and easy to work on. they just don't have the same spirit unfortunately

[aluntirlan]

Depends on how much power you want I guess. The M52B28 has near enough 200BHP as standard, and with a few mods (M50 manifold, BBTB, air filter, remap) you should easily see 235ish plus. Benefit of these are they're very easy and cheap to maintain, lots of torque and pretty cheap to buy - just make sure you avoid an early Nikasil block.

The S50B30 or S50B32 have a lot more oomph - nearer 300BHP as standard, but cost a hell of a lot more to buy and maintain. That said, these are absolutely marvellous engines if your pockets are deep enough

O/T where did you get your arches from mate?

Hi,

I am definately being swayed towards an M52. 230ish bhp would be enough and they are cheap. Plus so many of you guys have already done the conversion - lots of knowledge out there to call upon.I know of a M50 for sale for £250. Is this older engine a much heavier, inferior motor? Sorry to be such a dunce but I know very little about BMW engines.


The arches were fabbed from a sheet of mild steel. One offs. My mate Brian in a genius with a disk cutter and a welder!

AJ

[e21Jason]

The m52 2.8 is an all alloy engine detuned from the factory to meet german tax laws and wieghs the same as a m20 about 120kgs Used in the z3 2.8 and 328

Jason

[Jhonno]

Hi,

I am definately being swayed towards an M52. 230ish bhp would be enough and they are cheap. Plus so many of you guys have already done the conversion - lots of knowledge out there to call upon.I know of a M50 for sale for £250. Is this older engine a much heavier, inferior motor? Sorry to be such a dunce but I know very little about BMW engines.

It is significantly heavier, and much harder to get extra power from..

M52 would be ideal for what you want, plus all 'upgrades' are bolt on, so if you pop the lump, you just need to go get another standard one

[Simon13]

i think an S14 would be ideal, they're mega strong and rev like a food mixer

[aluntirlan]

Hi,

Just out of interest, my father in law's proper Group 4 Mk1 with a the Jondel Cosworth yb fitted weighed in at just shy of 900kgs. He couldn't quite remember when I asked him, but it was around 895kgs.

Mind you, Mike, my dad in law in mega fussy and owns a precision engineering shop. He even had a titanium strut brace made!

Thank you to all for your veiws. I'll keep you updated.

AJ