Another in a series of my what if scratch builds. This time a mid engined 4 wheeler. I reckon 100 BHP would be enough in a 400kg car (though more is alway better!). What's the lightest engine and gearbox with reverse that would make this?

I'm not interested in turbocharging a stock engine, tuning the knackers off something or picking something obscure or old lump. I'm not against some mild fettling though. What would you choose?

Yaris engine?

I would guess something like a 600cc bike engine (Yamaha r6?), chain drive diff and a starter motor reverse.

Possibly a smart car with the brabus uplift which makes close to 100hp but you have to make do with the flappy paddle gearbox. Banks put this in the Europa a while back, worth a search for it, orange car.

Pretty much any 600cc bike engine from the mid 90's onwards with an electric reverse. A carb'd CBR600 engine is 62kg with gearbox (if my memory serves me right) add a few more for the reverse so call it 70kg at most and will give 100-110bhp. No car engine/box combo will be near that.

Just to be a little different I would go for a late-ish GSXR750 motor. You did say "more is always better"!
14,500 redline. Titanium valves etc...

1.0 Ecoboost is only 97kg and 1.6 is only 114kg.
Would make for easy boost if 100hp turned out not to be enough.

[Edited on 30-5-17 by loggyboy]

A lot of FWD hatch engines make 100bhp. Having thought about this as a project myself before I think most could be positioned for a mid mount RWD configuration too. IIRC there's a number of smaller, lighter 3 cylinder motors around too. Personally I like the idea of a cheapish readily available engine and g/box - if one goes pop then get another one.

K series engine - 1.6 was lightest (engine only at 93kg) but 1.8 more powerful (104kg)
Gearbox about 35kg I believe

http://www.mgf.ultimatemg.com/group2/engines/engine_options.htm

and tuning information :
http://www.dvandrews.co.uk/

Regards
Hugh

Edited to add: Lightest fro a car engine and box combo anyway, bike engines somewhat different!

[Edited on 30/5/17 by hughpinder]

We've got a 2000 yaris 1.3 vvti as our runaround. Despite it being in the 100hp ballpark, I wouldn't use it as a donor due to how uninspiring it is to drive. Despite being NA, the lag is significant, vvti doesn't kick in with a honda vtec style punch so is less exciting, and it's generally a bit sluggish. Nice and small powertrain though!

K Series VVC 160 bhp & PG1 from a BRM with LSD and closer ratios.

Another one for the 600cc bike + mild hybrid drive for reverse.

BMW R boxer engine on a Citroen 2CV box will be pretty light, but needs more work to get it running.

Is going be a trike any way? I thought 400kg and 4 wheels only work utp 15-18kW for L7e/ MSVA?

Suzuki G13b and an SJ gearbox. Not easy to find these days, but very light and 120hp+. Put an MX5 1.6 diff in, and you've got a light package all round.

Bke engines are great for power and lightness, but finding a light diff isn't easy in the long ratio needed.

I seem to recall a figure of 85kg for Zetec SE engine and gearbox. Take your pick of 1.25, 1.4, 1.6 or 1.7 for the power!

quote:

---

Originally posted by JC
I seem to recall a figure of 85kg for Zetec SE engine and gearbox.

---

Not sure whether this still exists....boosts the 80hp figure!

http://www.c1gti.co.uk

Quoted engine weights can be very misleading if you do not know the build level. The difference between a bare engine weight and a fully dressed engine can sometimes exceed 20 Kg ( Clutch, flywheel, starter, alternator, inlet manifold etc. ) For info my Ford 1.7 Sigma engine with absolutely everything on it to make it run ( including oil in it! ) is 105 kg - includes mounting brackets but no exhaust manifold.

quote:

---

Originally posted by JC
I seem to recall a figure of 85kg for Zetec SE engine and gearbox. Take your pick of 1.25, 1.4, 1.6 or 1.7 for the power!

---

quote:

---

Originally posted by johnH20
Quoted engine weights can be very misleading if you do not know the build level.

---

quote:

---

Originally posted by johnH20
Quoted engine weights can be very misleading if you do not know the build level. The difference between a bare engine weight and a fully dressed engine can sometimes exceed 20 Kg ( Clutch, flywheel, starter, alternator, inlet manifold etc. ) For info my Ford 1.7 Sigma engine with absolutely everything on it to make it run ( including oil in it! ) is 105 kg - includes mounting brackets but no exhaust manifold.

---

quote:

---

Originally posted by Neville Jones

Bke engines are great for power and lightness, but finding a light diff isn't easy in the long ratio needed.

---

Thanks for the ideas. Bike engines are lightest for sure, but a drop in FWD car engine night be simpler if there's anything both light and powerful. Plus little bike engines have higher revs and closer gears to match. You're doing crazy revs at highway speeds in top AND have a very tall 1st gear.

Rover K series is a bit old school these days but a possibility. The 1KR-FE / Aygo engine is pretty light. 68 BHP stock is too low, but there is a turbo kit available. The Dee Ltd 80 BHP version is probably a bit pricey and still a bit low on oomph.

Peugeot do an 82 BHP tripple, I've got one, but it's not my favorite engine in the world. And it's new so still expensive. After that you've got the weight of a 4 pot which all seem to be 30+kg heavier and you need a chunk of extra power just to haul the extra wieght of the block.

The 1.0l ford ecoboost has been mentioned, available from 75 to 125 hp iirc. turbo'd direct injection triple so lots of issues there in controlling it but it is capable of 200hp. It is iron block so not the lightest but has a very small foot prin, A4 paper has been used in marketing info.

So, 1.6 ecoboost (100-180hp) may be a better choice, although it is 4 pot it is all alloy so may be a similar weight to the three pot iron block, 140hp in the focus may be the best choice, ecu's are expensive though until someone comes up with an OEM howto.

Doesn't the base model Caterham 160 use the Suzuki Cappucino 660cc turbo engine ? Wrong way round but similar to the spec of the Smart.

One of these ? http://www.autoblog.com/2014/01/28/nissan-three-cylinder-race-engine/

What about the Alfa/Fiat twin air - two cylinder turbo and available up to around 105hp. Probably difficult electronics, iron block and little tuning available but may do the job and will be small.

https://en.wikipedia.org/wiki/Fiat_TwinAir_engine



[Edited on 31/5/17 by Ugg10]

1.6 sigma engine would be the easiest/cheapest option. Light too. 1.7 is a nice engine if you want a bit more oomph.

Hi

The 1.6 sigma is very light and 100hp (1.7 is 120something with vvt)

I had one complete with flywheel, clutch, oil etc no alternator and water and i could squat down and pick it up and move it round the garage with no problems when it was fastened to a small pallet.

Nick M

BMW F800?

It is a Rotax twin cylinder with 85hp @ 8000rpmm, about 68kg with gearbox if you can believe realoem.

Hi Colin, for low cost, low weight, plenty parts the CBR 900 is a good option. I can pick mine up to waist height so must be pretty light. Then quaife box or starter reverse.
Good luck
(Alex ex Haldex)

Bloke next door to me has a puma with a 1.7 se in it, chipped and some inlet mods he reckons it's rapid and has 175bhp

I'm going to use a 2l blacktop in my midi.....

The standard 1.7 SE makes 125 PS so that is one hell of a chip!

Coozer, I am also planning to use the 2.0 zerec in a midi if I ever get time to work on it - for information, I weighed my 2.0 zetec complete with starter, alternator, oil, 5 speed gearbox, both driveshafts(mondeo), cast exhaust manifold and induction - 186 kg +-2. I dropped the weight by about 5 kg by getting rid of the bracket that the alternator and PS pump mounted on and making a special from angle iron!