modern 2 strokes

[MTv Dave]

Just read a thread about somebody re-building a classic race car that has a 1l 2-stroke.
I'm not that comfortable with them, but it has got me wondering if there are any new ones made with modern materials that are road legal?
Continuing the theme of super light cars with little engines from Diahatsu, I expect that more modern 2-strokes would produce reasonable power (100bhp/ton) with NA and not too much trouble, but can you get them running with EFI? Are they low mass, or do they need to be strong so made of iron?

I just want to get a feel for them, or if this is a dead end and not worth me pursuing?

[MTv Dave]

The_Burg said:

Pigeon said:

You can indeed get them running with EFI, and if you inject direct into the cylinder after the exhaust port has closed you avoid the problems with charge spillage.

I beleive Aprilla made a direct injection scooter, and Ford with the 'Orbital' engine a few years back. Loads of other refinement Hondas 'Active Radical' for example.
2 strokes are awesome, huge power for tiny capacity, ultra simple and sound amazing.
(Even smell fantastic running Castrol R or similar).

If your talking about the 'Lova' rebuild i for one can't wait hear and smell it running!

Yup, Justin's Lova. Looks like an awsome little car

I've never had any dealings with 2's before, hence my worry. I'd also want the finished product to be road legal, so emissions would be an issue for me.

I expect I'd want a relativly large (1l ish) capacity engine, so nicking one off a little modern scooter or somesuch isn't really an option.

My target wet mass is around the 450kg mark, so I was looking at 600-1000cc 3-pot 4-strokes from the GTti et al to get reliable 100-150 bhp (blown). If I can get similar reliable outputs for less money, mass, bloody knuckles or trouble and N-A then I'd be happy to go 2-stroke, but have zero idea on where to even start.


ETA - Alan, I have just visited your website - Are those LED clusters any good? I've been looking for some similar things, but ended up designing my own units, but would rather go with 'off-the-shelf' bits if I can.

Edited by MTv Dave on Wednesday 21st March 12:58

[MTv Dave]

Nice, neat and only 44kg!
No prices for the engines, so I guess they're quite expensive
The road/race version kicking out 200bhp from 850cc @ 9k rpm sounds good. Maybe it would last a little longer than the 275 bhp @10,000 rpm for the 1l drag engines

Edited by MTv Dave on Wednesday 21st March 14:12

[Mtv Dave]

The_Burg said:

No obvious signs of power valve or reeds, surely this is not a pure piston ported motor?
As regards a useable engine cheap and powerfull possibly a motor from jetski?
Up to 750 - 800 cc so 150+ bhp should be no problem.

See, things like that worry me, I have no idea what you are saying! I'm guessing it's something to do with moving fluids from below to above (or visa versa?) the piston?
Can anybody point me to a web source for more in depth info on 2-strokes and tuning them?

Edited by Mtv Dave on Wednesday 21st March 15:40

[Mtv Dave]

Not so much high power with low mass, but "fun" with low mass.
For me, I think this means about 100-150bhp (220-330 bhp/ton) and a reasonable spread of torque.
I'm looking for dyno graphs of tuned 2-strokes just to see how the torque looks across the rev range, if they're spikey then I'll leave them be.

[MTv Dave]

Can't get onto a bike on a public high way
I did have a little play on an RS 125 Aprilia a few years back. I thought it was mad, but I hadn't really experianced riding anything else or been in any seriously quick cars, so I'm not sure what I'd make of it now.

I'll have a scout around and see if I know anybody that has a bike I can have a go on somewhere private.

[MTv Dave]

Pigeon said:

You can indeed get them running with EFI, and if you inject direct into the cylinder after the exhaust port has closed you avoid the problems with charge spillage.

Just checked out your profile - how's the luck going with the engines? How much do you think you'd have to sell one for to make it worh your while? How long do you think they will last - bwtween needing tuning and between going pop?

[MTv Dave]

Maxc - your skidoo in your profile looks mad! As do the stats!

Now I know what these things can do, I'm really interested in getting a reliable setup over max output figures:
The car will be spend most of its life waiting in the garage. When it's ready I'd really like to be able to hop in and go for a spin once in a while and drive it to and from the track... If I have to play with the carbs everytime I turn the engine over, then it's more hardcore than I can handle. As I'm getting the vibe that getting the fueling right is critical for a stroker (I'm also getting into the lingo) it may be that I can't handle it.
I'm not going to be running a highly tuned engine, but I'm still worried if I go down this path I'll have a lot of extra work keeping it running on my hands but I'm really after building it then playing with it and just doing services and all the big & little jobs every 6 months with little to nothing in between...