Question for those with very technical knowledge of engine designs: Why is it that we don't see special-built, 2-stroke drag cars or ANY race cars, or even road race bikes for that matter? For dirt bikes, there is nothing like the power to weight ratio of a 2-stroke. I understand the lack of low-rpm torgue prevents it from being a good option for street driven vehicles, but for high-rev operations like racing, I have always been surprised they weren't used. Is the sole reason that racing on soil allows you to spin the back tire easily to get over the low-end torque issue? If that's the only reason, I would think that's not an issue for a 1000 HP drag car... I'm sure I'll get an education here. That's what I'm hoping for!
Thanks!

This is alittle off subject but alot of 2 strokes have some incredible low rpm torque. This is one engine that I hope my ship will have, I can then say I have the biggest big block! HA!http://www.bath.ac.uk/~ccsshb/12cyl/

That is AWESOME! Never seen anything like it. Just 100,000 HP from what is little more than a super-sized version of any other gasoline/diesel engine! Of course, I know that is a bit of over-simplification

The biggest reason the two strokes are going away is emissions. The small ones require oil in the fuel, and that creates polution. They also do not clear all of the old exhaust out of the cylinder as well as a four stroke, and that creates a sloppier burn, and that's pollution. If a blower is installed to fully vent the cylinder, fresh air/fuel mix is blown in, but that also means some of it is blown out the exhaust unburned, more pollution.

Even lawn mowers and chain saws have to meet emission standards when they are built. So good bye two stroke. Without 2 stroke production engines, there is not much to choose from to create performance versions.

They run very well, but they are dirty. Larger ones still need the wet sump, or oil in the crankcase. These do not need oil in the fuel, so that helps, but the other problems are still present. Still dirty in regards to emissions.

2 stroke torque and power are much better due to the fact they have a power stoke every rotation of the crank, instead of every other rotation.

AND, that is one AWESOME engine.

|UPDATED|12/13/2004 3:41:04 PM (AZT)|/UPDATED|

Ken,
I had you in mind when I posed this question. I knew you'd have the low-down. I get the emmissions thing. I don't know NHRA regulations, but clearly emmissions is not what is keeping someone from building some custom block, blown, 600 CI, 2-stroke engine for drag racing. Is there something rule like the "concept" of the engine has come from a production vehicle (althought very loosely)? There has to be some reason, as the top teams would go to ANY extreme to win, IF in fact the two stroke is capable of more power for this size and layout of engine. Make sense? I'm just a curious kid (40) who never grew out of asking questions!

There are two thing about 2 strokes in racing applications. First, there is very little to build it out of. No stock production units. You would need to start from scratch. Very expensive. Second, all engines need to fit into a particular class. These don't. That means they would be more for special shows, instead of competition. That's a lot of cash for show off. Guys will usually only do that with a monentary return.

|UPDATED|12/13/2004 7:17:11 PM (AZT)|/UPDATED|

I agree with your thinking but if 2 stroke had an advantage-someone would have done it by now.
Steve

Gas turbine engines are also engines that can have a tremendous advantage in racing, but they were driven out of existance due to emissions also. The military is having good luck with them in their tanks though.

I used to do a little work on 2 stroke Detroit diesels back in the mid to later '80s. The Army bought a new series of trucks back then, called HEMMITT's. They came in different variations. Cargo,tanker,wrecker,etc.
The powerplant was an 435-475hp 8V92 T/A Silver series 2 stroke Detroit. 92 cu.in/cyl.= 736 cu.in. Had a Roots type blower (which was used for startup and idle only) and a turbocharger mounted on top of the blower. The turbo would blow through the blower once the gas pedal was pushed and boost was starting to climb. Pretty neat engines those "screaming" Detroits were. And powerful too. But their one downfall was longevity.
Sarge

Geez, a blower AND a turbocharger. That had to be so cost effective I can't believe we've never seen something similar hit the consumer market . Pretty cool though, I must admit.