2-Stroke Formula Cars.

[FJBH10]

Anyone know why there has not been any recent 2-Stroke racing cars? As far as I can tell the Elva DKW of the early 60s was the last properly competitive 2-stroke in an upper racing series. Why not have high-revving 2-stroke open-wheelers nowadays?

The Elva mentioned above.

[Facts Only]

In the U.K 2-Stroke engines are not allowed by the MSA (except for historics and Karting) I believe.

Cant find the relevant section in the blue book though.

[toraabe]

Around 80% more power on the same displacement.

[NL_Fer]

Two strokes are limited to 10000rpm. They cannot rev higher, because of the mixture spooling is to slow.

[flynfrog]

RC engines do 5x that without problems. Im not sure what you mean by mixture spooling. This isn't a term I have heard before.

Edit my motocross engines and karts all do more than 10k RPM I have no idea where you are getting that number from.

[coaster]

I like your thinking FBH, why dont they engineer a 2 stroke with bearings sealed so the lubrication can be separate from fuel?
Poppet valves were considered obsolete in the late 60's by many and rotary valve experimentation was the pointy edge of experimentation.
Renaults pnuematic spring gave the poppet valve whole new lease of life, now the rotary valve is now considered a dinosaur.

Maybe such a revolution is due for 2 stroke.

[Tommy Cookers]

the (eg Ilmor) rotary valve was banned from F1
what changed in the 21st century was bore-to-stroke ratios became unprecedentedly huge
poppet valved engine gain by this as the valve area increases relative to the rpm and related airflow need
a piston ported engine loses by this (blatant effect of port depth reducing with stroke)
its only chance is to have lots of tiny cylinders (as MZ's Kaaden said)

ok the present F1 is a bit different

[NL_Fer]

RC engines do 5x that without problems. Im not sure what you mean by mixture spooling. This isn't a term I have heard before.

Edit my motocross engines and karts all do more than 10k RPM I have no idea where you are getting that number from.

A poor translation from my native language, where they are called spooling ports. I think scanvenging is the correct term. And the 10k i once read, many years ago. But i forgot about rc engines.

Still at 20000 rpm a four stroke is more efficient and modern aluminium blocks are not that heavy anymore. It still a massive weight reduction in diesel trains and ship engines.

[flynfrog]

RC engines do 5x that without problems. Im not sure what you mean by mixture spooling. This isn't a term I have heard before.

Edit my motocross engines and karts all do more than 10k RPM I have no idea where you are getting that number from.

A poor translation from my native language, where they are called spooling ports. I think scanvenging is the correct term. And the 10k i once read, many years ago. But i forgot about rc engines.

Still at 20000 rpm a four stroke is more efficient and modern aluminium blocks are not that heavy anymore. It still a massive weight reduction in diesel trains and ship engines.

this is not across the board number. Its pretty hard for a a 4t engine to rev to 20k and not float the valves. Id be willing to bet a 2t can give a 4t a run for its money at that rpm especially in NA conditions.

[andylaurence]

Noise. Both the volume and the tone. Who wants to listen to a strimmer?

[Brian Coat]

no racing 2 strokes: marketing and emissions regs

Jim Clark started his career in a 2 stroke, didn't he?

[J.A.W.]

2-strokes are severely restricted - if not outright banned - from most formula racing classes..

..but this is for political reasons, since the inherent work-rate is a major technical advantage..

..see here: http://www.aaenperformance.com/v4_racing_engine.asp - for a current off-the-shelf, 2T race mill..

[SectorOne]

If Motocross bikes are anything to go by, that powerband should be pretty thin
I´ve only ever been scared once while on a vehicle and that was giving a 125cc motocross the full beans.

[J.A.W.]

If Motocross bikes are anything to go by, that powerband should be pretty thin
I´ve only ever been scared once while on a vehicle and that was giving a 125cc motocross the full beans.

Not as "thin" as an N/A 4T 125cc unit - at anywhere near the same specific output, viz: Honda's NR 500/4 G.P. mill..

..an expensive flop.. which went to the extreme of being a defacto V8..
..but ended up being replaced by a simple 3cyl 2T utilizing MX tech..
..which went on to win Honda its 1st 500 G.P. World Title..

http://world.honda.com/history/challeng ... index.html

[Hillclimber]

Hi

Being a two stroke fanatic, I built a single seat race car using a 600cc Rotax (135hp) and used a CVT transmission with good results. I drove this up the Shelsley Walsh hillclimb in 35.03 secs. Having proven the concept i have a new project.

I am now underway with building a new Hillclimb/sprint car using a Prosport 3000 chassis plus an Evinrude two stroke V8 - 3.6 litre and circa 400hp with 425 lbs/ft torque. Engine + CVT transmission is less than 180kg. Hope to have it running for the 2018 season to disprove all historical comments about noise, smoke etc.etc.