2 stroke thread (with occasional F1 relevance!)

[Andres125sx]

Maybe I was too optimistic talking about 2000hp, but that´s not relevant at all since it was a reply to gruntguru who said that kart with 560hp/litre had more specific power than current F1 engines, and I replied to show that´s only due to the huge restrictions there are today because 30 years back they were well over that number even with race configurations, let alone qualy ones...


About turbochargers.... they would be as efficient with 2stroke engines as they are with 4 stroke ones?

[uniflow]

The Kart engine is restricted to 30mm carb and 13cc combustion chamber. Turbo / EFI not alowed. That is why this figure is so fantastic and if it wasn't for Frits Overmars involment I would not believe it.

[gruntguru]

[[...]So a four stroke turbo engine provided more than 900bhp/litre 3 decades ago.

...for about 10 laps or so.

So you do think that such peak figures could increase about 40%, from 900 HP /Litre to 1250 HP /l?
In which fields do we need the improvement, and where can we possibly find such huge increases?
Can we find the additional increase in BMEP and/or revs without blowing the engine after 10 seconds?

No doubt. Between 1980 and 2005 NA outputs rose from 180 bhp/l to 310 bhp/l. That is a 72% increase in 25 years.

So for the 30 years you are talking about, a specific power increase of at least 72% would be possible - without increasing boost. IMO if we went back to the original 1.5 litre turbo formula (no boost limit, no rpm limit and no limit on the number of cylinders) 1500 bhp/l would be possible. (2,400 bhp from a 1.6l)

If you don't believe me, think of the following scenario. Take a 2103 V8 (750 bhp in spite of the rpm limit and prescribed cylinder size). Use 5 of those cylinders to build a 470 hp 1.5l NA engine. Turbocharge to 6 bars - bingo - 2,500+ bhp.

[J.A.W.]

Bingo - just like that - a simple mathematical projection.. too easy..

Seeing it done in metal & having it holding together for any meaningful purpose is quite another level of effort..

Might be a sort of C21st equivalent - to the `50s BRM V16 - in cost & drama!

Honda, where are you?
Do it.. just for the hell of it..

[Abarth]

The increase in power output between 1980 and 2005 for NA Engines is in a big part attributable to technologies that allowed to increase engine speed, from 12000 to 19'000+. I doubt that forced induction and those speeds, to achieve 1500+ hp/litre are simultaneously bearable for an engine which has to last at least a GP Distance.
But anyway it's OT, and we should talk about 2 stroke concepts.

[uniflow]

The trouble with twostrokes is anyone can make their own in the back yard.

https://youtu.be/UdSw3QbZtKE

[riff_raff]

I doubt that the 1.5L BMW I4 turbo F1 engine ever produced more than 1200hp for more than a couple seconds, even in qualifying trim. While it's believable that the engine could produce up to 800hp in race trim, this was mostly due to the exotic toluene-based fuel compositions they used at the time. The rpm of the 80's era 1.5L turbo F1 engines was limited to around 13krpm due to the fact they still mostly used metal valve springs.

[gruntguru]

The increase in power output between 1980 and 2005 for NA Engines is in a big part attributable to technologies that allowed to increase engine speed, from 12000 to 19'000+. I doubt that forced induction and those speeds, to achieve 1500+ hp/litre are simultaneously bearable for an engine which has to last at least a GP Distance.
But anyway it's OT, and we should talk about 2 stroke concepts.

Whoa!! Who said anything about race distance? We are comparing 80's turbo era engines with what would be possible today.
80's turbo engine
Race - 600 bhp/litre
Qualy - 900 bhp/litre

Hypothetical 2015 engine built to same rules
Race - 900+ bhp/litre @ 3-4 bar
Qualy - 1,500+ bhp/litre @ 5-6 bar

[Abarth]

Well we talked about 2 Stroke which I suppose are covering a certain distance...

2 Strokes, comparing apples with apples, are interesting.
But for a comparison to actual F1 engines, we should not look to those aspirating a fuel/oil/air or oil/air mixture over crancase, as their efficiency in a race relevant rpm/load range is insufficient.

If we are not looking at regulations (i.e. race distance has not to be taken into account, as has been said), then we should look at an overall picture.
Needed fuel tank, space of engine, weight and whatnot when comparing engines for racing.

[uniflow]

Do it please, jaw will never accept he was wrong so let´s move ahead

Wrong about what A-125..?
Not wrong about you - plucking imaginary hp numbers out of the air..
..with zero idea about how to convert such fantasies into practicable race engines..

Uniflow put up something real..
& Abarth is correct to call you out on your fantasy conflation..

Those jugs are real alright, but I get your point.

[J.A.W.]

Uniflow, perhaps you misunderstood me..

I meant that - unlike - A-125..

You - had - put up something real.. ..not " a put up job"..

[uniflow]

See what happens when you read forums when you are half asleep, I see now. I guess I was just trying to say big business does not like racing formulars where home grown suff can make them look silly. Twostrokes are at a development stage where anything can still happen, as you can see with this Kart engine. Thats why I'm so interested in what's happening with small pockets of development still happening around the world, almost what you would call "under ground".
In M/C racing the fourstroke has saved the big four ( five if you count KTM ) by making these bikes parts hungry ( expensive ) to run, they like selling new pistons every fifty hours ( or less ) and there is so many other parts to replace.

[LucF]

I would be quiet too and not believe it, but the truth is different

https://www.facebook.com/mcd.twist.9/po ... nref=story

Kind regards,
Luc

[uniflow]

I would be quiet too and not believe it, but the truth is different

https://www.facebook.com/mcd.twist.9/po ... nref=story

Kind regards,
Luc

Luc, show us some evidence

[LucF]

I would be quiet too and not believe it, but the truth is different

https://www.facebook.com/mcd.twist.9/po ... nref=story

Kind regards,
Luc

Luc, show us some evidence

The evidence will come later, so please have some patient.
There is a reason why we have to wait for this.