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No replacement for displacement!

Started by WALKEN, February 16, 2016, 03:35:05 PM

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WALKEN

Max , maybe your misunderstanding me?

A 500cc jug is 500cc maybe 498cc but that is the diameter of the bore. A 990cc jug is 990cc bore. Soooooo my point is the bore is much larger on the 4 stroke to match the smaller bore of the 2 stroke hence more weight not to mention valves and the way the engine fires.  2 stroke= lighter, smaller, faster more efficient.   

Also about being "in the power band" a 500cc is much different than a 125cc or 250cc as you can easily lug a 500cc up a steep hill without going balls to the wall. If you get in trouble mid hill, simply twist the throttle. The only bad part is the guy behind you will get a face full of rocks. 

DD- I'd much rather rebuild a 2 stroke than adjust valves. And the engine breaking on a 4 stroke feels odd IMO.   

There is no debate from me that 4 strokes suck, they are just different. My confusion is that people debate that 4 stroke is better than 2 stroke?

DD pointed something out- The H2! Put an engine like that in a modern gpbike and you'll have a hard time getting that grin off your face! That is my point!

My buddy had 2 H2's a 500 and a 750. I once had a 600cc triple sled @ 100HP, sounded amazing with triple pipes, hard to keep the front end down in hard packed snow.   

Help me, help you!

doubledragoncc

Totally agree with you on the H2 grin Walken. When I said about working on the 4 stroke motor, I should have said, you dont have to work on it as it wont break so easily lol. I do miss the smell of castrol 2 stroke oil too. I spent too much time working on high end cars that 2 stroke kinda got lost in my life lol. A 2 stroke Aventador lol!!!

DD
GPBOC Live Streams: https://www.youtube.com/c/IASystemsComputerControls; i7 12700K 5.1GHz Z690 ASUS Strix Z690-A Mobo 32GB 3600MHz DDR4 RAM ASUS Strix RTX3080 OC 10GB DDR6X ASUS Ryujin 360 AOI Cooler ROG Thor 1200w PSU in ROG Helios Tower Case.

HornetMaX

Quote from: vin97 on February 17, 2016, 09:02:20 PM
Because the ratio defines how high the engine can rev.
Doesn't really make sense to compare engines that produce their peak hp at very different revs.
Well, OK. Let's settle at this: if we the take all the points that are in favour of 2s and we deem them important, and we take all the points that are in favour of 4s and we deem them irrelevant or we bias the comparison to introduce constraints like "same displacement" or "same revs" (mind, I'm not even sure revs are a real argument), then yes 2s are the world best engine humans have ever seen. But one could easily do the same for 4s, it would be as simple as having a min weight limit at 170Kg, and one of the 2s main advantages is gone down the drain.

Quote from: vin97 on February 17, 2016, 09:02:20 PM
The 4 stroke engine is more fuel-efficient (at the moment) but a four stroke bike will still be less weight-efficient, even if you take into account that the engine needs less fuel.
If you compare a two stroke race bike against a four stroke one with the same max. power, the two stroke will always win.
Even if they have to run with the same fuel restriction ?
Because you see, today in motogp the limit is 22 (or 24) litres, no matter how light you can make your bike.
It's not as, assuming a weight limit at 150Kg, if yamaha can make a bike that weights 140Kg, then they can carry on 10 extra litres of fuel.
That's not the way it works.

But if the suter is soooo much better thanks to its almighty 2s engine, we should see some pretty amazing laptimes.
I'll wait for them. And for the Ryger. And for the clearly superior 2s ourboard (marine) engines that should just piss on 4s any given sunday.

I'm out of the discussion (and I'll self-spank myself for jumping in it, again).

Vini

February 17, 2016, 10:18:50 PM #33 Last Edit: February 17, 2016, 10:36:47 PM by vin97
Quote from: HornetMaX on February 17, 2016, 09:52:50 PM
Quote from: vin97 on February 17, 2016, 09:02:20 PM
Because the ratio defines how high the engine can rev.
Doesn't really make sense to compare engines that produce their peak hp at very different revs.
Well, OK. Let's settle at this: if we the take all the points that are in favour of 2s and we deem them important, and we take all the points that are in favour of 4s and we deem them irrelevant or we bias the comparison to introduce constraints like "same displacement" or "same revs" (mind, I'm not even sure revs are a real argument), then yes 2s are the world best engine humans have ever seen. But one could easily do the same for 4s, it would be as simple as having a min weight limit at 170Kg, and one of the 2s main advantages is gone down the drain.
Fine, let's stick to comparing 2s to 4s with double the displacement.
The thing is, the points where 4s are in favour, are not relevant for race bikes (fuel consumption, emissions, nice flat power curve, service intervals, ...).

Quote from: HornetMaX on February 17, 2016, 09:52:50 PM
Quote from: vin97 on February 17, 2016, 09:02:20 PM
The 4 stroke engine is more fuel-efficient (at the moment) but a four stroke bike will still be less weight-efficient, even if you take into account that the engine needs less fuel.
If you compare a two stroke race bike against a four stroke one with the same max. power, the two stroke will always win.
Even if they have to run with the same fuel restriction ?
Because you see, today in motogp the limit is 22 (or 24) litres, no matter how light you can make your bike.
It's not as, assuming a weight limit at 150Kg, if yamaha can make a bike that weights 140Kg, then they can carry on 10 extra litres of fuel.
That's not the way it works.
Well, obviously you cannot use rules designed for only one type of engine when you have different engines racing against each other.
There has to be enough fuel available so that the 2s will make the full race distance.
It does not matter if the 2s bikes have to carry more fuel when they will be lighter overall at any point during the race.

Quote from: HornetMaX on February 17, 2016, 09:52:50 PMBut if the suter is soooo much better thanks to its almighty 2s engine, we should see some pretty amazing laptimes.
I'll wait for them. And for the Ryger. And for the clearly superior 2s ourboard (marine) engines that should just piss on 4s any given sunday.
The Suter 500 is a low budget bike.
You know damn right that it's completely impossible to get anywhere near the MotoGP or WSBK record lap times without having a full factory team and shit ton of money behind you.
Full technical papers on the Ryger engine are to be released in a few weeks.


One last thing: Two strokes are not unreliable. They are very reliable in their projected lifetime (probably moreso than four strokes), meaning they won't fail randomly.
They have shorter service intervals, yes but again you cannot compare a 2s rebuild to a 4s one. Putting in new pistons for a race weekend on a race-2s is absolutely no problem (cost- and timewise) for any moderately skilled mechanic.

Napalm Nick

SuperMax
QuoteI'm out of the discussion (and I'll self-spank myself for jumping in it, again).

Hahaha OMG a thread about 2 vs 4 strokes and you are OUT????  Don't you like ON-topic Mawk? 

Hehe Only kidding you know I'm pulling your legs.  ;)

I don't think anyone REALLY thinks 2 are better than 4 or vice versa. It's like comparing an orange and a banana because they are all fruit (hey haven't I used that analogy somewhere else recently?). I might LIKE the 2 stroke Banana more than the nasty lumbering old Orange but that only makes it better To ME.

However, it is an important discussion (fight) to have believe in, and as we know, when there is a belief , there are always extremists.......

Fight ON.

"The post you are writing has been written at least ten times already in the last 15ish years. Its already been reported, suggested, discussed, ignored or archived (but mostly ignored). Why are you doing it again?"

HornetMaX

Quote from: vin97 on February 17, 2016, 10:18:50 PM
Fine, let's stick to comparing 2s to 4s with double the displacement.
The thing is, the points where 4s are in favour, are not relevant for race bikes (fuel consumption, emissions, nice flat power curve, service intervals, ...).
Concerning fuel and emissions, they are not relevant in your opinion. But they are indeed under today's rules. And there's a reason (which is not "kill the 2s", before Hawk chimes in with that :) ).
[btw I don't think service intervals are relevant to racing, never said so]

Quote from: vin97 on February 17, 2016, 10:18:50 PM
One last thing: Two strokes are not unreliable. They are very reliable in their projected lifetime
Steve Jobs, get out of that body !
What's next ? The power curve of a 2s is not peaky, it's very flat within the powerband [AKA it's flat where it's flat] ?

Quote from: Napalm Nick on February 17, 2016, 10:26:29 PM
Hahaha OMG a thread about 2 vs 4 strokes and you are OUT????  Don't you like ON-topic Mawk? 

Hehe Only kidding you know I'm pulling your legs.  ;)
My legs are so pulled that I can kick the back of my head :)

Quote from: Napalm Nick on February 17, 2016, 10:26:29 PM
I don't think anyone REALLY thinks 2 are better than 4 or vice versa.
Oh man, I have a short-list of 3 forum members I can bet a "left lung+right kidney+your choice of testicle" combo on ...
Problem is, if I bet and someone takes, I'll win but then what ? I've go no use for spare parts :)

Napalm Nick

Haha yep those extremists don't need naming lol.
3 testicles are better than 2 'to stroke'  ;)
"The post you are writing has been written at least ten times already in the last 15ish years. Its already been reported, suggested, discussed, ignored or archived (but mostly ignored). Why are you doing it again?"

WALKEN

Help me, help you!

Vini

February 17, 2016, 11:15:48 PM #38 Last Edit: February 17, 2016, 11:24:16 PM by vin97
Quote from: HornetMaX on February 17, 2016, 10:50:18 PM
Quote from: vin97 on February 17, 2016, 10:18:50 PM
One last thing: Two strokes are not unreliable. They are very reliable in their projected lifetime
Steve Jobs, get out of that body !
What's next ? The power curve of a 2s is not peaky, it's very flat within the powerband [AKA it's flat where it's flat] ?
Make fun about it but it is a very important difference, especially when you have to finish a race.
An engine that fails randomly but has a longer average lifetime is worse than an engine that doesn't fail randomly but has a shorter average lifetime.

Saying that one engine is better in general of course is not possible.
That's why we differentiate between street and race bikes here.

doubledragoncc

That is a great video, really shows the beasts at work. I was lucky to work for Suzuki in Stuttgart along with Speed Products and we had some full blown RG500's to play with. Soooooooo much fun.

You just cant beat the 2 strokes for the fun. Im an old fart now and need a 4 stroke CBR with training wheels lol

DD
GPBOC Live Streams: https://www.youtube.com/c/IASystemsComputerControls; i7 12700K 5.1GHz Z690 ASUS Strix Z690-A Mobo 32GB 3600MHz DDR4 RAM ASUS Strix RTX3080 OC 10GB DDR6X ASUS Ryujin 360 AOI Cooler ROG Thor 1200w PSU in ROG Helios Tower Case.

WALKEN

February 17, 2016, 11:53:49 PM #40 Last Edit: February 17, 2016, 11:57:13 PM by WALKEN
Max is that you on the left wearing the pink shirt?    :-*

https://www.youtube.com/watch?v=P__cQwU0AMo
Help me, help you!

Napalm Nick

Quote from: WALKEN on February 17, 2016, 11:53:49 PM
Max is that you on the left wearing the pink shirt?    :-*

https://www.youtube.com/watch?v=P__cQwU0AMo

Haha!

Still better than being one of the jerks in the car tho.  ;)
"The post you are writing has been written at least ten times already in the last 15ish years. Its already been reported, suggested, discussed, ignored or archived (but mostly ignored). Why are you doing it again?"

Stout Johnson

Hehe, I have the feeling the whole discussion kind of went from discussing the differences to just trying to have a point. :)  The main (and from my understanding the only) initial real issue was that Walken kind of seemed to suggest that comparing a 990cc 2s vs a 990cc 4s would be a fair comparison. Other than that, there were no real substantial differences in opinion imo. MaX made some very valid points portraying pro's and con's of 2s and Vin made some very valid points concerning the 'raceability' of 2s, - so let's not end in a kind of black and white discussion like one could only love one concept and hate the other.

What I always wonder about, though, is that it always seems like people tend to think that 2s are superior because it can generate (in tendency) more max power per cubic capacity and is more weight-efficient. It is just a completely different concept where every stroke is being used for combustion, whereas 4s sacrifice strokes for better emission control. So (as often in life), advantages go hand in hand with disadvantages. And I'd agree with Vin, that per se (no other constraints than pure maximum power output per weight) the 2s might have an edge as the better concept for race bikes.  Fuel consumption, emissions, power curve, service intervals are not necessarily important in racing.

But looking at it globally, fuel consumption and emissions actually indirectly do matter in modern racing. And let me tell you why (I know the die-hard 2s lovers will totally disapprove the argumentation):
At least in non-developing countries 4s-engines have become the standard, and rightfully imo. I myself was raised in a country where even 80% of cars used 2s-engines - and the pollution was just really unbearable and close to being in compliance with the definition of grievous bodily harm. It is not comparable with the romantic memories of smelling some 2s exhaust gases on a racetrack evening. The hardcore 2s-enthusiasts might ask at this point "What do 4s-engine standards on public roads have to do with racing for god's sake?" Well (and I hope I do not hurt your romantic "pure racing" feelings here) the main reason why big manufacturers like Honda, Yamaha etc are taking the risky business of investing in MotoGP is not because of their competitive drive but because it is the single most important sales-promotional expenditure for sports bikes. And trying to sell 4s-bikes based on the success of 2s-racebikes is where customers would probably have second thoughts. So, in order to provide enough manufacturers incentives for investing in race bikes, it is a logic step imo to have the same engine technologies for racing bikes as for road bikes (imo going back to 1000cc class is also a result of that calculatio). Consequently, for the mainstream race categories (MotoGP, Superbikes, Superstock), it does only make sense to use 4s engines. But that does not mean that there won't be the possibility for niche racing categories with 2s engines.

So, the mainstream 2s-racing era is history imo, even if it might only be to the fact that 4s engines are the better concept for civil life public road usage and it does make sense for motorcycle manufacturers to invest especially in motorsports where there are engine concepts used that are relatively close to stock engine concepts. That is just my 2 cents on this topic.
    -----------   WarStout Kawasaki Team   -----------

Napalm Nick

A very valid point there Stout I think. It will always be about the overall profit. And although there is none in racing, it is a shop window driving sales and huge profits.  I am surprised the drive for electric and eco hybrid engines in motorcycle racing (other than the TT) is not further advanced considering how quickly these models are arriving on the streets (Just look at F1). Petrol based motorcycle racing will be considered very 'old hat' in next to no time.

The whole pollution debate is likely to apply to 4 strokes in the near future exactly as it appears to 2 strokes now. There will come a day where a battery isn't considered green enough (lets face it they aren't particularly green now!).

Fortunately I will be dead by then haha.
"The post you are writing has been written at least ten times already in the last 15ish years. Its already been reported, suggested, discussed, ignored or archived (but mostly ignored). Why are you doing it again?"

h106frp

Always try and catch the TT zero event, one of the few events that can still be considered 'anything goes prototype' although last years was obviously a case of huge budget=event win.