How high could you rev a built naturally aspirated superbike engine with conventional valves? The Honda is a good example since it uses an 81 mm bore screamer engine. Furthermore, the stock conrods and pistons are excellent. My question is, if you replaced the valve springs & ported the cylinder head, could you sustainably reach 16k rpm?or even more?Where is the limit for DOHC in terms of what an individual or small privateer superbike team could attain and mantain themselves?It would have been easy to estimate if they were allowed to push them in WSBK, but they are limited to something like 105 percent of what the base bike can do.
>>29031628you can reach 20,000 if you really want bud
The biggest hurdle is probably recirocating mass. The Honda RC116 revved up to 21,000 rpm. But why would you want to do that? The higher you go the peakier your curve gets until everything else is unusable.
>>29031628R116 gets 20k revs.If you have an engineering degree you can get an RC car engine and those cap at 50k. Why I say that some Portuguese YouTuber did that.
Road going Ducati v4s will rev to 16, but this anon basically nails it >>29031635Revs don’t necessarily equate to power, insofar as wang factor doesn’t win races.
>>29031635>>29031637>rc116 revs to 21kthat is a 50cc bike. I said superbike, 1000cc>>29031638>Road going Ducati v4s will rev to 16, but this anon basically nails ityou meant the v4r, not the v4s. the former will indeed rev to 16 k in 5th gear and 16.5 k in 6th gear, when on race fuel. but that thing has desmodronic valves, not dohc.
>>29031649Make it a I6. 166.5cc per piston and give it fuck all stroke. Use nitrometh because gasoline isn't going to burn fast enough and gear drive everything.
>>29031635It's valve float if you don't have desmo or pneumatic.They got 2.65L V8s with conventional valves to 16k back in the day so I'm sure you can make a 1000 live there with enough money. https://www.youtube.com/watch?v=DF8GTL0_rMAFor a small team though? Completely impractical. All their money is going to be in trying to figure out how the fuck to work the electronics to get the thing off the corner anyways.
>>29031661aren't you limited to a 4-cylinder maximum in most major races?
>>29031649>not dohc>>29031632this thing has DOHC
>>29031665(actually it turns out forced induction basically raises your rev ceiling because you can run smaller valves but they weren't allowed a ton of boost when they were revving the piss out of them)>>29031671Yeah but a lot lighter valvetrain and bottom end than a 1000.The RCV1000R was announced as 235hp @ 16,000rpm with steel valve springs. The RC213V-S is kind of a street version of that bike but it only went to 14k.
>>29031681you could potentially develop a head that uses bishop valves on the intake side. or pneumatic valves. I don't think valves are the limiting factor in engine design at any level
>>29031666Wait, we are obeying the rules satan?
>>29031706who do you think makes the rules?
>>29031681>The RCV1000R was announced as 235hp @ 16,000rpm with steel valve springsyou know ball, anon. i forgot that bike existed. it is probably what was deemed to be the most power a skilled privateer team can reliably use with steel valve springs. it is sad that it gets beaten in both power and torque by the current panigale v4r road bike. and so does the bmw superbike. the strongest engine alpha racing sell, in the bmw m1000rr superbike, the 150000 € one, is 235 hp. there is not one documented example i have yet found of any dohc engine beating even the current road going desmodronic ducati. not the privateer motogp bike from 2014, not any 4 cylinder 2002-2006 990cc motogp bike, not any world superbike machine (bmw around 235, yamaha 220, honda 235+ with bad power curve). nothing really points to dohc being competitive even with desmo.
>>29031649>that is a 50cc bike. I said superbike, 1000ccAnd? The theory is the same. Peaky curve makes it no fun for street use
The camshaft is the only limiting factor.
>>29031632Looks like you're missing a couple RPM, buddy.
>>29032026you are literally the third person that doen't understand basic physics and keeps spamming this 50cc engine when superbikes are 20x the capacity.
>>29031730not, it's not, valves and valve springs are
>>29032747Ford Indy V8 hit 20k rpm from a 5 liter.
>>29032826I don't think that's accurate sir
>>29032834They hit 20k but limited them to 16k for survival reasons then got regulation jail'd to 13k because they smoked the competition.Dont feel like finding source material tomight so here's a 20k rpm V8 from the same people and a legit source.https://www.roadandtrack.com/news/a40871299/please-put-this-20000-rpm-cosworth-f1-engine-in-your-car/
>>29032840Engines are pseudo-related.The Formula 1 Designated as DSV and the Indy as DFX, with the Indy (DFX) later versions being various displacements.https://en.wikipedia.org/wiki/Ford_Indy_V8_engine
>>29032824>valve springsJust stop fucking around and go desmodromic.
>>29032848Its almost like if you wanted to get hired at Cosworth you were either a pysco to start with or fresh oit of engineering school and hadn't run the gambit of others saying "nope, cant be done" so you just...did it.
>>29032850it does seem to be way superior to anything else
>>29032840That has pneumatic valves.The 16,000rpm CART engines were not 5L and were already addressed. You can spin anything to 20,000rpm until it breaks...>>29032848There's no connection between the F1 and Indy engines from the early 90s on when the HB and XB came out and the CA is totally unrelated to the HB either having had a V10 between.
>>29032856by anything else i mean anything not pneumatic
>>29032850>turned another muffler into a claymore mine because you missed your 5,000 mile follower adjustment.Cool on paper (or animated gifs) but extremely heavy on the maintenance side.And its one thing to say "eh, ill change my oil when thw weekend rolls around", you can let that extra hundred miles fly.But when your valves stop closing it becomes a serious issue.
>>29032857>There's no connectionThey were designed by the same people.I said "pseudo-related" for a reason.They shared the same concepts and design mentality.Kind of like the Australian Falcon I6's being pseudo-related to Cleveland V8s
>>29032865Ilmor's 90s engines are about as equally related by that standard.
>>29032857>You can spin anything to 20,000rpm until it breaks...Yes.Which is also why I specifically said >They hit 20k but limited them to 16k for survival reasons
>>29032866Do you know why the Dodge truck body style shifted to something that looks like a Mack (semi) truck front end in '94?Because Dodge hired a designer from Mack truck....
>>29032747Those 50cc bikes are doing exactly what you want. The answer is clear. Get a 50cc.
>>29032824>valves and valve springs areWhat good are those fancy titanium parts if you don't have a camshaft that lets them breathe properly?
>>29031628Just stop it with the GP Racer fantasies.You will never be Rainey, Schwanz or Mick Doohan.
>>29032872they're 250s. and they were designed to take advantage of the Japanese license system that restricted learners to a maximum of 250cc. 20,000 was the limit for what manufacturers were willing to push to the commercial market (in the 80's). but f1 teams have gone as high as 24,000 before running loses overtook power gains.the valves have never been the limiting factor.
>>29032026the MC14E's all have the same rev cut at 19,500rpm.however the original cams in the MC19 make more peak torque than the MC22 despite both having the same advertised peak power.the MC19 doesn't have an electric speed limiter either.
>>2903550724,000rpm F1 engines have pneumatic valves FOLLOW THE FUCKING DISCUSSION YOU RETARD. Literally if you run stiff enough valve springs to close large enough valves to properly feed a large displacement motorcycle engine you will fucking pull the valves apart, the last year they used mechanical valve springs in MotoGP Yamaha ran 9mm valves instead of 12 or 14mm just to be able to rev higher. (supposedly they actually got to 18k that way)The whole reason 4 valve race engines exist is because it effectively raises your rev ceiling 1.4x to run two small valves instead of one big one.
>>29036266so run pneumatic valves then fuckass.
>>29035507>they're 250sSome are. They also did a 50cc class. Mostly 2 strokes but Soichiro Honda hated 2 strokes.
>>29031628>ported the cylinder headlol, for what? The issue isnt power, those bikes have rev limiters because there are physical limits to what steel can do.You want more revs the biggest hurdle is the valvetrain switching to aftermarket high-performance springs will get you maybe a couple more RPMs but the OEM ones are already pretty close to the limit.The main difference between Superbikes and MotoGP prototypes are the pneumatic valves after all.
>>29031628Here is/was a custom CBX1000 that is claimed to reach 20000rpm, or near to it. Some debate on how accurate the tach is.https://www.youtube.com/watch?v=BYODFzLv3bYFor the most part it's just a demonstration bike and is only making those RPMs momentarily.
>>29036471if the valves were really the key to going fast, then teams would be investing way more into it. but they're investing in aero and suspension. you can build a whole custom head that has rotary valves on the intake and five exhaust valves, titanium crank and everything. and still get whipped by someone that spent all that money on tires and track time.
>>29031628>Honda Gearbox full of neutrals.If you dont understand you have never ridden a Honda
