RPM on V8

Venom · Post 27 Feb 2006, 23:15

Since the new V8's were invented I've seen figures stating limit from 16.000 rpm to 22.000 rpm.

Is there an official limit, if not what will the engines go up to?

DaveKillens · Post 28 Feb 2006, 00:32

Not yet, RPM is limited by the design and risks the engineers are willing to try. But there has been a rumor floating about limiting RPM..

jgredline · Post 28 Feb 2006, 01:34

Cosworth has a video of there engine on the dyno turning 20000 rpm.
This is not even there latest spec. Rumour has it the cosworth is up to nearly 21000 rpm

RacingManiac · Post 28 Feb 2006, 16:07

There was an article I read on an industry journal on engine and in it the article was talking about Renault's RS25 and RS26 engine. Renault was quote saying that by moving to the 2.4 liter V8 they can gain 3000 rpm on the V10, but not immediately as they have to be conservative initially....

Maybe moving into 20,000 rpm by the time European swing comes around?

DaveKillens · Post 28 Feb 2006, 17:20

Absolutely, freaking amazing. It's hard to conceive that at those accelerations the pistons, crankshaft, and valves can survive for two races. Just amazing.

Scuderia_Russ · Post 28 Feb 2006, 18:22

Cosworth have hit 20,000 on the track and 21,000 on the dyno apparently.

wowf1 · Post 01 Mar 2006, 00:15

That's all very well, but I wonder what the absolute maximum RPM these V8's can pull is before valves hit pistons etc. If there's a rumour of 20,000rpm on-track, I wouldn't be surprised if they could push them past 22,000rpm on the dyno.

What do you guys think will be the limiting factor? Regarding mechanical components I mean.

jgredline · Post 01 Mar 2006, 00:28

Since the engines don't use valve springs, bent valves should not be an issue. It will come down to Vibrations and how to get enough air through the inlet ports.

zjeeraar · Post 01 Mar 2006, 00:30

actually, i think a v8 can rev up to 25000 revs for a few seconds safe. But of course after that, it wont last 2 races after that!

DaveKillens · Post 05 Mar 2006, 16:59

wowf1 wrote:What do you guys think will be the limiting factor? Regarding mechanical components I mean.

With the advent of pneumatic valves, the valve/piston collision factor seems to be under control. But at such high speeds as 20,000+ RPM, I am sure even they aren't safe anymore.
The piston acceleration is incredibly high, well past the sane level any road car designer would design. And of course, that punishes the crankshaft.
It appears that with the present materials engineers are forced to work with, the practical limit is reaching a plateau.
As well, the actual combustion process must also be at it's limit. The fuel only burns so fast, and as the RPM's climb, there has to come a time when it just can't ignite, burn, and deliver a worthy amount of power.

f1.redbaron · Post 05 Mar 2006, 18:28

DaveKillens wrote: The piston acceleration is incredibly high, well past the sane level any road car designer would design. And of course, that punishes the crankshaft.
It appears that with the present materials engineers are forced to work with, the practical limit is reaching a plateau.

I had just finished reading one of Principessa's articles about that. Here are the numbers:

- Maximum piston acceleration: 10,000 g
- Maximum piston speed: 40 metres per second
- Average piston speed: 26 metres per second
- A piston accelerates from 0 to 100 km/h in 0.3 thousandths of a second
- 3 tonnes of force is exerted on the connecting rod

As you said, Dave, it is insane.

Mikey_s · Post 06 Mar 2006, 11:36

I must agree with DaveKillens, I think the limiting factor in the internal combustion engine is fuel... the rest is just engineering (OK, before you jump on me, the challenges are formidable - see redbaron's post!, but durability of components is engineering limited, the fuel is chemistry limited). The combustion process takes a finite time to initiate, propogate and thus deliver power - this is most easily seen in diesel engines - above a certain rev limit they just start to make black smoke as the combustion process is incomplete by the time the cylinder charge is evacuated from the chamber. This has been improved in diesel engines by finer atomisation of the fuel (higher pressure injection) and this is far less of an issue for gasoline engines where the fuel vapourises in the inlet manifold. However, flame propogation is most likely the limiting factor in this instance.

m3_lover · Post 06 Mar 2006, 19:13

With Mikey_S, In the new Audi R10, they couldn't raise the rev limit so it will be around 4 to 5 rpm. Just a random useless fact

RacingManiac · Post 06 Mar 2006, 19:33

m3_lover wrote:With Mikey_S, In the new Audi R10, they couldn't raise the rev limit so it will be around 4 to 5 rpm. Just a random useless fact

Its also a none-spark-ignition diesel....The engine supposed to have a max rev of 6k and max power between 5-6k. Due to the immense torque the engine outputs the R10 will actually have a 5 speed gearbox....

DaveKillens · Post 06 Mar 2006, 19:41

A little bit of history. Back when Honda were developing high revving multi-cylinder engines for motorcycle road racing in the early 60's, they built a six cylinder 350 cc DOHC engine that powered Mike Hailwood to glory. That too reached high RPM levels, I believe 16,000+. The current idea is that for high power engines you need high octane gasoline. But it was found that the present high octane gas was using lead to inhibit the knock characteristics. This also slows the combustion process. Instead, the Honda engineers had to go to lower octane (less lead) gas to make this type of engine run properly. The high octaqne gas just didn't burn quick enough.
Of course, going to the present we can formulate exotic fuels that most likely could handle the high compression and burn times. But the present rules in F1 do not allow exotic matrials or fuels.
I just can't wait to hear those shreiking beasties in action.