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Proper revv limiter
1
(46 posts, started )
Proper revv limiter
Heya!

This is a little update one for my rotary engine suggestion.
We should have properly jumping revv limiters.
What's my point?

First of all, you should be able to set your shift light at the RPM you like yourself.
It's not the hardest thing to put into LFS I think.

Second is that the actual revv limiter sound.
At the moment it's: wroomwroomwroomwroomwroomwroom.
What I like is: wrooom bababababa BANG bababa BANG babababababa BANG

Hard to write the noise but I think you understand what I mean.
And maybe 2 different ones.

As far as I know there is 2 different revv limiter types IRL, that is one that shuts down the fuel flow the other one is turning off the ignition and adjusts the ignition so it runs bad.

The one that turns off the fuel flow pretty much sounds like this:
Wraaababababababababababababababa

The one that turns off the ignition pretty much sounds like this:

Wraaaabababababa BANG babababa BANG The BANG is misfire which often is a cause by the revv limiter since it turns off the ignition on some cylinders.

I'm not sure if I got the think EXACTLY right but that's how I've understood it.

So in options you can therefor choose between 2 different revv limiters and you should be able to set the shift light.

Inputs?
Suggested many times.

I think the ones in LFS right now work just fine. However, I'd like it if we could adjust the limit. :P
Ok, nah just thought of it since I like sometimes to just go as high up on a gear to the limiter and just stay there for half a second then shift but here I don't like it since nothing is happening.
And when drifting you like to stay on the limiter and give out alot of smoke and at the same time like: WHAAAABABABABA BANG BABABABABA BANG BANG BABABA BANG BANG !! Instead of wroomwroomwroomwroom ... Gets boring after the first time
#4 - Woz
You CAN change the point the shift light comes on, just change your cars gearing.

The shift light in LFS is "dynamic" in that it comes on at the point where you get more power by shifting and not at a preset point. So change your gear ratio settings and you can move the shift point.

No you cant move the rev limiter BUT if you could you would soon find that engine damage starts to occur not far past the limit point so there is actualy NO point moving the limiter higher.
Quote from Woz :
No you cant move the rev limiter BUT if you could you would soon find that engine damage starts to occur not far past the limit point so there is actualy NO point moving the limiter higher.

ofcourse I can't move the limiter, that's why I made this suggestions...
Quote from Woz :you would soon find that engine damage starts to occur not far past the limit point so there is actualy NO point moving the limiter higher.

actually i think it would be cool if the limiter were moved and engine damage occured, because then youd have to rev it wisely and it gives you more to think about during a race
Quote from asbjoern :actually i think it would be cool if the limiter were moved and engine damage occured, because then youd have to rev it wisely and it gives you more to think about during a race

that'd be only one thing of a bunch of engine-related stuff. I don't really know about the "bigger" cars, but the smaller road cars' engines are still quite a step away from the real thing. I don't think that a 1.3 would spill out 115 hp at a certain number of revs, still have 1000 more to go until the red line and have the ideal shift-point before. ideal shift-point would typically be AFTER the red line, mostly because power'd peak just a tad before the red line. (the LX4 comes quite close, iirc)

so then you could trade ideal shiftpoint and best acceleration against endurance... and set your limiter accordingly, maybe with the option to disable it completely during race.

as for the limiter's behavior itself: I don't care too much, as I don't want to hit it anyway. newer cars' limiters are very smooth though.
My point with the limiter set by yourself is that you can set it to like 5,000 if you want to shift then etc etc. Not so high that you blow the engine ...
Quote from Bandit77 :that'd be only one thing of a bunch of engine-related stuff. I don't really know about the "bigger" cars, but the smaller road cars' engines are still quite a step away from the real thing. I don't think that a 1.3 would spill out 115 hp at a certain number of revs, still have 1000 more to go until the red line and have the ideal shift-point before. ideal shift-point would typically be AFTER the red line, mostly because power'd peak just a tad before the red line. (the LX4 comes quite close, iirc)

so then you could trade ideal shiftpoint and best acceleration against endurance... and set your limiter accordingly, maybe with the option to disable it completely during race.

as for the limiter's behavior itself: I don't care too much, as I don't want to hit it anyway. newer cars' limiters are very smooth though.

I've race prepared a 1.3l that put out 130hp at 6500rpm, and redlined at 7500. We set the shift light to 7000rpm as that was the overall optimum with the gearing used.

If you don't understand engines or gearing then it's probably best not to try and post technical stuff about them
Quote from Bandit77 :that'd be only one thing of a bunch of engine-related stuff. I don't really know about the "bigger" cars, but the smaller road cars' engines are still quite a step away from the real thing. I don't think that a 1.3 would spill out 115 hp at a certain number of revs, still have 1000 more to go until the red line and have the ideal shift-point before. ideal shift-point would typically be AFTER the red line, mostly because power'd peak just a tad before the red line. (the LX4 comes quite close, iirc)

What's your point? We have a lorry that produces peak power at about 2500rpm but it happily revs to over 4000rpm (due to incorrect gearing). A Series engines routinely put out over 130bhp in historic racing series these days (though they never did in period) and there are claims/rumours that someone got over 200bhp out of a naturally aspirated A Series for hillclimbing. Then of course rotary and forced induction engines can easily produce 5 times the power of the XFG for the same capacity. Capacity isn't what defines an engine.
I'm not saying I have tried every cars limiter but, I have tried more than the average person and I have never come across a rev limiter like the one in lfs. I have come across top speed limiters that behave like the lfs rev limiter tho, but the same cars did have different rev limiters. So the current rev limiter in lfs may not be realistic therefore it should be changed.
Has anyone here experienced a rev limiter like the lfs one?
Also the engine should not be damaged by simply revving it higher than the rpm gauge says is safe.
Quote from eight6er :I'm not saying I have tried every cars limiter but, I have tried more than the average person and I have never come across a rev limiter like the one in lfs. I have come across top speed limiters that behave like the lfs rev limiter tho, but the same cars did have different rev limiters. So the current rev limiter in lfs may not be realistic therefore it should be changed.
Has anyone here experienced a rev limiter like the lfs one?
Also the engine should not be damaged by simply revving it higher than the rpm gauge says is safe.

Nope I havn't experienced one like the one in LFS, that's why I made this thread
Quote from tristancliffe :I've race prepared a 1.3l that put out 130hp at 6500rpm, and redlined at 7500. We set the shift light to 7000rpm as that was the overall optimum with the gearing used.

with a stroke as short as you would get only in bike-engines or a highly optimistic redline?

Quote :
If you don't understand engines or gearing then it's probably best not to try and post technical stuff about them

thanks, tristan, for this piece of advice and how respectfully you put it. can I rely on your omniscience in any other areas of life?

Quote from ajp71 :We have a lorry that produces peak power at about 2500rpm but it happily revs to over 4000rpm (due to incorrect gearing).

yeah, a lorry has of course a very sporty engine set up for max power...
and for the rest: my point wasn't about capacity at all.


Quote from eight6er :I'm not saying I have tried every cars limiter but, I have tried more than the average person and I have never come across a rev limiter like the one in lfs.

Fiat Punto Mk2b just as one example (kind of to prove that there IS such a limiter IRL). Engine runs into the limiter, stays there without bouncing... quite the way we have it in LFS. But - to be honest - I'd expect something bouncey from a somewhat aged car - which LFS cars mostly are.
Quote from Bandit77 :
yeah, a lorry has of course a very sporty engine set up for max power...
and for the rest: my point wasn't about capacity at all.

You've missed the point entirely, a lorry engine has as much relevance to this conversation as what you think the XFG has in it, all we know about it is it is a 1300cc 4 cylinder 4 stroke petrol engine, we don't know anything else about it other than peak power and peak torque figures.
Anyhow, after all this discussion, can everyone agree on that we should get abit better revv limiter sound and revvdrop while it's on the limiter?
I personally would prefer a bouncing rev limiter, because that is what I am used to hearing and feeling in real life, so it would be more realistic to me.
Quote from eight6er :I personally would prefer a bouncing rev limiter, because that is what I am used to hearing and feeling in real life, so it would be more realistic to me.

That's the point with the thread.
With the "BABABABAAB" it's the jumping/revvdrops
Yes, I was agreeing with you.
Quote from Bandit77 :with a stroke as short as you would get only in bike-engines or a highly optimistic redline?

No, 1.3l with a 77.6mm bore and a stroke of 69.7mm, from the late 60s. Could have had more if we'd used a full on race cam at the expense of <2500rpm torque.

Quote from Bandit77 :thanks, tristan, for this piece of advice and how respectfully you put it. can I rely on your omniscience in any other areas of life?

Probably

-----

Most road cars have a crappy bouncy limiter because they're cheaper. Most race cars use a soft limiter, only turning into a hard limiter if you haven't changed gear at the first limiter. But there remains a very large quantity of road cars with soft cuts, and plenty of race cars with hard cut. The current one is actually the ideal limiter, is perfectly realistic, and doesn't need to be changed.
just keep letting on and off the throttle when you get to redline. at least thats what i do
Quote from Sueycide_FD :just keep letting on and off the throttle when you get to redline. at least thats what i do

But we want real revv limiter
#22 - Woz
Quote from Bandit77 :that'd be only one thing of a bunch of engine-related stuff. I don't really know about the "bigger" cars, but the smaller road cars' engines are still quite a step away from the real thing. I don't think that a 1.3 would spill out 115 hp at a certain number of revs, still have 1000 more to go until the red line and have the ideal shift-point before. ideal shift-point would typically be AFTER the red line, mostly because power'd peak just a tad before the red line. (the LX4 comes quite close, iirc)

so then you could trade ideal shiftpoint and best acceleration against endurance... and set your limiter accordingly, maybe with the option to disable it completely during race.

as for the limiter's behavior itself: I don't care too much, as I don't want to hit it anyway. newer cars' limiters are very smooth though.

Ideal shift point has NOTHING, should I repeat that again... NOTHING to do with the redline point of the engine. The ONLY things that determine the perfect shift point is the shape of the powerband and the gear ratios for the various gears.

Create a missmatch between these and the "perfect" shift point will be well below redline.
Quote from tristancliffe :Could have had more if we'd used a full on race cam

Now THAT's a pretty important detail. So your 1.3 wasn't fully optimized and therefore didn't have the characteristic of a fully optimized or at least consistent, sporty small engine.


Quote from Woz :Ideal shift point has NOTHING[...] to do with the redline point of the engine. The ONLY things that determine the perfect shift point is the shape of the powerband and the gear ratios for the various gears.

Ok, maybe my english is soooooo freaking bad. Did I say anything different apart from that you might not want to constantly shift at the ideal shift point if it lies 2000 rpm beyond the redline?

Am I the whipping boy? The more you guys (tristan, woz, ajp71 for the most part) write, the more I realize that my points are valid although you disagree. But I will put on some rose tinted glasses and just pretend it's all because I didn't make my points clear, because finally I don't want to write novels here trying to make my points clear to people who don't want to understand and I don't care about. There's no benefit to me - it won't change MY life or the way I see it.
As I understand it your initial comments were:

1. The redlines are too high for a 1.3 - total nonsense you could produce a 1.3 litre engine that redlined at 18000rpm if you wanted to, likewise you could build one that struggled to rev beyond 4000rpm. Typical redlines for small sporty road engines are probably between 7000-10000rpm, though that is often a long way above peak power/indicated max revs or the rev limiter.

2. Ideal shifting points should come after the redline - If they do then the gearing is wrong
Just to comment on the "realism" of the current limiter ...

My '97 VW Jetta VR6 has a soft-limiter almost identical to LFS' at 6500revs. Also, several CA18DET-equipped Nissans I've driven have had such a limiter, albeit with a bit more POP in the pipes from running stupid-rich.

I think what most people are looking for in LFS is a forceful ignition-cut style limiter. While it's common and widely-used in the standalone-engine-management world, it's not common in standard-ECU-equipped road cars [they use a fuel-cut limiter].

Just food for thought.
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Proper revv limiter
(46 posts, started )
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