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Rev Limiters,
1
(27 posts, started )
Rev Limiters,
Hi,

I know this has been discused loads before, but the rev limiters need to be more real life. Below is a link, of a Lexus IS200 on the rev limiter at standstill.


Video quality is crap (from a mobile phone) and you will need to turn sound up quite loud.

http://www.ajmarsden.co.uk/LFS/Rev limiter_NEW.avi

Cheers,

Copy the above link into your browser!!
How to ruin an engine in 1 easy step. Rev it more than about 3000rpm with no load on it.

If you change gear in time you won't know what the revlimiter is like. Besides, I think there are MANY more important changes LFS needs before we worry about how realistic the rev limiter is.
Ya, hehe, my Bimmer has those Cut-Cut-Cut limiters. My instrument cluster
is fruity (like ALL e30) and i have no tach, at least, i rarely do, so i shift by
ear. Problem is, the car is new to me so i have no idea just how high it revs.
Until one day, i revved 1st until i hit the limiter. I'd call it an intermitent engine
deactivator or something as it's very choppy and doesn't 'limit' as much as turn
off the engine until the revs fall, and repeat. That 2.5L inline 6 is one hell of an
engine, i had no idea it went that high, oh, and the sound when it's up there....
hehe, this is NOT my mother's old '82 320i
Quote from tristancliffe :How to ruin an engine in 1 easy step. Rev it more than about 3000rpm with no load on it.

If you change gear in time you won't know what the revlimiter is like. Besides, I think there are MANY more important changes LFS needs before we worry about how realistic the rev limiter is.

Wont ruin a car if its not there than more than 5 seconds. Most boyracers hold it on rev limiter then dump the cluch to gain a massive wheel spin

Also, Its not done that many miles, and it sure sounds good when its being put right throu the rev range
i think they need to drop the rev limiter by like 1k on most cars, right now u lose all your power about 1k from the limiter and theres no point of having it that high
They sure do. In the video you can see its slightly into red before the limiter kicks in. Just before this limiter is the peek power of my car, so why does LFS have a limiter around 4K past peek power@
#7 - K--
next thing you lot will be moaning that the rev limiters are too low!
you dont have to rev the engine all the way to the limit you know .. you can shift before it cuts power.

Oh and having peak power just before a limiter is poor for racing purposes, when racing you use a rev band which you operate within, ideally this band should have the most average power avaliable. If you have a late peak in power when you change to the next gear your not at optimum power and you've got to climp the power hill yet again.
It is why most boyracers are fooled by there apparent power gain, because there power output is steaper they think they've got more power avaliable.

A typical large bore exhaust system will loose you 20-30 hp in the low to mid rev band if your lucky (quite easily more) and if your really really lucky you might gain 1-5hp near peak power. As i said its an apparent power increase because it feels more violent when coming on cam etc.

Give me a venturi effect exhaust and mild cam any day
Quote from masternick :i think they need to drop the rev limiter by like 1k on most cars, right now u lose all your power about 1k from the limiter and theres no point of having it that high

Rev limiters aren't there to tell you when to shift. They are there to stop engines achieving dangerous rpms.
Quote from Huru-aito :Rev limiters aren't there to tell you when to shift. They are there to stop engines achieving dangerous rpms.

i have lots of DVD's with jap drag racing and lots of the racers there use the rev limiter to tell them when to shift it's fun to bounce off the limiter
I think the rev limiters should be adjustable on the race cars, and simulate bending valves, most small single seaters of over about 5 years ago will not have rev limiters and damage can easilly be done by over reving them.
Quote from masternick :i have lots of DVD's with jap drag racing and lots of the racers there use the rev limiter to tell them when to shift

Unfortunately I don't have DVD's about japanese drag racing, I guess the engines there are different. Normally running against the limiter isn't smart if you're seeking the highest performance possible since a rev limiter cuts fuel and/or spark and because of that the power output tends to decrease. Rev limiters are there to 1) protect the engine 2) limit revs temporarily to a certain level so ie full throttle can be used 3) limit speed.

But since I haven't seen jap drag videos I have no idea what I'm talking about
#12 - JTbo
Again. When you hit rev limiter at middle of cornering, it is same as you would suddenly lift off and floor the throttle pedal and we know what happens then. For me it is just one realism bit more and ppl need to be bit more cautious when racing because of it.

Also it is great sound when you drift, you get nice baning and rattle at corner exit as you will in reallife

Of course if we don't like realism but racing, then there is numerous of things to change, like adding powerups etc...
Quote from K-- :
you dont have to rev the engine all the way to the limit you know .. you can shift before it cuts power.

Oh and having peak power just before a limiter is poor for racing purposes, when racing you use a rev band which you operate within, ideally this band should have the most average power avaliable. If you have a late peak in power when you change to the next gear your not at optimum power and you've got to climp the power hill yet again.
It is why most boyracers are fooled by there apparent power gain, because there power output is steaper they think they've got more power avaliable.

Don't forget that most of these 'boyracers', at least here, have high-revving
japenese cars, hence the 'need' for the limiter. They must use very high rpm
to launch because their cars have no guts and need to be revved at 7000rpm
to get 125hp to push their 2600lbs 'social statement on wheels'. Now, imagine
trying to hold the revs very high at a stoplight...a rev limiter seems only
logical imo. Also, since these engines operate very close to their redline, it's
smart to have a way to protect the engine in the case of a mistake. This is
not a problem in, oh i dunno, a XJ Jeep with the inline6 where all the power is
there almost instantly (over 200lb-ft of torque at 1500rpm is something you
MUST experience to understand), at 3000-3500 it's all over and the engine is
barely capable of revving to it's own redline. It can humiliate many of those
SCC on the first 100feet. Something like 2 cars ahead almost instantly. In
that case i don't see the use or need for a rev limiter.
Quote from Huru-aito :Unfortunately I don't have DVD's about japanese drag racing, I guess the engines there are different. Normally running against the limiter isn't smart if you're seeking the highest performance possible since a rev limiter cuts fuel and/or spark and because of that the power output tends to decrease. Rev limiters are there to 1) protect the engine 2) limit revs temporarily to a certain level so ie full throttle can be used 3) limit speed.

But since I haven't seen jap drag videos I have no idea what I'm talking about

lots of those guys would also have aftermarker limiters that don't get so much so the turbo stays spooled when they are getting off the line

i would post a run or 2 of the DVD's but my internet has been slowed down lots for downloading to much

they also hit the limiter lots when drifting wich sounds great if u ask me
Lol. People who say you can saefly rev an engine for 5 seconds with no load on it amuse me. With no load, the conrods are under messive stresses, and it will NOT be good for the engine.

Also, revving an engine with no load on it (neutral for example), like boyidiots (oops, I mean boyracers) do in car parks tells you NOTHING about a car. You cannot EVER tune a car, or fix a misfire, or diagnose ANYTHING by revving it with no load.

Also there is NEVER an advantage to hitting a rev limiter whilst driving. If you do it just means lost time, never ever gained time (the rev limiter will momentarily cut power, losing acceleration and losing speed. Always always always better to shift before the limiter, although how much is defined by the torque curve (don't look at power curves here, they tell you nothing). You need the torque curve and the gearing to tell you when to shift, and how fast the car will be at any given moment.
Quote from tristancliffe :Lol. People who say you can saefly rev an engine for 5 seconds with no load on it amuse me. With no load, the conrods are under messive stresses, and it will NOT be good for the engine.

i never said it was good for your engine
Quote from tristancliffe :Lol. People who say you can saefly rev an engine for 5 seconds with no load on it amuse me. With no load, the conrods are under messive stresses, and it will NOT be good for the engine.

Also, revving an engine with no load on it (neutral for example), like boyidiots (oops, I mean boyracers) do in car parks tells you NOTHING about a car. You cannot EVER tune a car, or fix a misfire, or diagnose ANYTHING by revving it with no load.

Also there is NEVER an advantage to hitting a rev limiter whilst driving. If you do it just means lost time, never ever gained time (the rev limiter will momentarily cut power, losing acceleration and losing speed. Always always always better to shift before the limiter, although how much is defined by the torque curve (don't look at power curves here, they tell you nothing). You need the torque curve and the gearing to tell you when to shift, and how fast the car will be at any given moment.

The rev limiter is there to stop the engine getting to dangerous revs. You can hold a car on the limiter for more than 5 minuites without it causing major damage. Its more damaging if you hold it when the engine is over reving.
#18 - JTbo
Actually Turbo engines, with proper gearbox can be faster when sifting without lifting throttle, but this is only with high level race cars.

Also we don't have advantage from tires that get hot and wear out, still it is part of realism that makes racing more interesting and same goes with realistic limiters, imo.

Also changing limiter to more realistic setting should not be too time consuming, of course to get it work like in reallife could take some time, but I think it is not too difficult to make code that checks engine speed and cut's off throttle according to it.

You can actually tune lot of acceleration enrichments when revving engine at neutral gear, also I have seen often these motrcycle racing teams when I'm on track and they do adjustments to their engines same way, but those boy racers often don't know what to look when revving engine and probably they don't understand that fine tuning is needed to do on road, it is just rough tuning that can be by reccing on neutral gear.

Drag racers again has 2 to 3 limiters, one is for burnout and it sometimes is throttle limiter, then they have launch limiter, it is specially important with turbo cars as turbo need to be at full speed when launching, then of course limiter final limiter, it is adjusted to bit over shift point on turbo dragsters so they can flat shift without loosing boost.
Of course not all of drag racers are same, but these applys to most turbo engined dragsters that are increasing number nowdays.

After I install new ignition to my car, I will have two adjustable limiters, that is going to be next spring, then I need to start beggin similar system for LFS cars, LOL
Quote from JTbo :Actually Turbo engines, with proper gearbox can be faster when sifting without lifting throttle, but this is only with high level race cars.

Most race engines will be changed with full throttle, obviously doing this requires a fast shift, miss a gear and you'll normally bend a valve, if your unlucky you'll damage the piston (and that means replacing all of them to keep the engine balanced). These cars normally won't have a rev limiter or a sequential box, just straight cut racing gears.
Quote from marsden1002 :The rev limiter is there to stop the engine getting to dangerous revs. You can hold a car on the limiter for more than 5 minuites without it causing major damage. Its more damaging if you hold it when the engine is over reving.

You CAN hold an engine against a rev limiter for 5 minutes WITH LOAD!!!! i.e. in gear, full throttle, road resistance etc etc. Do NOT put a brick on the accelerator, put the car in neutral, walk away for 5 minutes and expect the engine to be 100% (or even 30%) fine when you come back. There is no load on the engine, and therefore the stresses on the pistons and conrods (and the crack) are huge, and whats more, there is no equal and opposite force WHERE IT'S NEEDED.

If you want to argue whether or not revving engines in neutral causes damage, please learn something about engines before trying to argue. Knowing how to bolt one together DOES NOT COUNT. A chimp can bolt an engine together. You have to know the internal processes and stresses to understand what I mean.
I don't think any new car you buy today will crap out from revving it a bit too
high in neutral. Let's not exagerate. At high rpm ok, but in the first half of
available rpm, i don't think you can do any damage unless it's a very sensitive
engine like a hi-tuned version or something.

If you put a brick on the throttle then you are giving it more gas than the max
rpm anyways, so you are basically telling it to go as high at it physically can,
which usually means damage. Hitting the rev limiter in neutral on purpose and
staying there for 5 seconds i agree, you are surely not doing any good.

As for the drag engines, don't those get rebuild after each race anyways ?
As a lot of racing engines do....
Quote from Fonnybone :I don't think any new car you buy today will crap out from revving it a bit too
high in neutral. Let's not exagerate. At high rpm ok, but in the first half of
available rpm, i don't think you can do any damage unless it's a very sensitive
engine like a hi-tuned version or something.

If you put a brick on the throttle then you are giving it more gas than the max
rpm anyways, so you are basically telling it to go as high at it physically can,
which usually means damage. Hitting the rev limiter in neutral on purpose and
staying there for 5 seconds i agree, you are surely not doing any good.

As for the drag engines, don't those get rebuild after each race anyways ?
As a lot of racing engines do....

Well. My foot was flat to the floor, and thats when the RPM limiter kicks in. Dont think this will do damage as the car has only done 5K
Before any race (at least in the UK) each car has to pass a noise test which involves holding the engine revs at half of max RPM for 5-10 seconds in neutral.

If it was damaging to the engine, competitors surely wouldn't be required to do this test when stationary and with no gear selected.

But LFS should have rev limits changed.
The noise test regulations vary. With our F3 car we are required to hold the car at 2/3 of max power rpm (not max rpm), which equates to just under 4000rpm. This is okay. But I wouldn't want to see any engine, tuned or plain, revved with no load any more than that. At least not for any length of time (maybe 10 seconds at the most), and if possible reach that rpm gradually. Do not blip the throttle to high rpms - this is a no no without load.
I don't see the attraction in revving an engine with no load anyway, if you HAVE to do it for a noise test fair enough, but why risk damaging you're engine, increasing wear and make everyone think you are a tosser(the last one is a certainty, not a risk)?

I would like a realistic rev limited in LFS because when I use a shifter, and I fluff a gear change (which does happen occasionally), and LFS has realistic engine damage, I would much rather it cut ignition to 2 cylinders, and top out at whatever RPM, than stretch a conrod/tag a valve going way past its safe loaded limit and ruining my race. This is why they are there on a race car, so that's how it should be in LFS,

LFS should be a racing simulation, not a tool for people to make crap video's of car's blowing up engines, we have a surplus of those already.
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Rev Limiters,
(27 posts, started )
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