revving = losing compression?

[phatfreeza]

hey guys... this should be a simple question... but...back when i first started driving, i revved the car up.. to hear the engine... plus i hear people doing it too.. my dad hears it and tells me not to do that because i'll "lose compression" ... maybe not in those exact words.. but, does anyone have any idea what he's talking about? i dunno.. thanks for any input!

[chubbychu]

lose compression? something about that doesnt seem right. i guess we shall just sit and wait for the almighty people to come in here and tell us whats up...

[civicSIracer]

you will not lose compression from revving your engine. when you have 150+ miles on your car and your rings and seals are toast, then you will lose compression.. a little revving wont hurt her.. just stay off of it when the engine is still cold..

[02NITEHAWKSi EP]

Any good racer or mechanic will tell you it is useless to rev up your engine unless your are racing or doing some tuning. Sitting there at high revs just to hear the pretty noise is just putting unessacery wear and tear on your engine. Loss of compresion is one of those things but not specifically and it happens over a long period of time.

True racers do not rev up just to make noise either because reving up just builds up heat. Higher temperatures equalls less power.

Think twice before just reving up like a ricer.

[jaydub]

<insert F&F line about "any real racer" here>

[sniperSI]

Originally posted by 02NITEHAWKSi EP

True racers do not rev up just to make noise either because reving up just builds up heat.
Think twice before just reving up like a ricer.

Hmmmm, so what about all that reving i hear them do on those f1 cars and rally cars, when i'm watching them race? :)

[trk]

Originally posted by sniperSI
Hmmmm, so what about all that reving i hear them do on those f1 cars and rally cars, when i'm watching them race? :)

yeah lots of folks rev before the track and even at autox I see them do it... I know I do it to get my engine ready for the abuse its about to take...

[mhx]

rpms kill engines :)

[Zero Three Si]

I've heard that when you buy a used car you can get a "compression" test to basically tell you how much engine life is left.

I think your dad is pretty much telling you, don't beat on your car or it won't last you a long time. Fathers do know best!

[civicSIracer]

Originally posted by mhx
rpms kill engines :)

engines arnt made to idel and be driven at 3000rpm.

[streaker666]

Originally posted by sniperSI
Hmmmm, so what about all that reving i hear them do on those f1 cars and rally cars, when i'm watching them race? :)


Hahaha, sorry, I just thought this was funny... F1 engines are not built to last more than 350kms (in the 2003 season, engines were meant to last for the Saturday qualifying session and the duration of the race without major overhaul...however, everytime they get the time they take everything apart and practically rebuild the engine...but this won't be the case in 2004, as the engine must last for the whole race weekend).

Now, the highest rpms a production car right out of the factory is probably at 9000 or 10000 at max...while an F1 engine, the leading group (BMW, Ferrari, and Mercedes) is rumoured to rev at 19000rpm plus...not to mention that exotic metals and alloys are used to build those engines to sustain the super high temperatures. To further discount your comparison to F1 engines to our production car engines, it is said that a leading F1 engine is about 80 to 90 kilograms...can you say that about our cars?...a 19000 redline producting approximately 900 horses that only weighs around 85kg? Those are totally different monsters...aside from the similar basic mechanisms of how engines work, that's where the similarity stops.

Also, every little bit of time a rally crew gets at the service stops they check every moving parts and replace what's necessary...again, these are racing engines that are meant to be serviced at high numbers of intervals...not meant to last like the production engines...

[sniperSI]

Don't be so literal, what i really mean is, A rev is a rev, it doesnt make you more or less of anything if you rev your engine, Hell, If anything it's probably better then driving; your engine is making power w/o the load of the gear box, the wheels, the car weight, its just the engine reving.

The problems it will cause to your engine are alot less then redline the bitch everday, I would bet if just reved an engine rather then drive the car, the engine would never die.

[phatfreeza]

Originally posted by Zero Three Si
...Fathers do know best!

ahahah i guess you're right! thanks for all the informative replies guys! i guess revving is pretty pointless for me cuz i don't auto-x or race or anything like that... learned some neat info.. thanks guys!

[KickerSi]

Free reving stretches the rods (Reving while not moving/ not having a load on the motor). You DO NOT want to stretch the rods or you car will go boom. Just thought you liked to know.

[BarracksSi]

Originally posted by civicSIracer
you will not lose compression from revving your engine. when you have 150+ miles on your car and your rings and seals are toast, then you will lose compression.. a little revving wont hurt her.. just stay off of it when the engine is still cold..

The rings & seals will be toast quicker if you rev when the engine's cold, too.

Race engines are tuned to the verge of exploding, and their flywheels are almost as light as LP records (well, not THAT light, but you get the idea). Most need to be kept higher in the revs because they might just quit if they're left to idle -- something about really hot cams and featherweight flywheels not contributing to smooth idle behavior.

I hadn't heard about revving without load being bad for the rods, though. Makes sense, though -- lost of mechanisms, from lifting weights to boiling water, are based on resistance. Lift without weights, and you'll either hurt yourself or not get very strong; put an empty pot on a gas stove burner and you'll melt the pot.

[MolonLabe]

BarracksSi is correct--even with powerful (by car standards) computers managing the engine functions, an F1 engine idles very high, and they are still finicky. A carbureted NASCAR engine hardly idles at all, mostly due to the carb, heads, and the insane cams that they use.

On the Si, in the short term, I kinda doubt that you can hurt the engine too much with free revving. We have a very good lower end and, for example, the Hondata gives you an additional 500 rpm with no decrease in reliability over the life of the car (as far as anyone has found out so far! These are still pretty new cars). It can't be good for the car, but you probably aren't destroying your engine either unless you just started it and all your oil is still in the pan. Doh!

:cool:

[02NITEHAWKSi EP]

02NITEHAWKSi EP reving up just builds up heat. Higher temperatures equalls less power.

This is true in drag racing. These engines are made to run for a few minutes at most. Due to all the wight restrictions and power losses by carring water and a cooling systesm, its a good idea not to build heat. Heat also just sucks the life out of horsepower...example intercooled vs. just a plain turbo. It's mostly in the application.

I just made my F & F comment because I laugh everytime I see a ricer at the track just reving the crap out of their car in the lanes before lining up. Then they get to the light and they still reving and building up heat that kills their ET due to loss of power.

Why am I the only one mentioning heat? F1 cars also have big air intakes and go quite fast so enough air is cooling the small cooling system and air cooling the eninge as well.

[BarracksSi]

Heat, mainly in regards to incoming air, is the enemy of power production.

But, race engines aren't going to be asked to last for 200,000 miles, either. And, with the exception of drag motors that get torn down & rebuilt every run, race cars will still warm up on the grid for a while AND run a warmup lap or two before the race itself. They don't want to beat the snot out of their engines by not having warm, smoothly-flowing oil.

So, the way I see it:

Heat robs power.

Generous oil flow, aided by a warmed system, makes engines live longer.