Technical over rev

[Drinu]

Hi guys,
I have an Uno 45 FIRE and last night I had to do a quick getaway from a side street. While doing so I mistakenly revved it too 7000rpm!! I only held it for 1/2 a second or so! I could smell some burning afterwards! Did I do a lot of permanent damage to my Uno??

Thanks

 

[bulldog5046]

hmmmm.... i know i probably should get it out of my head that if my model nitro car engines can handle 25 - 35k revs that my real car could..... but anywho i really rant my car, i redline 1st 2nd and 3rd on a daily basis, wouldnt suprise me if she packs up on me one day but she really does go for it.

i would imagen doing it the odd time or two is fine, wait for an experts opinion tho, and will no doubt have a go at me lol (probably louie).

Cheers,
Ryan Edge

 

[Fast Finger]

Half a second is nothing.
A red line is basically just the point at which the engine can not SUSTAIN the revs at such speeds. Hitting the limit occasionally should not really do any damage.
Is more to do with the build up of heat and the expansion of the metals which occurs as a result of this.

 

[Drinu]

ok guys,
as long as I didnt do a lot of damage I shouldnt worry!! Thanks for shedding some light on the situation

 

[Louie Bee]

i really rant my car, i redline 1st 2nd and 3rd on a daily basis, wouldnt suprise me if she packs up on me one day but she really does go for it.

i would imagen doing it the odd time or two is fine, wait for an experts opinion tho, and will no doubt have a go at me lol (probably louie).

Cheers,
Ryan Edge

Not in 1st too

I wouldn’t be too surprised if she packs up on you soon either

 

[Luke]

if your cars fuel injected, your ecu will protect the engine from being over-revved. With carb engines, its possible to over-rev them.

If you continually redline, you'll likely find your crank and big end bearings will wear more and go alot quicker than you hope.

Another key note is you;'re doing yourself no favours taking it right up to the redline, the engine power peaks at about 5500 RPM IIRC, and drops dramatically soon after, so really theres no need past 6k...

 

[bulldog5046]

if your cars fuel injected, your ecu will protect the engine from being over-revved. With carb engines, its possible to over-rev them.

If you continually redline, you'll likely find your crank and big end bearings will wear more and go alot quicker than you hope.

Another key note is you;'re doing yourself no favours taking it right up to the redline, the engine power peaks at about 5500 RPM IIRC, and drops dramatically soon after, so really theres no need past 6k...

power peak may be there but the the speed at which your traveling effects the power.

1st at about 20mph into 2nd then to 40-45 at a push into 3rd and take 3rd to 60 then just give up because it doesnt accelerate anymore at a reasonable pace.

i've only hit the rev limiter in 1st a few times and its at about 25-27mph, i could really do with a rev counter to see what i'm pushing it too.

i think it really doesnt help that i still cant get it out of my head that if tiny nitro engines can run at 25-35k rpm that a real can should be able to manage it easily.

sorry my poor uno, she makes me proud tho burning off almost everything that tries even if i have her fully loaded.

 

[Luke]

i think it really doesnt help that i still cant get it out of my head that if tiny nitro engines can run at 25-35k rpm that a real can should be able to manage it easily.

Because of the electrical and mechanical limitations make it a problem. Nitro engines and car engines are totally different. If you was to use a different crank and bearings, change the oil to dry sump (ruduces sump splash), headwork... Alot of modification...

Also nitro's are 2 stroke IIRC, average engine is a 4 stroke so twice as much firing in a single revolution. Note all the mopeds running their 2 stokes sounding like a hair drier keeping up high revs... Same principle as the nitro 2 stoke. The normal engine wont sustain the same kind revs

 

[cm246]

hello there mate the burnning smell might be from the clutch. if your clutch is worn on high revs the clutch cant transfer the power of the engine into the wheels and there is a lot of friction that increases the temp on your clutch hence the burning smell. but dont worry about it

 

[Drinu]

CLUTCH?!?!?!

hehehe Im still on the factory clutch and I am at 60,000km. When would it be time to change the clutch?? No slipping at the moment though. Im SURE about that!!

Thanks

P.S. I know there is no power above 5000rpm but I didnt know that I had already gotten above 5000 all the way to 7000rpm. It accelerated faster than I anticipatedhehehehe.

 

[M@nticore]

yo,check what happend to my uno in my photo gallery when I passed the 6500 RPM mark!!!