How To Race Engine For Preventative Maintenance?

[rd_volvo]

I've read that it's good to run your car at 5000 rpm's
for a certain amount of time once a year to clean out the upper
engine components and keep engine performing nicely.
I have a 5 speed. What's the best way to do this without
harming the engine.

ty
rd
99c70

[rd_volvo]

No, no free revs. On the road.

[geekysteve]

I'd just take it out on your favorite back roads (I prefer the twisties), leave it in 2nd or 3rd and have some fun.

Oddly, most engine stress comes while revving down; like, say you were driving hard, upshifting and downshifting, using the engine to assist with braking - that's when the crank, rods and pistons see the most load...one would think it would be during rev-up.

[dboat]

cheaper to just leave it in first or second and hold it up there on a relatively open road..
Geeky, thats why they say its cheaper to replace brake parts than engine parts... right?
Dana

[bizzy928]

Just make sure your engine is fully warmed before you go WOT.

[Lowejackson]

If most of your driving is stop start stuff it is good to let the engine breathe heavily every now and then. I drive an Alfa, where it is encouraged to drive for a few miles between 4-6000 rpm, particularly after a lot of urban driving. Give it a try and your engine should fell better afterwards. Bizzy928 is correct, let everything warm up first.

[geekysteve]

You got it, dboat - that, and I think the old addage used to be that clutches were more expensive than brakes (with the engine braking issue).

In response to the warm-up before WOT, that's another excellent point (can't believe I missed it), but one note of caution:

Make sure your engine oil is up to temperature - don't rely on the water temp gauge to indicate when the car is "warm". Water heats at about 3:1 ratio than the oil does, so even after your water temp shows "normal", chances are the oil isn't quite yet up to temp yet.

I've found that it takes about 10 minutes of normal driving to get the oil warm and about 15-20 minutes to get it to true operating temperature.

[tetz]

good to run your car at 5000 rpm's

Well, for me that means "drive it to work". Daily.

[IndigoGTI]

Originally posted by tetz
good to run your car at 5000 rpm's

Well, for me that means "drive it to work". Daily.

Amen

[DinosGSR]

I regularly rev my engine on the open road to 5k+ to remind my engine that it's a performance machine

I don't see how downshifting is any harder on the car than upshifting anyway, it's the same only in reverse, and in automatic transmissions, it automatically downshifts as you brake, so downshifting in a 5-6spd is essentially the same thing, as long as you don't rev down from a high RPM all the time, be sure to put most pressure on the brakes. I try to keep my downshifts at the 3k mark every time I down it....such as, at 40mph I can downshift to 3rd without a jolt and keeps it under a good RPM, 25mph to 2nd, and from there I drift to a stop using brakes only with the clutch in.

Assist the brakes by downshifting, not downshifting to assist the brakes. Brake pads are cheap, clutches aren't.

[2wheelsx2]

I think the only problem with downshifting creating a huge load is if you don't blip the throttle to match revs. Shifting heel-toe will always allow you to match revs so it's a non-issue anyway. If anyone is going to be hamfisted and jam the tranny into 1st gear at 30 mph, then it really doesn't matter how good you are with the brakes.

[geekysteve]

Originally posted by DinosGSR
I don't see how downshifting is any harder on the car than upshifting anyway, it's the same only in reverse, and in automatic transmissions, it automatically downshifts as you brake, so downshifting in a 5-6spd is essentially the same thing.....

While you'd think that's true, automatic transmissions have clutches and torque convertors which off-load drivetrain resistance to the motor during "downshifts" and "deacceleration" (under most circumstances). The clutches in the transmission slip, the torque convertor locks or unlocks to help reduce load on the engine...

I used to build NHRA Super Gas and Super Comp motors (along with some IMSA and REMAX circle track motors) for a number of years, and studied engine wear and load bearing effects quite heavily. We had a study that we often referred to that showed that the most rod/piston distortion occurs while an engine is revving down - odd, but true.

So much so, that if you go to an NHRA event, you'll find that the big HP motors go from WOT to closed throttle the second the chute is opened - they usually don't "rev down" while slowing the cars, even from 300MPH where engine braking would be a tremendous benefit. Of course, those engines are already on the limit of durability, so it's a bit of an extreme example.