rx7 SE

iTrader: (5)

So I've been in the rotary world for over 10 years now and adopted the method in high school of warming up the car in the driveway before driving it. I never really questioned why, I just saw other rotary owners doing it so I thought that was good for the car.

Recently I was reading through my BMW's owner manual and read that it said the proper procedure to warm the engine up was light load driving and not let it idle. So this got me thinking (knowing a lot more about engine dynamics now then in high school). I'm sure everyone who's been to an rx7 meet knows that once you start hearing the engines roar to life, you've got about 10 mins before anyone is going to go anywhere lol. But I'm thinking that technique really isn't in the best interest of the engine, I think that letting the oil pressure build up and then quickly transitioining to light load driving like piston motors require is also the proper way to warm up a rotary. The engine will get to operating temps quicker with a neglible amount of load on it.


Thoughts and opinions on this?

4g63rotary

iTrader: (5)

It's what I do with all of my cars but mainly because I lack patience, when I had the 8 I would drive at 2k rpm until it warmed up then went from there, it was recommended on the 8 forums several years back by a member. With that said I wouldn't know in all fact and honesty if benefits the motor at all. All I can say is the 8 in particular ran well up to the day I sold it at 80k miles which I suppose isn't really all that high by today's standards. I am interested in what some of the more experienced have to say on this.

Monsterbox

iTrader: (6)

The short answer is that it doesn't really matter

There's a million other things that will have greater impact on legivity and reliability than whether your car sits or moves during warm-up.

My first 13b went over 90k miles, making 330rwhp and is still running to this day. I'd let it sit and warm up to 160F before moving it.

My next engine, made over 500rwhp and I beat the crap out of it, even getting into boost at only 140f. No issues.

As long as you wait until water temps and oil temps are up before giving it hell it really shouldn't matter how you warm it up


Side Note:

You'll warm up quickly if you're moving, and therefore waste less fuel...maybe thats BMW reasoning?

j9fd3s

iTrader: (3)

long warm up wastes fuel. the engine is also running extra rich, with no real load, so you are kind of washing the cylinder walls/rotor housings with gas, which isn't great.

i live in CA, so our coldest is like 30F, i just start the car, put my seatbelt on, and drive slowly down the street.

the engine is perfectly capable of running a light load before its warmed up completely, so those long warm ups don't seem to have a point

rx7 SE

iTrader: (5)

Yeah I think we're all thinking the same thing so far. Gonna try light loading the engine for warm ups from now on.

unwritten-dinasty

I turn engine on, put on my seatbealt, turn radio on and put some music, drive.

James93A

Haha I like your technique Dinasty. That's about the same process for me.

j9fd3s

iTrader: (3)

sometimes its just a car... you drive cars.

Ravell

The reason it's often recommended by manufacturers to avoid warming up an engine by letting it idle is twofold. Firstly the driveline components are not warmed up by letting the car idle. Things like gearbox, differential, wheel bearings and cv joints.

But more importantly, the oil pressure doesn't reach its ideal level till about 1500 rpm. Letting it idle when cold, especially on older engines, can leave the top end of the engine with too little lubrication.

Whether this is also an issue with rotary engines I'm not sure. It depends on the oil pump performance, oil viscosity when cold and what's being lubricated, since there is no valve train to worry about.

Tom93R1

iTrader: (2)

Back in the days of carbs it could be a real pain in the *** to try and warm up a car by light driving. Pretty sure that's why warming up in the driveway became common practice.

With fuel injection I don't do any driveway warm up whether it's 0 degrees or 110 degrees out. Just take it easy until operating temps are reached.

j9fd3s

iTrader: (3)

lol, i was going to point that out. the P port does actually want a little warm up time, although even that, with no choke on the carb, and a locked distributor will idle @900rpm after about ~40 seconds.

JSmall

I don't drive my FB that often.. But when I do, I tend to start it up, check under the bonnet to make sure everything is as it should, get in the car and drive off. Takes less than a minute.. Driving lightly until its warmed up obviously.

Vicoor

Or in other words let it run about 30 seconds or so then drive. but keep the RPMs and loads down til it's got some heat in it, and don't blast til it's fully warmed up.

unwritten-dinasty

I have my Adaptronic set so it wont go past 3k rpm until 70c water temps is reached so i cant put load or blast it till its warmed up lol.

96fd3s

I turn it on and drive it straight away. Every day, multiple times a day. I don't let it idle whatsoever.
Just take it easy till its warm.

Barry Bordes

Think very thick oil.... like honey.... being pushed not just to the gauge sending unit location at the rear of the engine but through the alignment sleeves forward to the front bearing.
This is probably the most critical area for cold oil to get to. This will show up as wear on the front main bearing.

But like most I start mine and begin moving within a minute. My mechanical gauge shows that the pressure relief valve opens at 110 psi.
With cold oil it peaks early at about 1500 rpm. As the oil temp comes up this relief valve peak pressure is attained at higher and higher RPM.
I try to not hit this relief valve pressure as I warm the engine. This would be about 65*C oil temp if you have a oil temp gauge.

Barry

scotty R

iTrader: (13)

i recently was told to get in , put the seat belt on and start driving, letting it idle just seems to build carbon and driving it lightly will not hurt a thing as long as your not peeling around front a cold start.

i live in a sub division so i try to be a bit courteous to my nieghbours but usually by the time i get to the highway maybe 5 min down the road things are pretty warmed up and ready for some pulls

Barry Bordes

Yes and the slow-drive through the subdivision is also the perfect scenario for engine cool-down after boosting.
Barry

peejay

That's bunk. Cold oil will peg the oil pressure gauge on most cars at cold idle. You're not going to flow more oil than that.

My rotary warmup is to blip the throttle until it's warm enough that the plugs won't foul then drive away. Not to exceed 3000rpm until idle oil pressure drops below 60psi.

My piston engine warmup depends on the air conditions. If the windows are fogged up, need to build engine heat before driving off. If not, just drive the thing. The OEMs test engines by cooling them down to ~15F and then starting them, whacking them to peak power as soon as they build oil pressure, run at peak power until hot, then they shut it down, flood it with cold coolant (yes... into a hot engine!) until it is down to ~15F again, then repeat the process... for hundreds of cycles. Nothing I am going to do is going to duplicate that.

One of my friends would warm up his Zetec-engined car by doing a big long burnout out of his driveway, dumping the clutch as soon as the engine caught. The engine never complained but the transmissions did