How warm before High RPM, Boost?
 

What are the guidelines to prevent pre-mature wear or failure of engine / drivetrain during cold weather. I am using 0W-40 oil.

Presently I do limit RPM's according to CLT, but full boost is still available, right from the start.

Should I be using restraint until at full operating temp? By full perating temp, I would mean anything over 180*F, based on use of such thermostats by those who track and race.

I only use WOT after my Oil Temperature has reached at least 70´s and water 80´s.

I also have Rpm limit according to CLT in case but I use good sense to not use full boost ;)

Just personal opinion, but I never, ever, no matter what, ever, go past about 10-15% throttle until completely warmed up (needle dead in the middle). Boost is not even in question until that point.

Its extremely harmful to put stress on a cold engine, that's when the most wear happens

And on the flip side, I've never warmed up any car I've ever owned - street or strip. Stupid? Maybe. Hasn't burned me yet in 26 years of owning cars.

Agreed - I don't "warm it up" either, and don't see any need to sit there and idle it wasting time and gas.

Many seem to agree :party:

Yeah, but I've always flogged on 'em right away as opposed to your approach stated above.

I do this as well. I never get to the autocross early enough to get an early run group, and never have time to warm up the car in the paddock. Start it up, pull up to the starting gate, flag, and into boost.

I back into my garage at night so that I can hit boost pulling out in the morning.

Not that I recommend this to others, but it seems to work for me.

I follow the warmup plan outlined above. Nothing gets it warm like boost. I don't use coolant based limiting, either.

I too use 0w-40, which I like to think helps.

:laugh: now that's pretty boss right there

Wuss. Real turbo Miata owners hit full boost in reverse!

--Ian

the faster you boost, the quicker the pistons warm up, the less time it's running out of tolerances :P

This I can add. I spent a lot of time tuning EAE temp compensation holding AFR's during any boost / temp scenarios I might encounter. So, the car doesn't feel cold even when it is. When I was N/A, it felt like it was stiff when cold, so warming it up with gentle driving seemed natural.

The manual says crank, wait 10 seconds, drive. I didn't see anything else about taking things easy. But that is N/A.

As far as boost warming things up. If I am at 160* CLT and make a single boost run up to 6K, CLT goes straight to 190*. Braineack and Deezums are 100% right about that.

I remember when Scott also said that he boosts in the driveway, so I kind of thought he might have that perspective.

Like so many other questions, many answers.

I think I will tend to leave things as they are, which is to say be more concerned with low temp RPM than low temp throttle; not go crazy with cold power, but not beat myself up if I feel the need to punch it.

In for more thoughts / experiences.

Coolant temp is irrelevant. The arguments about not romping on it when the engine is cold have to do with oil temperatures, because cold oil is thicker and thus has a harder time making it through small orifices into the bearings/etc. Oil temps lag coolant temps substantially during warmup.

How significant this really is with synthetic multi-weight oils on a modern street engine, I have no idea. BMW cared enough about it to have a variable redline on some cars based on oil temp. Real race cars have external oil pre-heaters that get run for a while before they start the engine.

--Ian

120° oil before applying full load or high rpm. Coolant temp doesn't really matter unless you WUE is set crazy rich and you are worried about washing cylinder walls. Most engines have long since opened the tstat by the time they have 120° OT.

Emilio, I presume the tstat you are referring to is the coolant tstat, and therefore are saying that even Vlad is not being conservative enough, i.e. waiting for coolant to come to temp may not be enough to get the oil to 120*, which is the important criteria.

If so, I'm also hearing that pulling the "oil heater" hoses off the engine, a common practice, may not be the right thing to do, as far as warm-up is concerned.

I spent a handful of years working in a machine shop building prototype surgical tools and short production runs of exotic weirdness jobs my boss would quote. I'm not an engineer or a metallurgist, but I have seen first hand what thermal expansion does to things like aluminum. For that reason alone, I warm up my car in the morning.

I'll also be leaving the stock Miata oil cooler/preheater in place when I build my engine. Some people remove it as a "failure point" but its something I'm willing to tolerate for perceived benefits.
^^ Emilio gets it. I know you can set up a custom limiter in the MS3 if you add an oil temp sender to it, or you can add a low temp indicator light as a visual warning and use the big limiter between your ears ;)

I wait for oil temp to hit 180. I try to stay out of boost until then. Maybe conservative but with forged pistons it makes me feel all warm a fuzzy to know they are expanded a bit before I bring the pain.

This is my approach, although my oil cooler thermostat is a tad enthusiastic and, with street driving, it takes a long time to get past 160. I'm thinking of covering it with a blanket for street use.

Definitely most ideal to watch oil temps
However, for those of us with street cars, we gotta settle for water temp gauge :(

[QUOTE=EO2K;1188775]I have seen first hand what thermal expansion does to things like aluminum. For that reason alone, I warm up my car in the morning.

I have to agree with EO2K about thermal expansion, the piston expands before the head, which expands before the iron block. If you don't wait until your oil is around 150 or your street car is fully warmed up, your pistons will loose some of their clearance with the block and wear prematurely. Possibly leading to piston noise :vash:

Adding an oil temp gauge isn't all that hard. Alternately, if you have a real oil pressure gauge you can tell when the oil temp has come up because the pressure drops at idle.

As for the factory oil warmer -- I've had two of the stupid teeny coolant lines fail on me, one of them dumping all my coolant out at Laguna a few years ago, costing me a track day and a head gasket. They're gone, and good riddance.

--Ian

I have had lots of cars over the years. I have never warmed them up; only made sure oil pressure was up to normal. After that, I flog them like I stole them.

In all this time, I have never worn out an engine before corrosion destroyed the rest of the vehicle. No sense in having a pristine 100k+ mileage motor in a rusted out hulk. Maybe if I lived somewhere that salt & snow wasn't a factor (or it was an expensive exotic) I might treat them better. But I've never had an internal engine failure due to wear, so I'll keep on beating on them.

But you live in Rochester, where they rust out cars in 3 years. :) Come down south were my 25 year old car doesn't even have a lick of rust.

I drive it gingerly until the water temp comes up and add a minute or two before I flog my street cars. Autocross cars I try and do the same, but it's not as easy to do. Full power or RPM while cold is a good way to screw up the pistons.

Happens all the time in the watercooled 2 stroke world. Cold engine, full throttle, piston warms up and expands, cylinder still cold, piston literally sticks in the bore. Complete lockup.

Deviate has a 4000rpm rev limiter set for something like 140° clt. I'm pretty good about short shifting the first few minutes on my own but every now and then it catches me. Even then, I won't use WOT or high revs until the tstat is fully open to guarantee I have some OT. Deviate has no gauges beyond OEM. The race cars all have OT gauges.

On a Mazdaspeed Miata the Check Engine Light will come on if you flog it before it gets up to operating temperature.

I believe the new Focus ST has a low temp indicator as well.

The vast majority of modern ECUs on boosted vehicles also pull timing or dump boost until some thermal setpoint, usually CLT (probably because CLT sensor is already in place.) Hell, the econobox Nissan rental car I had the last time I was in AZ pulled timing until the low temp light went off and it was a tiny NA engine.

Anyone know what this is?
https://www.miataturbo.net/attachmen...ine=1418320691

Its a thermal vacuum switch. Its screwed into a water jacket on the intake manifold of my 390FE powered 1974 Ford F250. When the coolant is cold, its job is to block off the vacuum signal that goes to the vacuum advance diaphragm in the distributor thus prevent any timing advance beyond the static base timing. Once the coolant in the block reaches about 140° it opens up and allows the timing to advance based on manifold vacuum. (Yes, part of this is for emissions reasons but these devices date back much much further than emissions compliance.)

As you can see, this is absolutely nothing new. I'm happy to follow the trend.

Correcto-mundo. On dbw cars the throttle mapping acommodates temps, and you basically "can't" drive the car hard when its cold even if you tried.

If you don't heat the oil up and rev it, the bearings will not last long. It's not so much the boost than the RPM that matters. At the race track, you go out on a cold engine and rev it, you most likely are coming back on a tow truck. Drag strip is no different. Now for drag strip, some of those guys run on special lubes (no oil sometimes) so can't really follow that.

I have a 50C rule for a cold engine.
The oil has to get up to 50C (120F) before I rev or boost it.
Luckily, I have almost a whole mile of downhill narrow streets before I get to the main road. I just start and roll down the streets at idle, the engine warms up by the time I get to the first light.
Then I flog it.

Would you happen to know the CEL code that comes on?

I implemented a "trick" today. I set Decel Fuel Cut to start at 175 CLT temp. So, without a real gauge, or any lights, I can at least know when the CLT is at that temp by lifting the throttle. If the AFR goes full peg, indicating Fuel Cut, then I know the CLT is at that temp. More definitive than the OEM temp gauge.

#Threaddrift

Duuudee! Pics of your dentside. Nowww. I've got a 72 F100 with a 360FE.

What I did when I drove mine everyday, I just knew that say, it's 90*F outside when I crank for the day, it takes 5 min of my normal driving to get up to temp (coolant), if it's 30*F, make that 8 minutes. I would assume that with the factory oil wamer/cooler, oil temp probably lagged coolant by a little as the engine is warming up. I would generally give the car about 1-2 minutes of idling, then 2-3 minutes of normal driving before finding the rev limiter. Can't really say this "worked", I broke a few engines during this time, but I can say that all of them were bent rods, cracked piston, dead rings. None showed any meaningful bearing wear.

Under non-turbo-in-boost conditions most of the oil temp in a BP is from friction. I have both coolant and oil temp (measured at the filter, the hotter location) gauges in my car. During warmup, oil temp lags coolant temp by about 50F. When it's <40F ambient, oil might lag by 60F during warmup. But regardless of ambient temp, within 3 miles of freeway driving the oil is warmed up. At 3k rpm, it only takes about 90 seconds of running after the stock temp gauge reads normal for the oil to be fully warmed up.

Mobius,

Sounds like my 175* H2O is a good goal, then. Oil should be close or over 120* at that point. Thanks for the feedback.