RX7withNitrous

y don't you guys just use the turbo timer for what they are meant to be used for instead of using it to warm up your car for 10 minutes.

SoCalLove

Agreed. Doesnt hurt to release the lock a block or two before you pull into your garage.

And I heard that the AWS might hurt the engine. Due to the lack of oil on cold start ups (sorry, don't know much detail on that) and the stress on a cold engine. But anyhow, I just turn the car on in 1st. The AWS is just to warm the cats right?

Also on warming up, I let it warm up for about 2mins, then do light driving/no hard revving. 2mins good? I don't have a temp gauge yet, and I've been reading it takes awhile to get to op. temp.

RonKMiller

The only reason the AWS is there is to get the pre-cat heated up quickly. Blip the throttle on start up to defeat it. There is nothing worse in the universe than racing a cold engine to "warm her up", or letting it idle cold at 3000 rpm.

redrotorR1

Cold starts usually refer to shutting down and re-starting the engine before it has reached normal operating temperature. Yes, rotaries are sensitive to that. But, letting the engine rev to 3K rpm for 30-45 secs ... how is that any different that your light driving for the first couple of minutes? Technically speaking, yes, the AWS is doing small amounts of damage by revving high upon startup ... but, it's infinitely less damage than, say, driving WOT right after you start the car. And you are right about the AWS; it is there to warm up the cats (pre-cat and main cat).

Your stock temp gauge is good enough to tell you when the car is warmed up. It's bad at telling you when the car is overheating. Usually, my car takes about 5-10 minutes (depending on the weather).

pomanferrari

iTrader: (1)

I agree with you on these points for the stock turbos. However, for single turbo such as a T-78 that doesn't have a coolant line, a turbo timer should be used...

Rotarius

I got a Greddy TT and I started noticing that sometimes while turning the key to crank the engine the would be a .5 second delay for the starter to crank; a friend of mine has a greddy TT to on his GS-T and he told me that he was experiencing the samething before until one day his car would not start, he had to rip the wires on the harness to plug everything like stock and then he was able to crank his car up. Anyways, I unplugged my TT and so far that .5 second delay is gone. For my 7 I will drive slowly before reaching my destination and turn the fan on and let it idle for about a minute before shutting the engine off.
Anybody interested on a skeleton red Greddy TT with a FD (only) harness barely used in the box with instructions $70.00

Hyperite

As for your Greddy timer, do some research. Two of the wires are different for our American cars versus Jap which it is designed by and for. I recall R1 and R2 needing switching, but that could be my funky memory. I've got an HKS, no problems. I let it automatically decide how long to idle.
~Tom

RonKMiller

ALL engines are sensitive to cold starts - it's where 90% or more of engine wear occurs.

Driving immediately and gently after starting places a load on the engine and creates heat - lots of it. Heat is a good thing for engines, it's where all of the sealing surfaces are in agreement with each other and the oil is flowing at a constant rate. It's known as a steady state. The sooner everything inside is "happy" and warm the less wear you have.

High revving cold starts are HELL on engines - worse than anything you can imagine.

I always cringe when someone starts their car and revs the **** out of it to "warm" it up. It's what your Grandfather did. Your Grandfather was mis-informed about a lot of things.

I ALWAYS drive at least 20 minutes before boosting - it takes that long to "heat soak" the entire engine and components, much longer in cold weather.

redrotorR1

Ok, let's set this straight first. I'm not trying to flame you ... we're just in disagreement about a simple situation. First off, starting the car places a load on the engine ... in fact, the activation energy required to start the engine is higher than the kinetic energy required to keep the engine running. So in terms of heat transfer, it doesn't make squat of difference. And this sealing surfaces in agreement thing ... really, heat transfer in a closed environment is mainly about convective transfer, not conductive, as everyone likes to think. So in essence, the only thing that matters for this particular situation is the heat conductivity of the lubricant ... obviously the oil. (If you don't believe me, I'd be happy to recommend a couple of textbooks that I've been forced to study.) Your own statement that "the sooner everything is happy and warm, the less wear you have" is already contradicting what you previously stated. Well, isn't that what the AWS is essentially doing ... getting the engine parts "happy and warm" as soon as possible?

Yes, high revving is bad for cold engines. But, for a shaft and combustion surfaces that are made to withstand the pressure and heat transfer that happens at 7500 rpm and 120C, do you really think that these parts wear down because of cold start revving to 3000 rpm? Think about this ... if this were as detrimental as you think it is, your engine wouldn't last longer than 1,000 miles. I agree that, in the long run, the AWS will eventually wear down parts ... but I think the user will either A) run too lean, B) overheat, and/or C) wear out the carbon seals in the turbos by not cooling them down properly, well before the AWS kills a part in the engine.

And, I apologize for being such a pedant. Engineers are like that.

Mr. Stock

Turbo timer is a waste of money, in my opinion.

BTW, T-78 has a dry core? Are you sure about this?

RonKMiller

No apology necessary, we actually agree on everything.

The only thing the AWS does is allow the pre-cat to heat up faster in order to reduce cold start emissions.
That's all, period. It does not allow the engine to heat up any faster.

The pre-cat was and is a stupid idea, put there by Mazda ENGINEERS (j/k)
just to satisfy our federal emissions ****'s in their quest to make new vehicles run clean from the instant they start - to hell with the fact that the engine will wear out faster - MUCH faster - and that the incredible underhood heat generated will waste many expensive components way before their time.

The feds should have taken the money required to run the agency and bought all the old smoking junkers on the road instead. It would have been a better use of funds and would result in cleaner air. (which, btw, I am for big time - my wife drives a SULEV. Somehow, the Honda engineers finally figured out a way to make the air coming out the tail pipe CLEANER than the air going in the intake - now that's engineering.) Of course, 13 years of progress, better fuels, and microprocessors that are several thousand times as fast have a lot to do with it as well.

OK, now I feel better...........the interesting thing is that many new cars now have up to 4 cats. Wow.

I don't build 'em, I just fix 'em...and fly 'em.

A pedant? Better than a pedophile.

But, back to the original thread. Turbo timers are as usefull as a screen door in a submarine. They fall in the same category as a/f meters and egt sensors. Just more useless junk to clutter up the dashboard.

IMHO.

vudoodoodoo

I just sit in my car for a few minutes. I don't use that TT for that. Then I shut it down, turn the key to IGN, turn on the TT, set to 10 minutes, take out key and leave.
This will keep the fan on for 10 minutes to cool down the car more. Sorta like that fan mod.

rotary-tt

Here's some more engineering for you. Having a high delta t (temp differential) is bad. Ever take a glass from the freezer and put hot water in it? Snap\crack!. High temp differential in a motor is not good either. On a rotary where it is made out of dissimilar metals it would be more of an issue.

The AWS is for the pre cat. I just immediately blip the throttle to bring it down to a reasonable rpm. Then I drive the car immediately with no boost. I don't boost until the car warms up and the idle drops to normal.

I am my own turbo timer. I just let the car cool down by driving unboosted for a minute or 2 before shutting it off. If I was boosting hard I may let it idle for a minute or two and I open the hood. If the car is that hot I force the cooling fans on also. I'm working on wiring a turbo timer to just turn on the cooling fans, not the motor. I already do the 1-2 min cool-down manually. My switch to synthetic oil makes me worry much less about coking up the turbos.

fluxen

Ron, I can't see the logic in what you're saying here at all. Let's start with the turbos.

You've got these wheels spinning at enormous rpms, genrating a lot of friction despite their design and the massive temps to go with it. The fact that they spool down within seconds doesn't do anything to reduce the heat in them, it takes flow from the oil and coolant to remove that heat and bring the turbo down to a reasonable level. I'm interested in hearing a different view of that, if you have one.

The general temps: Of course your temps in the combustion chambers go down when you turn the engine off; as we know there are controlled *explosions* going on in there with the engine running. But, that doesn't mean turning the engine off is the way to prolong engine life.

When I do my track events, we're running in the 5000-8000 rpm range for 30 minutes straight. We come off track and my coolant temps are about 114C. I park the car, and I leave it running with the hood up. If I shut it off at that point, temps in parts of the engine are going to skyrocket, with the likely conclusion being deterioration of the coolant seals in the motor. It takes my car 10-15 minutes to cool down to a coolant temp of 85C or so, which is where I'm comfortable turning off the engine. So basically, I'm disagreeing with you when you say "You can let it idle all you want but more then a minute or two is not going to cool it down any more."

Does idling it that long cause wear on all moving parts in the motor? Sure. Is that amount of wear less critical than the damage to the coolant seals caused by turning the car off at 114C (237F)? I sure think so...

redrotorR1

The glass example is primarily due to the anneal temp of SiO2 (sand ... glass) whereas Al and cast iron (Fe2Al ... damn, where's my materials book when I need it?) has a much higher anneal temp. Good point, nonetheless.

RonKMiller, thanks for the backup. And nice poke there about the Mazda engineers ... d'oh!

Lastly, turbo timers are simply a convenience device ... any way you look at it, it's your $100.