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Discussion Starter #1
I know this is probably more suited for the drivetrain threads but i noticed theres not alot of action there, so I figured I'd post this up here.

I drag race my 90 SC automatic weekly. I'm having a great season (5 wins so far, leading the championship points in the street class) but as the rounds go on into the night, we get less and less cooldown time. I'm sure any of you guys that have ever bracket raced your SCs or XRs have noticed that the hotter they get, the slower and less consistant they get.

The last 2 races I've competed in, I've been in the final round, and in order to get some additional cooling, after then run, i've been turning onto the return lane, getting the car at about 30 mph, putting the trans in neutral, then shutting the car off and coasting the 1/8th mile back to the timing tower.

Until now, I havent really thought about it, But in past experience towing with a car dolly, I've known not to tow an automatic in "N" with the drive wheels touching the ground (turning.)

I just want to make sure my occasional 1/8th mile coast with the car off doesnt take the tranny out of my car and ruin my season. Thanks for the help!
 

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30mph for 1/8th mile won't kill the trans, especially if it is sitting and cooling down immediately afterwards. The reason they tell you not to do that is because when the wheels are turning, the parts inside the trans are moving, but the pump is not, so the parts are only lubricated by the fluid that is still in that area. Friction will heat up that fluid, and that heat is what causes the trans to fail. But that won't happen within the short distance you are talking about, and at the slow speeds you are talking about.
 

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Discussion Starter #3
30mph for 1/8th mile won't kill the trans, especially if it is sitting and cooling down immediately afterwards. The reason they tell you not to do that is because when the wheels are turning, the parts inside the trans are moving, but the pump is not, so the parts are only lubricated by the fluid that is still in that area. Friction will heat up that fluid, and that heat is what causes the trans to fail. But that won't happen within the short distance you are talking about, and at the slow speeds you are talking about.
Thats really good news, because it may seem like a little thing, but coasting from 30mh down to almost nothing at the base of the timing tower cools the car off whereas driving 1/8th mile at 20mph puts more heat in the car....the car is dead nuts consistant when its cool....i ran 2 passes last week where the car ran right on the number, only thousandths of a second difference. Thanks Mike!
 

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It is not my intention to hijack the thread but I have a slightly similar question.

Occasionally I'll throw the car into 3rd or 2nd (depending on how fast I'm going) to slow the car down a bit to prevent my needing to use the brake pedal (IE, today I was bedding in new rotors and when I was trying to cool them off I wanted to use them as little as possible before getting home). Is engine braking harmful to the transmission or engine in any way? Should it only be done when normal braking isn't enough?
 

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It is not my intention to hijack the thread but I have a slightly similar question.

Occasionally I'll throw the car into 3rd or 2nd (depending on how fast I'm going) to slow the car down a bit to prevent my needing to use the brake pedal (IE, today I was bedding in new rotors and when I was trying to cool them off I wanted to use them as little as possible before getting home). Is engine braking harmful to the transmission or engine in any way? Should it only be done when normal braking isn't enough?
Don't worry about it.
 

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Even though I do it myself a lot in my daily driver Eclipse, Ive always heard engine braking is hard on the engine.
Ive also heard this was bad. A couple of my friends are into the honda scene, and they dont downshift, or engine brake. Like coming off an offramp or stop light they just throw it in neutral and use the brakes to slow it down.

Is engine braking bad for the motor/tranny FWD or RWD?
 

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Engine braking in a manual and engine braking in an automatic are quite different, as there's a fluid coupling rather than a friction clutch taking the brunt of that "extra wear" people always associate with engine braking.

I've been engine braking my bird for years with no issues to speak of. Totally stock (except for J-spec separator plate, but we're not talking about shifts), ~130K mi. Don't even have a trans cooler on the thing. Just be careful about extreme gear differences...you don't wanna downshift from OD to 2nd (ever), or downshift into 1st at 60 mph.
 

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I've been engine breaking all my cars since I've been driving and my father as well. He or I has never had one transmission problems. Again like said above just use some common sense and never every go from OD to 2nd and you'll be fine.

Engine breaking is also fine in a manual and really doesn't wear part if done correctly, which means you need to rev match your down shifts.


To the OP not sure if you’d like to take this much of a step but a very good way to cool after a run is installing an electric water pump and a manual fan over ride switch. This way you can turn the engine off but keep the pump and fan running. Plus as an added bonus the electric water pump will free up a few extra hp compared to a mechanical one
 

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Discussion Starter #10
To the OP not sure if you’d like to take this much of a step but a very good way to cool after a run is installing an electric water pump and a manual fan over ride switch. This way you can turn the engine off but keep the pump and fan running. Plus as an added bonus the electric water pump will free up a few extra hp compared to a mechanical one
thanks 4 the ideas, but im trying to keep the car stock, its in beautiful condition, so i want it to be a "survivor" car someday. im just having fun bracket racing it for now.
 

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Engine braking in a manual and engine braking in an automatic are quite different, as there's a fluid coupling rather than a friction clutch taking the brunt of that "extra wear" people always associate with engine braking.

I've been engine braking my bird for years with no issues to speak of. Totally stock (except for J-spec separator plate, but we're not talking about shifts), ~130K mi. Don't even have a trans cooler on the thing. Just be careful about extreme gear differences...you don't wanna downshift from OD to 2nd (ever), or downshift into 1st at 60 mph.
safety measures prevent this. If your doing 80kph, and throw it into first, it will downshift into 2nd, and once the speed drops below 30kph...or 20kph(i think....cant remember off hand) it will downshift into first and damn near slam your head into the wheel lol.

but seriously, there are safety mechanisms to prevent hard down shifting like that. it would lock the wheels up immediately if you went from 3rd to 1st directly.
 
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