Things About Your FR-S/86 You've Grown Used To

[humfrz]

Originally Posted by RickyRacer

would it actually be safe for me to turn off my engine to engine break?

I want to try this just to feel the difference you are alluding to

But i dont want to wreck my car lol

OK, if you don't want to use your power steering or brakes -


humfrz

[Tcoat]

Originally Posted by RickyRacer

would it actually be safe for me to turn off my engine to engine break?

I want to try this just to feel the difference you are alluding to

But i dont want to wreck my car lol

Don't do that. The ECU does almost nothing during engine braking.

[Jordanwolf]

Originally Posted by Tcoat

Don't do that. The ECU does almost nothing during engine braking.

"One dead in car accident. It was believed he shut off the car while travelling at a high speed. City TV news."

[Adam_L]

Originally Posted by DarkSunrise

Yeah my understanding was that engine braking was dependent on CR and multiplied through the gearing. But your comment got me thinking about the CR part and whether that's true. Turns out when the engine is off-throttle, it does slow the engine in the compression stroke, but returns most of that energy in the power stroke (essentially like a spring that's being compressed and released). So CR may not have as big of an impact if any on engine braking as I thought.

No worries. That's why I questioned it, it had me scratching my head.

On that second link you provided, this was interesting to read:

" You have two engines, both are 1 litre with four cylinders. The first one has a short stroke, but a large bore. The second has a long stroke and a narrower bore. Both still have the same displacement but are of different shapes. Intake and exhaust are identical.

Provided the transmission ratios are the same, the short stroke engine will always experiance more engine braking in any given gear than the long stroke engine. This is because the surface area the vacuum can act on is larger in the short stroke engine because the pistons have a larger surface area."

I believe our FRS/BRZ cars have a shorter stroke (in general) then some other 4cyl cars ( 86mm stroke) , so that may help some with engine braking (while foot is off the accelerator, in gear). I tend not to compare 4cyl cars of say 1.8L to 2.5L , I could be wrong , but I think 86mm is a shorter stroke. Can anyone prove me wrong…. or with related info ?

[ermax]

Originally Posted by RickyRacer

would it actually be safe for me to turn off my engine to engine break?



I want to try this just to feel the difference you are alluding to



But i dont want to wreck my car lol

You loose power steering so be ready for that. Otherwise it’s harmless. Don’t use the starter to restart the engine though. Just turn the ignition back on while the car is in gear and it starts on it’s own.

[ermax]

Originally Posted by humfrz

OK, if you don't want to use your power steering or brakes -





humfrz

While engine braking it still generates vacuum so unless you plan to do this test for a damn mile the brakes are fine. Obviously you wouldn’t attempt this in rush hour. Man we live in such a nanny state now.

[PetrolioBenzina]

Toss it in reverse for mo better engine braking.

[p1l0t]

Just remember brake pads are like $20 and motors and trannies are more to the tune of $2000 at least even with some miles on them.

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[Jordanwolf]

Originally Posted by p1l0t

Just remember brake pads are like $20 and motors and trannies are more to the tune of $2000 at least even with some miles on them.

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This seems unrelated to engine braking. If engine braking was so bad for your car I'd have been through a couple engines already.

[PetrolioBenzina]

Originally Posted by Jordanwolf

This seems unrelated to engine braking. If engine braking was so bad for your car I'd have been through a couple engines already.

Me too.

[p1l0t]

Originally Posted by Jordanwolf

This seems unrelated to engine braking. If engine braking was so bad for your car I'd have been through a couple engines already.

I mean it's fine if you don't fuck up I guess... I don't risk it 95% of the time.

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[Jordanwolf]

Originally Posted by p1l0t

I mean it's fine if you don't fuck up I guess... I don't risk it 95% of the time.

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It's as simple as taking your foot off the gas though. The risk involved related to engine or transmission failure, I'd say, is quite low.

[PetrolioBenzina]

Originally Posted by p1l0t

I mean it's fine if you don't fuck up I guess... I don't risk it 95% of the time.

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How do you "fuck up" engine braking?

[Tcoat]

Originally Posted by PetrolioBenzina

How do you "fuck up" engine braking?

I had a long debate about this with him a couple of years ago. I am really not sure what this fear of engine braking is all about. The engine can handle both acceleration or deceleration equally well. It is not a one way machine.
This place makes me laugh sometimes!
"Redline all the shifts"
"Boost Boost BOOST"
"More grip"
"Get light weight pulleys for that huge instant acceleration"
"Oh you downshift and engine brake? You will ruin your engine. Cheaper to replace brakes than an engine"