Why do some people hydroplane and others don't?
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Joined: Dec 2001
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From: Broomfield
Hi, I've been lurking on the board and following the spinout/hydroplane threads for a while. There is one thing no one has asked:
What RPM was the engine running when you entered the turn/spin?
The reason I ask, is that I've spent a lot of time plaing around ( In a local parking lot ) learning the s2k's characteristics when I first got it. And I can get it to easily spin at higher RPM ranges when you even slightly reduce throttle input in a tight turn.
The reason ( and somebody correct me if I'm way off ) is that at high RPM range reducing the throttle causes a signifigantly higher forward weight shift then at lower RPMs. This is because the engine "brake" effect is signifigantly stronger at 7K rpm then at say 3K. So if you are taking a turn at high RPM it takes a LOT less throttle reduction to produce a a signifigant forward weight shift, and rear traction loss.
This is imprtant because perhaps the drivers that are spining are more agressive and driving the car at higher RPM ranges then the rest of us that are not having problems and unconciously leting off the throttle just enough to unbalance the car. Just a thought.
PS. This whole discusion has actually been really helpfull because as a new owner of an s2k the first thing I did after reading this board was go out for a day learned ( or at least did my best trying to) the in and out of the car.
What RPM was the engine running when you entered the turn/spin?
The reason I ask, is that I've spent a lot of time plaing around ( In a local parking lot ) learning the s2k's characteristics when I first got it. And I can get it to easily spin at higher RPM ranges when you even slightly reduce throttle input in a tight turn.
The reason ( and somebody correct me if I'm way off ) is that at high RPM range reducing the throttle causes a signifigantly higher forward weight shift then at lower RPMs. This is because the engine "brake" effect is signifigantly stronger at 7K rpm then at say 3K. So if you are taking a turn at high RPM it takes a LOT less throttle reduction to produce a a signifigant forward weight shift, and rear traction loss.
This is imprtant because perhaps the drivers that are spining are more agressive and driving the car at higher RPM ranges then the rest of us that are not having problems and unconciously leting off the throttle just enough to unbalance the car. Just a thought.
PS. This whole discusion has actually been really helpfull because as a new owner of an s2k the first thing I did after reading this board was go out for a day learned ( or at least did my best trying to) the in and out of the car.
Joined: Jan 2001
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From: Mish-she-gan
I believe hydroplaning rests almost entirely on the tire (tread compound, tread pattern, and tread wear) combined with excessive speed for the conditions.
Tire pressure, bump steer, throttle lifting in a curve, bad camber/caster settings etc. can all put you in the ditch but on the subject of hydroplaning it's the tires. One look at the tires and you know it's not a bad weather tire. Add that to a car that handles so well in the dry and many driver's can't make the required adjustment when the weather changes. They don't listen to their butt when the car starts to get nervous and they don't slow down.
Tire pressure, bump steer, throttle lifting in a curve, bad camber/caster settings etc. can all put you in the ditch but on the subject of hydroplaning it's the tires. One look at the tires and you know it's not a bad weather tire. Add that to a car that handles so well in the dry and many driver's can't make the required adjustment when the weather changes. They don't listen to their butt when the car starts to get nervous and they don't slow down.
Joined: Aug 2001
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From: Clearlake, CA
I agree that hydroplaning is almost entirely the tire, so the subject on this thread might be a bit off since many of the spin outs have happened on just damp, or even dry, roads.
Mostly what I'd like to discover is if a mechanical (vs. driver) factor is why a significant % (even though small) of the drivers find the S2000 rear goes around too easily.
Mostly what I'd like to discover is if a mechanical (vs. driver) factor is why a significant % (even though small) of the drivers find the S2000 rear goes around too easily.
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Joined: Nov 2001
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From: :spam:u
Originally posted by Cedric Tomkinson
I think this is an excellent idea. I totally agree with keeping away from driver error for the purposes of the thread.
Alignment settings are something that obviously needs checking.
I suspect the variant wil be tyre pressure, tyre pressures and tyre pressures!
There's a sticker on the door jamb on my drivers door that advises 32psi all round. For STREET use I can't see any point in changing that. I'm sure Honda and Bridgestone didn't just pluck that figure out of the air. I run mine at 32 psi all round and I find a drop of as little as 2lbs can make the car start to feel much less well planted! I check my pressures once a week with a calibrated guage I've had for some years.
I think this is an excellent idea. I totally agree with keeping away from driver error for the purposes of the thread.
Alignment settings are something that obviously needs checking.
I suspect the variant wil be tyre pressure, tyre pressures and tyre pressures!
There's a sticker on the door jamb on my drivers door that advises 32psi all round. For STREET use I can't see any point in changing that. I'm sure Honda and Bridgestone didn't just pluck that figure out of the air. I run mine at 32 psi all round and I find a drop of as little as 2lbs can make the car start to feel much less well planted! I check my pressures once a week with a calibrated guage I've had for some years.
Wish you Brits would learn how to spell TIRE though.
I would even like to make it mandatory that the first "Mod" everyone buys should be a good calibrated racing guage so when we have these discussions we are all singing from the same sheet of music regarding pressures.
Unless someone has an accurate guage any comment they make about pressures should be taken with a grain of salt.
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Joined: Nov 2000
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From: North Atlanta
Road surface will cause hydroplaning.
A good example, I was travelling north on I75 around Knoxville, TN at 65mph, it was raining lightly, all of a sudden the road surface material changed and the rear started dancing all over the place, the only thing I could do was slow down to 45mph very gently and get in the right hand lane.
I have been in rain with brand new OEM S02's and 45 was all the faster I could go with out hydroplaning. The tires are so wide and flat and the S2000 is so light in the rear, that it likes to hydroplane. Of course it was raining so hard that their was 1 to 2 inches of water standing on the Interstate.
Jim
A good example, I was travelling north on I75 around Knoxville, TN at 65mph, it was raining lightly, all of a sudden the road surface material changed and the rear started dancing all over the place, the only thing I could do was slow down to 45mph very gently and get in the right hand lane.
I have been in rain with brand new OEM S02's and 45 was all the faster I could go with out hydroplaning. The tires are so wide and flat and the S2000 is so light in the rear, that it likes to hydroplane. Of course it was raining so hard that their was 1 to 2 inches of water standing on the Interstate.
Jim
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From: WA
Actually, I was just thinking, the hydroplaning on its own isn't the issue. It's what happens as a result of the hydroplaning. In this case, the same thing that makes the S2000 such a great handler is also what causes it to likely spin more easily - a low polar moment of inertia - like most mid engined cars; a short wheelbase - and as we all know, the LSD.
Joined: Jan 2001
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From: Mish-she-gan
Hydroplaning and water issues aside, here's my theory on why we have a some of the wrecks in dry conditions.
Power to weight ratio comparisons (HP/LB)
------------------------------------------------------
2.7L Porsche 911 Carrera RS
210 hp/ 2,176 lbs .0965
Porsche Boxster S
250 hp/ 2,855 lbs .0876
S2000
240 hp/ 2,810 lbs .0854
BMW M roadster
240 hp/ 3,070 lbs .0782
Porsche Boxstetr
217 hp/ 2,778 lbs .0781
Ferrari Dino 246 GT
192 hp/ 2,642 lbs .0726
Audi TT
225 hp/ 3,410 lbs .0660
BMW Z3
189 hp/ 2,920 lbs .0647
MR2
138 hp/ 2,250 lbs .0613
Miata
138 hp/ 2,385 lbs .0578
Of the cars I've listed only the top two Porsches better the S2000. Consider the first car. It was the original Porsche RS car in the early 70s. It was born for the purest of reasons -- to clobber the opposition in Touring Car racing. This stripped down Porsche had thinner steel in the roof and doors, fiberglass hood, thinner glass, minimal underseal, even the clock and passenger's sun visor were removed. Pure race car.
You can see how S2000 ranks. Which of these car's would you suppect requires more driving skills and which do you think would be the most forgiving?
I rest my case.
Power to weight ratio comparisons (HP/LB)
------------------------------------------------------
2.7L Porsche 911 Carrera RS
210 hp/ 2,176 lbs .0965
Porsche Boxster S
250 hp/ 2,855 lbs .0876
S2000
240 hp/ 2,810 lbs .0854
BMW M roadster
240 hp/ 3,070 lbs .0782
Porsche Boxstetr
217 hp/ 2,778 lbs .0781
Ferrari Dino 246 GT
192 hp/ 2,642 lbs .0726
Audi TT
225 hp/ 3,410 lbs .0660
BMW Z3
189 hp/ 2,920 lbs .0647
MR2
138 hp/ 2,250 lbs .0613
Miata
138 hp/ 2,385 lbs .0578
Of the cars I've listed only the top two Porsches better the S2000. Consider the first car. It was the original Porsche RS car in the early 70s. It was born for the purest of reasons -- to clobber the opposition in Touring Car racing. This stripped down Porsche had thinner steel in the roof and doors, fiberglass hood, thinner glass, minimal underseal, even the clock and passenger's sun visor were removed. Pure race car.
You can see how S2000 ranks. Which of these car's would you suppect requires more driving skills and which do you think would be the most forgiving?
I rest my case.