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Old 04-02-2005, 11:16 AM   #1
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Mechanical over-revving

I just picked up another range 2 mechanical over rev yesturday. The engine seems to run fine still but I was just curious if type of abuse leads to problems down the road? Is this something I should be concerned about or do I just worry too much? Will this increase the liklihood of premature engine failure? Will I be covered by warranty if/when the engine finally lets go?

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Old 04-03-2005, 05:27 AM   #2
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Adam: Tool Pants would know better, but I asked my dealer to see if the prior owner to my 01-S had any. He laughed and said the valve stems would have been bent and I wouldn't have gotten this far...

That's an obvious overstatement but I was happy to hear that the computer showed none on this engine none the less. Run a search on 'Level 2' - I'm pretty sure there's a posting on it.

I think I'd have to give the kid in myself a timeout.

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Old 04-03-2005, 07:25 AM   #3
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If the valve stems were bent I would definately know that right!?? I remember the thread you are referring to and Tool Pants showed a OBII scan of one of his friends boxster S's that had 9 range twos. He said the guy was on his 2nd engine, but I couldn't tell if he was joking or not or if it was due to the over-revving. There wasn't much techical info in that thread either. No one seems to know much about this subject. There is a video of a guy with an Acura RSX doing a 3-2 shift at redline(like I did) on the net and his was engine finished. I guess the pistons slammed into the valves? If my motor doesn't seem to have any apparent damage do you guys think I'm in the clear??
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Old 04-03-2005, 04:16 PM   #4
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If you overrev to the point of valve float, you literally have the stems of the valves bouncing off the cam and such.

Hmmm, how could this be anything but bad for your box? I THINK that is why they have that whole red line thing?

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Old 04-03-2005, 04:50 PM   #5
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Well, I know it's definately not good but I took my car out today and it runs stronger than ever. I know that it was definately an over rev(again) because I was at redline in 3rd at appox 100mph and I dropped it into 2nd! The back tires locked up and stutter skipped on the pavement and the engine went weeeeeeee. It sounded kinda like a super-bike for a sec now that I mention it. I guess these Flat 6 engines can handle quite a bit! If there was any damage I think it would be immediately apparent(bad noises and blinking lights etc etc). I think I dodged another bullet but I'm going to be more careful from now on and not try to be ultra quick shift speed racer boy. Thanks for the responses.
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Old 04-03-2005, 08:04 PM   #6
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Damage is of course, a relative thing. Some damage is micro in nature and simply leads to issues down the road. Other damage is massive and immediate.

I am all for using the Box towards it strengths, as long as one knows that there is no cheating the laws of physics. You play, you pay!

But you seem to know that now and hey, who am I to talk???

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Old 04-04-2005, 07:28 AM   #7
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Very true, anytime stress is placed on a part it could weaken it enough to lead to complete failure down the road. Sometimes it is more immediate and easily noticed. I remember reading an article in a magazine around the time the Carrera Gt was released. An automotive jounalist misshifted and over-revved the to extremely high engine speeds....to the tune of 14,000 rpm when Porsche checked the computer. The result was immediate engine failure. Hopefully if my engine ever gives out it will be within the next 5 and half years so it will be covered by my warranty.
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Old 04-04-2005, 10:40 AM   #8
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Possibly not if you have a history of over-revving it

Be careful, and don't rush your shifts.
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Old 04-04-2005, 10:49 AM   #9
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Here's a technique that I picked up when I was running my Viper at the track a lot - the Dodge gearbox was definitely suseptible to a 3-2 mis-shift:

Notice when shifting from 1st to 2nd to 3rd that your hand is held much like you're holding a soda can, with the top of your wrist pointing to the passenger window. When shifting from 3-4, rotate your wrist counter-clockwise about 90 degrees, so that your wrist is now positioned as it would be on a bike's handlebar. Rotating your wrist like this will make it nearly impossible to go from 3-2. Practice this in your street driving so it's second nature, so that if you're under the stress of hard driving and upshifts you don't yank the shifter towards yourself and grenade the motor.

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Old 04-04-2005, 11:00 AM   #10
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Thankyou for the tip Andy. I will try that technique out. The 3-4 shift is the only one that gives me any grief. You think it would be the easiest too since it's just straight down...but like you said sometimes I have a tendancy to pull the shifter torwads me(to the left) when shifting quickly and the result is 2nd gear. I'm going to buy a B&M ssk soon as well so hopefully that will help. Less travel in the lickage means less of a chance to mess up I would think and hit the desired gear.
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Old 04-05-2005, 03:52 PM   #11
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Quote:
Originally Posted by Adam
I'm going to buy a B&M ssk soon as well so hopefully that will help. Less travel in the lickage means less of a chance to mess up I would think and hit the desired gear.
Hopefully yes, but remember it will also take less travel to get into the wrong gear too...
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Old 04-05-2005, 04:03 PM   #12
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Great advice from ntmatter.

I've been shifting like that for years. Thumb down, palm facing the passenger side for 3-4 shifts and 5-6 shifts. This is a good way to avoid the "money shift" (e.g. mechanical over-rev).


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Old 04-05-2005, 04:08 PM   #13
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Quote:
Originally Posted by ntmatter
Here's a technique that I picked up when I was running my Viper at the track a lot - the Dodge gearbox was definitely suseptible to a 3-2 mis-shift:

Notice when shifting from 1st to 2nd to 3rd that your hand is held much like you're holding a soda can, with the top of your wrist pointing to the passenger window. When shifting from 3-4, rotate your wrist counter-clockwise about 90 degrees, so that your wrist is now positioned as it would be on a bike's handlebar. Rotating your wrist like this will make it nearly impossible to go from 3-2. Practice this in your street driving so it's second nature, so that if you're under the stress of hard driving and upshifts you don't yank the shifter towards yourself and grenade the motor.

A

Thankyou very much for the advice. I've been using the technique you mentioned by keeping my palm over the top of the shifter when shifting 3-4 and it is working much better. I think I was unconsciously putting my hand to the side of the shifter from time to time which resulted in the mis-shifts. Now I'm more aware of my hand position...particulary when shifting from 3rd to 4th. I'm glad I became aware of this before I blew my motor!
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Old 04-06-2005, 08:32 AM   #14
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I started practicing this daily after I went from 3-2 at around 90 MPH at Thunderhill. The car went very sideways down the front straight, and all of a sudden the traction hooked up and I was moving toward a concrete tire wall perpendicular to traffic. I saved the car by inches, but since then have made it a point to rotate the wrist for any shift up out of 3, even in street driving. Actually, you could say ESPECIALLY in street driving; as with heel-and-toe, it's best to build the muscle memmory in daily driving so you don't think about it under stress.

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Old 04-06-2005, 05:47 PM   #15
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Where's the heel vs toe?

OK, this is something I've puzzled about for a bit. I know heel & toe is using your "gas" foot to work both the brake and gas at once. I've tried to find pictures on the web showing a foot in position and have come up empty. I presume the heel is on the brake and the toes are on the gas - is that true?
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Old 04-06-2005, 06:15 PM   #16
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No. The ball of the foot (toe) is on the brake and the heel blips the gas. You want maximum control for the braking. Another way is to use the foot in a slightly toed-in position for braking and roll your foot over to blip the throttle. I like the latter method.

Search for some Best Motoring videos on the net. They'll sometimes have a camera in the footwell showing how the drivers heel/toe.


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Old 04-06-2005, 07:27 PM   #17
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The basic idea on heel-and-toe is to blip the throttle to sync the engine with your downshifts. Good HAT technique will save wear on your engine and clutch by preventing that forward "lurch" if you downshift hard and the motor has to rev up to speed. You want to use the ball of your foot on the brake to have the best control and modulation of the brakes, and then use some other part of your foot to blip the gas while downshifting. Some pedal spacing (and feet) make it easier or harder to use different parts of your right foot - there's no one perfect answer. I tend to wedge my foot between the brake and gas, put the ball of my foot on the outside edge of the brake pedal and squeeze the top of my foot onto the gas to blip the throttle. You can try this, or your heel, but I'd recommend using the "toe" part of your foot on the brake because you'll get the best control.

Properly done, you should be able to brake hard and downshift from 5th to first with absolute smoothness. Practice this in your every day street driving, it's a good habit to get into that is also a good track skill.

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Old 04-06-2005, 07:47 PM   #18
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I tried the "heel and toe" thing the other day just to see what it was like and it felt really awkward. It doesn't seem like I have good control of the brakes or the gas and it was especially difficlut to reach the gas with my heel. I guess it takes lots of patience and practice.
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Old 04-06-2005, 08:56 PM   #19
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One more thing I realized about the 3-4 shift besides rotating my hand was to keep my elbow at a near 90 degree angle so I don't inadvertantly pull the shifter torwards me. When practicing those two things it is very hard to miss 4th gear when shifting fast.
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Old 04-07-2005, 12:06 AM   #20
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Here is a 1998 owned by a local guy, Ed. 253 range 2. I took the picture at a tech session in 2002. The owner was at another tech session we had a few months ago. Sould have hooked the car up to a PST2 to see what he has been up to.

He has the original engine.

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