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slight hesitation at 8k rpm ?

Old 11-20-2010, 07:21 PM
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MI slight hesitation at 8k rpm ?

Hello all
I have 2010 SII GT. Fantastic car. I have 1500 miles on it. I broke in the engine properly - but forcefully. I noticed today during my 'rev-a-day' fix a very slight
hesitation at 8k. Is this typical ? thanks for comment -
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Old 11-20-2010, 08:26 PM
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should be good all the way to 9000 but yea, the rpm increases slower once after 8000rpm so usually 8500rpm is good enough to shift. I hit 9000rpm only to clean out the carbon.
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Old 11-22-2010, 02:11 PM
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8000rpm is a lot to ask from any engine, and in this engine it means the each of the ignition coils is sparking 133 times per second. Yes, I'm sure things get a little imprecise at that speed, and imprecision will impact power generation.

EDIT: Holy ****, that means at 9000rpm, each ignition coil is firing 150 times per second. That's a spark once every 7 thousandths of a second. Holy ****. No wonder this car burns through coils so fast.

Last edited by fyrstormer; 11-22-2010 at 02:14 PM.
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Old 11-23-2010, 01:49 AM
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Originally Posted by fyrstormer View Post
8000rpm is a lot to ask from any engine, and in this engine it means the each of the ignition coils is sparking 133 times per second. Yes, I'm sure things get a little imprecise at that speed, and imprecision will impact power generation.

EDIT: Holy ****, that means at 9000rpm, each ignition coil is firing 150 times per second. That's a spark once every 7 thousandths of a second. Holy ****. No wonder this car burns through coils so fast.
yep
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Old 11-23-2010, 07:11 AM
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Originally Posted by fyrstormer View Post
8000rpm is a lot to ask from any engine, and in this engine it means the each of the ignition coils is sparking 133 times per second. Yes, I'm sure things get a little imprecise at that speed, and imprecision will impact power generation.

EDIT: Holy ****, that means at 9000rpm, each ignition coil is firing 150 times per second. That's a spark once every 7 thousandths of a second. Holy ****. No wonder this car burns through coils so fast.
In the world of electronics 7 milliseconds is pretty much forever.
I'm constantly working in picoseconds (ps is one millionth of a ms)

Our coils just suck!
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Old 11-23-2010, 09:12 AM
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Originally Posted by DarkBrew View Post
In the world of electronics 7 milliseconds is pretty much forever.
I'm constantly working in picoseconds (ps is one millionth of a ms)

Our coils just suck!
Electronics, yes, but not electrics. The logic circuits that charge and fire the coil aren't under any particular duress, but the coil has to charge up to a couple thousands volts in that span of time.

Also, a piston engine redlining at 6000rpm will give each coil three times as long to charge.

Last edited by fyrstormer; 11-23-2010 at 09:15 AM.
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Old 11-23-2010, 11:55 AM
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Originally Posted by fyrstormer View Post
Electronics, yes, but not electrics. The logic circuits that charge and fire the coil aren't under any particular duress, but the coil has to charge up to a couple thousands volts in that span of time.

Also, a piston engine redlining at 6000rpm will give each coil three times as long to charge.
The Mazda engineers would have know the peak RPM and should have ensured that the coils would be reliable.
Other coils are quite capable of reliable operation in this engine as demonstrated with BHR ignition.
Whether it's the switches or the step up windings failing these coils are not as reliable as they should be.
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Old 01-17-2011, 01:07 PM
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Not meaning to thread necro but I've actually been noticing a hesitation around 7k RPMs in all gears. It's more noticeable in the taller gears obviously.

40k miles on the tach currently.
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Old 01-19-2011, 12:47 PM
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I think I can feel the same thing you guys are talking about, I got a 09 r3 and It seems that some times at around 7000rpm, it does hesitate, kinda if id let go the throttle or if the car just lost 50hp, matter a a sec and smoothly goes back to normal. dont know, I feels like when I had heat soak with my 1.8t jetta
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