SpecE46: Harmonic Time Bomb Disaster
First I want to say I love the idea of this SpecE46 class, and big thanks to Jason Tower & James Clay for getting this going.
As a racer (SCCA) I have a few different concerns on a few things, but one major concern in particular; Harmonic Oil Pump Failure. I believe the first year or two will be a Very Expensive learning curve for both the racers & promoters in this new class.
From personal experience I can tell you that the aluminum block M54B30 is NOT well suited to long duration RPM pulls down a straight away in stock (SpecE46) trim as the current rule book is written. There is a well known & documented high RPM issue concerning Harmonics & Oil Pump Failure in the M54B30, that mostly happens in the 6700 to 6800 RPM range. This Harmonic OPF is greatly exacerbated by three (3) different issues.
1) A light weight flywheel & clutch, instead of the stock 38.5lbs (heavy) Dual mass flywheel & clutch. (the stock dual mass flywheel acts as an Extra Damper on the back of the motor)
2) Any ECU "tune" that extends RPM past the stock 6500 RPM limit. Namely a tune that goes to 6800 to 7200 RPM.
3) Any race track with a long straight away that allows the motor to sustain the dangerous 6700 to 6800 RPM Harmonic failure range. Typically multiple 8 to 12 second (or more) pulls in any gear, (namely 4th) that allows the motor to "stay" in this dangerous 6700-6800 harmonic window.
As the rulebook is currently written, the SpecE46 race community will probably see many Harmonically caused OPF engine failures.
"Specifications & Rules"
Engine: Stock M54 motor, "flywheel and clutch may be upgraded". This rule should be changed to: Stock flywheel & clutch.
"A custom ECU tune may be specified in order to ensure compliance and maximize power/reliability." This rule should be changed to either: 1) A stock ECU must be used with NO tuning software.
Or 2) A custom "Tune" may be used, but with a Maximum 6500 RPM limit.
I would Strongly suggest a change to the rulebook allowing the use of either or both:
1) An upgraded oil pump, in the stock location.
2) The use of an upgraded engine balancer.
The money that would've been spent on a LTW Flywheel & Clutch, and the money that would've been spent on the ECU "Tune" would be much better spent on the upgraded Oil Pump & Engine Balancer. This change in thinking will not only provide the SpecE46 racer with a more sustainable motor, but will provide a more level playing field for every entrant. That of course is because the "guy" with the biggest bank account will be able to afford a custom Ultra LTW Flywheel & Clutch, not to mention the use of a "Super Tuner" that can extract every last ounce power out of his motor,.....at any cost.
Some things for SpecE46 to consider.......
Rob #43 ITS/ITR/STU, BMW 325I, STU LAP RECORD
SUMMIT POINT WV 1:24:229 S.C.C.A.
(DynoDynamics http://www.vimeo.com/8486878 Dyno Video)
"Chance Favors The Prepared Mind"
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Originally Posted by RacerX
Nitrous is a little trickier than boost, but it's not the spray that kills motors, it's STUPIDITY!!
Last edited by Rob43; 04-11-2014 at 02:41 PM.
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