hellbents10

iTrader: (10)

We have been lucky so far with our COP setup. We are only at about 1900hp right now though on ethanol. We have turned it up but never made a complete pass at 40psi+. Last pass at 40psi was coasting to a 7.1@166.

Another thing to note here is we only see a max of 7900rpm. I see some big power Alky turbo cars running BS3 with COP at 3000+hp. I just fail to see why we should have problems and they do not. We run an external cam and crank sensor on ours.

I do not see how that big heavy chunky wheel would be moving around or getting bigger with RPM either????

Fireball

iTrader: (21)

It definately will grow, but an FEA analysis of a "rough" drawing calculated about 1.6 thousandths of growth at 8000 rpm....not enough to close up the gap.

probably more to do with the fact that the sensor is attached to the motorplate which is in turn mounted to the chassis.

Fireball

iTrader: (21)

Kohler is giving up on the coils...he hurt another piston 2wks ago and the only attributable factor is due to ignition...identical setup to Brown's car except brown has a distributor.

hellbents10

iTrader: (10)

Looks like Meaney is using a industrial coil on some of these cars now too. I might look into that for next season. I could see mounting the sensor to the front plate being a problem.

Fireball

iTrader: (21)

for the other engineering geeks out there

max displacement at 8000rpm (838 radians/sec)

The Alchemist

iTrader: (19)

Brian, I'm not an engineer, but do have a lot of experience using centrifuges in the lab, and sometimes, I've found it not just overall rpm that causes an issue but rather acceleration. We have a centrifuge here that spins to 20,000 rpm, but it takes a good minute or so to get up to that rpm and the samples are happy. But if we accelerate to 10,000 in 15 seconds, the sample vials will literally explode/implode.

So maybe it's growing more than anticipated due to harmonics or rate of acceleration.

Just tossing it out there... not that it matters at this point since it sounds like you've solve the mystery and have a solution to the problem.

Fireball

iTrader: (21)

I accounted for rate of angular acceleration. I did a run assuming 3000 rpm increase in 2sec and it didn't change the overall deflection

Shawn @ VA Speed

iTrader: (3)

forgive me for asking, but what big hp meth cars have bs3 with COP?

hellbents10

iTrader: (10)

Whats the guys name with the purple stang that was running in Pro street? I will ask Dave he knows, we ran him in qualifying and he went 6.10. It was a small block car too.

We were talking to the guys in the PS class that we were running in, and some said it has been and still is being done by other guys. I am the absolute worst with names though!!!

The Alchemist

iTrader: (19)

Gotcha.... you're a smart guy.

Fireball

iTrader: (21)

nah...I just stayed at a holiday inn express last night

JL ws-6

iTrader: (50)

I'm somewhat surprised that the EGT safety net that you had in place didn't prevent this from happening....

In the future would it be possible to add a pressure switch to the coolant system, if X amount of coolant pressure is detected it will also shut the car down? I mean this is what a 10,000 dollar repair again no? This kind of thing needs to stop or you'll be running at the budget level that it takes to run a blown alcohol car.

Fireball

iTrader: (21)

I don't have it on in the heat of battle...it's false triggered before...besides, I haven't had enough test passes to fully quantify it. either way, whatever happened here occurred WAY too fast to have helped in this particular scenario I believe...we believe it was nearly instantaneous since this wasn't a fueling issue

JL ws-6

iTrader: (50)

If that's the case... I guess it kind of should be putting the thoughts people have about nitrous being hard on an engine to rest.... Looks like turbo's are capable of chewing stuff up just as fast. Or, it's just the nature of that power level, and no matter now you get there it's going to eat stuff up in a hurry.


Is there anything that can be done to prevent it in the future? Swap to the MSD wheel? Distributor? Dump the whole ls platform? At least 1/2 the motor's toast again no?

Fireball

iTrader: (21)

I believe distributor would be best bet still...even if it wasn't COP "related" (which it may very well be, but the evidence points to the reluctor). With individual coils, they can fire at any time. A distributor can only fire a plug when its in phase with the rotor....you can essentially limit max timing using by orienting the distributor properly.

JL ws-6

iTrader: (50)

I agree with that... if it was me that wheel setup would certainly be on the list of things to ditch if possible.

Fireball

iTrader: (21)

something to ponder...having wheel mounted to front of balancer.

isn't an ATI balancer more-or-less supported by orings internally? maybe this is the source of the wheel moving in and out with respect to the pickup. more power and rpm could induce more harmonics.

FMX05

iTrader: (3)

It looks like they claim a .2° max crankshaft twist from peak to peak compared to nearly 2° with a solid pulley. All of that vibration and force has to go somewhere. I wouldn't doubt it moves around more than you care to think.

Ponyhntr

iTrader: (9)

When you bolt the wheel to the balancer, aren't the bolts going through and threading to the hub? I wouldnt think it would move that much uless the crank snout is flexing.

Phil99vette

iTrader: (11)

Just like we talked, mine rubbed also..... same damper