[Carolinaturbot6]

Now that I think I've got a handle on what detonation is, & what causes it, I'd like to ask another question if I may. Let's say for instance that your particular car has 400hp & you're using a 20 degree chip. If you were to get 10 degrees of knock retard during a wot run, is there a way to figure out how much hp you are losing because of it. I'm not asking for an exact amount here, just an estimate. I would assume you'd be losing half of the timing the engine is capable of. Would that mean that you're losing 200hp? If I'm way off here in my thinking, can someone learn me something? I'd appreciate any input that I can understand. Even if you think I'm an idiot.

Thanks

 

[Orlando_87GN]

I don't think it works like that..

When 10* happens, it's not like the ECM subtracts that much until you lift the gas. There are things like Knock recovery rate and I believe some form of multipler for multiple knock counts vs. severity.

I don't know more than what is visible in the chips source code.

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[Zap]

I can see where you're coming from Carolina.

Just to expand a little on your original question, I'd also like to see someone explain a little about the relationship between timing, boost, and compression ratio with different octanes, race car vs. street car, etc. Optimum levels of each etc.

 

[Carolinaturbot6]

Ya know Orlando, after I wrote that & posted it, I read it again & got to thinking the same thing. By the same thing I mean I realized that it probably didn't work quite that way. I guess I succeeded in making myself look exactly how I didn't want to look. Oh well, I'll learn something sooner or later.

Thanks for replying.

 

[Carolinaturbot6]

Post your own topic damn it! Just kiddin Zap.

Heck, I'm all for this thing called learnin!

 

[Zap]

I would rather infect someone else's thread!

It's my parasitic nature.

 

[Carolinaturbot6]

No explanation needed Zap. I work with a West Virginian. I know yalls a different breed. Besides, Steve warned me ahead of time.

 

[Steve Wood]

I don't have an equation but, no, you don't lose 50% of your power in the case you describe.

I believe there are two factors at play in this equation. Detonation slows the acceleration of the crankshaft. It has been demonstrated that the slightest amount of detonation will reduce the rate of acceleration at that given point in time. Think about it. Detonation tries to drive the piston back down the cylinder before it has had a chance to achieve top dead center-therefore it is a brake against acceleration.

Detonation begins suddenly but it stops more slowly. Simply reducing the timing a degree or two will not stop the reaction and certainly not instantly. Once conditions exceed the tolerance of the fuel, it begins but it does not immediately stop when conditions drop below the tolerance as it becomes somewhat a self-fulfilling event.

Once it has stopped, timing is restored at some pre-defined rate and the car makes less power until the timing is fully restored which may take several frames.

Power then suffers from both factors-negative acceleration mposed by detonation and by the lack of timing which results immediately afterward.

Perhaps Todd will improve upon my generalizations and correct me as required.

 

[Carolinaturbot6]

I do know that race gas burns slower than pump gas. Therefore, you can run more boost & timing. It was explained that the gas burns slower, so you can run more boost & timing without detonation. See, I'm learnin something after all.

 

[Carolinaturbot6]

Dang Steve, you're too quick for me. I'm starting to understand it alot better now thanks to your comments. I guess I was just wondering how much power you were actually losing during detonation. I suppose it's much more complex than that.

 

[Steve Wood]

It is one of those "it depends" problems. I am sure it can be modelled/calculated.

 

[Zap]

Steve is the Turbo Regal God, after all!

 

[Carolinaturbot6]

So you are losing that much timing, but only for a split second or so.

 

[Carolinaturbot6]

LMAO Zap. Maybe you should bow before him & ask for forgiveness for all of your past sins.

I'm just glad that he takes the time to explain things. There's alot of those who wouldn't bother.

 

[Steve Wood]

Originally posted by Carolinaturbot6:
So you are losing that much timing, but only for a split second or so.

How long depends upon severity and how the chip programmer set the recovery rate as stated by Mike above. It does not immediately return to full timing for fear that it would trigger detonation again but has some recovery slope which depends upon the programmer.



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Steve Wood

Growing old is mandatory; growing up is optional.


86 GN bought new, 87 T-type-81 El Camino with GN drive train-basically stock 86, 94 Caprice 9C1, 69 SS396 Camaro Convertible