Another new PUMP gas record, thanks Driven Innovations
The clever person know's when to call in the pro
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Feb 25, 2008, 11:57 AM
#362
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If you don't push the car to det, how do you know how safe a tune is? If you listen for det properly (det cans) or reliable knock sensor reading, you can push any car to slight det to have an idea of where the barriers are. If you don't do this, you do not know how to tune IMHO.
Just stopping at 20 psi or some random number and saying, "yep thats good", is not a school of thought. As a tuner you should max out the perfomance of an engine setup safely. If you don't know when the engine will det, and you don't know whether more boost will make more power, you are not doing your job.
Just stopping at 20 psi or some random number and saying, "yep thats good", is not a school of thought. As a tuner you should max out the perfomance of an engine setup safely. If you don't know when the engine will det, and you don't know whether more boost will make more power, you are not doing your job.
my real world experience came from several tuned setups (hondas mostly) on pump gas. We would see detonation on anything past 20-22psi on our 93 octane. you could see it in the graph and on the plugs.
and thats what knock sensors are for btw
Last edited by Tracy; Feb 25, 2008 at 12:02 PM.
Feb 25, 2008, 12:01 PM
#364
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Mike (Tracy) - please re-read my post #341. Pulling timing doesn't make the "builds EGT temps to unsafe levels, makes the motor lazy, hurts throttle response, VE, and more." If you think it does, please explain why??
You still haven't told me why you care about EGT's. Have you ever tuned a road race car?? They have EGT's in the 950-1000*C range.
In the 20psi and lower area where YOU are comfortable adding timing, you still can. Its in the 25psi and up area where you pull the timing so that you can increase the boost. This does not make the motor lazy or decrease the VE of the engine
Remember what I said a couple pages ago, 1psi of boost will make quite a bit more power than 1 degree of timing advance, especially on a 35R in the 20-30psi range.
I'm not trying to be mean, but you just don't seem to be grasping the concept of its all about maintaining a maximum cylinder pressure with out knocking........remember the old saying, there is more than one way to skin a cat......cylinder pressure is made with a combination of compression ratio + boost pressure + ignition advance.
Out of those 3 things, which one is going to yield the most power on its own??
You still haven't told me why you care about EGT's. Have you ever tuned a road race car?? They have EGT's in the 950-1000*C range.
In the 20psi and lower area where YOU are comfortable adding timing, you still can. Its in the 25psi and up area where you pull the timing so that you can increase the boost. This does not make the motor lazy or decrease the VE of the engine
Remember what I said a couple pages ago, 1psi of boost will make quite a bit more power than 1 degree of timing advance, especially on a 35R in the 20-30psi range.
I'm not trying to be mean, but you just don't seem to be grasping the concept of its all about maintaining a maximum cylinder pressure with out knocking........remember the old saying, there is more than one way to skin a cat......cylinder pressure is made with a combination of compression ratio + boost pressure + ignition advance.
Out of those 3 things, which one is going to yield the most power on its own??
Last edited by SloRice; Feb 25, 2008 at 12:03 PM.
Feb 25, 2008, 12:02 PM
#365
So you took what applied to one car and applied it to others in terms of timing and max boost? Every car will be a different... just a different cam can effect timing drastically.
Feb 25, 2008, 12:07 PM
#367
priceless...
Feb 25, 2008, 12:13 PM
#368
Be careful, as that is only true so long as the mixture is not ignited. If we sit and look at a static pressure gauge, yes. If we check the mass of O2 molecules inside the chamber, no. The lower SCR engine will have greater air mass at the same static pressure as the higher SCR engine. The lower SCR engine makes more power before detonation steps in.
Last edited by Ted B; Feb 25, 2008 at 12:16 PM.
Feb 25, 2008, 12:20 PM
#369
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Mark I'm not sure you will get many replies... but I believe all the stock ecu guys "listen/watch/read" to det with just logging the factory knock counts. Then I think the AEM guys log the raw knock sensor voltage, and maybe the AEM can do some interpretation of that raw voltage. I think there are very few tuners on this board using headphones to "listen".
priceless...
priceless...
Its all good Looking at knock raw voltage but how was it calibrated and has it been checked by the tuner, Most will likely say they told me knock happens @X but how do they know.
Mark
Feb 25, 2008, 12:20 PM
#370
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Be careful, as that is only true so long as the mixture is not ignited. If we sit and look at a static pressure gauge, yes. If we check the mass of O2 molecules inside the chamber, no. The lower SCR engine will have greater air mass at the same static pressure as the higher SCR engine. The lower SCR engine makes more power before detonation steps in.
Feb 25, 2008, 12:21 PM
#371
My tentative belief these days is the best option is to do both, and adjust the noise floor threshold table to match what one actually hears. It's hard to believe that listening can be so simple (two copper tubes and a set of hearing protection headphones), but it appears as though we have to give Mark Shead props for that ridiculously simple solution as well.
Feb 25, 2008, 12:27 PM
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My tentative belief these days is the best option is to do both, and adjust the noise floor threshold table to match what one actually hears. It's hard to believe that listening can be so simple (two copper tubes and a set of hearing protection headphones), but it appears as though we have to give Mark Shead props for that ridiculously simple solution as well.
Ted Have you tried it this way now.
Mark
