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Advancing engine timing for hp


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#1 Car6on14

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Posted 05 August 2008 - 11:06 AM

I asked this question in another post:

ME: i read that advancing your timing can help create more power, tho this was for a na engine, tho i also read about guys doing it on turbo engs and running hi octane fuel. Is anyone here running advanced timing to pull more power out of the engine? what kind of supporting mods are needed to do this besides hi oct fuel im assuming to prevent knock?

other user: Advancing your timing will definately increase your power right up until the moment that you blow your engine.

other user: 10* ( what our dizzy has to offer if I recall right ) shouldn't be able to do that... should it?

other user: 10* BTDC is what it should be set for. You can increase that all you want and as you do, you will notice the idle speeding up until you start to get detonation while idling. If you don't increase it that much, you won't get detonation until you start to accelerate or put the engine under a load. Too much detonation and good by pistons and/or rods.

Now im not looking to blow my eng, I just am looking to find if anyone here was able to advance there timing safely and gain some horsepower. and im not looking to get Mad hp from this, but if I was able to advance a few degrees and gain some free power I would be all for it, but not at the cost of harming my eng.





#2 FlattopMike

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Posted 05 August 2008 - 11:49 AM

I guess I was being a bit of a smart a$$ in my posts. Sorry.

The problem is that when these cars were new, they were meant to be run on premium fuel. At that time, premium gas was higher octane then what you can get out of a normal pump now. You can advance the timing a couple of degrees and it will respond with a little more low end kick but when the timing advances via the vacuum or mechanical advance, it will start to detonate. Now if your knock sensor is working properly, it will drop your timing back down as best it can.

There does seem to be a bit of a buffer built into the system before detonation but most people use that up by increasing the boost.

If you really want to advance it, you would need a high octane race fuel or aircraft fuel and it just wouldn't be worth it because you would get more out of it by increasing boost more.
[:-)

#3 Car6on14

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Posted 05 August 2008 - 12:55 PM

ah, exactly what I was wondering, so higher boost will yield greater power gains then advancing timing, and you do need higher octane, thanks for the answer! tho how do you guys usually check for knock, ive seen knock alert, is the sensor in our car pretty good? I also saw a cheaper DIY knock detector I thought about getting...

#4 1rst Gear

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Posted 08 August 2008 - 04:01 PM

QUOTE (FlattopMike @ Aug 5 2008, 05:49 AM) <{POST_SNAPBACK}>
I guess I was being a bit of a smart a$$ in my posts. Sorry.

The problem is that when these cars were new, they were meant to be run on premium fuel. At that time, premium gas was higher octane then what you can get out of a normal pump now. You can advance the timing a couple of degrees and it will respond with a little more low end kick but when the timing advances via the vacuum or mechanical advance, it will start to detonate. Now if your knock sensor is working properly, it will drop your timing back down as best it can.

There does seem to be a bit of a buffer built into the system before detonation but most people use that up by increasing the boost.

If you really want to advance it, you would need a high octane race fuel or aircraft fuel and it just wouldn't be worth it because you would get more out of it by increasing boost more.





I agree mostly with what FlattopMike said until he arrived at the fuel grades end of the discussion.......That totally depends on what part of the country you live in. I realize that some places can't get better grades than 91 octane so that henders horsepower production because it forces tuners to use lower ignition timing and more fuel to ensure no detonation occurs. In most places however you can find 93 octane at the pump no problem,which is way better than the 91 octane that was available as premium fuel over a decade ago when these cars were still being produced. Also compression ratio,fuel injector pulse width and displacement,elevation and temperature as well as boost like what was already suggested earlier will greatly effect weather you can bump the timing on your car as well. In short this is a very tedious balancing act which would best be left to a tuner with a good stand alone or piggy back wired in to support ignition timing adjustment electronically, leaving the mechanical setting of your distributor locked in at 10 degrees BTDC like it should be stock.
You can benefit greatly from increased timing under boost as well as before it, but it leaves you with little to no margin of error for tuning and fuel choices.
You get much more torque off idle up to the point of gear change (provided you can remove the proper amount of timing under boost) and your driveability is better to the point of boost threshold (before boost kicks in) but this limits the overall amount of boost you can run (Think 14-15psi instead of 16-17psi)
Also raising your boost pressure will only help you to an extent until you start reheating the charge-air after the intercooler due to the lack of compressor efficiency. This requires.....you guessed it more fuel, and less timing which ultimately yields less horsepower and torque.
If you decide to bump your timing via the distributor, my recommendation is to not exceed 12dgrees BTDC and only run 93 octane fuel if you have it available to you. And don't run beyond 15.5psi boost. I ran my Starion with this same set up here in Austin in 100+ degree weather and didn't experiance any ill effects.
Good luck with it bro
William
89' Merkur XR4TI
88' Mitsubishi Starion ESI-R
90' Volkswagen Corrado G-60
97' Mitsubishi Eclipse GS (Daily)
All most had me?........You never had me........You never had your car.....Granny shiftin, not double clutchin like you should.....Your lucky that hundred shot of nos didn't blow the welds on your intake.....Now me and the mad scientist gotta rip apart the block and replace piston rings you fried




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