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Since I didn't feel comfortable writing my own base tune, I spent the $$$ to have a reputable company write one for me. GT40 headed stock short block, V2-Si (approx 10 pounds of boost) on 93 octane. Here is a screenshot of the Base timing table in the tune they sent me. Anything stick out to anybody?


 

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Things "stick out" better if you look at the tables graphically.

Why did they pull the timing to 20 degrees at idle?? That makes no sense to me. Mine is at 30. I found the timing for peak idle speed for my combination and used it as the base idle spark. If you do not run timing that gives peak RPM at idle, you will have to run more fuel and that will make the engine and exhaust hotter while at idle. I had to bump UP from Holley base tune suggestions....not down.

Ford's base tune puts idle at 28 degrees and they add or subtract from that.
 

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How about 22 degrees timing under boost? That was the main thing that seemed strange to me
 

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Well it is a pump gas engine with cast iron heads. I would wager that the tune is conservative so you dont pop a head gasket and then blame them. I would treat this tune as a rudimentary base set up and then dyno tune from here.
 

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Well it is a pump gas engine with cast iron heads. I would wager that the tune is conservative so you dont pop a head gasket and then blame them. I would treat this tune as a rudimentary base set up and then dyno tune from here.
I wouldn't think 22 degrees on a pump gas motor with 10 pounds of boost a conservitive tune, would you? I was really leaning the other direction, thinking it's actually pretty risky for the combo. Not arguing by any means, just looking for opinions. Thanks!
 

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A lot goes into the process. This is a centrifugal S/C. Max boost (10psi) will be seen at max rpm. If this were a Kenne Bell blower that saw max boost at 2K rpm, then yeah, 22 psi on pump gas is kinda high. I doubt your engine will even see any boost at WOT until after 3,000 rpm, and then it ramps in progressively with rpm. How long is your engine going to see max rpm? 1 second per gear? Maybe? So realistically, you are not going to see 10 psi for but a moment. The same engine with the Kenne Bell S/C would see 10 psi from 2K rpm all the way to red-line. Different tuning strategy needed.
 

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The rule of thumb is 1*retard for every lb of boost. That is kind of what they did.
 

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I don't know what his static compression is or what the dynamic compression is, so I can't really comment on the 22 degrees at WOT.

I run 22 degrees at 26-28 psi, but I have race fuel and aluminum heads. I eased into mine, but I started at 19 degrees.

He will find out if the 22 is too much for his motor. He might not be filling the cylinders all that well, so it might be OK. That just might be backed up pressure from not getting air through the engine. :)
 

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If it were my car, I would take 3 degrees out of that whole table and adjust the idle area timing to 25-30. Check plugs and fine tune from there. You were at 23.3 degrees at 5K. Not exactly the ragged edge but more than I would be comfortable with during initial tuning. Guessing that you are 27 or 28 deg at the torque peak with a cam that fits your combo. I would be even less comfortable with that.
 
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