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Discussion Starter #1 (Edited)
Finally, got around to dyno tuning the car. The tuner first took the 9 data points of the Pro-M MAF and generated 30 data points. Plugged them into the Diable chip along with other parameters (injector size, etc). Did a couple easy pulls on the dyno to check A/F ratios. Running lean at higher rpm. Tweaked accordingly. Finally did a hard pull at WOT and the Lokar ss braided throttle cable bound in such a way as to not release!! Had to quickly turn off the ignition. No apparent harm done to the motor. Managed a couple more pulls, but the throttle cable was acting up. Could see it in some of the dyno profiles - not always giving full throttle when the pedal was floored. The last pull also showed some wobbling above 5,500 rpm. Wondering if valves were beginning to float? Thought I had adequate valve springs, but did not take into consideration blown application. Big valves have large surface area and there is 8 psi of pressure per square inch on the valve surface working against the valve spring. Intend to replace the Lokar with a polypropylene unit and go back for another dyno pull. Also, I now notice a hesitation from 1,800 to 2,000 rpm when driving. It only occurs at that narrow rpm range and in any gear (running a 5 speed). Your thoughts on the current tune and what to consider when I go back.

 

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Jerry.

The 'wobble' could be the valve springs or may be the plugs. What plug and gap are you running? I have exactly the same top end 'wobble' on mine and I've convinced myself it's the springs after trying a lot of stuff on the ignition side. Eventually I will go with a custom cam and change the springs at the same time for now I just don't rev it out beyond 5500 rpm.

The A/F ratio looks pretty good, what max timing did you wind up with?

Ain't the Kenne Bell torque curve wonderful? Have him make a pull from under 2000rpm you should find that the torque is still just about as high at 2000 rpm as it is at 2500rpm.
 

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Discussion Starter #4
Mike,

Was still running with 180 degree thermostat and cool plugs (Autolite 3923 gapped to 0.030”) during the dyno runs. This was my initial configuration to help prevent pre-ignition till I could get a dyno tune. Now that I've gotten a dyno tune, would you recommend changing the plugs to something different? If so, what plug and gap?

I suspect valve float in my case, too. Not too worried as I can shift above 5k rpm and still keep the motor in good power range for the next gear.

Not sure what total advance was. I have the dyno run files and the chip configuration file (.frg). Can view the dyno run files with WinPEP 7 software. Would that be in the one of those files?

jerry
 

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Discussion Starter #5
Update - the hesitation from 1,800 to 2,000 rpm turned out to be a dead spot on the throttle position sensor (TPS). Replaced it with a new one, set TPS voltage to 0.96 vdc at idle and all is well.
 

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Did you order a plain black lokar cable yet?
 

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Discussion Starter #8
Yes. Ordered a 36" and 48" from Summit early Satruday. Will use the one that fits best and return the other.
 
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