Just got back from Dallas Mustang Dyno pull

[Clark]

Sorry that I have not responded back any sooner, but have been out of town. Finally got the dyno run sheet and this shows the problem that happened at 4300 RPM when the trans. had the issue. Maybe this will mean something to you guys familiar with the dynojet program.

 

[68rustang]

I am just throwing a guess out there but I think your "problem" was the transmission shifting into OD. The car should always be run in "Drive" not OD. If the operator put it in OD then he was wasting your time and money.

Based on everything you have said it doesn't sound like the operator knew what he was doing. If the dyno can measure torque it can calculate horsepower or vice versa. Your graph clearly shows max power of being around 273. That is probably low and is just the max power it was making before it shifted into OD.

 

[ForceFed70]

I am just throwing a guess out there but I think your "problem" was the transmission shifting into OD. The car should always be run in "Drive" not OD. If the operator put it in OD then he was wasting your time and money.

Based on everything you have said it doesn't sound like the operator knew what he was doing. If the dyno can measure torque it can calculate horsepower or vice versa. Your graph clearly shows max power of being around 273. That is probably low and is just the max power it was making before it shifted into OD.

I've got to agree.. Looks like she shifted into OD at 4300RPM.

The only time I've ever seen a graph go flat like that is when you run out of fuel (need to upgrade fuel pump). BUT the Air/Fuel ratio graph at the bottom tells me that it's getting plenty of fuel.

It definately doesn't look like a torque converter lockup problem.

 

[Clark]

Thanks for the input,

Nitrous or anyone else, how does that air/fuel mixture look? The reason I ask is when I pull the plugs they look like new really burning clean. I am wondering if I need to move up the primaries some to get that a little richer at the lower RPM's

 

[Bullitt]

the only way to get an accurate reading on your plugs is to shut the engine off basically RIGHT after it's been run hard. if you idle for very long, it's going to clean the plugs off.

you're on the lean side up until it shifts. i'd recommend going slightly richer to around 13-12.7:1. but every engine likes something different. this is a good place to start though.

 

[ForceFed70]

the only way to get an accurate reading on your plugs is to shut the engine off basically RIGHT after it's been run hard. if you idle for very long, it's going to clean the plugs off.

you're on the lean side up until it shifts. i'd recommend going slightly richer to around 13-12.7:1. but every engine likes something different. this is a good place to start though.

I agree.

Max power is made at approx 12.5:1 air fuel ratio. Your not getting that rich until 4500RPM+.

I'm not a carb tuning expert so I couldn't tell you how to make it run richer at the lower RPM's without running too rich up high. Sorry

As a side note... generally people shoot for a 14.7:1 air/fuel ratio for cruising as it provides the best fuel economy without effecting throttle responce. It's only when you have your foot to the floor that you want to see the air/fuel ratio drop to 12.5:1 for max power.

 

[gtss]

I have to agree it was primarily operator error, but in some ways he was correct. an AOD transmission by design , when shifted into Overdrive eliminates any and all torque converter slippage. The input into the trans for 4th gear is a shaft directly splined to the outer shell of the Torque converter. therfore no slippage or lock-up without it actually being a lock up converter.
Then the problem is two fold, because unless modified the AOD ratio in overdrive is somewhere in the range of 0.67:1, This is a huge overdriven amount, which would result in dramatically reduced readings on any type of dyno
Gord