Do I lock the TCC at WOT on the dyno?

[BuickMike]

So I may be throwing my GN on the dyno soon for a couple pulls just for fun. I have a Precision 5 disc converter and have the ability to lock it at WOT. I usually have it set to lock around 90mph or so, but was wondering if I want to change that for the dyno? Do I leave it? Set it for a low enough RPM that it stays locked through the 3rd gear pull? Or is that too much and I should just leave it unlocked?

Let me know!

 

[salvageV6]

If you race it locked I would lock it, usually manually just after you enter third gear before rolling into the throttle, works on the dyno.

 

[fastblackracing]

If you choose to lock the converter and I would, Be aware that you can pull the the engine rpm down low enough to a point the rpm will be below the power enrichment rpm causing it to go lean at the low rpm until it climbs above the threshold. Not sure where yours is set at in your chip so you may just want to leave it at 90. This is something your chip guy could tell you, but I went through this problem once years ago. Now I have the fast system so not up on the chip stuff lately, just sharing and wanted you to know Now go have some fun!

 

[TurboDave]

If you choose to lock the converter and I would, Be aware that you can pull the the engine rpm down low enough to a point the rpm will be below the power enrichment rpm causing it to go lean at the low rpm until it climbs above the threshold. Not sure where yours is set at in your chip so you may just want to leave it at 90. This is something your chip guy could tell you, but I went through this problem once years ago. Now I have the fast system so not up on the chip stuff lately, just sharing and wanted you to know Now go have some fun!

I doubt that will happen. Since P/E is triggered by Load (LV8) not RPM. On all the data logs I've done over the last 20 something years, the PE flag is always set at around 0-2 lbs of boost which coincadentally is about where LV8 hits the PE threshold of 160, where it's set in the chip, it didn't care how slow or low my rpm was at. I can be cruising along at 30 mph and ease into the throttle, as soon as LV8 hit 160 (again about 1# of boost) PE was activated.
I've never seen (in all my years of wot tcc lockups) the rpm drop at wot lockup, pull the engine down to an rpm that shut PE off.
I suspect something else was happening in your car, not a PE issue.

BTW, one should NEVER do a wot tcc lockup until at least into 3rd gear for at least a couple seconds, something north of 85 mph.

 

[fastblackracing]

I doubt that will happen. Since P/E is triggered by Load (LV8) not RPM. On all the data logs I've done over the last 20 something years, the PE flag is always set at around 0-2 lbs of boost which coincadentally is about where LV8 hits the PE threshold of 160, where it's set in the chip, it didn't care how slow or low my rpm was at. I can be cruising along at 30 mph and ease into the throttle, as soon as LV8 hit 160 (again about 1# of boost) PE was activated.
I've never seen (in all my years of wot tcc lockups) the rpm drop at wot lockup, pull the engine down to an rpm that shut PE off.
I suspect something else was happening in your car, not a PE issue.

BTW, one should NEVER do a wot tcc lockup until at least into 3rd gear for at least a couple seconds, something north of 85 mph.

You could be right, It was definatley rpm related though And almost 20 years later I may have mispoken what Red told me it was. The rpms dropped on the 2-3 shift with converter locked and it was lean to the point of real knock the first 1-2 seconds in third.

 

[TurboDave]

You could be right, It was definatley rpm related though And almost 20 years later I may have mispoken what Red told me it was. The rpms dropped on the 2-3 shift with converter locked and it was lean to the point of real knock the first 1-2 seconds in third.

Knock at the 2/3 shift is VERY common if you're at or near the limits of your octane vs boost. Not a function of PE being turned off. Depending on how much putzing around someone did in the chip, it's "possible" that you could get a bit of a lean spike at the 2/3 shift.
But as I said, one should NEVER EVER lock the tcc before the 2/3 shift. The load draw down is just too much when the tranny hits, and will for sure cause 2/3 knock.
I tried that a few times over my racing years and locking before the 2/3 shift would 100% of the time adversely affect both my ET and MPH.

I eventually had the tune perfected enough that my best rpm could be attained if I programmed the lockup to occur at about 90 mph. Not locked I'd hit 112 mph, locking at 90, I'd hit 117+.

 

[fastblackracing]

Knock at the 2/3 shift is VERY common if you're at or near the limits of your octane vs boost. Not a function of PE being turned off. Depending on how much putzing around someone did in the chip, it's "possible" that you could get a bit of a lean spike at the 2/3 shift.
But as I said, one should NEVER EVER lock the tcc before the 2/3 shift. The load draw down is just too much when the tranny hits, and will for sure cause 2/3 knock.
I tried that a few times over my racing years and locking before the 2/3 shift would 100% of the time adversely affect both my ET and MPH.

I eventually had the tune perfected enough that my best rpm could be attained if I programmed the lockup to occur at about 90 mph. Not locked I'd hit 112 mph, locking at 90, I'd hit 117+.

Im gonna disagree with you on this the lean" spike" wasnt caused by someone putzing around in the chip. Pretty sure Red knows a thing or two about chips. I just wanted to inform the OP of potential issue from locking too early. End of discussion its His thread move along.

 

[BuickMike]

Thanks guys. I'll look at my WOT 2-3 shift MPH and lock it a little higher for the dyno. I'll add a little fuel initially just to be safe on the first pull.