I lose about 11-12rwhp unlocked through my PT-4400, Not sure what it loses on spray but I bet it's not nice. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Also, when I swapped from my stock trans to a Yank I went from 321rwhp to 303rwhp. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

 

I think Terry's comparo is inconclusive since now he dynoed 20rwhp less IMHO.

 

Here is some math that proves my point:

For the Yank:
30rwhp lost / 496 rwhp locked = 6.04% loss

For the TCI:
20rwhp lost / 476 rwhp locked = 4.20% loss

It's clearly a more efficient converter. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> I should have some 60' practice with it tomorrow @ 3300# raceweight.

 

[seriously]
What if the drop in rwhp is from the TCI using more hp?

 

That would imply the Yank somehow had magical properties. Two converters of the same weight both locked will dyno exactly the same, unless one is magical. For the price I wouldn't be surprised if Yank sprinkled a little pixy dust on their converters before shipment. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

 

Just to add a little fuel to this confusing fire...

Both of the TP converters I dynoed lost exactly 10 RWHP unlocked compared to locked. One was the TP4600 I used with my internally stock 11.56 combo and the other was the TP4200E I first used with my MTI 422.

 

Well here is my .02 who doesn't care what converter any of you use cuz i run a TH400 <img border="0" title="" alt="[Razz]" src="gr_tounge.gif" />

This might be a stretch but.........it is possible to lose horsepower through a built tranny of any kind versus a stock one and here is my theory:

Friction is the man cause of horsepower loss....minimize that and you will gain horsepower because the engine wont have to work so hard to move something that isn't creating friction anymore. Proof of that is going from stock stamped steel rockers in older SBCs and putting on roller rockers. Even if the same ratio but went to a full roller rocker you'd get more horsepower due to the frictional loss.

Now same applies to a tranny *i think*. A stock tranny from GM uses thicker and less clutches than an aftermarket tranny does. Also, they aren't designed to grab as much either. My guess is that the aftermarket trannies are obviously coming equipped with better clutches whether they are the raybestos blue or the alto reds (both are the most popular that i know of) and grab better than stock due to more of them (numerically) and being thinner to pack more in.....i think it causes some more friction internally and eats up a little horsepower.

This is just a theory but in my mind it makes sense <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

 

Guy's I think you're missing an important part of the equation. He went down in stall speed by about 400 rpm. Maybe his car CAN use the higher stall, don't know. Also, if new transmissions are anything like new engines, they tend to be "tight" until they get some break in miles. What "T" is comparing is the Yank locked/unlocked vs the TCI locked/unlocked, not the fact the car dynoed higher with the seasoned trans and Yank convertor. I bet as the trans gets some miles on it, his car will dyno higher. When I built my last LT1 last year, it was mechanically noisy when it was brand new. As it got some miles on it it got real quiet, even the exhaust tone changed to a higher pitch. The trans is a little tight right now. It WILL make more power latter!!! How much, don't know. Then you can compare the 4400 Yank to the 4000 TCI. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

 

FWIW, I dynoed my Yank Pro Thruster 4000 converter this weekend. I lost 9 rwhp unlocked vs. locked. Pretty good efficiency. About the best of the 12 converters I've owned.

 

TB, so what kinda 60's did you get?

 

My best was 1.50, not bad considering I was in "street trim". Hoping for a 1.40 60' on this converter in race trim, I might need to add another 400rpm stall to get there.

 

FYI, my Vig 3200 and PT4400 showed the same HP difference with 19 RWHP. However, the Vig 3200 had the synonamous mid-range dip that lasted ~500 RPM where the PT4400 does not.

Trevor