Brian Tooley Racing

iTrader: (13)

We had a SBF with 400 cfm heads that made 900 HP at the crank, it made 700 RWHP through a powerglide with slicks, it ran 158 mph on motor.

So an auto trans and slicks can eat a lot of power. Good luck at the track

s.o.m.SS

iTrader: (1)

Good to hear Jay. I'll have to stop by and take a look.

edcmat-l1

iTrader: (10)

But you cannot differentiate power loss from the trans, versus the converter, versus the rest of the drivetrain. So to say a certain 3 speed auto soaks up 75 hp is absurd.

JTM

Drivetrain loss was right around 24% with my th400/4000 stall with a sbc. Much more than 75hp thats for sure.

jason99frc

iTrader: (12)

FWIW The difference from my 4L60 UNLOCKED to my 4L80 unlocked was 37 rwhp with the same brand/diameter/stall converter. Im sure my 4L80E eats at least a few more hp than a TH400 since its basically the same but with an additional gear set. Locked for locked it was only a 25rwhp difference..
But only the track times matter.........................................

edcmat-l1

iTrader: (10)

THANK YOU JASON. The ONLY way to differentiate the power loss of ONLY THE TRANS is with a locked converter. The rest is just hypothetical.
Too much bullshit info circulating on the 'net.
I dont see no trans, 3 or 4 speed soakin up 75 HP. For that matter, a 3 speed soakin up a **** load more HP than a 4 speed.

regal

iTrader: (2)

well I know on our deal we are gonna tighten up the convertor and re - dyno it because the mph we ran on the dyno compared to what we ran at the track on the old setup is totally off which means we are blowing alot through the convertor

edcmat-l1

iTrader: (10)

Dont doubt that a bit. Converters will make or break ya.....

jason99frc

iTrader: (12)

Makes sense its the converter eating all the power not the trans. I didnt mention it before but back in 2000 I switched from the 4L60 to a TH400 with the same diameter/brand and stall speed converter and I only lost 1.5 mph at the track. I ran on a Wed night with the 4L60 did the swap on Thursday and ran with the TH400 on Friday. I know exactly what the losses were without ever seeing a DYNO. Yes a TH400 in a street drive 99Z back in 2000 I hated that f...n 4l60 then O sold the car and the buyer went an put a 4L60 back in, then I bought it back a year ago and did the 60 - 80 swap crazy history with my car. It was also the prototype INCON TT car. HISTORY HISTORY HISTORY.

regal

iTrader: (2)

The transmission is a power soaking monster , but I think with a little tighter convertor we will see better results, but the power is nothing to sneeze at, and like everyone else knows, It really doesnt matter what power it shows, what really matters is what it does at the track. The dyno is just a tunning tool, thats why when you start playing dyno games going from one to another to another you will be real dissapointed

jason99frc

iTrader: (12)

But if everyone realized that all the dyno king shops would almost go under.

Beaflag VonRathburg

iTrader: (176)

That's why I asked what the stall speed was. Big converters act as a sponge and soak up a lot of power.

edcmat-l1

iTrader: (10)

Yep. Its not the trans, as everybody thinks, its the converter......

regal

iTrader: (2)

I think everyone that has been around a dyno for any amount of time knows there are those guys looking for numbers. These guys just dont understand, wheels, what tire is being dynoed on, tranny, convertor, outside temp etc..etc... lead to good or bad dyno numbers, the point is to get a reference point and to mod and tune from that point using the same dyno to do so. Ivee seen it to where the point of where I positio the tires either on top of the roller or a little behind it makes a differance, there are just so many variables

SPDMETL

Numbers I've seen for trans HP usage are TH350--35HP and TH400--60 HP

edcmat-l1

iTrader: (10)

WHERE DO THESE NUMBERS COME FROM? TOO MANY PEOPLE TALKING OUT THEIR ***.
HOW ARE YOU COMPARING ONE TO ANOTHER, AND ELIMINATING OTHER FACTORS SUCH AS TORQUE CONVERTER, DRIVETRAIN, ETC. ARE YOU INSTALLING EACH TRANS WITH A LOCKUP CONVERTER, AND LOCKING IT?
IF YOU DONT HAVE CONCRETE NUMBERS AND TEST CONDITIONS, STFU!
YOU'RE DOING NOTHING BUT SPREADING INTERNET HEARSAY!!!!!
AND I DONT MEAN 'MY BUDDIES CAMARO THAT MY BROTHER SAW DYNOED AT MY UNCLES SHOP 2 STATES OVER, ON THE 32ND OF LAST MONTH'
YA'LL KNOW WHAT I MEAN CONCRETE TEST RESULTS UNDER REPEATABLE CONDITIONS WITH THE LEAST AMOUNT OF VARIABLES

edcmat-l1

iTrader: (10)

Come on man, that dont make a freakin difference. Some more internet garbage. The position of the wheels on the drum dont make a **** of a difference.
I dyno cars everyday. Top of the drum, on the leading edge, trailing edge. dont make a **** of a difference.

bowtiguy

iTrader: (10)

those drums all spin the same speed right..considering no slipage from a force fed car....

regal

iTrader: (2)

Ok, I have been dynoing cars for 5 years and Ive seen a differance on torque numbers, but I guess its whatever, I dont know

jason99frc

iTrader: (12)

sometimes I wonder why I post in these threads..Everyone has their bs theories with no facts.

I gave accurate examples above regarding real world tranny losses.
In the same car I went 4L60 TO TH400 AND 4L60 TO 4L80E ALL WITH 9" YANK 4000/4200 STALLS THE SAME 9" REAR, GEAR AND TIRE ETC... THE BIGGEST LOSS FROM ALL OF THEM WAS ~ 37RWHP UNLOCKED AND 25 LOCKED PERIOD with all other drive train parts being equal.
IF YOU WANT REAL ANSWERS CALL GEAR STAR(SUPPORTING VENDOR AND PARTNER OF YANK) ASK FOR ZACH, THE OWNER, AND GET YOUR REAL ANSWERS WITHOUT ALL THE INTERNET BS. GEAR STAR ACTUALLY HAS A GM TRANSMISSION DYNO IN HOUSE. WHEN I HAD THEM BUILD MY 4L80E THEY TOLD ME EXACTLY HOW MUCH MORE POWER MY 80E WOULD USE OVER MY 60E JUST BY ASKING WHAT CONVERTER I HAD AND A FEW OTHER DRIVLINE QUESTIONS WITHOUT EVER SEEING OR TOUCHING THE CAR. I GOT THE TRANS AND INSTALLED IT AND PUT IT ON THE DYNO. THEY SAID ~ 30 UNLOCKED AND 17 LOCKED. IT WAS 37 UNLOCKED AND 25 LOCKED. FWIW THAT TRANS DYNO IS 1,000,000 AND THEY HAVE IT BECAUSE OF THEIR RACING DEVELOPMENT PARTNERSHIP WITH GM.(OFF ROAD/BAJA/ENDURANCE RACING) I KNOW MOST PEOPLE HERE WOULD CALL GEAR STAR FOR A PRICE A HANG UP B/C THEY ARE STEEP ( I PAID 5700 FOR MY 4L80E) BUT THEY ARE THE BEST AND HAVE PARTS THAT NO ONE ELSE CAN AFFORD TO GET AGAIN B/C OF THEIR RELATION SHIP W/ GM. ANYWAY GOOD LUCK TO WHOEVER IS DOING WHATEVER THAT THIS THREAD STARTED FROM.

As for the dyno differences, I have seen a car vary up to 3 % depending apparently on how tight the straps are or position on the rollers? I don't know which, but there was no other explanation as engine collant temp, oil temp,egt and iat #'s where the exact same.