02Reaper

iTrader: (2)

Will a torque converter affect dyno'ed torque any? Let's say I am going from a stock converter (1.9 str 1600-1800 rpm) to an aftermarket stall (2.5 str 3000) would I show more torque on a dyno? Why or why not?

rufretic

iTrader: (37)

Any one have an answer for this? I'm interested as well.

02Reaper

iTrader: (2)

Damn, seems like every question I ask it just stumps people. Come on now.

samz28

my sig shows the delta of cam/boltons/verter, and i'm guessing the verter had alot to do with the low end torque since most of the other parts would be more top end flow, you can see the unlocked torque difference plain as day.

so yeah if its in similar weather and dyno'd properly you will see a bit of a difference. The higher stall point should show up too.

DrkPhx

iTrader: (15)

When dyno'd unlocked the converter will flash and cause a big torque spike that is a bit unrealistic so that's one reason you dyno with the converter locked to flatten the torque curve.

AK's WS6

Usually an aftermarket stall will eat up 10 to 20 hp on the dyno (but is works wonders on the street), hopefully someone will explain it because i'm really not a 100% shure why this happens

Ragtop 99

iTrader: (7)

An unlocked high stall converter will mess up the rpm reading and reported TQ on a dynojet. If you want a good dyno session, dyno at a place that can lock the converter for you.

dlandsvZ28

The shop that dyno tuned my H/C package (the works...everything except bottom end...98Z A4) refused to dyno the car with the Vig 3600 TQ locked unless I signed a release. Cam is 224/228 lsa 114/Stage II heads. Even has an electric water pump, cutout etc. and 3.73 gears, stageII A4. Like I said, the works.

They said it is extemely hard on the TQ and can possibly toast the converter on the dyno with the TQ locked.

As a result and not knowing the truth they dynoed it unlocked and it only put out 372/373 tq/hp. So the car should dyno approximately in the high 390/low 400 range with the tq locked.

First question, if it is hard on the TQ to dyno locked then how come I see so many dyno sheets with the TQ locked. Or does everyone have to sign a waiver?

Second question. What is actual hp/tq while driving? Is it 372 hp or maybe 400? If it's only 372 in actual driving conditions, then what's the big deal about dynoing with the tq locked?

skinnies

iTrader: (33)

Unless you lock it on the streets and/or track then dyno'ing it with it locked is really giving you false numbers. I dyno'd my car with it locked, but it gets locked on the streets/track.

Colonel

Dynos are tuning tools. Locking the converter on the dyno takes the slippage and flash (getting rid of the TQ spike) out of the equation and also gives you a more accurate RPM reading due to this. This can be very beneficial with loose stalls (4000+).

Ragtop 99

iTrader: (7)

It is hard on the converter, but the probability of damage is pretty small for just a couple pulls. However, they do not know the condition of your converter nor do they want to buy you a new converter if your lock-up clutch gets burned up, so they make you sign a waiver.