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Discussion Starter #1
Tonight is the big night... I'm finally putting my car on the dyno.

Unfortunately it has been completely winterized, including new winter tires, detuned intake, etc. However, I am getting it done for free (well, for a case of beer) by some friends at a local tuning shop. Their boss will be back in next week, so there's no time for me to retune it.

Now I've never dynoed an automatic before... it seems like it wouldn't work, due to the car kicking down a gear. I know the Dynojet can read it as you drive through the gears, but then there's also the issue of torque limiting in 1st and 2nd.

Because of this I will be trying to set it in limp home mode, so that it is locked in third gear. Nick told me about disconnecting the speed sensor to trigger this. Has anyone dynoed their automatic and done this?

Also, I need to know the gear ratios of the 4 speed automatic. Does anyone know this?

I'll be sure to post the results (good or bad) once all is done.
 

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I hope you mean "winter mode" not limp home :eek:
 

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Discussion Starter #3
Chris 9-5 said:
I hope you mean "winter mode" not limp home :eek:
Nope, I definitely mean limp home.

Winter mode will kick down a gear if you press the pedal down all the way, so I don't think that works either.

Limp home locks it into third... it might be a bit of trouble to get it rolling, but once it's going it should be okay
 

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Are you sure that an ECU sensing the throttle body in limp home, with a CEL on will allow you full boost :confused:


I also had problems (trying to Dyno my auto) that without the rear wheels moving the ECU allowed no more than base boost only - presumably thinking the front wheels were just spinning.
 

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Discussion Starter #5
Chris 9-5 said:
I also had problems (trying to Dyno my auto) that without the rear wheels moving the ECU allowed no more than base boost only - presumably thinking the front wheels were just spinning.
That may prove to be a problem... they do only have a two wheel dyno.

I am not sure if limp home will retard boost or not, but it's an idea Nick gave me awhile ago. Hope I can get him to chime in on this thread before I leave.
 

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Could still be interesting, I got 208bhp with base boost on my 150 bhp 2.0 :p

Plus a little help from some hardware ;)
 

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Discussion Starter #7
Well, after talking to Nick it sounds like locking it in 3rd with winter mode is the way to go... and it shouldn't kick down. I'll test it out on my way to the dyno to see what my steepest torque request is in that setup.

Removing the speed sensor puts the transmission into a 3rd lock. I guess it is different than the limp home mode we all know and love.
 

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Yep Stipud has one of the special 2 speed boxes ;)
 

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Discussion Starter #12
No luck getting it to boost. The graph is pretty dang impressive for 0.55 bar however, considering I normally boost around 1.2-1.4 bar in third gear.

I tried winter mode (red first graph), then normal mode (middle graph), then sport mode (last graph), all with the same horsepower results.

Unfortunately, as I was worrying, winter mode also kicked down, so the lowest RPM measurement I have on the graph is 3500. I was more excited to see what happened around 1800, where my boost came on.

Better luck next time I hope :cool:

 

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You turned TCS off, right?

I always go tray sliding, and with TCS off and my rear wheels at a dead stop sliding on trays I still boost... :confused:
 

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stipud said:
I dont have TCS.

Maybe next time i'll jack up the rear and spin the wheels by hand :lol::roll:
...you don't?

Oh... weird... could try disconnecting your ABS module next time you do a dyno.
 
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