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Discussion Starter · #1 ·
I tried searching, but I couldn't find much info on it. Can overdrive handle a lot of power? I am going to be pushing just over 600awhp and I know there may be a time or two when I want to go faster than the 135mph I'm limited to in 3rd. Will this be an issue?
 

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Yes it will be an issue, it wont handle the power and you have no reason but at the track to do 135 mph.
 

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The_EE said:
and you have no reason but at the track to do 135 mph.
You should mind your own business, maybe he is faster then 135 in the 1/4 :rolleyes:



OD can not handle power. I've heard they do make a taller 3rd gear. Thats mostly for RACE CARS because you lose 4th. Don't quote me on that It's just hearsay.
 

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Yeah they're right about the NO part. My buddy blew 3 transmissions on his truck from towing in OD, not exactly 600hp full throttle, but a good enough load.
 

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Discussion Starter · #5 ·
In theory, I agree with you all. Does anyone have first hand experience? Does anyone know specifically why it can't hold the power (e.g. what is the weak link)?

The reason I ask is because I just emailed Scott at AMS who has an AWD auto Mirage with a 42R that is making 700+awhp. I've heard he traps in the 150's and he said that he has no problem going into OD down track.

????
 

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Well Scott knows his shit. This is on a fully built auto tranny and I'm sure it won't last long.
 

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I have pushed my car in OD with no failures, but it traps higher with a lower ET if I stretch the RPMs higher in 3rd. Although I have a built trans as well.

You can achieve ~140 MPH on a 25" tall tire spinning the motor at ~9800 RPM in 3rd gear. That can equate into low 10's considering you make enough power and don't leave the driveline at the tree. This is where your torque converter becomes very important. A factory restalled unit will not yield that performance level.

If you become concerned about 3rd limiting your top end go to a 26" tire. I would recommend fortifying your driveline as well, beginning with the rear axles. I am assuming your center diff is welded, if not that is the first mod you need to do or your trans won't handle >400HP to begin with.
 

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Autos love the tall tire. Get some 26" tires and launch the hell out of it. You should be able to get to 150mph or more on the 26" tires depending on revs as people have said.
 

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GotARed said:
Well Scott knows his shit. This is on a fully built auto tranny and I'm sure it won't last long.
Why is that?

You guys are getting me worried about using an auto fwd tranny. Might have to switch to manual awd sooner if a built a/t cant reliably hold the power.
 

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Discussion Starter · #13 ·
4g64fiero said:
Why is that?

You guys are getting me worried about using an auto fwd tranny. Might have to switch to manual awd sooner if a built a/t cant reliably hold the power.
I think he's referring to the OD not lasting too long. I don't knwo how much power you are looking to make, but Scott made over 700 at the wheels when his setup was in his Talon.
 

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TucsonTSI said:
I think he's referring to the OD not lasting too long. I don't knwo how much power you are looking to make, but Scott made over 700 at the wheels when his setup was in his Talon.
Over 700 eventually, but I have a feeling that may take a while. Still trying to learn my way around tuning my megasquirt and figuring out how to eliminate the tcu.
 

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4g64fiero said:
Over 700 eventually, but I have a feeling that may take a while. Still trying to learn my way around tuning my megasquirt and figuring out how to eliminate the tcu.
Why eliminate the TCU?
 

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HighPSI TSi Guy said:
Why eliminate the TCU?
Because staying in third because you have a standalone is gay. My tcu goes into limp mode because its not connected to an ecu. I'm not gonna leave an extra ecu in there just to satisfy the tcu.
 

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4g64fiero said:
Because staying in third because you have a standalone is gay. My tcu goes into limp mode because its not connected to an ecu. I'm not gonna leave an extra ecu in there just to satisfy the tcu.
You can make it work. I've set up EMS cars running a TCU plenty of times. It only connects to the ECU in a few places. I'd have to double check but I'm 99% sure it should still work with a megasquirt installed. I've done so much custom wiring harnesses on DSMs I've got the electrical system pretty much momorized off the top of my head. I can go over the wiring with you if need be. It should all work though. Personally, I'd ideally want a TCU with reprogrammed shift points and shift pressures so that it'd drive normal under normal driving and shift high and hard where you want it for racing.
 

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HighPSI TSi Guy said:
You can make it work. I've set up EMS cars running a TCU plenty of times. It only connects to the ECU in a few places. I'd have to double check but I'm 99% sure it should still work with a megasquirt installed. I've done so much custom wiring harnesses on DSMs I've got the electrical system pretty much momorized off the top of my head. I can go over the wiring with you if need be. It should all work though. Personally, I'd ideally want a TCU with reprogrammed shift points and shift pressures so that it'd drive normal under normal driving and shift high and hard where you want it for racing.
Yeah, I noticed there was an eeprom chip inside the ecu. It sounds like an good idea to reprogram it.

Its quite possible I got the wiring for the tcu wrong. I'd like it if someone did go over the wiring with me, it be a very useful sticky!
 

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4g64fiero said:
Because staying in third because you have a standalone is gay. My tcu goes into limp mode because its not connected to an ecu. I'm not gonna leave an extra ecu in there just to satisfy the tcu.
All you need to do is supply the TCU with 12V, RPM input and throttle position and it will work just like from the factory. The best part is you don't get timing pulled out between gears.

You can even do a set up utilizing a double pole switch, cut the TCU 12V supply, run it to the middle pole; one outer pole would go to the TCU and the other switch position to power your manual shift box. This eliminate climbing under the dash to connect and reconnect the TCU or running another fused power supply for the manual shift box.

It is only necessary to disconnect the 12V power supply to take the TCU out of the loop, everything else can stay connected in manual mode with no side effects to the TCU as long as you only switch power when the ignition is off.
 

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4SFED4 said:
All you need to do is supply the TCU with 12V, RPM input and throttle position and it will work just like from the factory. The best part is you don't get timing pulled out between gears.

You can even do a set up utilizing a double pole switch, cut the TCU 12V supply, run it to the middle pole; one outer pole would go to the TCU and the other switch position to power your manual shift box. This eliminate climbing under the dash to connect and reconnect the TCU or running another fused power supply for the manual shift box.

It is only necessary to disconnect the 12V power supply to take the TCU out of the loop, everything else can stay connected in manual mode with no side effects to the TCU as long as you only switch power when the ignition is off.
That is nice to know, I was worried about other things. I couldnt find that info when I searched.:dunno: :)
 
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