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Texas Speed is not 100% sure it will work - the current harness. They believe the harness wil actually work, just not sure of the type of connector. They say that you may need to change the connector.

 

I asked them if they had a pin-out for the current connector to see if the truck connector could be re-wired. I guess they are digging to see if they can find one. I also said it could be to their advantage if they could come up with a complete truck conversion package, including wp, harness, tb, FAST manifold, and any necessary bracketry to re-locate and pulleys, etc..

 

The guy on the phone, although I forgot to get his name (sorry), sounded like that was a possibility and that he would start looking into something like that.

 

Would be nice.

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So...why not do the 90mm intake with the BBK 80mm tb? No wiring problems, only the problems with wp, pulleys, etc.. Then if the BBK were just a little portable, meaning p&p, there would be very little if any difference. Even if you couldn't port it out some the difference would be pretty minimal.

 

The big difference is it's doable now. :)

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Ben I am taking alittle different approach, I think we are going to try something me and BigTex have talked about. It will allow you to use the truck water pump without a clearance issue. I am on my way ouy to get the idler pulley rite now, going to get a Fbody and truck to see which one works. I am starting some of the fabrication today. If this works out it will make the swap easier for the truck guys.

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After doing some more digging into the 90mm swap, I have found out what the differences is between the two systems:

 

The 03+ trucks and SUVs use a throttle body with two throttle position sensors. Each sensor is fed a +5v and ground reference signal. Depending on the throttle blade angle, the output voltage is read from near 0 in the closed position and near 5v at WOT. The pedal assembly has a similar design with two sensors working on the same 0 to +5v scale. There is a control module that watches the TB and pedal and reports to the PCM the throttle position. Sensor 1 on the pedal setup is compared to sensor 1 on the TB, and they should have close values at all throttle positions. The same thing for sensor 2 on the pedal and throttle body. I think the two sensors are very slightly different, so the PCM will see two values that closely match. There is some internal processing that watches the position the pedal compared to the blade angle. If it detects values in either the pedal or TB systems that don't meet its thresholds, then it sets an engine code. It usually goes into reduced power mode, because if you have a TB failure, you don't want it to be WOT on you.

 

Now the C5 Vette and LS2 systems are similar in their sensors, with the C5 having a throttle control module like the trucks. The LS2 has a more powerful PCM and all its throttle control stuff is internal. The TB and the pedal both have two positions sensors like the trucks, but there is a big difference in their design. Instead of two seperate +5v and ground inputs, they only supply one 5v and ground. Thats not a big issue, but the sensors work differently. One sensor records 0 to 5v but the other is reversed and reads 5v to 0. In their processing, the values from each sensor are added together for error checking purposes and the total equals roughly 5v. So at low throttle, one sensor reads 1V and the other reads 4v for a total of 5v.

 

The speartech solution would replace all the throttle control components from the truck system with ones that were designed to work with the reversed sensors of the LS2 throttle body.

 

I am currently testing out some various ideas to get the LS2 TB to work on our trucks. It doesn't look like its going to be a simple harness swap. I have taken both types of throttle bodies apart and its not a simple parts swap between the two units. They have different shapes, motors, and sensor locations. I wish I knew more about simple electronics. Ideally, a harness would have an electronic component that would take the +5 to 0 output of sensor two and reverse the reading to 0 to +5v. With that, I don't think any other changes would be needed to make the throttle body work (besides custom idle tuning in the PCM).

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After doing some more digging into the 90mm swap, I have found out what the differences is between the two systems:

 

The 03+ trucks and SUVs use a throttle body with two throttle position sensors.  Each sensor is fed a +5v and ground reference signal.  Depending on the throttle blade angle, the output voltage is read from near 0 in the closed position and near 5v at WOT.  The pedal assembly has a similar design with two sensors working on the same 0 to +5v scale.  There is a control module that watches the TB and pedal and reports to the PCM the throttle position.  Sensor 1 on the pedal setup is compared to sensor 1 on the TB, and they should have close values at all throttle positions.  The same thing for sensor 2 on the pedal and throttle body.  I think the two sensors are very slightly different, so the PCM will see two values that closely match. There is some internal processing that watches the position the pedal compared to the blade angle.  If it detects values in either the pedal or TB systems that don't meet its thresholds, then it sets an engine code.  It usually goes into reduced power mode, because if you have a TB failure, you don't want it to be WOT on you.

 

Now the C5 Vette and LS2 systems are similar in their sensors, with the C5 having a throttle control module like the trucks.  The LS2 has a more powerful PCM and all its throttle control stuff is internal.  The TB and the pedal both have two positions sensors like the trucks, but there is a big difference in their design.  Instead of two seperate +5v and ground inputs, they only supply one 5v and ground.  Thats not a big issue, but the sensors work differently.  One sensor records 0 to 5v but the other is reversed and reads 5v to 0.  In their processing, the values from each sensor are added together for error checking purposes and the total equals roughly 5v.  So at low throttle, one sensor reads 1V and the other reads 4v for a total of 5v. 

 

The speartech solution would replace all the throttle control components from the truck system with ones that were designed to work with the reversed sensors of the LS2 throttle body.

 

I am currently testing out some various ideas to get the LS2 TB to work on our trucks.  It doesn't look like its going to be a simple harness swap.  I have taken both types of throttle bodies apart and its not a simple parts swap between the two units.  They have different shapes, motors, and sensor locations.  I wish I knew more about simple electronics.  Ideally, a harness would have an electronic component that would take the +5 to 0 output of sensor two and reverse the reading to 0 to +5v.  With that, I don't think any other changes would be needed to make the throttle body work (besides custom idle tuning in the PCM).

 

You are correct, good job figuring that out :thumbs:

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