Initial Development And Prototyping Of A 102 mm GM LS Throttle Body On A Supercharged Tundra

I have a nick Williams on my supercharged LS and it's a very nice unit.

 

Just an FYI, the 95mm LT5 TB has a different bolt pattern than the 90mm / 102mm LS TB. I've seen the LT5 TB listed as both 109mm x 70mm and 126mm x 70mm. The 90mm LS TB I have is 104mm x 70mm, and I believe the 102/103 is the same bolt pattern.

https://paceperformance.com/i-23967695-holley-performance-throttle-body-adapter-717-17.html
https://www.texas-speed.com/p-17249-katech-gen-5-lt1lt4lt5-112mm-throttle-body.aspx

 

@armyoffoo thanks for answering my questions and getting the info.

 

I got those bolt patterns backwards...I edited my post to correct it. The 90mm LS throttle body I am using is 104mm x 70mm, the 112mm LT5 uses the 126mm x 70mm. The 102/103mm should be the same as the 90mm. See adapter dimensions below:

 

@snivilous what was the Whipple inlet?

 

I'd have to pull up the CAD, I want to say it was 90-95. Maybe 92mm?

 

102mm but the bolt spacing I’m wondering

 

Will the values relearn if you don't have a scanner to clear the original values? Torquerush won't have Toyota terminals until end of month or so. But the ones from Amazon look good as @armyoffoo stated.

 

I'm not sure how long it takes to relearn on it's own, but resetting the learned values had a noticeable effect.

 

Going to see about a silver blade 102mm that needs some work. Will send it out to be overhauled. The model 12570790 motor is supposed to handle turbo and PD applications. Won't have much into it so will see how it is when I get the D2A.

**I just read on Torquerush site just now that he offers a similar TB with a larger motor.**

 

@armyoffoo the emulation codes you enter are for the D2A to translate to the Toyota voltages to GM? Works with all size of TB's?
Just getting my ducks in a row...once I get my 102mm will pull the snout again for porting.

 

Correct, those are the "stock" voltages that the new TB is scaled to emulate. If TorqueRush asks you to do it differently though, follow their advice.

Since I posted that, they asked me to use the latest firmware via Auto-Update, 12V Constant, A-to-A, Toyota preset for the emulation, and using the recording for the new TB. For me, there was no difference in TB behavior after making those changes, I think it was more for baking our testing into the latest firmware.

 

Thanks! I'm waiting for a 102mm gasket to show up so I can mock up the snout for porting and direct mount to snout.

 

Here is a screenshot of the settings and a recording of the GM throttle body signals. In the chart you can see me moving the blade from it's resting position to fully closed, and back to fully open. The values in the black boxes are the Closed and Open values that the GM TB recorded.

 

@armyoffoo Thanks for the graph and info. I should be getting the D2A next week and will hopefully add to the testing. Got a 102mm TB and will see how it goes. Also ordered the Toyota plug to rewire the D2A.

 

The Whipple snout is 3.15" square.

Army's GM TB is 4.094" x 2.756".

 

Finally processed the supercharger scan. You'll be hard pressed to make the 102 fit I think. Milling the center out to 102 on the snout will cut into the stock bolt holes to start with. Additionally, using Army's bolt pattern for his TB (listed above) the mounting holes barely overhang the snout flange in every direction (shown below two orientations at 90deg).



Below is a 95mm outline, which you might be able to port the snout to handle. Though you would need a spacer most likely between the snout and TB to grow the bolt hole size unless you can find a smaller pattern than Army's to directly tap the snout.

 

Yeah, I think a different snout will be key to getting anything over 90mm to work. Unless you have the Whipple.

 

Here's a picture of the adapter plate that Snivilous had made, the mounting holes are on the edge of the 90mm opening. The plate narrows from 90mm to 84mm at the Harrop snout.

 

Darn lol guess we'll need another plate

 

Not so fast, you can probably post machine the adapter you have to work. Army's bolt pattern and the 102 circle fit fine, though an O-ring seal between the TB and adapter might not work with the fasteners we used, but you could just RTV it.

 

When the time comes I'l just have you make a new one lol

 

@snivilous Thanks. I ordered the gasket to see if it would work and got ahead of myself. Was hoping I could get it to work. Oh well.

I think I was able to get my order of the TB and D2A cancelled. Torquerush was helpful in getting it sorted out.

 

Well we could always just do a billet snout and fix all the issues in one go

 

High hopes dashed...back to sending the RC F out for porting. 87-88mm will have to do. Thanks for all the info!

 

Billet snouts would be the way to go, but would be damn expensive considering the shaft running through it. I've been looking at alternatives based on the modularity of the 2650. Maybe Harrop could verify that this would work (physically bolt up, pulley coupler engage, pulley lines up, etc.)...then one would only need the D2A, a custom intake, and custom vacuum line routing. I'd guess there's something similar for the Maggy take-offs.

https://www.ebay.com/itm/276172758193?shqty=1&isGTR=1#shId

 

Would this one work better?

https://www.ebay.com/itm/204074319391

 

I saw that one also and thought something about it looked off to me, like the pulley coupler was in the wrong position...then I realized it faces the "passenger" side. In Australia, that's the left side of the vehicle, so it would be pointed at our battery.

 

Well both my orders for D2A and TB weren't canceled. Shipping and Return shipment to Canada is crazy. So we'll see how it goes...

 

Man that 102mm is huge! Top TB is stock 76mm bored to 79mm, middle is RCF 84mm and bottom is GM Silver Blade 102mm.
Getting the D2A tomorrow. Will be porting snout to 93mm, hopefull to get 95mm and using a 102 to 93 -95mm adapter. May have to stack adapters if snout mounting holes compromise 102mm seal. Will go from 4.5 inch intake to 4 inch throttle body to 3.75 snout inlet.