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

Got @armyoffoo throttle body today, and spent a couple minutes taking it apart while I waited for the wife to come wrench on her new car.





Was a bit of a destructive deconstruction. Had to drill out the throttle plate bolts and went ahead and ground off the cap that held the bushing for the shaft so I could press the shaft out the side. But I have all the parts here, and took pictures of the process so far. Need to look at pulling the gear off the shaft, otherwise next up is designing the new one!

 

Yeah! Awesome !

 

Maybe I should make a separate thread since this thread is for GM throttle bodies.

I got the gear and shaft separated, turns out they're an integrated assembly but luckily it broke in a workable direction.



The shaft has this toothed plate that is integrated into the gear, tapping the shaft out broke the lip of plastic that holds the plate in. Not sure how the shaft is actually retained into that plate, but doesn't really matter.

I have two thoughts moving forward, I can either make the new shaft index into that same plate impression, or even lock into the larger cutouts in the plastic. But that would involve removing the shaft from the gear and hopefully not fracturing the gear. The other thought is to cut the shaft and use the slotted portion as a female groove that slides over a male stub that is the actual shaft.



Kind of like a flat head screw driver and slot. The downside potentially is making the assembly wider because of this compound shaft arrangement, and the stock shaft has this fancy curve in the cut so the curved throttle plate would butt up against it which isn't really an issue but just complicates things a bit and makes it less elegant. There's also the issue if I go down that path that I'll probably need another throttle body to cut up to test the assembly without breaking the shaft free (I can glue it back together to make it a functional test unit, but you wouldn't want to run that permanently).

And the third alternative is just design my own gear entirely. But that has complications due to how the sensor is setup.



The sensor is some magnetic based system, hall effects maybe? Regardless, there's two magnets integrated into the gear that the sensor picks up position from. There's no physical connection where a sensor gets spun to determine throttle position. This makes me lean towards cutting the shaft because that's the least intrusive method, the gear remains entirely intact and someone could do that at home with a cut off wheel, and then I'm not reverse engineering where the magnets go and how big they are etc etc.

With all that said, I've moved onto the design process. And these are some insanely complicated little parts. The sensor body for example doesn't even have a consistent bolt pattern which makes it very time consuming measuring all the dimensions. I also haven't entirely figured out how (assuming it's needed) to space the motor away from the sensor without compromising the sensor body.

Now to go work a job that actually pays and screw with this more tonight

 

Actually I may have just figured it out. The motor plugs directly into the sensor body, unless I moved the motor down and over, and then wire some leads between the two. This would push the sensor body away from the throttle body, but with the compound shaft setup I described that's happening anyway. If the motor is like this, and using the compound shaft, and then add another idler gear or replace the stock one, that results in the motor being spaced out and just trimming the stock shaft to length. That might work nicely....

 

Great thinking with the spacer solution.

The TB has twin hall sensors.

Don’t forget part 89452-35030/TPS4-35030 is a stand alone 4 wire TPS that looks like it functions with the same twin hall outputs. This could allow the custom gear shaft idea to integrate nicely.

 

Measuring all this shit has been an absolute pain in the ass. I can't imagine where Toyota came up with some of these geometries. Like for the sensor body, there is nothing consistent with the 6x rivet pattern. There aren't any combination of 3x rivets with the same separation, let alone all sitting on the same line. Either someone was insane designing this or there's some justification I can't begin to comprehend.



But I'm finally starting to put parts together in the assembly. Right now over all width is at 7.362", which is ~1.61" wider than a stock throttle body, and after subtracting the throttle plate diameter increase is ~0.75" wider than if only the throttle plate diameter increased. Though if you did a direct scaling of the stock throttle body actually comes in almost dead nuts proportionally wider.

I might buy that TPS that Jowett posted since I feel like it's going to be insanely wide getting the sensor and gear combo to work, and if that TPS can be made to work it might drop the width a lot. Right now I'm using the stock throttle blade shaft, cut it down, and then have the actual throttle blade shaft interface into it with an alignment sleeve that holds them together. The other issue with this is I'm worried play will develop, if there isn't too much play to begin with since obviously you need a slip fit to be able to assemble it.... Though there's ways to solve that, set screws to tighten it together, weld it, etc.



The other TPS theoretically would remove this interface altogether, but then we go from "pimp out your stock TB" to entirely stand alone system which sounds like more work than this is already ending up to be.

Slowly making progress, now that most of the important parts have been put into CAD I can actually start designing things.

 

Excellent work!

The 4 pin TPS looks to have the proper rotation. Factory connector should be part number 90980-10711, available through dealer, OE aftermarket Tyco/AMP # SSC-4S-A , or china. Maybe we can track down a 6 pin to plug into the factory harness and make adapting plug and play.

Edit. This should be the 6 pin mating part that will plug into our harness.

https://www.bmotorsports.com/shop/product_info.php/products_id/5863

We could also look at re-pining the factory pins into the 4 pin connector.

 

Spent some time this morning flushing it out a bit more. Right now it's at 94mm, and there's no way (easily) push that higher. The Tundra bolt pattern with a .030" wall thickness around the bolt heads ends up there. The alternative is to make an adapter plate, which seems kind of dumb, but would allow the size to get pushed up since we wouldn't be stuck with the Tundra pattern. Maybe use the RCF bolt pattern so those spacers still work. But that's also drifting from the initial objectives of eliminating adapters.

Thoughts?

Also with the electronics pushed outboard, the spacing of the stock gear train actually ends up fitting with plenty of clearance. These pictures are with the stock idler gear, so theoretically there's three custom parts: the housing, throttle blade, and the shaft which is pretty cool!

 

This is amazing. Honestly 94mm seems pretty good especially learning the limitations of the trans shift and learning/control. That's a substantial increase in throttle area

 

Hmm. Well ima keep my eyes on this thread now… I’ve got a 76mm throttle off a 3ur on my mr2 right now. More air may be a benefit in the future…

 

And the more I think about it, it doesn't make sense to do some adapter setup because you physically can't port the superchargers beyond the factory bolt pattern anyway. So best case you port your blower and match the TB size. Anything more and you have a custom bolt pattern tapped into the snout so need a spacer regardless.

And this is ignoring the Whipple which needs a spacer to begin with.

 

Wow, that looks really nice, great job! The 94mm would be plenty for most, this is a huge jump up from the RCF.

 

Just a thought here, but would it be worth making one of these with a GM bolt pattern (110mm?) to bolt onto a harrop GM snout like Viktor G's setup? But with the Tundra electronic hookup?

 

At least for my setup, GM 95 TB, I got it shifting pretty decent. Will upload a video after the rain stops. I've ran it for about a month now with torque converter flex apply/release off. Supposed to keep converter cooler and stop/prevent shudder issues. Gas mileage and shifting has been great. I think the 94mm TBwill make great power. Corvette's running the 95mm TB make 1000hp.

 

This is simply awesome.

My only critique (hopefully constructive!) is how the two shafts connect. The keying is great for alignment, but screams stress riser. If that outer sleeve can take some of the rotational load… splines, press fit? There is some decent load and high cycling there…

 

That's what @armyoffoo and myself used for the TB conversion.

 

I think this would also work well...with an adapter like what @snivilous has already made for me in between to mount to the stock location and taper down the TB to snout air flow. That would enable larger blade sizes, mount directly to the Whipple, and still keep it stock-mount compatible with the appropriate adapter. Maybe there could be a mix-and-match setup with different blade housings and mounting adapters to suit different needs? No idea how much work any of this is, so if I'm nuts just say so...that 94mm option looks money to me. I'm rocking a 90mm TB with stock Harrop 85mm pulley and it scoots hard, so with a 94mm and pulley drop it'll be wild.

 

@armyoffoo thought you sent me the info on the sizes. GM 90mm, 102mm, 103mm and 110mm share the same bolt pattern. The GM 95mm is the odd one out.

 

Correct, from what I found. I was saying if Snivilous' rendering above is 94mm, that would be enough for most, but then could do modular housings/adapter plates for different intakes/SCs. If the housings are made using the 90/102/110 bolt pattern, then only the stock pattern adapter plate (like what I currently have, below) would be needed for most, but not for the whipple or those with the GM front snouts.

 

Thanks. Didn't want to confuse the different setups. Was for @Grippy_Blu if he went with the 110mm setup he could still have options.

 

I could see having two variants, though I hadn't thought of doing the GM style just since no one except Viktor runs that snout, and it's only compatiable with the Harrop.

I'm not a big fan of it, though I'm not particularly worried but also haven't done a stress analysis. There's not a lot of options to interface with the stock shaft besides this or welding to it, which honestly may just be the answer and if someone can't weld then they can send me/buy an assembled unit and I'd do it for them. Though that's not a simple endeavor either since everything needs to remain concentric and have to keep the shaft cool so the gear doesn't melt etc... I can look at the torque capability of the gear and apply those loads to the shaft and see what the shear margin is, that's probably the first step.



The 94mm feels like the sweet spot, and if someone wants bigger then I can do a one off or they go with the products originally in this thread. Making a larger TB and then requiring an adapter for a stock bolt pattern just seems like extra shit and cost for the product 90% of people would end up buying. And I can always do one offs for the people that don't want the stock bolt pattern and want to go bigger. I want this to be as close to the big TBs as possible but something a normal guy in the General SC Thread can buy and just bolt on.

 

@armyoffoo finally got a response from HPT.
Guess we are out of luck. They did it but for a different model.

 

Hmm so meaning we won't be able to dial the driving habits?

 

That was for the shifting relearn reset. Just changing throttle position vs accelerator and dialing in shift rpm's has me about 90% there. I did disable flex lock apply and have the tcc set to @snivilous lock/unlock rpms give or take a 100rpm.

 

@reywcms here is shifting at about 20 percent throttle. You can have more or less but it shifts well with my shift kit. 1-5 shift
https://vimeo.com/933558333

 

Are you using the latest Beta version? When you run the beta and connect to the vehicle it performs a firmware update on the MPVI unit. After that, it's there for mine, I just performed the relearn, but haven't done a test drive...Reset All Adaptives doesn't run successfully, but Throttle Relearn completes.

 

Hmmm. I downloaded it twice. It did a firmware update. I wonder if it's only on the 2.5 Gens on up. I thought the 992k ecu's were on a different model but at least you got it. I did have a shop do a shift relearn back with the 103mm TB.
I'll give it a 3rd time to see...

 

If one shop's software can do it, I don't see why HPT can't figure it out...sounds like a BS answer, or not worth their time with the limited demand? Maybe we should all open support tickets and apply a little pressure

 

seems good to me lol

 

Here's about70 percent throttle. Got a nice 1/8 mile on ramp...
https://vimeo.com/933557458