Sniv Speed Shop - Custom Parts and Design

Oh snap- did you mention a front kit lol tundra build pictured for inspiration lol

 

Who’s your buddy over at RLT? I’ve not found anybody that will open up Dobinsons.

Those parts look NICE, Mr SYIV!

 

Dang! How wide is that track width?

 

Can’t remember exactly but it’s over 93”

 

Miles is the owner good dude. He can assist you

 

Miles will touch just about anything. We've been very good friends for a long time. He's in Salt Lake City, but people have shipped him shocks, dropped their truck off, flown him out to rebuild stuff, all kinds of shit. He's the only "certified" Dobinson rebuilder in the western half of the US, he flew down to their Florida office and they taught him a bunch of shit. They actually showed up to King of the Hammers this year (February) to talk to Miles and I got to give the President and COO I think rides in my buggy hahaha. Bar none he is definitely the man for Dobinsons stuff. Some of the parts I got are specific for Dobinson stuff, there's some little finger wrenches in there somewhere for the adjusters I think.

 

All those goods look just stellar.

 

Killer work! Nice touch with the pentagon bolt headed pieces!

 

Miles was adamant that the Schrader caps were some shape that would prevent people from screwing with the nitrogen charge in the shocks. I understand his logic, don't know if I agree. Because of that there's a whole suite of custom finger wrenches to torque them and random Pentagon holes in other wrenches to remove them. I think engraving "Don't touch, return to RLT" would be better but oh well, I just design what the bosses want.

 

Showing my ignorance, but isn’t checking the nitrogen charge part of Uber-shock maintenance and one of the first things to check if your shock is behaving oddly? I would think that leaking nitrogen would normally indicate a failed seal and eventual shock failure. I also realize that it’s not as simple as putting your tire pressure chuck on it, either…

 

Ehhhh not as much as you would think. You point out the obvious issue that unless you have a 300psi gauge you can't get any real value from it, but also checking the pressure in itself can cause a lot of fluctuation in the pressure since the nitrogen cavity is so small. And then even if the nitrogen pressure is fine the seals can still be blown, you can have oil in the nitrogen cavity, nitrogen in the oil, etc. And ironically if nitrogen is all gone the seals may be fine, though most likely the shock has cavitated so badly it's not.

His reasoning is people are more likely to drain all the nitrogen, and learn nothing of value in the process. So best case they learn there's no nitrogen, worst case they just screwed the shock (and really worst case think the preasure is fine and there's not enough). And unless you have a nitrogen tank laying around you're not fixing any issues anyway, so probably would've been better going to a place like RLT just to get a diagnosis to start with. So the pentagon caps act as a low level wall to tell people to chill.

 

RevB sent out for quote!





I'm sending out more designs for shock stuff so figured I'd throw an updated throttle body together.

To recap, the RevA taught me a lot and ended up actually working really well--until it had more issues with the throttle blade getting stuck. The fact I got it to work at all and prove the system is capable was great though. The two biggest issues was the assembly process and integrating to the drive gear and then the throttle blade sticking.

What I decided to do to integrate with the drive gear is to reuse more of the stock throttle blade shaft, all the way to and past the inboard throttle blade screw hole. My plan is to actually use that hole as an alignment pin with the throttle blade shaft extension. I had a lot of issues breaking the injection molded gear off the shaft, so my plan is to try and do as minimal assembly as possible so the stock bearing and its position get reused, the shaft gets cut past the hole, the alignment screw threads in, and a sleeve slides over the works. This way the shaft gets cut once and that's all the work that's done to it, which should really open up the potential to make this an upgrade kit that people can assemble themselves.



The throttle blade getting stuck was the main functional issue I had, or a combination of it getting stuck and not sealing well enough. To fix that I decided to go with a lip on the throttle body bore since that's already being machined, and this will keep the blade itself a simple geometry of just being a flat plate. This isn't exactly good for airflow, but neither is having a huge throttle blade and shaft sitting in the bore. I have a lip on the top and bottom which tapers down at the mid point of the tube. The throttle blade should have some room and be floating until full closed when it will seat against the lips and seal it off without radially contacting the bore.



There's a variety of other tweaks and features. The gear train area is almost untouched and worked beautifully out of the box with the electronics box mounting perfectly even though it has an extremely complicated mounting geometry. I also hogged a lot more material off, shaving 33% or right at 1 pound of material off the body! She was an absolute chunker at 3 lbm before.




I don't know if the RevA throttle bodies will move on in life. I might try and machine the lips into them for the throttle blade so they can be functional units, but that sounds like a lot of effort for not much gain. Hopefully RevB can be closer to a production unit, I only sent for a quote of 2x again since I don't want to be out a lot in the event the RevB has issues. While I don't know if the 95mm is worth it for most people, it is a very cool piece of hardware and certainly cheaper than a lot of pointless upgrades people do. In my testing the truck required absolutely zero tuning or tweaking to run the 95mm, no twitchy or slow throttle, no idle issues or adjusting idle, no adapters or harnesses, it was literally a straight plug and play which was the whole point of going down this path, so hopefully it can recoup the money I have into this once I get it working nicely.

 

I'm still game to test it out and compare to the GM 95mm and whatever. Getting my airload situated was the biggest hurdle with my misfires...

 

Yea we'll still do that, the RevA has too much potential for issue for me to want to send it out. If it's not the throttle blade getting stuck after 4 weeks then it's the injection molded gear breaking off where it's glued back together, or the hackjob delrin spacers to seal the throttle body, or the slotted throttle blade to make it line up nicely If RevB works smooth I'll send you one for testing.

 

We’re ready when you are my friend

 

Awesome! Merry Christmas to you and your family.

 

RevB of the throttle body is moving along. Had parts sitting around for a few weeks but finally got to working on it a week or two ago. There were two features the machine shop missed/messed up, not a big deal and some quick post machining on my end.





Assembly was otherwise mostly fine. The integration of the butterfly shaft to the stock drive gear shaft didn't work out how I liked, but it may have been for the better. I end up with the two shafts indexing into each other, and then a sleeve going over them to keep them concentric and that's it. That results in both shafts essentially floating axially, which actually might work better than trying to really constrain them. In the case of the butterfly valve and shaft, it can axially move a couple thousandths, but I think this might help prevent it getting stuck, and since there's now a lip for the valve to seat against at full closed it doesn't need to precisely sit anywhere anyway.



I also welded up an intake coupler that's a bit easier to install than my straight tube from before, and since I'm removing the throttle body constantly this helps a lot.



Overall it has worked flawlessly (knock on wood) right away. There was troubleshooting I ended up doing which ended up as nailing down the process to make the truck play nice with it and wasn't actually a mechanical issue. The truck seems to learn into the throttle body, but there's a bit of a sequence to get it to work to do that. For example, I flashed a new tune to turn off the cat O2 CELs (guess those O2 sensors decided to finally fail at >300k) just so I would know if an actually important CEL popped up. But flashing a new tune, and installing the new throttle body, together made the truck absolutely freak out. The TPS would end up pulsing and over reacting trying to control idle, and/or would send itself into a baseline TPS position and lock out the throttle from working at all. But if I ran the truck with the stock TB and drove around and it was fine, and slapped the new one in without resetting anything (ie reflash it) then it would respond fine albeit the idle was really high. Another solution I found from the TPS pulsing was to manually control the throttle, which would have to hold it at the high end or higher than what rpm the throttle would pulse to, but after holding it constant eventually the truck would seem to learn how to control it and then could let off the throttle and it would maintain the idle there.

Ultimately though, once I got the truck to hold idle (at like 2500rpm, so first warming up the truck with the stock TB I'd say is mandatory) then the idle REALLY SLOWLY starts to drop. But there seems to be idle control learn limits, because the idle would drop maybe 200rpm or 1% TPS, and then I'd have to restart the truck and then it would drop the same amount. I ended up sitting in the shop restarting the truck over and over until the idle was low enough to drive it, and then it eventually kept dropping to the point of being "normal". The stock idle TPS was 17.8%, I'm not sure what this one is at but I think it's in the 11-12% range, and it took it a fat minute to eventually get there.

In park idle I'm at 1000rpm and the truck sometimes blows an IAC code, which I've never gotten before. It's weird because on the RevA throttle body it would throw a "stuck open" code if it couldn't command the TB shut enough to lower the idle, where as it seems to be able to command it closed just fine since it hasn't thrown any other codes, but it seems to refuse to close the TB more to lower the idle. Not sure what the deal is, and frankly that code could be turned off since it doesn't affect anything or raise the idle in the tune since the idle is only <1000rpm when the truck CTS is >50C. In gear, the idle is low enough it doesn't blow the IAC code for some reason, but in gear idle is probably close enough to the target setpoint it's fine, not sure what it idles at, probably 600-700rpm in gear.

Besides figuring out all that stuff, just like RevA the tune is untouched and it seems to drive completely fine. Maybe 1% of the time I get a somewhat harsh or more firm than usual shift, but that's almost always when the transmission is cold. The throttle body gives the intake a very raspy and kind of deep tone at medium throttle, it sounds kind of cool and unique. There is a high pitched annoying whistle that was really bad with the previous intake tube, and the new tube quieted it down 50% but it's still there, but at least is below cruising throttle setting so cruise control it's still quiet. Not sure if it's the throttle body or the intake tube setup ultimately causing it.

I've done some offroad miles, drove it to the airport at 4am, lots of pulls and high speed cruising, neighborhoods, the whole gauntlet. Besides that IAC code in park at idle (which is hit or miss when it happens), I have had zero issues or adverse effects and this is with the same tune that used the stock throttle body. Because of that, I started building the second unit, which is actually "complete" sitting on my desk here and has already had the machining tweaks done to it. However I seem to have run out of throttle body parts (at least after having broken so many drive gears last year). I had one left that I took apart, but I'm not sure what it came from since the motor and drive gear are different. The motor is longer and cylindrical, which isn't a big deal since I have lots of spares but is interesting--it could work worse case if someone had this style.



And the drive gear while broadly the same has a completely different return spring setup with an internal spring and this plastic collar thing and then an outer spring, where as the "newer" style throttle bodies have one single piece spring and no plastic band. The plastic band for the inner spring is just enough of a hindrance that it makes the drive gear sit up a bit far and the sensor suite kind of squishes it down. I think it would work, but there's considerably more resistance on the assembled unit than I'd like so I ordered two more throttle bodies that I will grab parts from for this second RevB unit.



Once I have the new drive gears, I will swap them out in the second unit and install it on my truck.



Assuming it behaves nicely I will send the first RevB unit to @Mdl for continued testing on a differently setup truck, and Mike has lots of throttle body experience so I can get feedback how it reacts compared to the current GM units he's been experimenting with.

The RevB feels REALLY close. The transmission shifts feeling harsh sometimes when cold I think can be addressed via tuning, or just accept the nature of the beast and let the trans warm up before you get on it. The IAC code in park is the main concern, ideally this works with any truck without tuning adjustments. It's weird it never threw an IAC code on the RevA but threw every other imaginable code. I'm not sure if there's an angle limit that it needs to achieve idle by and that's the issue, in which case I could rotate the "full closed" position so full closed in closer to normal idle, but the stock TB can travel about as far closed as this I thought.

I'm also not totally convinced about the floating shafts setup, I think for the butterfly valve shaft that's probably fine, but for the drive gear I don't know if I like the fact it can scrunch up and run into the sensor suite. On the current installed one I actually put an O-ring between the TPS nub and the drive gear counterbore to keep it somewhat preloaded down to prevent it riding up. That seems fine but feels like a janky solution. The stock setup has press fit bearings to hold everything axially, which I'm trying to avoid because press fitting bearings when you have a plastic gear molded to the shaft is extremely hard to not break the gear off. I currently use the OEM gear that's pressed onto the drive gear shaft, what I might do is have that sit into the bore and then have a screw come in from outside that then captures the bearing so the drive gear is axially constrained. That might be a simple solution, and then keep the butterfly shaft floating with the sleeve to align it with the drive gear shaft---this is also a nice solution because it's easy to DIY, you remove the stock drive gear and shaft and then cut the shaft at one of the stock butterfly attachment holes and that's it, and you don't have to be precise about it since that interface isn't axially tight.


Anyway, figured I'd update this. RevC might be a pre-production unit that a handful of people can buy at a discounted price. It's hard to commit to a finished design without that revision already being actively tested, but the flip side is that buying effectively one off units for hundreds of dollars every few months isn't cheap either so that might be a good middle ground now that I seem (knock on wood) to have a design fundamentally working and just ironing out some bugs.

 

Man you're close. Assuming MDL's testing going good, I'd love to guinea pig a rev.C, especially now that my truck is a garage/camping queen and isn't my wife's daily.

 

That's the perfect test person! That's why Mike was a great candidate, he's used to things not working so i'd feel less bad if the TB has issues

 

Hey, Hey come on man! I'm more than happy to test it with normal air load and with a 20% increase to see how it shifts and idles. Looking forward to it!