SC bypass switch

So I've eluded to the desire to do this mod (some might call it a reverse mod lol) where I could use a switch to force my SC into a bypass mode in some other threads. Its mostly for when I'm driving up a grade on a freeway and boosting to keep up with traffic due to how the SC goes into boost and the auto liking to hold tall gears.

I finally knocked out the mod.
A 1999 Camry surge tank/vacuum tank thing


A three port vsv solenoid thing, plus Honda Odyssey windshield sprayers cause why not


Test plumbing mess- do not reference this setup, I derped and its not right, hence making the below picture.


High speed super AutoCAD schematic of the plan

Repurposing some old project wiring that is already drawing power, had a ground and an LED by my boost gauge. Goes through the firewall where there was a blank hole (I guess the OEM blank grommet fell off long ago...) Using an old o2 sensor grommet with it's wires.


Now I have an oem looking rocker switch to switch into perminent bypass mode and an LED by my gauge letting me know.


Gone with your first world problem of boosting when I don't want u to.

Since driving around proving it worked, I need to finalize mounting the components, but yeah, reverse mod somewhat completed... made with eBay used toyota parts and spare wire, switched, vacuum lines etc I had lying around. For some odd reason this doesn't feel as good as other mods I've done haha.

* Edit, the addition of so much plumbing plus the diameter being reduced for the addition components introduced some lag to the S/C's responsiveness- should be an easy fix simply taking the restrictor piece out of the OEM bypass valve hose. Or better yet relocate it on the vacuum tank side of the Y split to give the initial engine startup bypass valve motion it's snappiness back.

 

Sweet

 

@eon_blue

 

I really like this idea. Might do the same thing to mine

 

Having been on the forum for a while, I know I'm not alone with the feeling the S/C comes on just a bit too easily, or said differently, at too low an RPM/load- its not an everyday thing, just when I'm in San Diego (more hilly) or driving to the high desert- really annoying to switch into overdrive to get back into vacuum and sometimes even have to slow down-- or just say F' it and pedal down but burn up a bunch of gas doing it (13-12:1 af vs Stoich if not in boost). If TRD had gotten an OEM ECU reflash to be part of the kit, IMO it should not have just been fuel/timing correction, but tranny shift point changes as well. If one gets a valve body upgrade like the transgo kit, I believe it not only makes the shifts faster, but the down-shifting more aggressive, so that mod (which I need to do regardless) could also nip this issue in the butt.

But I'm glad I finally did it- I knew it could work, just took a while to find the right kind of parts, and then get them used on Ebay. I can link the parts if people like.

 

I’ve just put the supercharger on my truck. It was a, how do I put this, crazy idea to begin with. My truck just rolled over 250k. With everything that I’ve done to my truck, arb lockers, bumper, winch, and many more mods I just decided to revamp my truck instead of buying a newer one. In the last few months, I’ve completely rebuilt the front suspension and steering, added the supercharger/7th injector kit, and now I’m painting the truck. Lots of little things in between as well like replacing all of my evap lines and sealing up the evap system to finally get rid of a P0442 that has been pestering me for a few years. Anyway, I’m kinda wondering about my fuel mileage and how I’m going to have to drive the truck to keep it out of boost if I wanted to. I’ve basically bought/built a completely different truck that I’m still in the process of finishing. I’ve only driven the truck like 50 miles since the supercharger install, just to make sure everything was ok and good to go, then onto the next part of the project. Anyway, I don’t need a parts list, one trip to pick and pull, and I’ll have everything that I need although some other people may benefit from a parts list/breakdown. Thanks for the idea, I’m always trying to think outside of the box to start with. I’m not really concerned right now, but if gas hits $5 bucks a gallon again, I had just planned on removing the supercharger, I kept all of my stock parts just in case.

 

My brother from another mother, not crazy at all- I really really wish I had gotten a double cab, because with whats being released these days, I just don't see a worthy 1st gen replacement. If I had a double cab I would be all-in in just overhauling and keeping the 1st gen- even with just the extended, I'm still pretty much rebuilding and revamping this rig. I'm even entertaining the thought of buying a double cab and swapping over...

IMO don't worry about MPGs, when the SC is in bypass mode it's parasitic drag is supposed to be negligible, so with this bypass mod you should be good to go. One caveat is altitude and tuning. At 0 inches vacuum your tune might still start pulling timing and enrichen fuel- mine is kind of on the tip here at ocean level, so if I go to death valley I'll still be pulling timing and adding fuel at high (yet non-boost) load. But at higher altitudes where I really intend to use this, it should be fine.

 

@Speedytech7

 

I’ve been thinking the exact same thing. If my truck was to get totaled, and I had to purchase another truck, I’d be looking for another first gen. There just isn’t a replacement for these trucks out there in my opinion. The only thing that I would have done differently knowing what I know now is probably bought a prerunner double cab with a 2.7 and converted it to 4x4, then hang a turbo on it. Haha. Might not opt for the front locker next time around either. But hindsight is 20/20 and I’ve owned this truck longer than any other vehicle in my life, and I’m still happy with it. It doesn’t owe me anything. I’m at sea level as well, just a different ocean.
Looking at everything I’ve done and been into on this truck, the only thing that hasn’t been touched is the base engine, transmission, and transfer case. I know exactly what I’ve got. I replaced valve cover gaskets once and underneath everything had a brownish tint, nothing was black, no sludge at all. If I buy something different, there’s no telling what I’ll bring home, new or used. Im often approached at gas stations with people wanting to buy my truck, every time that just makes it worth more to me! They either want to buy it or they ask is that big black pipe (snorkel) my exhaust.... I’m like hell yeah, roll coal mafia old lady!! Haha

 

Just realized on my long trips this switch could be used as an "87 octane only" safety switch- with our ECU's knock circuit not being as adaptive as newer cars, I really do get an MPG increase simply running 87 (modern setups constantly probe the threshold and advance timing, recouping the expense of 91 octane with advanced timing), plus its cheaper. Now to find a switch that has that label, cause why not.

 

Well damn, that’s what I thought you did this for in the first place. That’s one reason why I thought it was such a great idea! If gas hits a hike, flip the switch and fill her up with 87.... my original plan was just to remove the supercharger, but I like this method much better! The more you think about it, the more things you can control. It makes the truck more versatile. Sort of like my AR15, I put down the big money on that project, then realized that I enjoy plinking with .22lr more than 5.56 or .223. Invested into a cmmg 22lr conversion, and boom... two different rounds through the same gun, and the ability to switch back and forth in less than 45 seconds.
Like I said before, I always think outside the box...

 

I saw this and wanted to post "get out of my head" but didn't, then-

Seriously, are we f*ckin related? Looking at the 22lr conversion as well for a number of reasons- but I really like versatility, practicality etc. Love how I can switch my XD40 over to shooting 9mm easily- just tickles me when something becomes more versatile with little investment.

IRT why I did it in the first place, it was more so for those looooong freeway mountain inclines/grades that are just at the right percent that just keeping up with Grandma in the civic next to you going 65mph you are getting into 4psi partial throttle boost, wasting good gas out of the tailpipe and raising EGTs needlessly-- or what I end up doing is kicking into overdrive and going into the big rig lane going slow with all the other 18 wheelers... But yeah, long commutes where I know I'll be burning the whole tank of the freeway, this will be great. I will probably still use 91 for city driving because LA, you need to be able to smash it at anytime to avoid idiots.

 

So I finally had a long trip on the freeway- I need to hunt down a vacuum leak because the bypass doesn't stay bypassed for long, and then boost is possible. I need to re-plumb everything (still the janky proof of concept setup) and maybe will need a larger vacuum tank. But its still useful as a short spurt bypass switch for those intermittent inclines I was bumping into in San Diego.

 

Bypass switch gets a legit switch thanks to OTRATTW's drama free custom text option.

 

I’ve not thought much about this mod lately. I’ve had a lot going on. Anyway, my truck is an automatic, and I thought about tapping into the ect button. Have the supercharger bypassing if the ect button wasn’t pressed. I like those switches that you got, I have the same style, and I’m running out of places to put switches and gauges. Haha

 

I find myself pressing the ECT button if I don't want boost- raise the revs to reduce low-RPM ping, I'd be tempted to wire it the other way around- flip on ECT and also disable boost for those mountain passes.

Now that I have a switch with a light for the bypass, I need to re-purpose the LED in my A piller. Also need to button up the bypass mod, there is a vacuum leak so it doesn't stay bypassed for that long.

 

Can you update this post with some photos of the final install? Without having a supercharger on my truck, I’m having a hard time knowing what is going on.

 

I still haven't buttoned up the install. I guess I can make a better plumbing diagram though...

 

Maybe you can use these as your starting point so it makes sense to me:

 

https://www.customtacos.com/forum/1...tronic-control-supercharger-bypass-valve.html