Blow off Valve for 4th Gen

Hey all,

Not sure if this is going to sound crazy, but I know there are some seriously sharp minds on this forum, so I figured I’d throw it out there.

Has anyone looked into installing an aftermarket blowoff valve or diverter on the 4th Gen Tacoma? I’ve been thinking about it lately, especially in the context of towing. My theory is that a properly tuned aftermarket BOV could help extend the life of the turbo—particularly under load, like when towing uphill.

I’ve noticed the turbo working noticeably harder during those climbs, and it got me wondering if venting excess pressure more efficiently might reduce long-term stress.

Would love to hear if anyone’s experimented with this or has insight into whether it’s even feasible or beneficial. Appreciate any thoughts!

 

Boost pressure is already regulated with the wastegate, no need to regulate it externally.

The big things that kill turbos are:

1. Lack of oil changes/incorrect oil
2. Not allowing it to cool for a bit before shutting off the engine after running hard
3. Running it hard before the oil has warmed up

Modern turbos are water cooled to help mitigate #2 but #1 and #3 still apply

 

Would it be easier to just lighten up on the skinny pedal if you feel it’s struggling?

 

since they use recirculating bypass valves by design, an aftermarket one would more than likely throw your sensors out of wack and potentially affect the engine negatively.

 

Stop it right now. Seriously, stop.

The idea of installing an aftermarket BOV, if one even exists, is about as wise as deciding you wish to begin smoking crystal meth laced with fentanyl and heroin. As a recreational activity. This is just no bueno.
--------------------
Toyota engineers spent hundreds of millions of dollars designing this engine. You are not smarter than them.

See above. The warranty shall not be voided by poor use of a crack pipe.

You are welcome.

 

The turbo working harder on hill climbs is exactly what it's there for. Not sure where you're coming from.

Also, you appear to be conflating the wastegate and the blowoff/recirculating valve. They serve very different purposes.

 

Well I promise not fire up my Crack Pipe

I promise to follow DM93's advice and take appropriate precautions and planning. Especially when I am pulling our canoes over the Pali and H3. Just traveling over the mountain, I definitely hear that turbo working hard.

 

I am in Hawaii and we are not the Rockies by any means however when we do travel from one side of the island to the other the travel over the mountain there is some pretty good elevation climb and fall. When the trailer is fully loaded with 3 canoes and equipment it does get kinda heavy. Not to mention the overall length from tailgate to the tip of canoe it is about 50' in length.

 

That is a pretty impressive trailer length for a Tacoma, not gonna lie. How much does the setup weigh? I'm guessing the canoes are pretty light despite the size.

If the turbo housing isn't glowing red hot after a climb, then you're not really pushing it.

 

A blow off valve or diverter valve is designed to relieve pressure in the intake tract when you get off the gas pedal (transition from boost to vacuum). The waste gate controls pressure when under boost by bypassing excess exhaust gases around the turbo wheel so it doesn’t compress the intake charge beyond the desired threshold.

When towing up a hill you absolutely do not want to be venting pressure from the intake, that compressed air is what gives the 2.4l four cylinder engine the power and torque of a v8 from years past.

 

Great to know! Thanks appreciate it. Now that I got that mental slippage out of my mind I can concentrate on upgrading the suspension.

You are correct the Canoes are not that much they each way about 550 however because of the length most of the weight is in the trailer because there is a lot of metal braces to handle the torque and flex of towing something that long.

The trailer has the ability to carry 5 however the most we usually carry is 3 because if we put the extensions on to get two more on top it is sketchy and I would never tow that with the Tacoma. I have done it with my work flatbed but even with that it was sketchy.

 

so you want to create a boost leak and make the turbo work harder to make up for the boost leak?

 

1. Get an OBD reader of your choice (Scangauge, Ultragauge, Bluetooth, who cares).
2. Monitor engine and transmission temps.
3. Watch temps occasionally
   1. If either gets too hot, downshift and/or slow down.
   2. If temps look good: relax, and remember that Toyota generally under powers things, and your engine will likely have a long life of pulling canoes.
4. Enjoy your paddle!

 

Sound is probably not the best gauge of engine stress here.

My truck sounds awful when I'm chugging along in low gear, but you know it's actually taking it easy.

 

Just to be clear, BOV's don't regulate boost pressure; they eliminate turbo surge when the TB closes suddenly and the pressurized air pushes back against the spinning turbo. When a turbo is operating close to its boost limit, this sudden spike in pressure can potentially damage the turbo bearings or spool wheels.

@BuscoT In this case, Toyota is running at 15psi which I believe is well within the turbo limits so no BOV is necessary.

However, some might argue that a BOV will reduce wear on the bearings. While they are not wrong, Toyota uses a ball bearing turbo which is pretty robust and at 15psi, I don't think its worth it.

Other might also argue (and are probably correct) that a properly tuned BOV can increase turbo response by allowing the turbo to keep spinning after the TB is closed. The back surge of your charged air will slow down your turbo and it will have to be re-spooled, but its a thin line to walk as a BOV that is too aggressive will dump all of the charged air in your pipes which will basically put you back into "turbo lag" mode.

That said, if you are inclined to run a BOV, it might complicate things with the ECU and require more than just a bolt on charge pipe and vacuum tubes. When the BOV opens, the air will continue to flow through the spinning turbo and out the BOV. Whether is "recirculated" or not, this air flow will continue to be metered by the MAF and the ECU might not know how to handle it. Worst (but not likely) case is you can suddenly let off the gas after a hard pull but the ECU will read air flow from the MAF and continue to add gas despite the TB being closed, causing your engine to go way too rich and stall. Best case, you blow a lot of gas out of your exhaust (or the Toyota ECU is smart enough to ignore the MAF when the TB is closed).

Bottom line, I don't recommended it but if you do put one on, I recommend you know, or get someone that knows, what you/they are doing. Its pretty complicated.

 

And if you have a turbo/engine issue, I suspect it'll void your warranty.

 

Probably

 

The turbo inlet is designed to reduce surge (see documents attached above), it's relatively small, and ETC doesn't allow the throttle to suddenly snap shut like a mechanical throttle so no BOV required with the stock setup.

 

If you install a VTA BOV, and your vehicle is equipped with a MAF you will get rich spikes in the STFT and no benefit. Possibly set the MIL as well.
I’m not familiar with the bypass system on the 4th gen but typically they offer no benefit to longevity.

 

But they sound cool ..