Knowing the capabilities of the Toyota H engine (1 Viewer)

[BoostedLC]

Hi guys new to the forum here ! I just wanna ask if someone has already tried to turbocharge their Toyota H engine (3.6L) and how much boost can it handle if turbocharged ? talking about a stock Toyota H engine. Thank you in advance and have a nice day!

 

[mudandrock]

8psi Is factory on the 12HT, and when you add boost, you have to turn up the fuel. You must run a pyrometer and keep your egt under 1000 degrees if not intercooled. The H engine is almost impossible to source parts for, and a turbo would be a great way to destroy it. Never turbocharged an H, but I know lots of guys that have turbocharged their 2H and messed it up.

 

[BoostedLC]

8psi Is factory on the 12HT, and when you add boost, you have to turn up the fuel. You must run a pyrometer and keep your egt under 1000 degrees if not intercooled. The H engine is almost impossible to source parts for, and a turbo would be a great way to destroy it. Never turbocharged an H, but I know lots of guys that have turbocharged their 2H and messed it up.

Thank you for the info sir well noted. I was planning to turbocharge my Toyota H but it seems it can't handle boost at all. Might plan to engine swap it to a 1HDT instead afterall. Thank you again sir have a great day.

 

[mudandrock]

1HDT is a great choice!

 

[John in Utah]

and when you add boost, you have to turn up the fuel.

Just out of curiosity, couldn’t you achieve modest improvements to EGTs and performance by adding a turbo without adjusting fuel, especially at altitude? Would it even be worth the trouble?

 

[roscoFJ73]

The H engine would be ok turboed, with a sympathetic foot. Drive it carefully and get ready for an upgrade. But a lot depends on your H engines condition. A 40 year old engine that has never been rebuilt or had the head off is an unknown quantity.
Most turbo shops in Australia demand to do a compression test on an old engine and if they think its a bit worn out, they wont touch it.

 

[gerg]

John your egts would be under your control as your engine would be getting the air it's being robbed of from the altitude. If you didn't adjust the fuel and added a turbo you would be able to keep your foot into it where as without it yould have to back off to keep egts in check so I guess in that regard it would be a performance improvement. Sort of getting back what you've lost. Turbos help a lot with hilly terrain.

 

[John in Utah]

John your egts would be under your control as your engine would be getting the air it's being robbed of from the altitude. If you didn't adjust the fuel and added a turbo you would be able to keep your foot into it where as without it yould have to back off to keep egts in check so I guess in that regard it would be a performance improvement. Sort of getting back what you've lost. Turbos help a lot with hilly terrain.

thanks for the reply. I figured as much but don’t have any real experience with a turbo motor. I imagine there are a lot of folks driving a H like I drive my 3B and 3L ... flat out and just trying to keep from being ran off the road. And it doesn’t seem too common for NA diesel owners to fit a pyro, I know I don’t have one.

 

[gerg]

Na trucks can run dangerously high egts without alot of smoke. It's a testament to how tuff some of these engines are regarding heat. You never know what the previous owner has done with tuning until you check timing and egts. Once a turbo is on it gives you tremendous control over egts. Right now your at the mercy of ambient pressure and temp. A turbo just makes the truck so much more drivable, fun and I guess you could argue safer when it comes to merging on the freeway and stuff.

 

[Joe45]

What can be done, outside of a turbo, to get some more power out of the H engine (if anything). I have thought of a way to cool the air coming in, even though it's not a turbo.
My HJ45 has the H, and I am considering whether to swap it with something like a 12HT or a 1HZ in the future. I've heard a 2H isn't much of an improvement/not worth the trouble.
A 5 speed is getting swapped in for sure, as my top speed now is 45/50mph and cruises at about 38 mph. I'd like to be able to do about 60-65 without winding up/stressing the engine. I want to maintain reliability.

 

[AussieHJCruza]

The H engine governor should be set at circa 4k rpm and max power is 3600 rpm. If you have 4.11 diffs and stockish tyres, you should be able to cruise at a lot more than 38 mph.
It may not have enough power to pull an overdrive top gear depending on what your terrain is like.

 

[Joe45]

The H engine governor should be set at circa 4k rpm and max power is 3600 rpm. If you have 4.11 diffs and stockish tyres, you should be able to cruise at a lot more than 38 mph.
It may not have enough power to pull an overdrive top gear depending on what your terrain is like.

Yeah I have to check what gears it has. I have a feeling they may be something like 5:56, but no way to know until I check. Unfortunately, I can;t find any information using my VIN number.
I have 33" tires on it.
I am also worried that the H won't have enough guts when I put the camper on this rig. It'll be a homemade lightweight with a popup. But also will be carrying a spare fuel tank, water tank, etc. to be a little overlanding camper.
I live in he high country in Arizona, and I want to be able to drive it anywhere, including up mountain roads and down in valleys.
A swap with a 12HT or 1HZ may be needed in the near future.

 

[AussieHJCruza]

See if you can get a tiny tach or some other way of seeing what RPM she's turning

 

[Joe45]

See if you can get a tiny tach or some other way of seeing what RPM she's turning

Yeah. Good idea.