1hdt fuel mileage (1 Viewer)

[Lumpskie]

FWIW... here's the order that I did things.

1. Bumped up to 35s - this made a noticeable difference. I cruise at 75 mph at 2300 rpm. Better drivability too.

2. Bumped up boost. Much lower EGTs, more power and better economy.

3. Adjusted boost compensator. HUGE difference. Way better fuel economy, way more power. My EGTs went up a bit because I wasn't in fuel cutoff all the time.

I would do all 3 of these things.

 

[HillCountryTX]

FWIW... here's the order that I did things.
1. Bumped up to 35s - this made a noticeable difference. I cruise at 75 mph at 2300 rpm. Better drivability too.
2. Bumped up boost. Much lower EGTs, more power and better economy.
3. Adjusted boost compensator. HUGE difference. Way better fuel economy, way more power. My EGTs went up a bit because I wasn't in fuel cutoff all the time.

I would do all 3 of these things.

@Lumpskie and @IanB thank you! This gives me something to work with, I sure do appreciate y'alls' patience and advice!

1) Since our HDJ81 has the stock tire size (31x10.5r15) and we have a 5 speed manual, I'm definitely at the upper end of high-RPMs on the highway, so anything I can do to lower these is a good thing. Sounds like 33's might be the way to go! Unfortunately we'll have to wait as our current tires have plenty of tread left on them

2) Also sounds like I need to get a pyrometer/boost gauge BEFORE I start messing the boost. What do you have/recommend? @IanB mentioned a manual boost adjuster...is this what you're talking about? Or is this something I can adjust without buying any additional equipment (besides a pyrometer/boost gauge)?

3) Again, I'll need a pyrometer/boost gauge to get a baseline. Any idea how to do this or a thread on how to do this?

Thanks!!!

 

[Lumpskie]

@Lumpskie and @IanB thank you! This gives me something to work with, I sure do appreciate y'alls' patience and advice!

1) Since our HDJ81 has the stock tire size (31x10.5r15) and we have a 5 speed manual, I'm definitely at the upper end of high - RPMs on the highway, so anything I can do to lower these is a good thing. Sounds like 33's might be the way to go! Unfortunately we'll have to wait as our current tires have plenty of tread left on them

2) Also sounds like I need to get a pyrometer/boost gauge BEFORE I start messing the boost. What do you have/recommend? @IanB mentioned a manual boost adjuster...is this what you're talking about? Or is this something I can adjust without buying any additional equipment (besides a pyrometer/boost gauge)?

3) Again, I'll need a pyrometer/boost gauge to get a baseline. Any idea how to do this or a thread on how to do this?

Thanks!!!

So, you'll need 3 distinct things.

1. Boost gauge - this is the sensor and gauge that will tell you what boost pressure you're running
2. EGT gauge/pyrometer - this will tell you how hot your exhaust is running.
3. Manual boost controller - this lets you increase your boost pressure. (you use the boost gauge to see how adjusting this affects boost pressure)

The idea is that you want to move enough air to keep EGTs down without overwhelming your turbo. Stock turbos can run 14psi (I believe) without issue. The steps involved would go as follows:

1. Buy and install gauges.
2. Drive around and note how hot the exhaust gets. (If it gets too hot, you'll need to increase air or decrease fuel to lower them... so proceed to step 3)
3. Purchase and install manual boost controller
4. Bump boost up to maximum safe value and monitor EGTs.

Strictly speaking, you can stop here and observe for a while. But, at some point you'll want to do the next steps.

5. Open Boost Compensator (Closely note the orientation of every piece in there)
6. Modify Aneroid rod so that you can insert it into boost compensator without messing with side pin
7. Adjust Boost Compensator to correlate to high boost level (that you dialed in with your manual boost controller)

8. Enjoy your new found power, better fuel economy and low EGTs!

Here's a picture of my gauge setup:


Here's my manual boost controller before install:



Here it is installed:


Here's the line that get's the boost controller inserted into it:



Here's what your aneroid looks like stock:



Here it is after modifying it to go back in the compensator:


For more information, look at my build thread. I included more detail there and feel free to ask questions in my build.
Lumpskie's Diesel 80 build

Good luck!

 

[IanB]

@Lumpskie and @IanB thank you! This gives me something to work with, I sure do appreciate y'alls' patience and advice!

1) Since our HDJ81 has the stock tire size (31x10.5r15) and we have a 5 speed manual, I'm definitely at the upper end of high-RPMs on the highway, so anything I can do to lower these is a good thing. Sounds like 33's might be the way to go! Unfortunately we'll have to wait as our current tires have plenty of tread left on them

2) Also sounds like I need to get a pyrometer/boost gauge BEFORE I start messing the boost. What do you have/recommend? @IanB mentioned a manual boost adjuster...is this what you're talking about? Or is this something I can adjust without buying any additional equipment (besides a pyrometer/boost gauge)?

3) Again, I'll need a pyrometer/boost gauge to get a baseline. Any idea how to do this or a thread on how to do this?

Thanks!!!

If your tires have lots of tread left, then you can sell them! Hit up Kijiji and you can probably find some 33's for not much more than you can sell your 31's for, there's no reason to ride out tires that don't fit your world.

Definitely get gauges BEFORE you start making changes to your tune blindly. I used VDO gauges, but there's LOTS of options for this, including some 2in1 and digital displays with many sending unit options to monitor just about anything you want. A manual boost controller is something installed in the wastegate reference hose that bleeds off some pressure and affects when the wastegate opens, allowing your boost pressure to be adjusted. I used a Dawes unit and it's worked really well.

With the gauges, install the EGT probe pre-turbo in the manifold, there's threads here in the diesel section outlining exactly where and how to do this. It's a bit nerve wracking doing it with the manifold on, but I've never heard of anyone that's had issues because of it when done carefully. Some grease on the bit, and the engine running to blow any chips out seems to be the ticket. For boost gauge I tapped into the hose that feeds the factory dash light sensors, located up behind the airbox.

 

[carbon60]

I just ran at 14.05 l/100 km (16.74 mpg) on 557 km (346 miles) of mostly 90 kph (56 mph) driving, with a couple days of commuting thrown in.

 

[Lumpskie]

I filled up yesterday after a week of daily driving (again, 75-80 mph) to work and driving up to the cabin on the weekend.. I drove roughly 330 miles on 17 gallons. The exact miles per gallon was 19.2. I'm pretty happy!

 

[HillCountryTX]

Thank you yet again @IanB and @Lumpskie...the suggestions and advice are priceless. And also for the real-world fuel mileages too. We've still been getting about 15 - 16 mpg (US Gallons) consistently over the last several fill ups, so eventually I will be doing the 1) Bigger tires, 2) Boost adjustment, and 3) Aneroid pin modification. I'd love to be in the 19 mpg range, especially doing 75-80 mph!!

I will definitely be doing the Boost Gauge/EGT (Pyrometer) install before I touch anything related to the fuel/turbo. It's our daily driver, so I don't have the luxury of experimentation

 

[landcruisertx]

I got 24 city 28 HW km/gal in my 80 with 315 and both bumpers .. mostly flat .. 1HD-T are thirsty ones .. much more than IDI like 1HZ engines ..

Hey doing research on these engines for a diesel swap. Do you mean that the 1hz will get about the same mpgs as the 1hd-t? I was planning on getting a 1hz and turboing her.

 

[Tapage]

Hey doing research on these engines for a diesel swap. Do you mean that the 1hz will get about the same mpgs as the 1hd-t? I was planning on getting a 1hz and turboing her.

If you can get a1HD-T go for it ..

and yes .. to get the same power from the 1HZ it will be as thirsty as the 1HD-T if not more ..

 

[landcruisertx]

If you can get a1HD-T go for it ..

and yes .. to get the same power from the 1HZ it will be as thirsty as the 1HD-T if not more ..

Living in Texas I run the AC all the time. What kind of mileage would I expect average?

 

[HillCountryTX]

@landcruisertx we used to live in central Texas with our HDJ81 (5-speed manual) with the 1HD-T. Before we refreshed our injection pump we saw about 14-16 mpg (US gallons) very regularly, whether driving on the highway or urban roads and while using our AC during the summer months. We had our injection pump refreshed (i.e. bought a rebuilt one and swapped our original one out doing the whole core deposit thing) and our fuel mileage improved to around 16 - 18 mpg pretty consistently, even with the AC running. Currently we are getting 15 - 17 mpg with AC out of Texas, but it is probably time to refresh the injectors now Hope this helps!

 

[landcruisertx]

@landcruisertx we used to live in central Texas with our HDJ81 (5-speed manual) with the 1HD-T. Before we refreshed our injection pump we saw about 14-16 mpg (US gallons) very regularly, whether driving on the highway or urban roads and while using our AC during the summer months. We had our injection pump refreshed (i.e. bought a rebuilt one and swapped our original one out doing the whole core deposit thing) and our fuel mileage improved to around 16 - 18 mpg pretty consistently, even with the AC running. Currently we are getting 15 - 17 mpg with AC out of Texas, but it is probably time to refresh the injectors now Hope this helps!

This helps a lot. I’m doing a lot of research on doing a diesel swap. Since I’m in college I want to make this save me money in the long run while not over complicating my whole world The 1hd-t seems like one of the best options. Currently doing a lot of research on the Cummins R2.8. Looks appealing because it’s modern and an all in one system.

 

[IanB]

This helps a lot. I’m doing a lot of research on doing a diesel swap. Since I’m in college I want to make this save me money in the long run while not over complicating my whole world The 1hd-t seems like one of the best options. Currently doing a lot of research on the Cummins R2.8. Looks appealing because it’s modern and an all in one system.

As far as saving you money, the payback period on a swap like this is going to be like 15 years in the future...it's the wrong reason for doing the swap IMO.

 

[landcruisertx]

The reason for me wanting to do a swap is my 1fz ticking really hard. So it’s either a new 1fz, a used on and run it for a bit, or finally the best option have a bad ass diesel turbo whistle everywhere I go

 

[chapel gate]

i get 26 US mpg pretty easily out of my 1HD FT.

 

[landcruisertx]

i get 26 US mpg pretty easily out of my 1HD FT.

Would it make a difference if I swapped a 1hd-t or a ft?

 

[Lumpskie]

The best I've gotten out of my 1HDT was 22 mpg. But I like to spool the Gturbo and cruise at 80 mph.

 

[Tapage]

Would it make a difference if I swapped a 1hd-t or a ft?

You will get more power out of the FT more easily if that's your goal .. to get standard numbers both get them easily while the FT it's a much more expensive engine .. and hard to come by.

 

[Lumpskie]

Be careful comparing imperial gallons as well... The British gallon is 1.2 times the size of the U.S. gallon.