6bt cummins NV4500 1996 LX450 swap (2 Viewers)

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That’s a great questions. I was talking with a hot rodder before I started my swap. He mentioned the 3-5 degree mounting angle to me. Before I mounted my motor, I read through some Cummins specs and what information I could find and found some figures for the Cummins. I’ll get on my laptop and find that data and post up for you to look over.
Maybe just a recommendation for best fit in the 80 series in regard to the firewall and trans tunnel clearance? 🤷‍♂️
 
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Maybe just a recommendation for best fit in the 89 series in regard to the firewall and trans tunnel clearance? 🤷‍♂️
If you do a one inch body inch, you’ll have adequate room to move the motor back and clear the trans tunnel. I suggest measuring the angle of both drivelines before you pull your Toyota motor. Also take some good reference measurements of the height of your transfer case. When you build your transmission mount, you’ll have those measurements to get the height right at the transmission mount.
 
If you do a one inch body inch, you’ll have adequate room to move the motor back and clear the trans tunnel. I suggest measuring the angle of both drivelines before you pull your Toyota motor. Also take some good reference measurements of the height of your transfer case. When you build your transmission mount, you’ll have those measurements to get the height right at the transmission mount.
All good suggestions. I do however, hate body lifts. Just my preference.
 
All good suggestions. I do however, hate body lifts. Just my preference.
Understood, Sir. I crawled under the truck today to check the clearance with the bellhousing bolts. With this body lift, I have good clearance to remove my bellhousing bolts whenever I need to service my clutch, etc.
 
Now that I’ve moved my motor back and have the Cummins mechanical fan up and running, I’ve started working on the air box and intercooler. I’m also wiring up a pusher fan on my AC condenser. I had a buddy build me a simple air box and flip my intercooler and build a bracket on my frame rails. All of my piping still lines up nicely.
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Trans cooler is installed. I tapped some threads for a temp sensor. No leaks right now.

This trans cooler was a “new - old stock” item I bought off eBay for a bargain price. It has a piece of polycarbonate on the outside to view the oil level.

Right now on the highway I’m averaging between 110-140 degrees F.

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Been doing some math and something does not seem to lined up with your set up and the rpms you are getting...
If you are running 35s, nv4500 5th gear is 0.75:1, and 3.55 diff, at 70mph you should only be at around 1800rpm
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Am I missing something?
 
Been doing some math and something does not seem to lined up with your set up and the rpms you are getting...
If you are running 35s, nv4500 5th gear is 0.75:1, and 3.55 diff, at 70mph you should only be at around 1800rpm
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Am I missing something?
That’s a great question. Those calculations are very close to where I’m at. I don’t think the tach on my dash is 100% accurate. I’m feeding the tach with a Dakota digital box that’s measuring rpm’s on my alternator. I had to calibrate the Dakota digital box. To do this, I used a harbor freight rpm meter to measure rpm’s on the crankshaft pulley. This may be causing an inaccurate reading within the calibration.

Also, those online calculators are a mathematical formula and can’t always account for variations in driving conditions and engine efficiency. I’ve had mechanics tell me the online calculators give a good ballpark range.

65mph is where I am seeing the sweet spot in terms of fuel efficiency and rpm’s. I am getting around 20 mpg when I keep it at 65mph and control my shifting.
 
That’s a great question. Those calculations are very close to where I’m at. I don’t think the tach on my dash is 100% accurate. I’m feeding the tach with a Dakota digital box that’s measuring rpm’s on my alternator. I had to calibrate the Dakota digital box. To do this, I used a harbor freight rpm meter to measure rpm’s on the crankshaft pulley. This may be causing an inaccurate reading within the calibration.

Also, those online calculators are a mathematical formula and can’t always account for variations in driving conditions and engine efficiency. I’ve had mechanics tell me the online calculators give a good ballpark range.

65mph is where I am seeing the sweet spot in terms of fuel efficiency and rpm’s. I am getting around 20 mpg when I keep it at 65mph and control my shifting.
Driving conditions shouldn’t have any effect in a manual transmission.
 
Driving conditions shouldn’t have any effect in a manual transmission.
This is my humble opinion…….. In terms of calculating final mph and rpm based off gear ratios, tire size etc; driving conditions would have an impact on mph. I’ve read that driving conditions can cause a 5-10% variation in the online calculators.
 
This is my humble opinion…….. In terms of calculating final mph and rpm based off gear ratios, tire size etc; driving conditions would have an impact on mph. I’ve read that driving conditions can cause a 5-10% variation in the online calculators.
Something has to slip for there to be any error.
Loaded radius might cause a slight error.

I think your on to something when you talk about calibrating the DD gauges. I’m getting close to doing that on my project, same engine. We upgraded the alternator from the existing 1 wire as my electrician said that sound be more dependable signal, IIRC.
 
This is my humble opinion…….. In terms of calculating final mph and rpm based off gear ratios, tire size etc; driving conditions would have an impact on mph. I’ve read that driving conditions can cause a 5-10% variation in the online calculators.
It would affect MPG but definitely not MPH. That 5-10% would be true potential for an automatic or if your clutch is slipping.
 
Something has to slip for there to be any error.
Loaded radius might cause a slight error.

I think your on to something when you talk about calibrating the DD gauges. I’m getting close to doing that on my project, same engine. We upgraded the alternator from the existing 1 wire as my electrician said that sound be more dependable signal, IIRC.
Please let me know what method you end up using to measure the engines rpm’s when you calibrate your DDB. I would love to find another way to measure mine.
 

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