RPM observations

[Chris078]

Just took mine out for a spin after sucessfully reassembling the dash.
Apart from the heater flap! which means I have to pull it all apart again :censored::censored::censored:
anyways, I now have a Tacho installed and have made some interesting observations.

Gear Speed RPM
1st 35 2100

2nd 20 750
40 1850
60 2100

3rd 40 1600
60 1600
80 2100

4th 60 1000
80 1400
90 1600
100 1800

It's interesting just how low revs are needed. I was really revving it out in 2nd, and at 2100 I was actually quite scared I was going to break something. The noise was unbelievable and starting to sound very metallic.
Same as in 3rd at 80. 2200 seems to be the max RPM you would want to/can use.

Someone smarter than me can probably do the math and work out how accurate the speed/rpm is. These speeds were taken from a GPS app on my phone (though the speedo is accurate to within 3-5 km - reads low). Tyres are same diameter as the 7.5R16 (235/85/R16)


I'm not sure if it's possible to use revs higher than 2200 or so. I know I wouldn't like to be in it when you were doing so.

<edit> I've tried to space those numbers out, but the spaces get deleted when I post???

edit 2 > updated some numbers

[Dervish]

Sorry mate, but your tacho is way out.

https://www.aulro.com/afvb/images/imported/2016/03/198.jpg

This graph is generated purely mathematically so it doesn't account for things like our tyres being a larger diameter than normal 235/85r16s, but it should still be very accurate.

[Chris078]

Interesting.
It seems to read the idle speed ok. Wonder what's going on.
Have to break out the manual and have a closer look.
I didn't think it was right having a whole 1000 rpm not used.

235/85/r16 has the same circumference as the 7.5R16 so they should not make any difference.

<edit> fixed. was set for a different amount of pulses per revolution.
edit 2 - It may be mathamatically possible to get a perentie to 133 km/hr. I would not want to be in it when trying!


Now need to adjust the 1100 rpm idle.

[Blknight.aus]

wait till you hear one engine braking in second at about 70...


hmmmm the passenger hated the smell of burnt brake fade in the evening

[Vern]

Yep tacho is out. When its revving on the governor it should read about 3200

[Chris078]

hmm. I think I need new springs on the injector motor. can't get it to idle lower than 800. I can undo the bolt and leave a gap and the arm won't go back against the bolt unless I force it. Might be because it looks like it has always been idling high and I think there may be a bit of a ridge worn in the mounting plate.
I assume you can get the springs from Isuzu. Have to go out there anyway to chase up an oil sump plug and gasket; can't find those for sale anywhere.

[BadCo.]

Interesting.
It seems to read the idle speed ok. Wonder what's going on.
Have to break out the manual and have a closer look.
I didn't think it was right having a whole 1000 rpm not used.

235/85/r16 has the same circumference as the 7.5R16 so they should not make any difference.

<edit> fixed. was set for a different amount of pulses per revolution.
edit 2 - It may be mathamatically possible to get a perentie to 133 km/hr. I would not want to be in it when trying!


Now need to adjust the 1100 rpm idle.

Wait to you get a turbo, accelerating from 100 is great fun.