Happy 13BT Highway RPM

[Hulsty]

Wouldnt less boost cause you to work the engine harder to maintain speed and use more fuel ?

 

[crushers]

lowing boost will not increase fuel mileage, your right foot and fuel settings will.

 

[boogie74]

Cool, Thanks!

I'm pretty happy with the way the cruiser is performing at the moment.
Also pretty happy with the fuel economy. Don't think I will change any settings.
As I was driving I was remembering the right foot advice of crushers.

Cheers!

 

[Hulsty]

Boogie I am averaging the same fuel consumption as you, maybe a freckle less. Just installed my pyro toinght though.... Will post in your pyro temps thread.

 

[crushers]

anything over 25 imp gal / mile is respectable with a 13BT...

 

[Greg_B]

Glenn, updated numbers in my post.

gb

 

[benniebez]

Post updated aswell Glen. I'am thinking of changing up to 35" soon, I think it shall keep speed well as there is enough grunt still left, and the turbo is only boosting upto 0.55bar.

 

[Glenn-BJ74]

Based on all this data I have developed spreadsheet that simulates all those gear (4.11 diff, 5th gear ratio, Mark underdrive), and tire size combinations (33” and 35”). It predicts actual speed and RPM fairly accurately now .The hardest part of dialling in the spreadsheet was estimating the effective tire diameter. My 33” Truxus (Interco says 32.8”) are actually 30.56” in diameter spinning on the highway. The vehicle weight and spinning of the wheel make that difficult to estimate so I calculated it from other data and worked backwards. In any case it works.

If anyone is thinking of going 33” to 35" (with any diff ratio) I can tell you what speed you will be going at any target RPM ( 2200 to 2400 RPM - the sweet spot) or RPM and speed

 

[Malahki]

Hey Glen-BJ74 I am in the process right now of switching from 4.11's to 4'56's. I am running 35" MTZ's. What RPM will I be doing at 110km/h? (5 speed manual H55f)

 

[Glenn-BJ74]

4.11, 35's, 5th gear at 110 kph (actual) = 2460 RPM
4.56, 35's, 5th gear at 110 kph (actual) = 2730 RPM

If you can confirm your existing RPM at actual speed with 4.11s, I can give you a better estimate with the 4.56s.
Looks like you are close to the sweet spot now for highway. But off-road too high?

 

[Malahki]

4.11, 35's, 5th gear at 110 kph (actual) = 2460 RPM
4.56, 35's, 5th gear at 110 kph (actual) = 2730 RPM

If you can confirm your existing RPM at actual speed with 4.11s, I can give you a better estimate with the 4.56s.
Looks like you are close to the sweet spot now for highway. But off-road too high?

Here are my actual readings with 4.11's from earlier post
5th Gear
2300RPM - 100km/h
2600RPM - 115km/h
2800RPM - 124km/h

Doing the math that would make 110km/h at 2480RPM. Looks like you were pretty dam close, the difference obviously being tire diameter.