Hwy speed for cummins conversion truck

[DVolk]

Does any one have a idea what i should exspect for a stock 90 cummins

with a blue bird 5. 9 bus 190HP pump . NV 4500 5 spd trans .



4:11s 35" tires .



The truck acts really low geared .



I have not really nailed the go pedal so im not shure if its really turning all that fast , but she did make 20 + lbs of boost though a littel though when i goosed it a bit .



This was around 60 to 65 mph



Does any one have a gear vendors to fit a NV 4500 ?

 

[BAnsley]

Check out randys ring and pinion they have calculators that should give you what you need. Later Brian

 

[HRDROKN]

Seems that I can remember getting about 85 mph with a first gen in my 85 Crew Cab... . even after pump tweaks and POD's. It sure got there faster though :-laf I was running 35's w/4. 10's



I think the gov spring would be the key there!

 

[DVolk]

I got 366 springs here if i can get them done in the truck and i can get any gaskets that get messed up and not screw my pump up as i got 2 springs and 2 pumps and 2 trucks

 

[therabbittree]

well my excursion had a NV4500 and 4. 10 gears. it has 12v rated at 160 hp 11mm plunger p ump etc. its modifed had 4000k gov springs and 37" tires. . i can run about 3000 rpm and be at 80-85 mph if that helps you... i would chec kit is fully moving pump arm when you floor the accelerator pedal. My first gen needed a to have lot of adjustment to get full pump arm travel. Ie if you back off the max rpm adjstment scre till the arm no longer moves forward un stopped then tighten the lock nut etc. seeif the linkage then allows full travle. . etcetc. . i imagine it would doa about 95mph or so maxed out with your smaller tires.

Thanks

Deo

 

[DVolk]

Ill have to check to make shure im getting full throttel or not .

I do know she is short legged in the gears , it sounds like it any way only has

the down pipe then about 3 feet of tail pipe , in low range its really low like 15 miles per hour in first gear

 

[Applegator]

With 35" tires. 4. 11, in O/D at 2000 RPM, we calculated you are going 69 MPH.

 

[Batphreak]

This may be silly and un-needed. You do know that 1st in the NV4500 is a low "granny gear" don't expect much out of it for speed even with the transfer case in hi range. For normal driving start in 2nd, not 1st.

 

[DVolk]

The truck runs about 69 MPH according to the speedo in the truck .



I was hopeing for a littel more :-( , oh well



My 92 will get 80 MPH with 3:55 and 33's .



I thought id get mid 70s , my transmission is a 97 vintage NV4500



To the commit about granny gear , i use second as well as first

 

[Applegator]

We calculated your 92 truck at 80MPH, your RPM is 2100.



So the 4. 11 truck at 2100 RPM makes 73 MPH which is closer to what you want.

 

[Forrest Nearing]

put a governor spring in it and get some more RPM out of it... I bet that pump is starting to defuel before 2400rpm