lower gears

[Chadahootchie]

Would turning 2000 rpms at 60 would be to low for a diesel? It would be like 2300 at 70. I dont really drive on the highway that much its mostly a city truck. But when it is on the highway I'm towing a truck. There 5.38 gears

[BadDogPSD]

Originally Posted by Chadahootchie

Would turning 2000 rpms at 60 would be to low for a diesel? It would be like 2300 at 70. I dont really drive on the highway that much its mostly a city truck. But when it is on the highway I'm towing a truck. There 5.38 gears

No, 1900-2000 is good for hwy driving.

[gtspowerstroke]

Shoot with my 3.55 gears and 35" tires I'm turning about 1700 at 70!

[Chadahootchie]

Originally Posted by gtspowerstroke

Shoot with my 3.55 gears and 35" tires I'm turning about 1700 at 70!

thats about what my truck does now but it seems like its working to hard when towing. I mean I know I dont have an intercooler but even if my truck is on stock setting at 65 towing my woods truck Im at 1200* egts.

[dereku]

your sig doesnt say it you have an intake those help a lot. The FRP shim mod can lower EGTs slightly. CAT and Muffler delete also help. Otherwise its all turbo. And check for boost leaks. What is the highest boost number you can hit.

[elibenson]

I think that 5.38 would be way too low for a 7.3l truck, unless you are running some ridiculous tires on it. My 6.4l (higher revving than a 7.3l)F450 with 4.88's is close to 3000 rpms at 80mph. You can't do that with a 7.3l.

With 5.38 gears with 35" tires, in over drive(0.71:1) at 2700 rpms, you will be doing 73.6mph. In my opinion, that is a pretty scary RPM to be cruising at for a 7.3l.

[Chadahootchie]

Originally Posted by dereku

your sig doesnt say it you have an intake those help a lot. The FRP shim mod can lower EGTs slightly. CAT and Muffler delete also help. Otherwise its all turbo. And check for boost leaks. What is the highest boost number you can hit.

I have all that stuff on my truck and they highest boost I can hit is 20 psi.

[Chadahootchie]

Originally Posted by elibenson

I think that 5.38 would be way too low for a 7.3l truck, unless you are running some ridiculous tires on it. My 6.4l (higher revving than a 7.3l)F450 with 4.88's is close to 3000 rpms at 80mph. You can't do that with a 7.3l.

With 5.38 gears with 35" tires, in over drive(0.71:1) at 2700 rpms, you will be doing 73.6mph. In my opinion, that is a pretty scary RPM to be cruising at for a 7.3l.

I have 38's on my truck and plan on putting 40's the next time or bigger. I would consider 5.13 but wouldnt want to regear the truck and put bigger tires on the truck and then it would still not be correct.

[jamstoyz]

if you run 40's than go with the 5.13's i have a 4.30 and my rpm at 70 is about 2250 to 2300. at 60 its at 2000. i like having this gear cause it relieves a lot of stress off the motor and tranny.

[Chadahootchie]

Originally Posted by jamstoyz

if you run 40's than go with the 5.13's i have a 4.30 and my rpm at 70 is about 2250 to 2300. at 60 its at 2000. i like having this gear cause it relieves a lot of stress off the motor and tranny.

Are you sure your speedo is corrected because at that mph and rpms and gears you should be running a 31'' tire.