2003 with a 5 speed transmission?

[AH64ID]

How does the rokkteck make the truck sound in the 1200-1600 range? On stock timing my truck is SUPER noisy and I couldn't imagine 2° more down there.

Did you mean 2800 at 75? It should only be ~2500 at 75.

Speed, not rpms, is the biggest factor for fuel economy. As far as towing rpms become more important, 2000-2200 is the sweet spot.

 

[NIsaacs]

Did you mean 2800 at 75? It should only be 2300 at 75.


I think the OP has 4. 10's, 2300 @ 75 seems low for that ratio.

Nick

 

[AH64ID]

Thanks. . hit the wrong key, should be about 2500, not 2800... or 2300

 

[rscurtis]

That was my thought too, until I remembered that the 4500 does not have the deep OD ratio that the auto has. I don't recall the ratio, but it's not . 69:1.



The timing from the Rokktech is noticeable only when the engine is cold, as in cold weather. For the first mile or so, it sounds like a 12 valve until the ECM retards the timing.

 

[cerberusiam]

AH pointed it out before I posted that 2800 was a little high. Either the speedo or tach is off or its a fat finger.

The 4500 and 5600 with 4. 10's is roughly what the G56 is with 3. 73's, 2400-2500 at 75 mph. Great for towing, not so good for mileage at higher speeds.

 

[AH64ID]

NV5600 has a . 73:1; NV4500 has a . 75:1, G56 AD has a . 79:1, G56 AE has a . 74:1, 48RE had a . 69:1, 68RFE has a . 82:1 and a . 63:1. .

I really want a manual trans with a . 83:1 and a . 65:1. With 4. 10's and stock rubber you would be able to be at 2,000 rpms at about 1,22,32,44,54,68 and 80 would still only be 2350. Add some 285/75's and you would have a nice setup.

 

[cerberusiam]

I really want a manual trans with a . 83:1 and a . 65:1.

Yep, 7 speed double countershaft transmission, 4 gears below 1:1 and 2 above. Too bad it is but a dream. :-laf