nevrnf

Did some searching but being new to the Cummins i am asking.
How does a 62/71/13 compare to a 64/65/13. Will the smaller housing on the 64 give me quicker spool like the 62 with a little more flow?
I know i need twins but after the $$$ spent doing this engine conversion i just can't swing it right now.
Engine specs are
03 CR
Helix 1 cam and springs
F1 stg II's
Studs
Floor it CP3 kit
4" exhaust and BD manifold (3rd gen)
intake elbo and grid delete
AD 150

Rpainter

the 65 turbo would spool faster down low but run out of cool air on the top end. the 71 would spool slightly slower down low in the rpm band but would have more air to cool the higher rpms.

BigJohnston

So how would a 62/71/13ss compare to a larger 64/65/13ss? So is a smaller compressor wheel with a larger turbine better than a bigger compressor wheel and a smaller turbine? I am just asking because I am in the same boat, HTT recommends the 64/65/13ss? I have a 62/74/14 and it is very laggy at my elevation(4000ft) and with a low stall TC. I would definitely get the 64/71/13ss if it wasn't for these factors.

BTW sorry to hijack your post but I think we are both trying to get the same info. Thanks, Tom J.

rip 112

The 62/71-13ss offers a better drive pressure ratio compared to the 64/65-13ss. The 64/65 is intended to move a very close amount of air but at a quicker initial rate than the 62/71. The 62/71 however is more oriented to moving higher rpm air through while being relatively cooler. So considering you have an auto the 64/65 would be more ideal.

nvernf, I would consider the 62/71 before the 64/65, with sticks and cp3 upgrades you're looking at things getting possibly toasty in the top end, you need plenty of airflow. I would even be looking at a 64/71 for what you have.

BigJohnston

I agree the 64/71 is a better turbo but the turbo lag I am getting from having low stall torque converter and being at 4,000ft elevation is killing me.