may go C-18 from C-16

Yes the C-15/C-16 head is fine for this application

 

The limiting factor is the fuel system. The only net gain from this modification is torque, but no extra Hp. The problem with the extra torque is building a clutch that can harness it and use it. If you build big power with one the torque rise is so steep that nobody that I have talked to can get a clutch to survive for longer 250,000 miles. The other thing is they seem to consume an extraordinary amount of fuel for the same Hp output of a modified C-15/C-16. Why? I don't know, but my thoughts are on the fact the thrust loads between the cylinder and piston are much higher with the longer stroke crankshaft versus the short rod of the C15 Acert engines that are found in these engines.

The other problem with these engines is finding a turbo that will respond quickly, yet move the volume of air need to support the same Hp in the larger cubic inch displacement. If you want a C-18 with a 1000Hp the turbo has to be larger than a turbo on a C-16 for 1000 Hp this makes for a sluggish pig at low engine RPM in the C-18

 

I know where a C-18 crank is for sale that has only been used for some dyno testing. It doubt it has more than 25 dyno runs on it. PM me if you're interested.

 

I guess what I was wondering, when you said they didn't really get any more power out of the 18, was if the head was restricting airflow enough to be the issue.

 

No, the head will flow more than enough air to support more Hp than you will ever be able to build and use in a street application.

 

When you say the fuel system, do you mean being able to get the fuel into the head and to the injector?

 

Biggest issue we have with the Eatons are the drivers always seem to pound the springs out of the friction discs long before the friction material is burnt off. Not big power either, 450hp up to 600hp.

 

Eatons are junk, I've got 8 or more sitting in my steel bin with the same issue you speak of, im hoping the lipe clutches ive been replacing them with will last a lil longer.

 

The injector is the limiting factor when reaching for the stratosphere no matter which engine you are working with. Filling the injector with the fuel passage in the cylinder head may also start coming into the equation once you get past the other limits of the injector