I recently heard that you should not run a pipe with the 2 inch power band on a stock Zen; and that a standard cone to cone is the only way to go. Is there any truth to this?

I dont see why you shouldnt run a 2\" band pipe on a stock 260... it has great topend rpm capability with a broader torque band then a RPM pipe. On some hulls with some setups you might not need a band pipe... but that still wouldnt leave any reason why you shouldnt run a band pipe.


If there is...then id like to know also, as ive never run a band pipe..only steel RPM pipes.

I didnt think so either. Thinking about building a CTB, and I have a muffled pipe with a 2 in band.

If any thing, a 2\" band pipe MAY NOT be able to get short enough on some header styles.

** keep in mind that stock engines using less exhaust duration will run best on a SHORTER pipe length than the mod engines do.

I was thinking I would use a 90 deg header and exit it out the transom. Should I be able to get the power and RPM out of it with this config?

mitchesx wrote:
A 90* header would be the best choice, and run it from 1/2\" to 1\" SHORTER than a mod engine would with the same pipe / header combo.

Ok, so after measuring my rigger from the center of the SP to the weld in the cone, I get 14 in. So 13 to 13 1/2 inches sounds like the right number range to work with? This includes the bend in the pipe which is 100 to 105 degrees. My cat with a quote stage one modified endquote Marine Specialties motor is set at 13 1/2 with a 100 deg header. Am I too close there?

Like all tuning, start long, which would be in the case of a stock engine, same as the mod one. Run it and keep shortening 1/4 at a time until no further rpm or power is noticed.

Scott wrote:
Thats interesting, as i remember my stock 260 liked the pipe at the same length i pretty much run my mod motors at (i ran the steel china pipe from american rc @ 11-1/2 to 11-3/4 with a 472/insane mono. 15960+ w/ stock 260, 17600-17900 w/ mod 260).

Will Nichols wrote:
Really whats the case ...

A stock engine with HIGHER compression and less EX timing will have GREATER TORQUE ..
so we load up the engine with more prop and settle for 1500/2000 less rpm than a mod engine, yet have 2 or more LESS actual HP on tap.

What few realize is that if you back off some on prop load then run on a shorter pipe, you can get some more RPM out of a stock engine along with some more HP.

It is really just a case of another way too find more speed and power from a stock engine. Actual pipe tuning differs from just putting on the most prop it can pull and calling it maxed out
Note my quote above: I state equal pipe and header, Nothing said of prop

Either tuning way is fine, just know their are other ways getting too the same place