THE PROGRAMMING TRUTH
Over the past couple of months on many forums one of the hot topics has been the need for an EFI programmers on a Can-am ATV running an exhaust. On one side you have the die hard "No you don't need a programmer" group, and on the other side you have the "Your going to kill your motor if you don't run a programmer" group. So MUDandDIRT along with the Ms MudNutz teamed up to get the facts on this question.
We got two Can-ams for our test. The first was a new 07 Outlander 800 with 20 miles on the odometer and a brand new 08 Outlander 650 with 40 miles on the ticker. Both were bone stock with stock air filter and no snorkel system.
The testing was done by myself (MUDandDIRT) using a Dynojet Wide Band Commander monitoring RPMs, Throttle Position, and Air/Fuel ratio on each bike. Two runs per throttle position range were ran on a closed road with a slight hill. Throttle positions were adjusted using the throttle position stop screw and the Wide Band Commander reading the TP sensor. Throttle positions ran were 100%, 80%, 60%, 40%, and 20%. Idle A/F was also recorded. The wide band sensor was welded into the stock exhaust can and the HMF pipe before the can.
A short lesson on A/F readings. Most dyno tuners have found that peak HP comes at about 13.5/1 air fuel ratio. Anything higher then 13.5 is a lean condition (To much air) and anything below 13.5 is a rich condition (To much fuel). I personally feel that any (+ or -) 1 point in either direction justifies a programmer. Those limits would be 12.5 on the rich side a 14.5 on the lean side.
THE CAN-AM OUTLANDER 800
The 800 was the first up with stock exhaust. Two
runs per TP range was ran and recorded. Below are the average results
for each range
We unbolted the stock exhaust and
bolted up the HMF with no programmer.
Our conclusion is that just bolting up an HMF to a stock 800 does lean out the motor. This lean condition will not hurt your motor over a short period of time but could cause long term wear to the motor due to the extra heat a lean condition causes. Also let me note that these reading were made with a stock paper filter. I highly recommend the UNI replacement filter but replacing the stock filter with this high flow filter will cause the mixture to lean out bumping them into the danger zone.
MUDandDIRT suggests a programmer to adjust your bikes A/F mixture out of the outer limits into a safer range.
THE CAN-AM OUTLANDER 650
The same tests were made with a Can-am 650 using
our HMF exhaust. Stock muffler readings were not made but the HMF
readings were recorded.
Again this is with the stock paper filter that does not flow as much as the preferred UNI replacement filter from Can-am. Our conclusion is that a programmer is highly recommended with the 650s running an exhaust. At slow trail speeds our test bike would be running in a dangerous A/F range.
In the end the decision to fork out the $200 to $300 bucks is up to you. I personally think that it is worth the money to put the A/F ratio back into specs. Of course you are going to have the cases on either side that one bikes A/F was dead on with a programmer and another was WAY out of wack. No two bikes will run the same and no two readings will be the same. But are you certain that your bike is running perfect throughout the whole RPM/TP range? For those that don't I suggest a programmer.