Yamaha Wolverine Forum banner
1 - 20 of 29 Posts

·
Super Moderator
Joined
·
2,050 Posts
I don't want to rain on your parade but you actually might end up increasing the exhaust temps unless you put a fuel controller on there. You have effectively leaned out the A/F ration even more now. If I were you I would seriously consider getting a fuel controller, or even a PCV with ignition timing too.
 

·
Banned
Joined
·
420 Posts
My exact thoughts on the leaning. I'm sure you are correct FTM
 

·
Super Moderator
Joined
·
2,050 Posts
yea I was planning on getting the power commander anyway
if I notice any problems ill put the baffle back in until I get it
Gotcha. Just be mindful, leaning it even more can than stock opens the door to detonation, which can cause engine damage if you don't notice it. The last thing you want is a hole in your piston lol. If you don't run it WOT too much until you get a power commander you should be safe.
 

·
Premium Member
Joined
·
437 Posts
I don't want to rain on your parade but you actually might end up increasing the exhaust temps unless you put a fuel controller on there. You have effectively leaned out the A/F ration even more now. If I were you I would seriously consider getting a fuel controller, or even a PCV with ignition timing too.
FordTruckMan, I don't know how the amount of exhaust pipe restriction (or lack of) affects the AF ratio? Does an O2 sensor measure exhaust pressure too? Please explain. Thanks
 

·
Super Moderator
Joined
·
2,050 Posts
FordTruckMan, I don't know how the amount of exhaust pipe restriction (or lack of) affects the AF ratio? Does an O2 sensor measure exhaust pressure too? Please explain. Thanks
Well, the simplest explanation is this:
A/F ratio is just that, the ratio of air to fuel that the combustion chamber is seeing. When you open up the exhaust, you are increasing the amount of air capable of flowing through the system. Since the wolverine runs an open loop fuel injection system(no O2 sensor), it cannot respond to the changes in air with appropriate changes in fuel. So, we have increased our air without increasing our fuel, which is a lean condition when compared to stock.

Now, this would not necessarily be an issue, but the Wolverine runs rather lean to begin with, so leaning it out even more is where we begin to risk the integrity of the engine. If the Wolverine had an O2 sensor, it would see the A/F ratio was leaning out, and add more fuel. But, it doesn't, because that cost's more money lol. It uses what is called an open loop system, where it runs off a preset fuel and timing map to apply specific amounts of fuel and timing advance depending on the throttle position, engine RPM, atmospheric pressure & temperature, and engine temperature. This system does a pretty good job under a general variety of conditions. The problem is, it is all preset based on the manufacturers machine design. So, if you make a change to the design of the machine(open up the exhaust for example), it has no way of knowing that, and will continue to try to run just like it always has.

There is another type of system that can be used, and Power Commander offers a kit to do this. This is called a closed loop system. This system is basically the same thing as the open loop, but it adds an O2 sensor. This is basically a hunk of metal that when voltage is applied to it, it creates a measurable voltage differential(narrow band) or a measurable current(wide band), dependent on the gas composition surrounding it. This is calibrated to the ideal gas ratio of combustion, which is referred to as stoichiomteric. This ratio for gasoline is 14.7 to 1. So you need 14.7 times as much air as you do fuel. The closed loop system is what automobiles use now.

All of this is the very basic idea, there is waaaaay more to it than this, but this should give you the idea.


I should add, the reason the exhaust being opened allows more air flow is because it is the "choke point" of this system. I have typically found that on stock systems, cars, trucks, atvs, etc, the biggest restriction of the air system is the exhaust. It is usually to reduce noise. More often than not, if you open the exhaust, the stock air intake can flow a tremendous amount more air than it could before. After learning this, I quit upgrading the intakes on my vehicles, because the marginal gains over stock were not worth the cost. The results were always better per dollar with the exhaust and tuning.

Hope this helps.
 

·
Premium Member
Joined
·
437 Posts
Thank you. I thought the two functions (intake,exhaust) were completely separated by the valves but I just asked one of the mechanics here in the shop and he explained valve overlap to me. Now I understand how exhaust pressure affects the intake side. Thanks again.
 

·
Registered
Joined
·
367 Posts
Why didn't you just disconnect one endlink instead of full removal? Disconnecting one side eliminates all function of the sway bar but allows you to reattach it with one nut if you choose to hit the high speed road home
 

·
Registered
Joined
·
213 Posts
Discussion Starter · #14 ·
ill never hook it back up. ive removed them from both my rhino and grizzly as well, they all go on the trash pile. ive never had an issue. taking it off doesn't instantly turn it into a death machine. sense then ive had it around our backyard track and on the road and all is good. its not a racecar, id much rather have the flex on the trails
 

·
Super Moderator
Joined
·
2,050 Posts
ill never hook it back up. ive removed them from both my rhino and grizzly as well, they all go on the trash pile. ive never had an issue. taking it off doesn't instantly turn it into a death machine. sense then ive had it around our backyard track and on the road and all is good. its not a racecar, id much rather have the flex on the trails
Do you notice any more tendency to lift the inside tire if you take a turn at speed? The only thing that would concern me is is powersliding would be less predictable and make it feel tippy without the bar in place. But hell, if you don't do much of that, the benefits of removing it certainly seem better.
 
1 - 20 of 29 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top