Tuning

bartiger said:
From pirate racing: with a decat you need a PCV etc

Without a fuel correction, your engine would run to lean..

Or iam wrong??
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Yeah, that's why I'm asking. Was wondering if it was running with a decat and no remap
 
Usually a decat requires an optimized mapping to achieve the best result.
Without the cat it has less back pressure. The sharp cam has much overlap and AFR will react quiet sensitive with the tendency to run lean.

There are two options:
1. You buy from a tuner you trust a proofed package of mods with his matching mapping. For exemple programmed in the PCV or directly into the ECU.
2. You choose your own tuning package and have programmed your individual mapping on a dyno into the PCV or similar.

(Option 1. will turn out less expensive at the end.)

A third option might be, ad some tuning items and just belive that you have the fastest Pilen on earth.:p
 
I'm familiar with tuning, AFRs, etc. What I haven't seen (perhaps haven't looked enough) are dyno runs from individuals, not shops, of a vitpilen 701 with a decat with a chamber and no tune.
I don't mind spending on a pcv but why do it if not needed. Also different regions have different gas quality and plays an important role as well.
I'll do some testing in the next few weeks and will report back.
 
BTW, a stock bike with a cat will benefit just as much from tune. What I'm wondering is if when decated if it will be further from optimal then when stock.
 
At WOT and high rpm (with or without airbox lid, original exhaust with cat) AFR will be around 12.5
So you‘re right, there is some margin of about 0.5 to weaken the mixture without loosing power.
On the other hand you‘re not only removing the cat, you‘re also have a smaller silencer with less volume. This has also an significant impact on the back wave and is not linear. I would be surprised if you make a lucky punch with the original map.
 
Yeah, I talked about that with the Pirate Racing guy. It's not the cat itself that's so magically good, it's the volume of the pre muffler. The engine needs it.

Even for racing a fully tuned engine, this engine needs that volume at about the same length from the exhaust ports.
 
chvit said:
By mid do you mean a decat?

I'm planning on trying that setup: Shark src4, decat, airbox lid removed, fuel dongle and sas removal.
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Yes, the Arrow set has a mid pipe with a chamber that replaced the cat.
I haven’t felt any need for a Power Commander. No popping on decel. No surging. No flat spots. I’m still very happy with my setup.
 
I was told by a reputable source that one should take it slow for the first 25 minutes at least after you warm it up the first time, because it will run lean until the bike adjusts itself.

Then, as @Ray R suggests, it should run fine.
 
In the closed loop area a trim and/or an adaptation is state of technique but in the open loop area there is nothing like this it's all controlled via dataset and not regulated.
 
That's right and the caveat with all ecu tricking devices. The intelligence of the ecu will be bypassed.
 
If a device manipulates a sensor value it hinders the physical calculations from the ecu models.

Any piggy bag device just can shift input values. Then the regulation still work, but there is a risk of out of range in extreme environment like e.g. high altitude or high temperatures. In case of the O2 eliminator the ecu is blind.
 
I know what you mean. Luckily the tables in the ECU don't scale limitless and there are still other sensors doing their job. IAT, ambient temp/pressure, engine temp, etc

I haven't had any problems in 7000 miles up 7500' altitude or 115 deg F. Runs like a champ, no knocking, no surging, not running warm. And so have many other. Airbox lid removed, and cat still installed.
 
I keep hearing Pirate Racing but here in the USA, the source is Rottweiler Performance.

The Stock ECU is always going to run the Air fuel mixture as lean as possible because the bureaucrats believe that we are messing up their ozone. This causes engines to run hot. One area in particular is low rpm’s beginning from idle. Bureaucrats test and regulate this area with O2 sensors such that an overlay remapping device such as a Power commander will be overridden by the ECU unless a device to manipulate the sensor (dongle) is put in place. The goal is to have an optimum air fuel ratio mixture throughout the entire rpm range with smooth torque curve/power output. All of this facilitates normal internal combustion engine operating temperatures.
 
Yeah been having that since I ride motorcycles on any bike that had thinwalled stainless exhaust headers. Suzuki, BMW, Ducati, Indian, Husky…
 
Just meant to imply the needless heat resulting from emissions controls forcing lean AFM ratios can be corrected. So why not correct the AFM ratios throughout the rev range?
 
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