That's right. If you're going the autotune route the dyno is just a waste of money. But why ruin a perfectly good dyno tune?

 

Well, I think there is some confusion here. O2 sensors in the headers are a final input to the ecm based on the sampling of the exhaust gas telling the computer to increase or reduce air fuel ratio by controlling the fuel. The maps don't change, sensors don't have anything to do with the mapping, they simply measure the degree of "combustion" from the exhaust. Narrow band means that the feedback from the O2 sensors only causes adjustments to fuel in steady state, no use in WOT, warm up mode etc. Wide band are used in cars and some European bikes, those sennors feed input to those efi systems across a much wider rpm load.

 

So then the autotune basic in the power vision that uses the narrow band factory sensors is a waste of time?

 

I'm gonnabe really extreme here and say do what you want. Closed or open loop the technicalities of each far exceed the capabilitities of these motorcycles.....so what you believe you might, comparing the two, save a few mpg, achieve 0-60 o.5 secs faster, or even achieve 5mph more than the guy with the other system.

Unless you are dealing with multi valve and ported fuel technology nothing is going to make that much difference between the option, agreed all improve the stock situation.

Unless I was really gonna do something with the head and cams I would choose the most economic solution open to me to release those few ponies restrained at the factory....other than that take your choice and go with that which appeals to you most......in most cases usually the most expensive seems best so go with that if it makes you feel better....


no offence to anyone just my rant....

R

 

First, the HD narrow-band O2 sensors work in the low-end and midrange (cruise range) and are disabled as TP (throttle position) or KPA (MAP) approach WOT. Next, wideband O2 sensors will not communicate with a stock HD ECM. Thus, if you want to run closed-loop with a stock HD ECM with no add-ons you are limited to the stock sensors. These work mostly as switches to keep AFR to spec so the engine runs within EPA mandates, and are adjustable only in a very narrow AFR range. They have utterly nothing to do with the bike's performance or fuel economy when the ECM is optimized properly to begin with.

Wideband systems that work in closed-loop do exist, however. The PCV with AT option works with the PCV, not the ECM. Thundermax is a replacement for the stock ECM and it works with wideband sensors in closed-loop. The Rev. Performance EMS works with widebands after RP reworks the ECM to run with them. The PCV-AT costs $300 for the PCV and $300 for AT, and both T'Max and EMS cost more.

Open-loop operation is not as limited as some think. I've been running open-loop with my Power Vision for >2 years and it works well without any feedback from O2 sensors. I have wideband sensors installed, but they are only used for datalogging and tuning, and do not function at all in normal operation except for monitoring purposes. I do monitor Lambda (AFR) in real time with the PV display unit and I can attest that open-loop does keep AFRs in a fairly tight range, usually ±2%. When I perform datalogs I see average variances usually ±1%, and that's good enough to be unnoticeable to the rider, unmeasurable in fuel economy, and unmeasurable by any performance yardstick. The ECM uses other sensors on the bike (FCHT, intake temp, and MAP). They do a surprisingly good job of keeping AFRs as specified in the AFR table, even as altitudes and temperatures change.

 

It's really good for only about -0.2 to +0.08. Using a modern Lambda-based bike as an example you can go from .980 (14.4:1) to 1.00 (14.68:1). Stock is around 14.6:1.

 

Once again, the AT-100 option for the PV will not allow you to run closed-loop. This kit is only good for tuning purposes, as once the tune is done you will either have to run open-loop or replace the WB sensors with stock NB units. Or, you can really get radical and install both of them. With both installed you can tune with the WBs in open-loop (NBs disabled) and then run with the NBs once the tune is accomplished. Be advised that when you do the latter you'll be forced to run within their range, which is very narrow, with little variance from stoich (14.6:1). IMO running stoich is ideal, but you don't need the NB sensors to do it.

There would be little use in tuning your bike on a dyno and then buying the AT-100 kit, as the latter is designed to tune the bike. Once you get a dyno tune you won't need the AT-100 at all, unless you want to fine-tune the tune, but if you do that you have little need for a dyno tune in the first place unless you have specific problems that need to be addressed. With the PV you can tune the bike yourself with either stock or WB sensors, but you can run closed-loop only with the stockers.

Not to belabor this, but a dyno tune does have its advantages. If you're trying to extract every .1HP out of the motor, for racing purposes or whatever, you are best served with a dyno tune. Any self-tuning device like the PV can only give you the AFR (Lambda) you specify, but proper values are well-known and you can get it very close without actually measuring HP/TQ.

 

Narrowband sensors in a stock environment monitor the low-end and midrange, not areas above that. Most calibrations I've seen disable closed-loop at about 60% TP (older bikes like mine) or 85 KPA.

Wideband sensors like the Bosch LSU427 units used in the DynoJet kits for the PCV and PV monitor the entire operating range and do so along a very wide AFR range, far wider than are usable in a Harley application. The stock NB sensors do neither and are much more limited. They can, however, tune a bike across the entire operating range--but they're still limited by their narrow range.

 

Bull's eye! But aftermarket WB tuning solutions do exist for Harley applications.

 

This thread needs some XIED option thrown into the discussion!
Still trying to learn.
Hap