96" Throttle by Wire, Street legal stage 1 vs. SERT Stage 1 vs. SERT Tuned

[springer-]

The new 08 Touring models have "Throttle by Wire".

What to do to compensate for a stage 1 (air cleaner and exhaust) upgrade on a new 08 touring model? There are several options, the Legal Stage 1 dealer download, A SERT Stage 1 download, a SERT Dyno Tune, PCIII and a ton of other products as well. Lets start with stock ECM. The Harley Delphi EFI system is the most sophisticated EFI system available on a motorcycle today. All the add on products and replacement products, IMO, are a step down from what comes with the bike stock. For me that eliminates all the replacement and add on products like the Tmat, PCIII, DFO's, Race Fuelers, etc.

I recently tuned an 08 Road King. It has an air cleaner and independent duals but is otherwise bone stock, including stock cams. The dealer did a Street Legal (SL) Stage 1 download to the ECM. We did a baseline with the SL Stage 1 download. In hind sight we should have run the full map for a better comparison but we only ran a Full throttle run, you will see that later in the post. After running our baseline we installed the SERT Stage 1 Map and then ran another baseline, this time we ran the entire Map and proceeded to Dyno Tune the engine.

The way we tune is VERY different than 99% of the other tuners out there. This is a huge issue of debate and not one I am going to get into but I will tell you the differences. Most (probably 99%) tune with AFR. The ECM adjusts using O2 sensors that read AFR. Wide Band O2 uses AFR. Many dyno sheet critics look at the AFR on the bottom of the sheet. Aftermarket tuning devices use AFR, like the Daytona WEGO system. Most Dynos have AFR systems built in for Dyno tuning. At this point you should have a picture painted that the industry relies on AFR devices for tuning.

We don't use AFR for tuning, we can't see the AFR, have no way to measure AFR and don't adjust for AFR.

If not AFR, what? We use combustion science to tune the engine. When fuel is burned it is a chemical reaction. The chemical reaction gives off by products, these are the emission. CO, CO2, HC and O2 are all emission in the exhaust gasses. AFR only looks at the O2, the least important in the equation. Carbon Monoxide, CO is partially burned fuel. Carbon Dioxide, CO2 is fully burned fuel. Hydrocarbons, HC is raw unburned fuel. Oxygen, O2 is left over that isn't used in the combustion process. In a perfect world all the O2 is combined with all the HC during the combustion process, this doesn't happen. We look at the exhaust gasses and then adjust for a proper burn. The gasses tell us how the timing is, if there is too much or to little fuel for the amount of oxygen available etc.

I am not saying EFI can't be tuned with AFR. I am not saying that we will get higher numbers tuning without AFR. But I would say the number 1 comment we hear from our customers is "It runs so much smoother now". We have retuned several bikes tuned by some top notch, highly regarded performance shops. Typically we achieve better gas mileage, smoother running engine and more power through out much of the partial throttle range. We don't often obtain better max numbers at WOT but we also don't typically lose power at WOT either.

There already seems to be a misunderstanding of the throttle by wire system. I have seen post about the throttle plates lagging behind the throttle. For example, you twist the throttle and the plates don't open all the way and seem to have to catch up. This is by design and is not a issue of the servo being slow or anything else. The EFI system knows the engine can't use all the air at that RPM and if it were to open up fully it would actually hurt the performance. Kind of like the way a CV carb works. On some types of Dynos the drum is very heavy. When you whack the throttle wide open and the engine is at 1500 RPM's, the EFI will not allow a throttle position of more than 30%. Then as the engine revs increase and hit 1750 RPM's it allows the throttle to go to 40% and so on. The EFI doesn't allow 100% throttle until the engine hits 2750 RPM's. If all that is being observed is the throttle plate to hand grip position it would look like the plate is lagging behind and holding back the RPM's, it isn't.

[springer-]

In this first graph you can see an example of the throttle position vs. RPM. Note that it only goes to 30% @ 1500 RPM. The Blue line is the SERT Stage 1 Map with NO modification. The Yellow line is after we tuned it. There is over a 10lb Torque difference at 25% throttle.




You can follow the progression through 3000 RPM's and see that 100% throttle isn't hit until 2750.



















The above Dyno graphs are broken down by RPM. They show all the different throttle positions at a specific RPM. The ECM Map is broken down several different ways. The AFR table is RPM vs. MAP (Manifold Absolute Pressure). You will notice on the Dyno graphs that each is broken down by RPM vs Throttle position.

The reason for that is the MAP (Manifold Absolute Pressure) is a much wider range and wouldn't accurately show the relationship of Torque vs RPM at a given map (SERT Table) location.

The next 2 pictures give an example. In the first picture the highlighted area covers from 1500 to 3000 RPM's at 100 Kpa. It is a relatively small part of the table. But when you change to the VE table, as in the second picture, that same small area now represents 60% of the throttle range.

[springer-]

Nearly all dyno sheets show wide open throttle runs. But how often do we ride at wide open throttle? Much more time is spent at part throttle and that is where gains can often be made. 5-10 lbs of torque in the 15 - 40% throttle range is very noticeable. As above the Blue line is a SERT Stage 1 download and the Yellow line is after a dyno tune. These graphs represent a specific throttle position across an RPM range. Just the opposite of the above graphs.

Note that as the RPM goes up and the throttle position stays constant the Torque drops off. As the throttle plate opens more the torque rises and the tuned (yellow) line separates from the Blue line.

[springer-]

In the following chart it shows actual torque changes based on Map positions. This is the SERT tuned vs. SERT Stage 1 canned map.



Here is a comparison at wide open throttle between the Street Legal Stage 1, the SERT Stage 1 and the SERT Tuned Map. Earlier in the thread we discussed the Throttle By Wire and the fact that it doesn't allow 100% throttle plate opening until 2750 RPM. Note on this graph the RPM starts at 2000, well below the 2750 RPM required for 100% throttle position. At 2000 RPM there is a 14lb Torque gain over SL stage 1 with O2 sensors, remember this is a STOCK cam. At 2000 RPM's the max throttle position is 60%.

[adlerx]

All great stuff springer but I can't see the pics just little red x boxes. What's up with that?

[BVBOB]

Did you retain function of the 02 sensors after the tune was completed?
BTW, awesome info, where do you find the time for this?

[HDMD88]

I see why you don't want to debate tuning with the SERT....so I won't start one but I do have to say, sorry, I don't agree with your method, and leave it at that.

[springer-]

Originally Posted by adlerx

All great stuff springer but I can't see the pics just little red x boxes. What's up with that?

The pictures are linked from my webserver. Try refresh and see if that helps, if not right click on one of the red X's and select "Show Picture". If it still doesn't work see if you can get to our website, it may be a temporary thing.

[springer-]

Originally Posted by BVBOB

Did you retain function of the 02 sensors after the tune was completed?
BTW, awesome info, where do you find the time for this?

No we disabled them.

[springer-]

Originally Posted by HDMD88

I see why you don't want to debate tuning with the SERT....so I won't start one but I do have to say, sorry, I don't agree with your method, and leave it at that.

I don't have a problem debating tuning with a SERT, it is our preferred device. But I am not going to debate AFR vs 4 Gas tuning. Not all have to agree with our preference.

[adlerx]

Working fine now. Thanks Springer, pretty amazing difference huh? Pretty sure a guy could definately feel the difference in the pants!

[Bubba Neil]

You disable the 02's by editing AFR table or by another method?
Just how close was the stage 1 timing map from the finished product?

Thanks for posting this.....

[baggersport]

To address a couple of questions asked about the bike tuned in this post;

Stock 96" with S.E. air cleaner and True Dual exhaust (I think they are Hard Chrome brand) that are 3" as soon as they leave the head all the way to the end (with whatever baffle came in them).



.

[RidingJerry]

Thanks again for taking the time to post info and teaching us something.

[ohiomotoxer]

Some of the EFI hacks would prolly work on HD's