| Author | Message | ||
     Captain_america |
Ok, so there was a pretty long thread that Highscore started here: http://www.badweatherbikers.com/buell/messages/290431/549073.html?1269321108 About how the IAT effected horsepower numbers on the 1125. He also shared how he thought the inner air box provided no benefit to guys that ride on the street. Being as though I know that a 10 degree drop in IAT results in a 1% power increase and noticing that the IAT reading on my cluster always reads extremely high, I decided to move it closer to the butterflies where it might get a more accurate read of air temp going in the motor. I briefly posted how I did it but Ratsmc hit me up and thought we should do a better job with some instructions and pictures for you guys. It's very easy to do and as he said its a "no-brainer" Sooo here they are: ++++++++++++++++++++++++++++++++++++++++++++++ Things you will need: - 2 pieces of 18 gauge wire preferably Black/white and White/yellow. - 4 pieces of .125" x 1" long heat shrink. - 2 pieces of .25" x 3" heat shrink. - Tech Flex heat resistant wire shielding .25" or regular electrical tape. 1. Take the IAT sensor out of the grommet.  2. Remove the grommet for the intake duct.  3. Remove both parts of the air box (inner and outer) I would suggest covering the throttle bodies. I taped them over.  4. The plastic ends holding the air filter are !!VERY VERY VERY!! soft and if you start with too large a drill bit it will go right through the plastic and rip the shit out of it! So start with a small bit with high RPM and slow feed rate (sorry machinist talk) and work you way up usually skipping one bit at a time. I started with a .125" bit and ended with a .5" The IAT grommet is .75 inch. A typical step drill is exactly the right size and cuts the plastic in a pretty controlled manner.   Note: if you are running with the inner airbox in, you should mount the IAT sensor on the right side.  5. Fit the IAT sensor grommet in the hole. It will be small. You will need to ream it out with the .5" drill (very easy to do) until the grommet fits. 6. Cut the IAT sensor wires halfway between the connector and where it joins the main harness.   7. Peel that fancy electrical tape, with the glue all inside it, off the connector side wires. 8. Strip both wires. (about .25" is all you need) 9. Cut two pieces of wire that you will use to extend the harness and strip them on both sides too. Make sure the wire gauge is similar (never use smaller)... 19 inches is perfect. 10. Tech Flex heat resistant wire shielding .25". Cut about 4" shorter than extension wire. You can get this at an electronics or stereo store. I found it at Fry’s Electronics. Alternately, you could just use electrical tape. You will need to slide the tech flex over the wires. Then slide the .25" heat shrink pieces over either end of the tech flex. Lastly slide the .125" heat shrink pieces over each individual wire on each end.  11. Make sure the heat shrink is away from soldering heat! 12. Matching similar colors, solder one end of the extension wires to the IAT sensor connector wires. Unfortunately, and this sounds stupid but with the limited time I had I could not find matching colors. 13. Finish that end up by sliding the heat shrink down into place and heating with the heat gun.    14. Important! If you plan on putting the wire through the hole where the IAT sensor used to be, like I did, then feed the wires down the intake duct and through the hole. I also routed the wire through the old IAT hole in order to limit movement. I used a .75 inch grommet from Home Depot in the hole to prevent any friction.  15. Now the tricky part... Do the same to the side that connects to the harness on the bike. This part was a pain in the ass. 16. Ummmm, Your Done! Put everything back together. Those photos were courtesy of Ratsmc so here are the couple I have:     | ||
| Dannybuell |
Excellent presentation! I just bookmarked it! | ||
| Therealassmikeg |
Nice write up captn'& ratsmc! Very neat and professional mod. Have you guys noticed any difference in performance with ambient sensor mounted here? | ||
| Boogiman1981 |
very nicely done think i'll be doing that tomorrow the air temps are WOW high | ||
| Captain_america |
Thanks! Honestly it's hard to tell if there is any difference in performance. It seems to pull harder but I don't have a dyno to really determine anything... I'm so light my bike doesn't even know I'm on it and it always rips! I'll tell you what though.... It helps me sleep better at night. the IAT is no longer reading all that hot air from the radiator fans. That thing is DEAD accurate now. Other thoughts about this: Cold Air = Dense Air = More Fuel Required Hot Air = Thin Air = Less Fuel Required So if the air is lets say 70 degrees and the IAT is reading 110 (which was common) would that result in a leaner air fuel ratio? Maybe that's part of the lean problem with these bikes? IDK.... | ||
| Mountainstorm |
I think you are on to something Cap'n. Excellent tutorial. | ||
| Ratsmc |
After doing this yesterday, I am pretty amazed actually at how close to ambient the IAT is reading. I am also surprised at how stable it is. Previously, i was getting readings that ranged from 15-30 degrees above ambient temp. That number would also swing all over the place and didn't seem to really care whether I was moving or not. I haven't had the opportunity to calibrate my butt dyno and put in enough miles to really notice any difference but as Captain America said, it was well worth it without any performance improvement. Now I know that the engine is responding to reality and it is reading a more stable value. If you have all the stuff, this is a really, really easy mod. My fit and finish is not as nice as Captain's (his are the bottom pics) but I am still happy with the results. (Message edited by ratsmc on April 17, 2010) | ||
| Dmhines |
Great mod ... put it on my todo list! I would love to see actual dyno tests though ... | ||
| Jeepinbueller |
I'm still skeptical of the mod even though the execution is flawless, capt'n. My question is this: why would the elves put the put the ambient temperature sensor at the front of the intake knowing full well that the radiator fans dump hot air right on it without calibrating the ECM to deal with the discrepancy? I understand the premise of the mod and everything ... I'm just kind of wondering if we're bypassing some sort of safety that's built in to the ECM programming (maybe a correction factor of the AT). That's all ... I look forward to seeing what comes out of it for you, and keep us updated  | ||
| Captain_america |
I dunno what those elves were thinking lol | ||
| Ratsmc |
Jeepinbueller, I spent a good deal of time thinking about that and honestly I cannot come up with a reason for putting the sensor where it comes on the bike. There is absolutely no way to get a reading of the temperature of the air going into the motor where it is. There is also a huge variability in the temp in that spot that, again, does not reflect whet is actually going into the motor. Basically, there might have been a reason for putting it where they did but there is no way that they could build a fueling map that could account for the radical swings between reading and actual. There is a possibility that they compensated in the fuel map for the fact that most of the time it reads hot but that would leave the motor running rich when the temp reading swung the other direction relative to actual. But the fact is, the stock motor runs lean. The IAT location may or may not be a factor in how lean it runs but I can tell you for certain that after this mod, my bike ain't running rich. Dmhines, I think that getting a useful dyno comparison would take a pretty extensive set up in order to control the variables. I would love to have the opportunity to do this but until I get my ass back to Oakland I have no dyno and this is the sort of thing that gets expensive on someone else's equipment. (Message edited by ratsmc on April 17, 2010) | ||
| 03fatboy |
I am not at home, but is there any chance of anything on the probe itself falling off and being sucked down one of the throttle bodies? I definitely like the idea, but that is the only thing that I would worry about really. Like I said I am not at home to see the sensor itself. | ||
| Captain_america |
Not unless the little resistor wires come out of the sensor.... I've never seen nor heard of that happening before. Plus these sensors are use in the intake tract of all EFI cars just like this. I'm also thinking that the cooler, more accurate IAT reading might also signal the ECU to advance the timing slightly. There has been a trick that I've seen with LS1 motors where guys put a fixed resistor in the harness plug to help get more timing out of the computer which helps out their 1/4 mile times... | ||
| Xelerator |
IIRC, that's relating to degree Celsius. ...a 10 degree drop in IAT results in a 1% power increase (Message edited by xelerator on April 18, 2010) | ||
| Captain_america |
Xelerator.... I think your right. Kinda hard to find a real answer. I saw one that said 10C change = 3% change in air density = 3% power change. Hahaa If you type: IAT and Horsepower on Google this thread comes up number six on the list!  | ||
| Littlebutquick |
if we ask easy rider nicely he might try the mod back to back on his dyno .unless he has tryed the mod already  | ||
| Ratsmc |
Yeah, I was thinking easyrider is probably the best able to test it. | ||
| Dannybuell |
easy rider where are you? | ||
| Rodrob |
As stated in my original post on this way back when, does anybody know whether or not the ECM is actually programmed to adjust mixture relative to the AIT's reading? One would think so, but you never know, until you know. | ||
| Captain_america |
Rod, I would like to know the exact the same thing. Does the input from the IAT change ARF and timing or not.... My guess is yes... | ||
| Orman1649 |
There was a post last week I was reading that discussed some ECM tuning and such. It had all sorts of links to ECMSpy as well as some other loggers and such. This got me doing some reading. Here is a table I pulled out of the ECMSpy Buell Tuning guide.... Inlet Air Temperature correction values Air Temp.(°C) Fuel (%) -40............125 0..............110 25.............100 50.............90 75.............82 100............74 125............68 If this is true…. using some numbers that have been tossed around in this thread... 70F would be about 21C which would be about 102% fuel I think 110F would be about 43C which would be about 94% fuel I think If those numbers are even close to correct, moving the IAT sensor would bump up the fuel by about 8% Disclaimer: I am not saying I know anything about how the fuel mapping on the 1125 works or claiming the above info is even accurate. These are just numbers I pulled out of the Buell Tuning guide and did a few calculations with. | ||
| Captain_america |
Nice Orman, I hope that IS true. As Rodrob Said : One would think so, but you never know, until you know. I happened to throw some Lucus octane booster crap in the tank last night and this morning on the way to work my bike turned into a V-Twin Indy car. It was .... WOW! | ||
| S21125r |
Fuel map correction is slightly different for my eprom (bue2d) but in line generally speaking. Also found a map and table related to spark and air temp. One map (air temp max spark advance reduction) appears to plot load vs rpm for a gross correction number (assuming) that is later mutiplied by a percent factor (air temp spark advance reduction scaling). | ||
| Vinb |
Well looks like I have something to do tomorrow night thanks. I like upgrades under ten bucks that I get to do. | ||
| Fastcarr |
Air Temp Correction table from 08 1125R with 062 flash. Temp(C) Percent Fuel 125.000 75 100.000 80 75.000 86 50.000 92 25.000 100 0.000 109 -40.000 128 Air Temp Spark Advance Reduction Temp (C) Percent 46 100 44 75 42 50 41 25 40 0 25 0 0 0 So no change in timing until air temp is 41C and even then by looking at that table (too large to post here) its a max of 2-4 degrees. | ||
| Captain_america |
I'm not sure I follow your spark table but 105 degrees is when the timing starts to change? My IAT will never read that hot now. Maybe only for a few seconds after some heat soak, but once I start moving it drops right down. | ||
| Glitch |
My question is this: why would the elves put the put the ambient temperature sensor at the front of the intake knowing full well that the radiator fans dump hot air right on it without calibrating the ECM to deal with the discrepancy? I'm wondering if it's there because originally the radiators weren't supposed to be where they ended up. In one of the Erik interviews he said something about H-D not liking the way the original design looked. They didn't want it to look like a Japanese Race Replica. I believe the 1190RR is more what the bike was supposed to be, before H-D got involved. This is however only my guess. WRT whether or not the ECM was programmed for the hot air dumped from the rads, the only way to really know would be to dynotest with a sniffer for A/F data. Great mod by the way! | ||
| S21125r |
4 degree gross spark correction comes in @ 7700 rpm, and that assumes your iat is reading 114F+. Chances are you will be well over 50-60 mph at that point even in first gear and will have sufficient air flow over iat sensor. The earliest the correction comes in is @ 3000 rpm with a 2 degree retard @ 114F. Heatsoak might have a small impact at take off if the conditions were right. | ||
| Avalaugh |
Great info guys, just a question though, i run the inner air box lid, why must the IAT be mounted on the right hand side ? | ||
| Ratsmc |
Avalaugh, as noted in the instructions,it is suggested that if running the inner airbox cover, you position the IAT on the right side. There is no reason either side is better. |
