Questions After First Start of my Hahn Stage 2 Turbo Kit

    You need more run time to determine if you are actually running leaner than normal. Make sure you calibrated your AFR gauge per the instructions and that it is sitting flat and tight. Sometimes those copper washers get wedged weird when tightening the sensor down.

    Google AUS Injection and just give them a call if you want to send out your injectors for cleaning. They are very nice people.


    On many of the vacuum lines, you are better off using zip ties than worm clamps. Worm clamps often get over tightened and eat away at the rubber that can cause small leaks.


    From experience, bolts love to get caught in the below places...


    On the passenger side between the frame and coolant hard line.


    On the drivers side underneath the intake manifold down by the starter and power steering assist box.


    Above the plastic shield that sits on the bottom side of the intercooler and radiator.


    Air is your friend. Jack up the front left side really high and take a air gun and blow around like crazy.

    Owner of Slingshot #263 that has some stock parts left on it. :D

    Two more, I had a rattle could not find where it was from the factory. There was a black bolt sitting between the frame rail and the plastic side panel on the passenger side about where the hand grip is. The how I found it was I was changing the oil and the threaded end had finally dropped thru between the plastic and the frame. So I just pulled the plastic and it dropped out

    I'm planning on taking it out on the road for the break-in ride soon, but don't plan on trying to test the turbo until I see where the AFR numbers are during regular side road speeds. Then I'll decide if I need to have the tune tweaked and/or use AUS Injection. Personally, I like knowing the fuel injectors are matched well.


    I've noticed that the screw clamps on small vacuum hoses don't necessarily seem to clamp evenly. A cable tie wight well provide a better fit.


    While I have looked under neath the Slingshot, I haven't actually gotten under it to look up. I like the idea of uysing the air gun, too. I just upgraded my air compressor to an upright 20 gal 155 psi Craftsman unit and it shoud have more capacity than my old Bostitch 6 gal pancake unit.

    Just so you are aware, I haven't seen that high of AFRs at idle (after idling several minutes) with injectors that needed to be cleaned or that were not flow matched. I also doubt the tune at idle is that different from the Alpha tune to the Hahn tune if they are both set in open-loop as Dave explained. Open loop tunes usually have an AFR in the mid 13s and closed loop is shooting for 14.7. Closed loop tunes are almost always rougher in nature.


    Start it and let it idle for a few minutes. Let the machine warm up and give the ECM time to adjust the throttle blade correctly. If it is idling lean, it will idle rough and almost seem like it is missing. If it seems to be running just fine, I would try to re-calibrate your AFR gauge.

    Owner of Slingshot #263 that has some stock parts left on it. :D

    Quote from TravAZ

    Just so you are aware, I haven't seen that high of AFRs at idle (after idling several minutes) with injectors that needed to be cleaned or that were not flow matched. I also doubt the tune at idle is that different from the Alpha tune to the Hahn tune if they are both set in open-loop as Dave explained. Open loop tunes usually have an AFR in the mid 13s and closed loop is shooting for 14.7. Closed loop tunes are almost always rougher in nature.


    Start it and let it idle for a few minutes. Let the machine warm up and give the ECM time to adjust the throttle blade correctly. If it is idling lean, it will idle rough and almost seem like it is missing. If it seems to be running just fine, I would try to re-calibrate your AFR gauge.

    Thanks. I had been thinking about recalibrating the sensor, just in case. The idle seems to run smoothly. I had Bob/MEFItune do the initial ECU reflash at the beginning of July, 2017. I've just been lazy and haven't gotten around to cleaning up all the loose tools in my carport so I can get the wheels back on and test drive the thing.

    A quick test may also be to find someone close by that has a different afr gauge. There are ones like the AEM (30-4110) that has an o2 sensor that does not need to be caibrated. Just screw it in, plug in the connectors and tie in the power and ground and leads and you're good to go. BUT, you never want to run a heated O2 sensor (one that has a power wire that preheats the sensor) without the heated lead hooked up. That will give you false readings for sure. It's a slight PITA, but at least it will confirm that you have a true afr issue or not

    Nobody gets outta here ALIVE

    Quote from funinthesun

    A quick test may also be to find someone close by that has a different afr gauge. There are ones like the AEM (30-4110) that has an o2 sensor that does not need to be caibrated. Just screw it in, plug in the connectors and tie in the power and ground and leads and you're good to go. BUT, you never want to run a heated O2 sensor (one that has a power wire that preheats the sensor) without the heated lead hooked up. That will give you false readings for sure. It's a slight PITA, but at least it will confirm that you have a true afr issue or not


    That is the AFR gauge that I ended up with. It seems to be working good for now.


    @BKL There is one more place to look for your bolt. If you stand straddle of the right front A arm and take your left hand and reach around the back of the motor where the thermostat housing is there is a little hole/pocket just big enough for a bolt to hide in when you drop it trying to mount a new windscreen. Don't ask me how I know, and don't ask my wife how many bad words I said over and over again when I thought I was going to have to start re-dissembling our sling to get said bolt out of the bell housing! LOL


    Tim "Ghost" Ganey
    Winfield, Alabama
    205spam412spam2868

    Quote from Ghost


    That is the AFR gauge that I ended up with. It seems to be working good for now.


    @BKL There is one more place to look for your bolt. If you stand straddle of the right front A arm and take your left hand and reach around the back of the motor where the thermostat housing is there is a little hole/pocket just big enough for a bolt to hide in when you drop it trying to mount a new windscreen. Don't ask me how I know, and don't ask my wife how many bad words I said over and over again when I thought I was going to have to start re-dissembling our sling to get said bolt out of the bell housing! LOL

    I'll take a look.

    Quote from Bill from Hahn RaceCraft

    @BKL:


    Can you please describe the precise conditions under which you are perceiving a lean fuel mixture? There is an art to understanding AFR readings, as the optimal numbers vary based on RPM and load.


    Tell me RPM, load, and engine temp, as well as the reading you're seeing.

    Bill, I started a Build thread that lists links to the various threads I'v posted about things I've done to my Slingshot - BKL's Build
    The following is copied from my Build thread and summarizes my initial test ride -
    Today (Jan 25, 2018), I finished getting all of my tools cleaned up and got all of the accumulated trash from the turbo install cleaned out of my carport and the Slingshot, so I finally took my Slingshot for its turbo break-in ride. I only rode for just over 5 miles and thought I'd post some of my impressions. AFR seemed to stay around 15.5-16 at idle, dropping down to the 13-14 range or lower during acceleration. I like to use the transmission to slow down, but I noticed the AFR crept up to the 19 or higher range if I used the trans to slow down, so may need to rethink this driving style. After about 4 miles of sedate (non-boosted driving), I finally gave it enough gas to feel the turbo kick-in and heard the hiss of the system when I took my foot off the gas! Woo Hoo! I didn't want to work it too hard until I had a chance to post here and maybe try to get some video of the numbers during a ride. I need to figure out how to hold my camera/phone focused on the gauge during a ride to capture the video to post here. I'll try to add some ore pics of various things later.


    I'm still thinking about how to hold my phone steady on the meter since I don't have anyone who want to ride with me at the moment (Wife is in her 3rd week of bronchitis and is sensitive to exhaust fumes, anyway).

    Edited once, last by BKL ().

    @BKL the numbers you are mentioning are the same numbers I see on my AFR. The only concern I have its at the higher end when you are boosting, that's when you should see the 12-13 AFR . The numbers go higher on deceleration because your foot is off the gas and the throttle closes. At idle after mine is warm I see the 14-16 range. I have been driving like this for over 10,000 miles. I believe you are defiently fine, you just need to watch the boosted numbers. Boosted you should keep seeing the 12-13s you see higher numbers that is when you should worry.


    Sent from my SAMSUNG-SM-T537A using Polaris Slingshot Forum mobile app

    Quote from bigdew

    @BKL the numbers you are mentioning are the same numbers I see on my AFR. The only concern I have its at the higher end when you are boosting, that's when you should see the 12-13 AFR . The numbers go higher on deceleration because your foot is off the gas and the throttle closes. At idle after mine is warm I see the 14-16 range. I have been driving like this for over 10,000 miles. I believe you are defiently fine, you just need to watch the boosted numbers. Boosted you should keep seeing the 12-13s you see higher numbers that is when you should worry.


    Sent from my SAMSUNG-SM-T537A using Polaris Slingshot Forum mobile app

    Thanks for the feedback. Never having driven a boosted motor before, I had no idea what AFRs should be other than having read that AFR numbers around 12-13 as being most desirable and that I should worry if I see lean numbers, but that info had little detail to it. Having only driven it about 5 miles so far, with only about 1/2 mile under boost towards the end of the ride, I'm still getting accustomed and learning what it does. I hope to get the body panels & hood back on in the next couple days and then I'll take her out again.

    Quote from BKL

    Thanks for the feedback. Never having driven a boosted motor before, I had no idea what AFRs should be other than having read that AFR numbers around 12-13 as being most desirable and that I should worry if I see lean numbers, but that info had little detail to it. Having only driven it about 5 miles so far, with only about 1/2 mile under boost towards the end of the ride, I'm still getting accustomed and learning what it does. I hope to get the body panels & hood back on in the next couple days and then I'll take her out again.


    I'm sure there will be those that comment contrary to what I am going to say but take all of it with a grain of salt!


    If you changed your clutch set up when you added the SC/TC you might not want to turn off the nannies until you become comfortable with the clutch transition.


    ESPECIALLY if the roads are wet!


    Especially if your setting at the main red light in a small town on an uphill grade with a car close behind you with the local PD sitting on the other side. jes my .o2


    Tim "Ghost" Ganey
    Winfield, Alabama
    205spam412spam2868

    Quote from BKL

    Thanks for the feedback. Never having driven a boosted motor before, I had no idea what AFRs should be other than having read that AFR numbers around 12-13 as being most desirable and that I should worry if I see lean numbers, but that info had little detail to it. Having only driven it about 5 miles so far, with only about 1/2 mile under boost towards the end of the ride, I'm still getting accustomed and learning what it does. I hope to get the body panels & hood back on in the next couple days and then I'll take her out again.

    Here's a quick guide to AFR's:


    Your Slingshot benefits from a closed-loop feedback system utilizing an exhaust oxygen sensor. This is operational when the engine is warm, at part-throttle (cruise) and, in some cases, also at idle. Under such conditions, the optimal AFR or "target" is 14.7:1. The system will "toggle" back and forth in a range of approximately 13.7 to 15.7 as it seeks the optimal fuel mixture.


    Insofar as steady-state WOT (wide-open throttle) boosted operation, when we enter open-loop mode and the engine management ignores the O2 sensor - as mentioned here, the optimal range is 12:1. AFR's as rich as 11:1 under such conditions are suitable, but anything richer than this (such as into the 10's) will begin to erode power, and can lead to premature spark plug fouling from excessive fuel. At the typical boost levels we run (less than 10 PSI), anything in the mid-13's or higher under WOT is considered over-lean and cause for concern, unless it's only evident just at the beginning of such WOT operation (transition).


    Under deceleration, the engine management is calibrated to cut nearly all fuel, so you may see 18:1 or higher. This is normal, and not cause for concern.


    As to recording your AFR's under WOT, what kind of gauge have you utilized? Many offer some fashion of internal datalogging, so you may be able to extract that information for analysis after a power run.

    IIRC, the factory O2 sensor is wideband (Correction - WRONG - See Bill Hahn's post below. I made a poor ASSumption since both O2 sensors looked pretty much the same. My apologies). Here's a link to a short explanation of the differences between narrow and wideband O2 sensors - Why is a wideband o2 sensor better for tuning AFR than a narrowband o2 sensor? Isn't my 1/2/3/4/5 wire stock o2 sensor good enough? - DIYAutoTune.com

    Edited 3 times, last by BKL ().

    Quote from BKL

    IIRC, the factory O2 sensor is wideband. Here's a link to a short explanation of the differences between narrow and wideband O2 sensors - Why is a wideband o2 sensor better for tuning AFR than a narrowband o2 sensor? Isn't my 1/2/3/4/5 wire stock o2 sensor good enough? - DIYAutoTune.com

    The factory sensor is indeed narrow-band, as are most on normally-aspirated engines. For the most part, narrowband sensors have the useful range of about 13.7 to 15.7:1 air-fuel ratio, which is why they are less than optimal for analyzing a boosted machine's ideal AFR, which at 12:1-ish lies below their effective range.


    GM turbo engines like the LNF use wideband sensors stock, which is a wonderful thing for not only tuning, but inherent failsafe capability.