alpha turbo probably lean condition

  • Hi all - just picked up a 16 with an Alpha turbo already installed. I've noticed a coupe of times that if I wind it out in 2nd and then hit 3rd too quickly, the engine will stumble as if it's hitting a super lean AFR. I'm absolutely terrified to run it hard at all at this point. It doesn't have gauges installed and I'm happy to install, but I'm new to turbos (NOS guy :)) so I'm not entirely sure how to proceed. So a few questions :

    1. Is it possible to use ODB to spot lean mixtures?

    2. If I do find it to be lean, what'st the next step? on NOS builds I've always upgraded fuel rail and injectors - can I tell if that has been done already?

    3. Is there a way for me to be able to determine which EFI MAP is being run?

    thanks much!

  • Just my 2 cents... I'd contact Bob at as he did the tunes for Alpha. You might also check that the MAP sensor (a 2-bar sensor which was adapted to fit in the stock location) is secure and not leaking. DDM sells a plastic bracket which will secure 2-bar map sensors in the Slingshot manifold.

    I've got an Alpha supercharger, and I used Brisk RR14S spark plugs gapped down to 18 thousanths to prevent spark blow-out at high RPMs and boost.

  • Running a turbo without AFR/Boost gauges is asking for engine problems. You need to be able to watch AFR when boosted or you risk damage from a too lean condition. I bought an Innovate SCG-1 AFR/Boost gauge, which while it can display Boost and AFR or AFR & Boost, only one of the values is easily read with the other being displayed in the top left corner of the gauge with relatively small text. I wish I had purchased an Gauge which shows AFR numerically in the center of the display with Boost indicated around the circumference of the gauge. With the Innovate SCG-1, you need to also get an external data logger module, but I thunk certain models of the AEM gauges may have data logging capability included. I'm not sure on the specifics of the AEM gauges, but they seem to be more popular.

  • 1. Is it possible to use ODB to spot lean mixtures?

    2. If I do find it to be lean, what'st the next step? on NOS builds I've always upgraded fuel rail and injectors - can I tell if that has been done already?

    3. Is there a way for me to be able to determine which EFI MAP is being run?

    thanks much!

    1. The Slingshot does not use OBDII. It uses MEFI OS. The best way I can describe the tuning for it would be this, the OBDII tuning programs like HP Tuners are like a Play Station 4 and MEFI is like an Atari 2600. Things that take 5min to adjust in HP Tuners take 45min to adjust in MEFI. You can use MEFI to scan but the scanners and Slingshot adapter is like $370 if I am not mistaken. You can data log but I am not sure you can clear codes.

    2. If it is lean, it's potentially in the tuning. However, with that said, I have had 2 Alpha kits in here at ZZP and both were heavily on the rich side. To the extent that changing nothing other than fueling we picked up over 10whp if I remember correctly. If you want to check injector size, pull an injector and google the part number on the side of it. Both kits we had here had 60# injectors in them which most of the kits out there come with in my experience.

    3. I believe the Alpha kits come with a 2BAR MAP. Again, you can google the part number on the MAP sensor on the intake manifold and it will tell you.

    As far as gauges, running a turbo kit without any is potentially dangerous to your engine. I would personally run the AEM Fail Safe Wide Band gauge. It monitors both boost and air/fuel on the same gauge and with real estate for gauges being scarce on a slingshot its nice it does both. I have been running one for 4 years and really like it. It also stores up to 3hrs of data although what you can monitor on the Slingshot is fairly limited compared to what you can see with things like HP Tuners. But it is less than scanning software and you can connect to the gauge via a standard supplied USB cable. We sell them here…m-wideband-failsafe-gauge I also have a skin that I could send you so the info you want is automatically pulled up instead of having to build your own setup.

    As far as being hesitant to push it, detonation is extremely easy to hear on a slingshot. When making a pull, if you start to hear what sounds like a rattle or marbles dropping on a glass table top, that is detonation. Get off the gas if you hear that. using good premium octane fuel is essential for a boosted slingshot. If you get gas from places like Costso, Sam's Club, or some other non national discount fuel station, chances are you're likely getting shitty 93 that really isn't 93. Switch your fueling purchases to places like Shell, Speedway, Mobil, or BP. They typically all have good fuel all of the time. But it is still possible to get bad gas from any of them so you just need to listen and be aware.

    Regarding the falling on its face doing a 2-3 shift, can you recreate it? If you can and can, take someone with you to fill and send me a video or a link to where it is posted I can give you my 2 cents. It would be helpful to see the tach while you're doing this. You can email me directly at

    ZZPerformance EST 2000 - Go Fast Not Broke

  • Just my 2 cents not seeing your situation in person. Any chance prior to the actual shifting, you were up on the rev limiter? Quite often short shifting could eliminate that stumble. When you hit the rev limiter, the ignition is cut off to individual cylinders resulting in a rich condition. After the shift and getting back into full throttle mode, you have to "clear it out" a bit before you get back into a burnable fuel mixture IMHO

    It will cost you nothing to try it to see if it eliminates what you're feeling when driving it your way

    Growing OLD is MANDATORY

    Growing UP is OPTIONAL

  • I experienced a situation a few months ago where my system would bog down when I hit 4000 rpm under heavy acceleration. I managed to clear what I believe was a dirty fuel filter on the fuel pump in the gas tank by running several cans of Sea Foam or its cheaper Walmart equivalent over the course of a month or so. I added an entire can at a fill-up and then added another can after the next fill-up and did this over several fill-ups. I now add a can of Sea Foam (or its Walmart equivalent) once every month or two.

    I really wanted to avoid replacing the fuel pump with its attached filter since Polaris wants several hundred Dollars for one. I found a couple sources that sell just the pump portion which you reconnect to to the assembly. See this thread - Bad gas?

  • Thanks all! I reached out to Bob MEFIburn with the details of the ECU and he confirmed that it already had the correct map (Thanks Bob!). Then after I reinstalled the ECU, the check engine light came on a couple of times (first 10 minutes or so), and I haven't had the problem again. I'm not sure if it's just happy circumstance at resetting the ECU or maybe a fueling issue like BKL described above clearing out, but it's good times now!

    thanks again for all the advice!

  • We have worked a bunch with the Alpha kits here and there a couple issues we see commonly with them.

    - Check your Oxygen sensor, it is most likely between the turbo and the cylinder head in the header. If yours is like that, your oxygen sensor is probably starting to read incorrectly. The stock Oxygen sensor can not take that kind of heat and pressure and will start to read incorrectly, which will affect your air fuel ratios. The oxygen sensor can be picked up at most auto part stores for not much.

    - Alpha shipped their kits with non-flow matched fuel injectors. Most of the time they seem to work, but we have worked with several Alpha turbo guys that have had issues and had their fuel injectors sent out to find that there was a difference of over 10% in some cases between the set. We have sent a bunch of sets out to Ausinjection to have them flow matched -

    - The 2 Bar MAP sensor that Alpha sent with their kit has an issue that can allow the MAP sensor to work its way loose and even pop out of the manifold underboost. If the MAP sensor pops out under boost, the engine will not get enough fuel and engine damage can happen very quickly. This is the entire reason we have the MAP clips, shoot me a PM and we can get you one.

    - Pull your spark plugs and check what the part number is. Alpha played around with a lot of different spark plugs over the years, but we have seen a lot of the plugs installed being absolutely the incorrect style of seat. The Ecotec uses a taper seat plug and we have seen a lot of gasket seal plugs installed by them. Get the right plugs installed or make sure you already do have them.

    - Alpha has a very small exhaust turbine housing on their turbos to help with spool (.48 A/R). It produces quicker spool, but really starts to back up some heat and pressure as you up the boost.

    Hope that helps, feel free to give us a call also if you have any other tech questions on that kit.


  • @Dave@DDMWorks' comment about tapered vs gasket seal plugs raises a question. I was on and saw the listing for NGK LTR6IX-11 6509 plugs, which are clearly pictured as tapered plugs, but when I Googled NGK LTRIX-11 6509, the listing on Amazon showed a gasket seal plug, yet the NGK website shows a tapered plug. The same thing happend when I searched Amazon for the NGK 92182 plug. Amazon's pic showed a gasket seal plug, but NGK shows a tapered plug.

    I originally decided to try the NGK 92182 plugs after reading posts from Funinthesun over on TDS -…-plugs.12698/#post-274148 (I, too, was cocnerned about gapping the stock plugs down to .030 that Hahn uses). I now have around 18000 miles on the NGK 92182 plugs I installed during my turbo installation and just ordered new set of the NGK 92182s, but was wondering if I should try a different plug, instead. I found a recommendation for this Brisk plug (, but I can't remember where I found the recommendation.:/ The Brisk and the NGK plugs are similarly priced.