Project F-Bomb
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I'm wondering if your turbo is sized right for your application. I would think that with it so far from the engine it might need to be smaller on the exhaust side to help it spool up faster. The turbo on my S4 is in the V on top of the engine and makes instant boost as soon as you put your foot into it. I hope you have an air cleaner on the turbo now that you are driving it. In that one video, I saw puffs of dark smoke coming out of the exhaust so it is definitely running rich.
For some reason, I haven't been getting alerts for this thread so I had to catch up with about 2 months worth of posts.
For some reason, I haven't been getting alerts for this thread so I had to catch up with about 2 months worth of posts.
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3,970 Posts
According to the minimal research I did, the turbo is appropriately sized for the engine. But I think you’re right about needing a smaller compressor since it’s so far back.
No air filter on it yet. The one I bought when I bought the turbo doesn’t fit.
I need to pull a spark plug and see how bad they are. Maybe put a fresh set in.
No air filter on it yet. The one I bought when I bought the turbo doesn’t fit.
I need to pull a spark plug and see how bad they are. Maybe put a fresh set in.
Compound turbo baby.
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4,772 Posts
That is a good point, large pipe for the exit is good but too big before the turbo would slow the velocity and cause the turbo to be lazy. I would get some kind of air filter on it before he runs it much more rather than chance having to do a rebuild or replace a turbo.
I bet those plugs are pretty black as well.
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Got some issues sorted out. Throttle wasn’t sticking. It was being held open slightly by vacuum. Why it only started doing it recently, I don’t know. But I added a return spring and it’s fine now. Engine is pulling almost 25” of vacuum at idle.
Spent some time redoing the tune, and it’s better. Not perfect, but better. It still goes stupid rich and bogs down a little when I really get on it. Same as before the turbo.
It does make decent boost (almost 10lb), but not till 4k. Which wouldn’t be that big a deal if it didn’t redline at 5.
As long as it’s running well and drivable, I’m not gonna mess with it for now. Maybe over winter if I find somewhere indoors to keep it.
Spent some time redoing the tune, and it’s better. Not perfect, but better. It still goes stupid rich and bogs down a little when I really get on it. Same as before the turbo.
It does make decent boost (almost 10lb), but not till 4k. Which wouldn’t be that big a deal if it didn’t redline at 5.
As long as it’s running well and drivable, I’m not gonna mess with it for now. Maybe over winter if I find somewhere indoors to keep it.
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4,772 Posts
Fuel injection works better with boost but it may take a while to dial in just like a carb but once it's dialed in it will work much better than a carb. I have had both and the carb turbo setups that I had in the 70s and 80s were always trouble especially with altitude changes.
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Funny, I had this exact conversation with my father in law this morning. I still think it’s worth it. Drivability is still better than with a carb. At least as well as I could tune one. With the Sniper unit being able to control timing, activate the cooling fan, plus a dozen other things I’m not currently using, it’s way more than just a fuel injection system.
I’m slowly figuring out the software and how to read the fuel and timing graphs and what different parameters mean. I just need to keep learning and figuring it out. Worst case, I bring it somewhere and pay to have it figured out.
I was gonna replace the plugs today, but they don’t actually look too bad.
A little sooty around the threads, but the porcelain and electrodes are clean. I had plenty of other important stuff to get done to get it ready for a show next Saturday, so of course I did none of it, and instead messed with the interior a bit.
Finally installed the pressure gauge for the air ride. Using a hole saw to try to drill through the bezel doesn’t work well at all, so I did the same thing as I did for the boost gauge, and just got it hot and pushed it through.
Painted the silver bezel black to match the rest of the gauges.
Next step is lengthening the harnesses so I can actually connect the gauge to the sensors all the way at the back of the truck.
I’m slowly figuring out the software and how to read the fuel and timing graphs and what different parameters mean. I just need to keep learning and figuring it out. Worst case, I bring it somewhere and pay to have it figured out.
I was gonna replace the plugs today, but they don’t actually look too bad.
A little sooty around the threads, but the porcelain and electrodes are clean. I had plenty of other important stuff to get done to get it ready for a show next Saturday, so of course I did none of it, and instead messed with the interior a bit.
Finally installed the pressure gauge for the air ride. Using a hole saw to try to drill through the bezel doesn’t work well at all, so I did the same thing as I did for the boost gauge, and just got it hot and pushed it through.
Painted the silver bezel black to match the rest of the gauges.
Next step is lengthening the harnesses so I can actually connect the gauge to the sensors all the way at the back of the truck.
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Yay! New problem!
If you’re wondering how it’s even running that lean, it’s not. It’s running Jeff Bezos rich. Swapped out the o2 sensor and it came down to normal range for about a minute, then back to this. Both sensors were super black and sooty, so I’m hoping that’s the problem. I’ve got a new one ordered. Hopefully it gets here by Friday. If it’s not the sensor (and I’m not super confident it is), the only other thing I can think is the EFI unit itself has an internal problem.
If you’re wondering how it’s even running that lean, it’s not. It’s running Jeff Bezos rich. Swapped out the o2 sensor and it came down to normal range for about a minute, then back to this. Both sensors were super black and sooty, so I’m hoping that’s the problem. I’ve got a new one ordered. Hopefully it gets here by Friday. If it’s not the sensor (and I’m not super confident it is), the only other thing I can think is the EFI unit itself has an internal problem.
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Yeah, now I’m starting to think the issues I’ve had from the very beginning aren’t necessarily tune related, but a fundamental calibration issue. New sensor will be here tomorrow. I’ll install it and see what happens.
Does the sniper have a method for calibration? Does it have its own wideband controller? Different sensors have a different output curve and require a controller to translate the the output signal into something the ECM can use. There should be a way to calibrate the controller or at least check the calibration.
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No way that I’m aware of to calibrate. But I remember not too long after installing it I had to download new firmware and update it. I’m searching Holley’s site now to see if there’s a new version out that I can download. Maybe that’ll help.
A quick search tells me that Holley uses a specific proprietary wideband sensor and their ECM is programmed specifically to match it. Maybe there are 2 different sensors that the Sniper can be programmed to use - NTK or Bosch. If the software gives you a choice make sure you have the correct type selected. Otherwise it seems there is no fix other than to buy another Holley wideband sensor.
Being forced to run proprietary hardware would turn me away from using a Holley system. I've been screwing around with Megasquirt enough to almost have a handle on it and being able to calibrate for nearly any common O2, MAP, crank, temp, etc. sensor is a plus.
Being forced to run proprietary hardware would turn me away from using a Holley system. I've been screwing around with Megasquirt enough to almost have a handle on it and being able to calibrate for nearly any common O2, MAP, crank, temp, etc. sensor is a plus.
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Software doesn’t give any choice. Both sensors I have are Bosch. Both worked fine in the past. Or at least didn’t read impossibly lean. New sensor should be here tomorrow. If that doesn’t work, I’ll be calling and emailing Holley.
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Fixed it!
Not sure if it was the new sensor (unlikely), or completely erasing and reinstalling the operating software, or both.
Even better, I’m well on my way to fixing fixing it. I put in some more time with the laptop and found the ‘target air fuel ratio’ parameter. No before pic, but this is what I adjusted it to
Originally, the top couple rows were 10.0-9.3 AFR. These ratios are all based off manifold pressure. My guess is the system is calibrated to a V engine, and there’s a significant difference in fuel requirements based on MAP readings in a big inline engine. It’s still a little rough above 3500, but I’m gonna give it a few drives to learn and adapt, and make more adjustments if needed.
Not sure if it was the new sensor (unlikely), or completely erasing and reinstalling the operating software, or both.
Even better, I’m well on my way to fixing fixing it. I put in some more time with the laptop and found the ‘target air fuel ratio’ parameter. No before pic, but this is what I adjusted it to
Originally, the top couple rows were 10.0-9.3 AFR. These ratios are all based off manifold pressure. My guess is the system is calibrated to a V engine, and there’s a significant difference in fuel requirements based on MAP readings in a big inline engine. It’s still a little rough above 3500, but I’m gonna give it a few drives to learn and adapt, and make more adjustments if needed.
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3,970 Posts
Yeah, it runs like shit. I reverted back to the base tune, adjusted the timing and it’s a lot more drivable. Im just gonna run it like this the rest of the season and bring it somewhere to get tuned next spring.
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