Recently upgraded my tiny turbo to a 2560r 14411-91f00

this car is only run on e85 (about e75 rn)
was testing out high boost and doing some ignition timing tuning. First issue is leaning out under higher boost levels. I did two pulls where this happened, along with what I think is clutch slip.

3rd gear log of leaning out. I had about 1/4 - less than 1/2 a tank of ethanol. New walbro 255, kraken 700ccs.
Went ahead and filled the tank and did some lower boost pulls, didnt lean out, but they were low boost.

spicy e85 table

the leaned out pull, thats clutch slip right?


I also have an issue with my aem 4110 where the gauge and tunerstudio read similarly at idle, but the richer it goes, the more its off, to the point where low 11's on tunerstudio will be 10 pegged on the gauge, ive been going off the tunerstudio reading, is this a bad idea? Ive tried like every fix and voltage spread values i can find. I have a spare sensor, but im not sure thats the issue so i havent bothered with it.

If anyone has any ideas on the leaning out, how spicy that ignition timing is, or whats up with that clutch slip and aem gauge shoot please.

 

Your duty cycle is maxed out, what's your fuel pressure at?

Edit to avoid a 3rd post: at 300whp, you'll already be maxing out the 700cc injectors on E85 according to calculators. Time for bigger ones. With a stock NB system, you also have to go crazy big on the fuel system to compensate for the non-referenced FPR.

 

Also, I haven't seen an AEM "classic" wideband work correctly in years. All have sensor issues or calibration issues, or output issues. I'd suggest switching to an X-series, Spartan, or similar CAN capable wideband.

 

I would trust the gauge over tunerstudio. Tunerstudio is only going to tell you a value based on the voltage from the gauge and the calibration you've provided. If you tell it that 0V is 14.7 and 5V is 14.7 it'll tell you 14.7 all day regardless of what the sensor is actually reading. I've had my gauge be off by a bit and unplugging/replugging the gauge output to the ECU (using the factory plug), fixed the issue.

That's a ton of timing... You're running more at 15 PSI than a lot of people would run at WOT on an NA engine. I would expect you could pull a good deal out in boost and not lose any power. Hell, you might even gain some power.

 

Damn, I though I'd have enough room to get away with it, Would you recommend bigger injectors, or just get a referenced fpr? Which would be easier/more cost effective?

I got it from a shop locally who had stock because they used them for the cars they built, I didnt know there were major differences and knew i wanted at least a name brand setup. I only noticed the huge difference and others' experiences after I started looking it up. Shame, Ill add this to the list as well i suppose

I knew it was pretty high, Doing testing i kept gaining relatively decent power in some ranges, and losing in some. This is because I would just take a chunk, add (x) amount, do a run, rinse and repeat up or down.
Overlaying the runs on vd, I benefitted from more timing closer to redline, but slightly less than in the midrange. I just kind of meshed those together looking at the logs and that was the result. I do lose power taking off timing at this range. Maybe the base timing is slightly off? That was a whole thing at one point too that i thought I figured out.



Can you send me your spark table when you get a chance? I know you have lower comp, just as a reference. I cant find many e85 spark tables on here.

 

Regarding my comments on your map, I'm just going off of what I usually see on here and around the internet. I'm not a tuner and I've never been on a dyno, so take it with a grain of salt.

Here's what I'm running right now. We're usually around E65 so with blending I'm probably running a few degrees less than this in boost since my scaling is setup for E75. I 'm not sure how optimal this is. I haven't scrutinized it too much, but the car seems to be pretty happy with it.




This is the AFR cal table I run for reference. I think I'm on the same gauge as you (AEM with no buttons).

 

I'd recommend ID1050x, and a referenced fpr. It's a bit of a chicken/egg scenario, you can go big injectors but might as well fix the fundamental problem of the NB's FPR first. The calculator I was using still assumes you have 58psi of fuel pressure at peak duty cycle, you likely have less, given your logged DC at supposedly only ~250hp.

The older model using the LSU4.2 sensor was released in....? Google AI can't even figure that out. The X-series was released in 2015. Before you go further into tuning, I'd replace it. Typically I'd suggest a Link or Spartan wideband, unfortunately one is quite expensive and one is perpetually out of stock. So I'd go with a known good vendor of the X-series, or get a Spartan 3 lite, which doesn't have CAN. https://www.14point7.com/products/spartan-3-lite-v2

I'd be a little surprised if your timing is correct. Because of NB's separate and non-adjustable cam/crank sensors, much timing adjustments are in the 1-2 range, where as yours is 10. If you accidently read the 10 degree line and tried to put it on TDC, your timing would be 10 degrees off, and your table would make much more sense. High teens vs. high twenty's in the boosted cells.

Here's a decent thread with a picture: https://www.miataturbo.net/megasquir...-engine-63718/

I always put it at TDC, making sure the locating dowel is at 12 and the x4 bolts aren't at a 10* angle, it's usually pretty obvious. At this point the mark pointing at TDC is your TDC mark, and that's what needs to line up with the -10 mark when adjusting timing. So you should see one at 10 and 20 when shooting with your timing light, not TDC and 10.

 

For the referenced fpr, do you know of any good threads or information i can find on this. Is this converting to a return style system, or just bypassing the tank fpr and putting a referenced fpr in the bay, with the returnless system and stock rail?

 

Yeah that’s basically it; bay-mounted regulator with a vac line to it. I suppose you could remote mount the regulator wherever you wanted, many ECUs run on-board MAP sensors with long reference lines and don’t suffer for the length of tubing.

Whatever you do for bypassing or deleting the in-tank regulator, just make sure you reinstall or substitute the little dump hose off the regulator on the pump hanger. It helps keep the pump pickup submerged in fuel.


As for the rail, you can do it either way, but converting to a return system isn’t necessary. Just make sure
you use a regulator appropriate for each type of system. Some are designed to mount post-fuel-rail in the system, and keep the set pressure between the pump and regulator, for use in return systems. Returnless ones are meant to keep set pressure in the line to the rail regardless of what the pump is outputting pre-regulator. (I hope that makes sense)

I will second the ID1050x rec, I have a set in my K swap and while it’s a different animal than a boosted BP they are great. Rock steady idle, and the data from Injector Dynamics is plentiful and accurate, which eliminates a lot of tuning variables.

 

Only one I found for a returnless system with a brief Summit search was a $200 fuellab unit. All others were 5-15psi for carbs. Maybe I missed a few options though. For that price I'd be looking at going to a return system. But for now, since I know you're doing the engine rebuild, get the 1050x, install a good fuel pressure sensor and wire it to the ECU, and make your decisions with that.

 

Is that a stock compression ratio cast piston engine? For a stock motor that is some pretty strong timing if the engine actually is seeing that, most likely it isn't. Not sure on your engine setup but your table has more advance after 6500rpm than what I ran and I was very low compression. I had 8.5 to 1 pistons and a thick cut ring head gasket. I never bothered ccing everything to calculate my true compression ratio, but in reality it was likely less than 8 to 1.. Plus I was running a much larger turbo than a 2560 and an auto tranny with a loose converter. Both of which would be more tolerant of timing than a small turbo/manual setup. My top rpm number was 6900 on my timing map so after 6900 the timing numbers just carried on up. at 220kpa i was 26 degrees at 6900rpm, so the same as your 220 kpa 6500 rpm number. My top timing numbers at 6900 rpm follow, just to give you and idea what I ran..... 260kpa I was 25 degrees, 300 was 23, 340 was 22, 350 was 21, 360 was 19, 370 was 17... My timing was pretty aggressive. I was running usually in the 330-340 kpa range, so 22 to 23 degrees but only for 6 seconds or so at the track. If you're stock engine, small turbo, manual tranny you may want a tad less..

You should degree your balancer and confirm the timing marks on the cover, pulley and piston tdc.. If you are on speeduino and the 4 tooth crank wheel still there will be a little ignition retard as the rpms climb higher due to lag in all the electronics and the predictive coding. Speeduino does not have a setting to factor for slew as does megasquirt. I cant remember exact amount of retard I was seeing when I had my car (unfortunately I sold it) and was running the 4 tooth crank pulley, It wasn't a huge amount. Maybe a couple degrees at 6000ish rpms, but it was there. I made up for the high rpm retard by adding a little extra trigger angle.

 

People running X-series are they using the selected option in the drop down menu or inputting custom values based on what AEM has in their paperwork that you get with the gauge?

 

I don't like calibration settings I can't see, so I always do my own.

 

that's understandable. The reason i ask is because i also have an X-series AEM gauge and I used one of the settings in the drop down in tunerstudio. The gauge matched what tunerstudio read and ive had it that way for 2 years now. Still wondering if I was supposed to have entered in my own settings using the supplied information from AEM.

 

More than likely they’re the same, that’s just my preference.