HELP! Blew engine, and am now paranoid. Need help/opinions.
 

So, I blew the engine in my Miata after turbo install (melted 3 of 4 pistons while tuning via tunerstudio). My setup was a stock 99 engine (with mazdaspeed cam) in a 96 Miata using stock 96 fuel system/injectors and the 96 sensors. I was running all flyin miata intercooler piping/intercooler/manifold/3" catted exhaust. My turbo was a rebuilt s13 t25 (8 psi wastegate). I have a MSPNP for a 96-97 from DIYAuto. Here are the maps I was running at the time of death (I don't know how to turn the maps in tunerstudio to thumbnails, so I took pics of my screen, literally):

https://www.miataturbo.net/attachmen...ine=1371162221

https://www.miataturbo.net/attachmen...ine=1371162221

https://www.miataturbo.net/attachmen...ine=1371162221

So, I am now rebuilding the engine with Carrillo A rods, Supertech 8.6 pistons, Supertech +1 valves and springs. Planning on also running a 2560 turbo and 550 RC engineering injectors with FM dual feed rail and Walbro 190 pump. I'd like to run 15-16 psi.

From what I could tell by researching, I thought those maps were safe (the timing map is what FM issues with their 01 Hydras). By looking at the maps, does it look like my injectors were overwhelmed (stock 96 with 155K)? Do I need less timing? More fuel? This has been a very costly mistake, and I definitely want to build it right this time, and do not want to go down this road again. Please help, I just want the car to stay together.

Thank you,

Jason

Those maps look a little hot to me for an initial tune. Sure they maybe the optimal settings with the right fuel and if everything is calibrated properly, but if there are sensor issues, you could be in serious trouble. I have not seen as many maps as others here with more ECU experience, but even so, it stands out as a bit risky for the maiden voyage. Also, I think you have some fuel system limitations that make matters worse.

Next time around, have a much more conservative tune, and work your way up once you know all the bugs are worked out, and all components are adequately matched.

Way to little injector capacity and the spark map is a bit aggressive for starting out (what's with the huge jump 1000-2300?). Injectors were, most likely, your main problem.

Don't buy RC injectors buy something ev6 or ev14 from Deatchwerks or Injector Dynamics, the better spray pattern will substantially improve how your car runs.

As was said above, use a very conservative spark map to start out and get your fuel and reliability nailed down, then make more power with your spark map.

** rescale your spark map, you don't need the 100 column and the rest could be redistributed more evenly.**

I ran a stock 97 fuel rail and pump with 600cc injectors feeding a gt2560 at 18psi on a stock 97 engine for close to 4 years reliably, you don't really need a fuel rail IMO.

I agree that it wasn't getting enough fuel and had too much spark advance. Your AFR target table SUCKS.

Stock injectors?? Really?? You stupid or something??

Don't bother with the fuel rail or fuel pump. But do get properly sized injectors please.

You could have the most awesomest fuel map, it would be perfectly worthless if you do not have the injectors to deliver the intended fuel.
Translation: you were running too lean for the amount of boost you were feeding the engine.

I second the suggestion to use EV14 injectors.

Well, from what I had read, the stockers should have supported 8 psi. Live and learn.

I'll look at injectors other than RC, thanks.

Anyone have spark and AFR target maps they'd like to share for me to start out with (unfortunately my MS is a 8x8 AFR target map)?

Thanks,

Jason

Stock injectors and excessive timing.

On the my afr targets, where do you see the problems?

Thanks,

Jason

Question for all the guys replying that timing was too aggressive. When I first started my MS3x I used Brains 1.6 460cc base map. I started a thread and asked if the timing was conservative enough to make it to the dyno. Brain replied it was very conservative. But it looks more aggressive than jrmotorsports55's where peak torque would occur. What areas of his map are too aggressive, high load high rpm? What should a stock short block miata be targeting for timing?

https://www.miataturbo.net/megasquir...x-start-72267/

https://www.miataturbo.net/attachmen...c2cb91e8_c-jpg


Also jrmotorsports55 was this on 91 or 93 octane?

The taper from 12.7 to 12.0 between 100 and 156kpa means you're running too lean for my tastes. 12.7 at 100kpa is fine, but it needs to be 12.0 by 128kpa and 11.8 by 156kpa. It's not a big issue, but combine that with aggressive timing and pump gas and you'll melt pistons over time.

I was running 93 octane.

Thank you for the explanation on the afr targets. Do you see any other issues with the fuel map?

Thanks,

Jason

Many people dont get the idea behind the afr chart... its a wish list... just because you "wish" to tune for 12.0 doesnt mean you ARE running 12.0. In other words if ur fuel map is shit... thats what you'll be running until the autotuner has had a chance to correct it.

Did you even bother to check if the injectors were exceeding 80% duty cycle?

Next time turn on "include AFR Target" and use the TS built in table generator for your AFR table as a starting point for tuning with VEAL.

I hope you understand now why we harp on learning to tune with MS before turbocharging. You will make mistakes!

Sorry to hear that man. I'm pretty new myself and the hardest thing for me was trying to not rush the turbo build and checking everything twice before the "first" run. Like everyone else stated, the main problem that I see was you using your stock 96 injectors and your spark map was a little too aggressive for the first run. Here's a link to my post from last night. It has my current maps on there if you would like to see. It's by no means highly tuned but I have been driving it reliably for almost 2,700 miles now @10psi(knock on wood). Well good luck on your build and getting bigger injectors.

https://www.miataturbo.net/mspnp-55/...9/#post1021289

I get that, and I did try to gradually work it on to boost to allow it to correct. Guessing I didn't wait long enough, and it looks like even though I read that my equipment could have handled the boost I was running, I overwhelmed it.

Now I just need a solid starting point for the new engine, as I do not plan on making this mistake again.

Thanks,

Jason

I agree! Tuning N/A was definitely easier and also fun. Before turbocharging I was running a stock 1.8 with RX7 550cc injectors. My friend looked at me crazy when I told him. Well it worked!

Your timing is very hot. Do you happen to have a log while tuning?

No logs unfortunately.

Jason

A bit of levity, to lift your spirits:



Q: How do you make a plumber cry?

A: Murder his family.




A horse walks into a bar. The bartender says "Why the long face?" The horse replies "My wife was just diagnosed with terminal cancer."



Q: Why can't a T-rex clap?

A: Because they all died during the Cretaceous–Paleogene extinction event c. 66,000,000 BC.



Q: What's worse than biting into an apple with a worm in it?

A: The holocaust.



Q: Why did the six year old girl drop her ice cream?

A: She was hit by a truck.





You don't have to be a parent to understand the horror of walking into a room to discover that the baby has crawled out of his crab and onto the pottery wheel that you forgot to turn off. And while the baby is spinning around and around, the dog is sitting there all calm, like a person, gently using his paws to shape the baby's soft cartilage head into something a bit more modern.

It might be the classic tale of bad parenting, but let's see where the dog is going with this.





Also, both your AFR and timing maps look fine to me. I'm with the crowd which suspects that you may have simply been exceeding the capacity of the fuel system, and wishes that you had a log showing actual AFR while in boost at high RPM.

No one has told him how to avoid it next time.
You need to actually watch an air fuel gauge as you tune it to ensure that the ecu is doing what you think it is.
Dann
Dann

I'm going to have to compare my timing map now, you guys got me paranoid. I just took the 99mspnp base timing map, took 2 degrees out of the entire thing, and ran it on 91 octane. I also live at elevation which is a det deterrent of its own, i made sure the (real) opg didn't fluctuate at the slightest, i didn't hear knock, and my afrs are excellent.

Set the overboost cut at what u want, then watch the gauge. Disconnect the wastegate flapper and start tunning that way. then ensure the map keeps flowing... you gotta get that shit close enough before you use auto tunner and keep ur eyes glued to the afr gauge.

27 degrees at 8psi is quite a bit.

You can feel out the fuel table before getting anywhere close to dangerous levels also. First tune should be very gradual and meticulous. If you see VEAL adding fuel down low, grab the whole table and bump up the cells a few points before tuning the next row up. As you found out, it's much safer to be more than a tad rich than to be more than a tad lean.

Stick? How to: blow up your engine??

+1

And take logs and review them after every run, as great as VE analyse live is, you shouldn't trust it, all sorts of things can make it spew out incorrect adjustments.

Even better, get someone else to either drive, or watch the laptop - also have them listening with detcans - if the AFR's get too out of line, or det occurs that person can signal to back off the throttle.

Thanks for the input, I'm definitely thinking this should have been a two person job while road tuning.

Jason

Do you guys not verify your timing??

Base timing? Yes, was verified.

Jason

I dont like when people ramp up timing near redline like that, especially when you've actually tuned your timing latency. I realize that additional rpms naturally add in knock threshold, but I still dont like the practice, especially on stock cams where the power is going to drop off regardless.

at 8psi, you were barely adding any ignition retard over the stock tables...which would be be around 27° or so.

But the injectors can handle 8psi.

Meh, it's better as a one person job in my opinion if you're just using TS VEAL. At the very least, the driver must be able to safely and continuously monitor the boost and vac gauges. For me, street tuning, I don't feel safe glancing back and forth at my laptop in the passenger seat, so I have the boost and afr gauges on the A-pillar. I know if there is an issue instantly, and don't need to wait for my passenger to tell me to back off the gas.

Oh god here we go. :facepalm:

I have afr and boost gauges in my pillar as well, and don't remember seeing issues. Guess I wasn't looking enough.

I'm going to figure out what size injectors to get, and work on putting together a revised timing map and mod my afr targets based on the feedback in this thread. I'll post what I come up with.

Thanks,

Jason

Ehm, wrong place to mention suggestions of course, but it would be helpful to noobs if VEAL could warn for injector duty cycle over a threshold.
Since VEAL is seductively easy to use, the temptation to get going (before having everything under control) is hard to resist.

Duty cycle is not only Req Fuel and VE table (and you have to know that you should do math to check if you're in trouble) so it would help to get a fast clue of an unsuitable setup (TS: "I can't reach AFR target regardless of how much I increase Duty Cycle. Stop trying you MORON!").

TS knows you are trying to do dumb things, why not let the noob know/learn?

If the function is there, it only shows how much I know (and that it's too well hidden)...
Changing to RX8 yellows this weekend :noob:

You can add one to your dashboard if you so incline.

TS, like most software, is a tool. The user is responsible for how that tool is used.

I just want to add something to this as well. Remember that the stock injectors are old in any given car and might not be in tip top condition. I have seen some to be even 10-20% difference in flow. That means possible cylinders that are leaner than you think they are and since the O2 picks up an average of all 4, it doesn't exactly show what happens.
At the least if someone is planning to use stock injectors, I would take them out and have them flow tested/cleaned!

How come you have no logs but were still tuning?
27* is way over what Im running FWIW.

I agree, and admit it's not something I thought about. My injectors have 155k on them, probably didn't help my cause.

Thanks,

Jason

Are you still running stock injectors?

STOCK INJECTORS CANNOT SUPPORT MORE THAN 6PSI.

or so.

I was, as I was under the impression I could go to 10 psi on stock injectors. Apparently, I was misinformed.

Thanks

Jason

you can go 15psi on stock injectors*

































* so long as your fuel rail pressures are 200psi.

[QUOTE=Braineack;1021859]you can go 15psi on stock injectors*


A major kit vendor is selling a kit that claims to make 200HP with stock injectors, at 8-10PSI, and a second kit vendor is not far behind. That isn't helping those of us who want to "roll our own". We're likely to want or need to save money and use what information we can scrape from others.

I'm a noob, but I've been reading, and my conclusion (so far) is that it might be possible, if everything is perfect, and you're holding your mouth just right, and you're using a rising-rate fuel pressure regulator to cram more fuel through the stock injectors than they're supposed to, and achieve these numbers. I don't think it's prudent to attempt it without a lot of guidance and experience with stand-alones and FI, or have a lot of hand-holding from the vendor.

My heart goes out to the OP, who has lost his motor! That's a big bite, and one that doesn't have to happen. The stickies in this forum are great, and they're full of correct information.

However, I haven't found any that look specifically into some of the ways that kit makers cut corners to meet power goals, and to meet price competition. I think this would be extremely helpful for those of use who are trying to get up to speed quickly.

I'd volunteer to do this, but I'm too new in the game to have the experience I'd need. Hell, I hope I don't end up like to OP when I get the turbo installed in my car! I *would* be willing to do it after I have enough experience to be credible and get things right.

Eh? You completely contradicted yourself there.

Better as a one man job, but not safe looking at the gauges... 2 people means one can concentrate on driving, and the other on engine vitals.

Experienced tuners don't need a helper, but for noobs it's an absolute boon.

Do you even know where the A-pillar is?

Yup i've disagreed with them many times... what they dont mention is that they are running 8psi at 13:1+ afr ratios... Why? Because if they say their kits only make 180 at the wheels and are limited by the injectors you'll go to the competitor that claims their kit makes 200 using the same injectors. If the op had started reading this forum and the truth first, his motor still would be in 1 piece.

Last time i got into it with Corky from begi... even his own math showed that the stock injectors max out at 180ish crank hp which is about 6 psi.

At 100% duty cycle i started leaning out at about 6.5k rpm and went up to 12.2ish afr by the 7.2k redline. Again that was at 6 psi.

Alright, I've tweaked my AFR targets, does this look better:

https://www.miataturbo.net/attachmen...ine=1371255585

Also, I did some digging, and found that the DIY 1.6 map is for a 2560, which is what I'll be running. Does this timing map look pretty safe as a base to work with:

https://www.miataturbo.net/attachmen...ine=1371255585

Again, thanks everyone for your help, and not beating me up too bad. This has definitely been a learning experience, and a mistake that I will NEVER make again.

Thanks,

Jason

Your next main concern will be the VE table because that is what your ecu will actually be running. Whatever it says on the VE table is how much fuel the ecu will spit out.

Yes your afr table looks better. Personally i'd go to 12 afr at 101 kpa and 11.5afr for the 156kpa

To triple 88a note my previous sarcasm..

Sigh.

To Op,

The ve table is that actual fuel numbers the ecu is using. The afr table I just a long term target that auto tune is slowly working towards, it will get there eventually but if your 8psi pulls are 20% too lean the auto tune just makes sure they are 18% too lean next time.

So you do a pull at the lowest pressure your setup will allow you to run. Which is 6 or 7psi of - vacuum-.
You watch the boost Guage to ensure this and you check the data log after. Double check afr against known good values at this pressure and if it isn't within 5-10 percent you go to your ve map and add the right amount of fuel to get it there.
You then move to the next kpa row up (still way in vacuum no way near boost.
Using the numbers you just found for the last row check the next row looks sensible, if not adjust it manually.

Now do another logged pull and repeat all the way to 100kpa.
Now once you have cruised around with auto tune with one eye on the wide band gauge and auto tune has trimmed the last few percent so it drives really nice, you cut the wire holding your waste gate open and continue tuning the same way 1psi of boost at a time.

Dann

Theoretically you could, as long as you boosted your fuel pressure A LOT with an AFPR, which you don't really want to get into since the MS with larger injectors can do the job at lower fuel pressures.

In other news, I've been running my stock 99 injectors with a walbro 255 fuel pump and an sr20 turbo on 7psi for years with no issues. I don't even remember my duty cycle.

Triple, I'll tweak the AFRs a bit.

Dann, thanks for the step by step procedures, much appreciated. I do get that the VE table needs to be right before using VEAL now (I was thinking VEAL would take bigger swings in tuning runs, now I know better).

How does the timing map I posted last night look, safe enough to tune with?

Thanks again,

Jason

For injectors, I am thinking ID725s with PNP harnesses. Sound good for my application? based on the turbo/boost levels I plan to eventually hit, I'm thinking I should be fine.

Thanks,

Jason

As you can see in my signature, I am running stock 2001 injectors with an EMB and my Autotune, BUT my AFPR takes my fuel pressure to 95psi @15 lbs of boost. I maintain a steady 12.5 AFR whenever I am in boost.;)

The version of stock injector on the NB2 running a higher fuel pressure will support at least 8.5 psi of boost (Mazdaspeed). My 2002 on stock injectors easily supports 7psi, 182 rwhp, tuned at 99 degrees ambient for 91 octane and I'm still pig rich in boost.

The NB2 is a different animal. With 10:1 compression ratio and the variable cam we make more horsepower at lower boost.

Well yeah at higher fuel pressure....

NB2's run a higher pressure, around 55 - 60 psi stock as per factory design.

The fuel pressure on an NA is regulated to appx. 42 PSI above manifold pressure. Thus, the pressure differential across the injectors is a constant, and flow through the injectors (mass units per unit time) remains constant regardless of load.

The fuel pressure on an NB is regulated to appx 58 PSI above atmospheric, regardless of manifold pressure. As a result, the pressure differential across the injectors decreases as manifold pressure increases, and the effective flowrate of the injectors is lower at higher loads, and higher at lower loads.

This, the difference in fuel pressure between the two cars is not a constant. At 100 kpa of MAP, the NBs fuel pressure is ~ 16 PSI greater. At 10 PSI of boost, the NBs fuel pressure is ~ 6 PSI greater.

An injector which is rated to flow 230 cc/min at 42 PSI (the nominal NA fuel pressure differential) will flow 246 cc/min 48 PSI differential (what an NB will experience at 10 PSI of boost), which is a 7% increase.


I would not hang the safety of my engine on 7%.

(7% smarter than FaeFlorida is still dumb enough to keep you out of the electric chair on the grounds of "not mentally competent to stand trial.")

NB2 injectors are 265 cc/min. I did a search here. Showed up in FAQ. I expected better from you, Joe. You are my hero for getting the science right.