Turbo LS Miata - SD

[wow]

I built myself a turbo LS Miata and now I?m to the point of tuning it.

Engine - SBE lq4 6.0
Cam - comp 54-454-11 (see attached for specs)
Springs - comp beehive 26918-16
BTR hardened pushrods
Turbo - VSR 78/75 1.25 nex gen
Wastegate - VSR 44mm
Injector - seimen deka 80?s
Fuel pump - single walbro 450
Fuel line -6an
Corvette regulator
Super t10 trans (4 speed)
Monster clutch
Ls6 intake
Cable truck throttle body

1st car I?m ever tuning.
Trying to teach myself.

HP TUNERS MPVI 2.
Obviously gen 3 ecu on SD 3 bar os

I input the injector data from an excel sheet that I found on ls1tech and have gotten it to the point of idling and I can drive it around reasonably, but I don?t have to balls to creep into boost and watch the afr?s/spark knock

Now.
I added 115% of fuel on primary ve beyond the 1 bar readings and I downloaded Matt happels timing table on a similar tune setup just to play it safe.

Problems:
A) cold start fires first try and right at commanded AFR; but as it heats up, it starts to get rich and will then idle at like 13.1 when fully warmed up
B) hot start sometimes backfires (exhaust) and just keeps cranking...... if I stop cranking and try again directly after it backfires, it will fire up

I will attach my tune file when I get home.
I won?t have any logs until tomorrow.

Any help would be greatly appreciated.

[wow]

Here it is running on said file listed above.

https://www.instagram.com/p/B-a9Zy-n...=1dpmmolip3vw7

https://www.instagram.com/p/B-xkjuyn...=1ii0kqzgqgouo

[cobaltssoverbooster]

you should be careful with matts tunes. sometimes you dont know how much he has scaled the air load axis which cause the ignition map to run in a different zone than you may have in your setup.

you need to go into advanced reply mode and attach your current tune file so we can see what you are trying to do. we can tell you to do something but without a tune file we cant tell where you are starting from or see how you interpreted our suggestions.

[kingtal0n]

crank -> backfire.... crank -> start

is often a symptom of camshaft angle sensor failure

as for tuning. read every single setting. Make a list of the settings you understand and separate them from the ones you are not sure of.

Then look up research every unclear term.

Then its easy. Dial in the injector size. Use a referenced regulator (regulator needs vacuum signal). Adjust VE table to match the engine. Always shoot for 14.8 to 15.2 in cruise/idle regions. Never let the engine wander into anything below 14.5's for more than a few seconds while cruise/idle because that will waste fuel and foul the plugs.
Drop A/F from 55-80KPA say mid 13's
Then by 85-105KPA drop the a/f to around 12.2 to 12.7 (depends on the situation) i.e. very hot engine, high load, highway regions, err on the side of richer
from 105KPA to about 150KPA around 12.0~ is typical
Then start dropping to the 11.8 to 11.2 range as it moves to 200KPA (15psi of boost)
This is the point at which pump gas is questionable. 93 octane I would stop between 14-17psi of boost on typical stock engines (of any kind) when using gasoline.
You can push it sometimes 22-24psi on 93 octane. I've even seen someone go 33psi on 93 octane before, using negative timing in some places. i.e. You better know what you are doing.


Verify the map and tps sensors reported values match the actual values of the atmosphere, engine pressure range, and throttle. Dial in spark timing by starting low and creeping up on the torque, might need a dyno or EGT gauge if you don't have experience with that.
Again for the sake of getting you started. Typically timing for modern engines (post 2002 era) on 93 octane drops into the low 20's say 21 to 23 around 0KPA at WOT. I actually run a bit less in the turbo spool region to help throw some heat on the turbine for when its cool and to keep the combustion pressure down for when its hot (low timing).
Again pull out timing from 105KPA to 150KPA should move from say 18* to 15*
Around 150-180KPA I use roughly 13* (pre-dyno)
180-210KPA I will start 9* and try 10 an 11* on the dyno

Trick is to use the lowest timing possible while still holding down the EGT to give the maximum head room for safety with the stock cast pistons.
On the dyno you can push an extra degree or two for a peak number, but I take that back out once the car goes back to the street.

everything else in the computer is just behavioral mods for regular driving. Only the VE table, enrichment state, and spark timing really control/contribute the WOT scenario.
In my gen3 computer I use a table under Spark->base-> "AFR timing" (the button says base) this allows you to adjust timing based on commanded a/f ratio. SO when the spark tables maxes out you can still have full control over the final timing. This keeps you from having to scale the tune. I would start with the stock file for your engine and simply adjust from there, rather than somebody elses file.

[5FDP]

I'm not sure I'd run a 450lph pump on a corvette regulator. I think the pump would over power it.

[wow]

Ok, sorry, ill go through the replies in a second...? in the meantime, as promised, here is the tune file to see if you guys see anything out of the oridinary.

miata rev6.hpt

[5FDP]

Couple additional things.

Change cylinder volume to match the 6.0 engine size. Right now it's at a 5.3 engine size.

The MAF dtc's need to be set to MIL on first error for speed density, just disable the SES box.

The VE is probably 115% too rich now. No need to scale it that way past 110kpa.

[wow]

you should be careful with matts tunes. sometimes you dont know how much he has scaled the air load axis which cause the ignition map to run in a different zone than you may have in your setup.

you need to go into advanced reply mode and attach your current tune file so we can see what you are trying to do. we can tell you to do something but without a tune file we cant tell where you are starting from or see how you interpreted our suggestions.

I understand. I literally just copied the file over because 12* sounded a lot better than 20+. Like I said, I didn't have the balls to go into boost, but I would much rather have a safety than to just blow It up and try again. lol

crank -> backfire.... crank -> start

is often a symptom of camshaft angle sensor failure

as for tuning. read every single setting. Make a list of the settings you understand and separate them from the ones you are not sure of.

Then look up research every unclear term.

Then its easy. Dial in the injector size. Use a referenced regulator (regulator needs vacuum signal). Adjust VE table to match the engine. Always shoot for 14.8 to 15.2 in cruise/idle regions. Never let the engine wander into anything below 14.5's for more than a few seconds while cruise/idle because that will waste fuel and foul the plugs.
Drop A/F from 55-80KPA say mid 13's
Then by 85-105KPA drop the a/f to around 12.2 to 12.7 (depends on the situation) i.e. very hot engine, high load, highway regions, err on the side of richer
from 105KPA to about 150KPA around 12.0~ is typical
Then start dropping to the 11.8 to 11.2 range as it moves to 200KPA (15psi of boost)
This is the point at which pump gas is questionable. 93 octane I would stop between 14-17psi of boost on typical stock engines (of any kind) when using gasoline.
You can push it sometimes 22-24psi on 93 octane. I've even seen someone go 33psi on 93 octane before, using negative timing in some places. i.e. You better know what you are doing.


Verify the map and tps sensors reported values match the actual values of the atmosphere, engine pressure range, and throttle. Dial in spark timing by starting low and creeping up on the torque, might need a dyno or EGT gauge if you don't have experience with that.
Again for the sake of getting you started. Typically timing for modern engines (post 2002 era) on 93 octane drops into the low 20's say 21 to 23 around 0KPA at WOT. I actually run a bit less in the turbo spool region to help throw some heat on the turbine for when its cool and to keep the combustion pressure down for when its hot (low timing).
Again pull out timing from 105KPA to 150KPA should move from say 18* to 15*
Around 150-180KPA I use roughly 13* (pre-dyno)
180-210KPA I will start 9* and try 10 an 11* on the dyno

Trick is to use the lowest timing possible while still holding down the EGT to give the maximum head room for safety with the stock cast pistons.
On the dyno you can push an extra degree or two for a peak number, but I take that back out once the car goes back to the street.

everything else in the computer is just behavioral mods for regular driving. Only the VE table, enrichment state, and spark timing really control/contribute the WOT scenario.
In my gen3 computer I use a table under Spark->base-> "AFR timing" (the button says base) this allows you to adjust timing based on commanded a/f ratio. SO when the spark tables maxes out you can still have full control over the final timing. This keeps you from having to scale the tune. I would start with the stock file for your engine and simply adjust from there, rather than somebody elses file.

ok, cool. I have quite a few spares that I can try. When I had it on a naturally aspirated setup, it never backfired like that. I have the same exact tune as the N/A setup, just new injector data, MAF disabled, 3 bar os, double/triple fuel in "boost cells" and matts timing table. I blew up the engine but I didn't swap the cam sensor over, SO, its a very good possibility.

Also, holy crap. What a load of information! I thought I was starting to somewhat get the hang of it, BUT you just schooled me lol
I have been trying to watch and read as many tutorials as I can and explore on the software to gain the knowledge rather than paying a "tuner" $600 to do something that I will eventually learn how to do.

I have been following goatropegarage on youtube and he seems to know his stuff and makes it really easy to understand, but ill take in all the information I can get at this point; I just want to make sure it comes from a reliable source, hence why im here.

I'm not sure I'd run a 450lph pump on a corvette regulator. I think the pump would over power it.

Well from the statement listed above, I guess im going to start looking for a different regulator. I planned to redo the whole fuel system to 8an with a surge tank anyway. I was going to run twin 044s in the surge tank feeding the rail and keep the 450 feeding the surge tank. I don't know. I just wanna make 700hp or cap it at 15psi..... whichever comes first. Just don't want fuel to be the limiting factor.

I haven't checked for pressure at the rail. I will do that and follow up with you tomorrow.

[kingtal0n]

Aeromotive says you can support 700hp using ~6/16" Fuel line on gasoline using their stealth in-tank pump

https://aeromotiveinc.com/tech-help/...th-fuel-pumps/

it would be reasonable to rate the 340 Stealth to 700 flywheel HP EFI forced induction

So theres that. Unless using E85 you won't need huge lines and all that.


The reason you need a reference regulator is because every psi of boost removed 1psi from the fuel pressure.
For example if fuel pressure is 50psi and you run 20psi of boost, now you have effectively 30psi of fuel pressure.

Also another tip, keeping base pressure a bit lower (say 40-45psi) will help the fuel system components last longer and the pump will generate less heat.

Only turn the pressure up to 50-60psi if you need the fuel.

[cobaltssoverbooster]

if you select injectors using an online calculator you will find that 700 hp requires roughly a 700cc/min injector at 85% DC and 43.5 psi. If you convert that to full system demand then your are using roughly 700cc/min * 8 inj. = 5600cc/min this converted to lph is 336 lph. you would have to use 336 lph of fuel not including the required overhead to maintain system rail pressure at full song. the 340 stealth would be cutting it to close for comfort in my book. Best to go in the 400 lph range and have the overhead.

even Aeromotive recommends the Phantom 450 or dual stealth at anything > 700 hp. if you want any cushion at 700 hp you'd be wise to upgrade beyond the single 340.

[wow]

ok guys, here is a tune/log of idle and a couple of revs a the end...... can you check it to make sure its decent enough to move forward and start building the primary VE?

you will also clearly see the crank, backfire at the beginning of the log too.

Thanks in advance.

Idle test with a few revs.hpl

Tune.hpt

[5FDP]

Try changing the MAF dtc's to MIL on first error with the SES box unchecked. See if it starts up better with that.

[wow]

Try changing the MAF dtc's to MIL on first error with the SES box unchecked. See if it starts up better with that.

Sorry! i meant to change it, but i forgot. I'll do it first thing tomorrow and let you know :]
I also need to change the trans back to manual. This was one of the older files that ran a little bit better at idle with a more stable afr.

[5FDP]

Changing of the transmission type really doesn't do anything unless a segment swap is performed. I ran into a weird background issue a long time ago on a truck with a TH350 swap, I changed the type because there was no segment swap available and it acted all funny. Since then I've kept the transmission type as it was from the factory truck it came from, then disabled all transmission related DTC's and engine/tranmission abuse modes.

[kingtal0n]

if you select injectors using an online calculator you will find that 700 hp requires roughly a 700cc/min injector at 85% DC and 43.5 psi. If you convert that to full system demand then your are using roughly 700cc/min * 8 inj. = 5600cc/min this converted to lph is 336 lph. you would have to use 336 lph of fuel not including the required overhead to maintain system rail pressure at full song. the 340 stealth would be cutting it to close for comfort in my book. Best to go in the 400 lph range and have the overhead.

even Aeromotive recommends the Phantom 450 or dual stealth at anything > 700 hp. if you want any cushion at 700 hp you'd be wise to upgrade beyond the single 340.

I wasn't suggesting to switch to a smaller fuel pump lol. Just pointing out that a 'small' line size 5/16" and 6/16" can actually feed some serious power. I think I've seen 800 or 900rwhp on factory 5/16" With E85.

So the need to uprgade to -8an and run a whole new fuel system etc... its alot of work for very little difference at sub 700hp ranges.

[wow]

So the need to uprgade to -8an and run a whole new fuel system etc... its alot of work for very little difference at sub 700hp ranges.

Well with it being a drift car, a surge tank is a must!
As for the line, i figure i would upgrade it since im going to be ripping 3/4 of it out anyway....... going to have to do that with a refenced regulator as well

........ and now i just remembered that i was supposed to check fuel pressure today but i forgot to

[kingtal0n]

Did you ever consider a hydromat type of material to sequester the fuel in the tank

[wow]

Did you ever consider a hydromat type of material to sequester the fuel in the tank

Yeah I have, but I dont really know how well that would work with the stock Miata?s tank because the pump sits at like a 45* angle
Idk, I just never really pursued it

[wow]

Welp, it would help if I had the cam sensor plugged in lmfao. Couldn’t really see it and the connector was pinched underneath the coil. Oops!
Plugged it in and it fires up perfect every single time. Noob mistake.

Also, started playing in the ve in the garage just by revving it in all sorts of matters to get it in the ballpark before I start driving it; then I’ll really start to dial it in.
It’s halfway decent right now, but after 3200, it goes pig rich all over.

I’m going to stay out of boost until my refenced regulator and other stuff for fuel gets here.

When it arrives and I install it, can the reference port be plugged into the intake manifold or does it have to go on the turbo compressor?

Will I just duplicate the fuel table above 1 bar and do the same at the 2 bar mark for starting off while creeping into boost before I start modifying the boost cells? Or what would be a smart way to start rich and slowly back it off?

Also; got a code p1637 for alternator L terminal....... found the main power wire completely toasted..... so, I think I’m just going to go 4 gauge from alternator to starter and starter to battery just to eliminate any starting/charging issues that may show up down the road and also upgrade the grounds

[cobaltssoverbooster]

1) happens all the time. nice find!
2) the reference line has to go to the manifold so it can see vacuum and boost.
3) disconnect the charge pipe and tune the engine wot. wherever the wot run passes through the ve you can double that fuel for every 101 kpa increase from that point. its rough but it woks. Then you can connect the charge pipe and work on tuning to your gate pressure. You'll have to vary max pressure with your foot a little if you have a high pressure spring installed. once done you can refine the data in higher boost pressures by looking at the fuel trends. Slowly walk up on the controller until max desired pressure or desired hp is achieved.
4) run it in 4 gauge and you'll never have current related issues again. Thats how i run my new n/a dragster. power wire runs to the battery in the front of the car. (lower right on picture)(its legal because i run the charge signal through the disconnect to shut the alternator off in emergencies).