Sshamrockk:

I ask about VE table as mine is dipping back down at the high loads above 135kPa and 5500. I am just doing a mental experiment as to why before I actually begin physical diagnosis.

When I rebuilt my manifold, and set the car back up, I had also redone (2) welds on the hot side charge piping.

Then, first time I ran it up, when I let up, something went "bang". I don't know if that was something major or something like a V-Band adjusting.

So, I'm on a 1999 with a baby turbo, and suspect the following:
Charge piping leak
Turbo out of air (to right of choke line) (though I don't think I'm there yet)
Damage to turbine. (though it still spools the same as before when punched at 4kRPM)
Damage to CAT (but see damage to turbine
VICS broken

But also, I think it reasonable to believe that running out of Intake or Exhaust efficiency would cause VE to go down.

I will not be looking into this for cause until mid-September, but was wanting to see what your 1994, poorer intake, and larger turbo, but more boost, table looked like. For Science, not to confuse.

 

There is nothing wrong with what you're describing. I see it on many miata's, including ones with a big ol EFR6758

The BP really runs out of steam past 6 grand, and many smaller turbo setups like yours the VE numbers drop past peak power because the car isn't flowing more air, so it doesn't need more fuel.

 

I think that is likely as well. I will be very interested in what the car looks like on a true dyno. The little guy is serving me well.

 

Yeah, my car requires less fuel past 6 grand. I think unless you have cams and a port, that's pretty normal.

 

I'm curious why he doesn't have you on any cruise cells for afr target. You could easily be in the 15s for some of the highway cruise areas, no?

Brains basemap has a solid chunk in the 15's from 20-70 kpa range at 1700-5300.

And Vlad, you said you'd expect 106 for trap speed since your car did the same at 210 mustang. Matt's dyno is a mustang dyno, so this is 240 on a mustang!

​​​​​​OP, do you have a knock sensor? If you do, do you have any logs doing a pull? Thanks!

Question for the experienced members... How would you say that timing map compares to the 'average' turbo miata table. Brain's basemap seemed a lot more conservative than this and I believe it was y8s's street map. That said Matt can probably monitor knock in real time while tuning, so I'm a bit surprised that this is just DIY's basemap and not one that has been tuned specifically for this purpose. Any thoughts? I'm going to pull up DIY's maps for the NB1 and compare since the compression is different.



This is from the miataturbo wiki:


I believe 94 was 8.8 and then the rest of the NA8s were 9.0. The NB1 moved to 9.5.

 

It wouldnt hurt to change my cruise cells, its tempting to squeeze out as much fuel economy as possible, since going turbo its taken a huge hit, partially from my heavy right foot im sure. But no knock sensor, didnt see the need to add one with a stock motor, and somewhat conservative tune.

 

I've been averaging 26ish mpg all around use. Should go up with the hard top.

 

14.7 is fine for cruise, that's what many of us run. Some of us even have a special dash in tuner studio to learn what gives us the best mileage. Some folks would rather not put more NOX in the air.

Don't listen to the ****, I have warned many of you before.

 

/\ all true

 

15.5AFR is the best for mileage. You can target that when cruising.

 

Share info on the special dash.

I'm presently running the 15.5 referenced by Shuiend. I have no idea what my gas mileage is at cruise, because my daily is 11 miles and my foot is heavy.

 

Here's mine, I might make a few things bigger. I made it so I could glance with my laptop on the passenger floor.

 

yeah if you wanna get all scientific about it, above are some very helpful things to monitor/log. ultimately you're balancing torque/efficiency with pulsewidths or amount of fuel injected. it's not just a matter of running the leanest mixture, because if you're not getting maximum torque then you're giving more throttle more of the time, which results in more fuel being used ultimately

 

I think Perez tried something like that as well. Run same place at same speed and monitor pulse width (and assuming equal power). I was kind of expecting some sort of XYZ plotting of the parameters.

Dyno would still seem the best / only way to truly tune for maximum economy. That was Hustler's conclusion IIRC. Year's back I read so much MT.net, and now I get some things confused.

 

Yep this has a lot to do with it. There are several good books you can find on tuning that go into details far deeper. What I have seen consistently across them all has always been 15.5AFR at cruise for best MPG.

It was Hustler who was watching PW to get the best mileage. Then I crashed that car into a guard rail.

 

Would anyone mind commenting on the spark map? Just in relation to brains basemap...
To my amateur eyes it looks like the map used here is even more conservative. It's obviously making good power, but is the relative lack of spark advance what's causing the drop in torque pretty early on?

 

I'm also interested in seeing other spark maps from similar builds, not just brains map..

 

My comment is, I don't think many of us actually use a base timing map. We all did for a short while, but after the first drive and log, we changed it. And never looked back.

I am about to run a different motor in my car, but I won't load some base tune. I am going to run a recent tune and see what this motor wants different, then adjust it accordingly.

 

Get your car tuned by someone or spend the time learning how to do it yourself? Or else a basemap is really all that your car need, maybe retard the 2-3k +100kpa slightly for 91oct.

 

Honestly I was expecting some kind of tuning of the spark map.. I run 93 oct so the current map is probably ridiculously safe, but it makes plenty of power, and my driving habits keep me a close to boost threshold, no noticeable lag. Only issue i have with he tune is it can be jerky at low rpm when in traffic, and when it gets colder outside i was hitting over-boost, so I had to lower the duty cycle of the boost controller, so during the day when its warmer, i'm running less boost than desired.. Might up overboost protection by 1-2kpa so I can keep the original duty cycle settings.