Hi all,

I've got a tune from Reverant that my car will start up on and I can autotune it to run reasonably well. However, it's for a F/I car, so I'm only using the bottom half of the VE/AFR tables (up to 100).

Is there an easy way to modify an F/I tune to fit an N/A car, say, by changing the y-axis values of the relevant tables to go from 0 to 100 in smaller increments? Are there other tables I should adjust?

I'm using TunerStudio and my car is close to stock apart for the DIYPNP, COP kit, LC-1, GM IAT sensor and a cat-back exhaust.

- Tom

 

Just change the MAP values to go form 0 to 104

 

And spark table and afr table

 

If you are not going to switch to F/I at some point soon, then I can mail you new N/A tables. You will have to autotune the VE table though, as I don't have a properly tuned 99-00 1.8 VE table (stock Miatas are rare these days).

 

My best guess is that it'll be several months before CCR Racing gets the Rotrex kit approved for the 1.8 '99 - '00, so I'm just looking to get a good N/A tune for now.

This is what I got so far (the fuel map is far from done - I almost just started to auto tune):







It's not going too bad, actually. It starts and idles nicely. It pulls fine too. But when I come back to idle, it dies promptly.

Any comments are welcome.

Reverant, if you have something of a better starting point for me to work from, I'd be most grateful.

Cheers,
- Tom

 

It's a bit weird. When coming back to idle from higher revs, the engine stalls. I can keep it alive with 1% throttle, but if I lift my foot off of the accelerator, it dips and dies. If I have kept it going at 1% throttle for a while before I slowly lift my foot, sometimes it will only dip really low and slowly come back up to 850 rpm where it will idle perfectly.

There is absolutely no problem with starting the engine and settling at idle.

I tried going a bit richer (13:1) between 0 - 1000 rpm and 25 - 45% afrload. No change.

Any ideas? Any idle settings to check or post screen grabs of?

- Tom

 

I do have something in mind, I'll email you tomorrow. How much idle PWM % do you have once the car is warmed up?

 

32.4 - 32.8 %

 

Open the bypass screw so that the idle PWM % is around 25% when warm, and the issue will be mostly fixed. I will look into it however, for a better fix.

 

Thanks, man. That definitely made a huge difference. I just got to do some revving in the parking lot (I'm at work) and it didn't stall once. I'll give it a proper drive later in the day.

Cheers,
- Tom

 

I went for a drive at lunch and it didn't stall on me

It still dips when coming to a stop, e.g. at lights, but recovers immediately and settles to a nice idle.

- Tom

 

Working on a fix for that as well.

 

I've been fiddling with the afr table. I haven't run it yet - just looking for comments at the moment. I'll need to some behind-the-wheel research of where I'm actually at in the map when cruising to better choose the cells for fuel economy numbers.

Any thoughts:





Cheers,
- Tom

 

Reverant & one-niner,

Do you have a link to bone-stock dyno plots of 01-05 Euro or Jap miatas?

 

on the highway where is your crusing location on the fuel map

 

Sure. My car bone stock and with a Monsterflow intake filter kit. Back to back dyno plots.

 

Here are my maps. I'm a noob so be gentle... My timing map is super-**** so I'm not showing that. I also need to rescale the VE map axis




AFRs (red line) at cruise transitioning to WOT:


AFR at WOT:

 

We had an owners' club dyno event last year. Three '01 - '05, all naturally aspirated, were dyno'ed. The one that made the most power was stock, running RON 95 fuel and had the highest mileage . The result was 134.5 PS and 149.2 Nm. The two others produced 131.6 PS/146.3 Nm on RON 99 with an IL Motorsport CAI and 133.3 PS/148.7 Nm on RON 95 with a K&N air filter.

The two bone stock '99 - '00 present both produced 137.5 PS and 155.6/156.7 Nm.

Here's my dyno (note it's a '99 on RON 99 fuel with a Larini cat-back exhaust as the only "power" mod):



My power is fine compared with the stock versions but I'm down on torque. I suspect my VICS might not work as it should.

- Tom

 

Thanks. Interesting that the 99's make more power than 01+.
Does your 99 have the same intake mani as the USDM 99/00 ("VICS") manifolf?

Do you have a link to some dyno sheets of bone stock 01-05?

 

No, the EUDM 99 manifold is different than the EUDM 01-05 manifold. In fact, the 99 has VICS and is exactly the same as the USDM manifold. The 01-05 is the square-top manifold.

Jason, the dyno plots I posted above are of my own car:

Bone stock: 137.7hp/15.6tq
With air filter kit: 143.2hp/16.2tq