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-   -   pre-dyno tuning / minimizing dyno time and ching-dow (https://www.miataturbo.net/megasquirt-18/pre-dyno-tuning-minimizing-dyno-time-ching-dow-24676/)

y8s 08-09-2008 04:44 PM

jondoe why's your map go from 25 to 44 and 32 to 44?

also set your advance to 14 at idle and pretty much all the 800 and 1200 rpm cells under 55kpa.

johndoe 08-09-2008 05:15 PM

Y8S this is what I'm using for AFR targets currently. So MLV changes everything around idle and I change those 4 cells back to 44 because I've tried manually lowering the VE in those cells and the idle gets rough and there's a lot of popping going on. I'm also currently at 18 degrees advance in those cells, I'll try 14.

y8s 08-09-2008 05:36 PM

if you datalog the 55-65kpa cells below 1800 rpm, what AFR do you get?

hustler 08-09-2008 05:41 PM


Originally Posted by johndoe (Post 294408)
Y8S this is what I'm using for AFR targets currently. So MLV changes everything around idle and I change those 4 cells back to 44 because I've tried manually lowering the VE in those cells and the idle gets rough and there's a lot of popping going on. I'm also currently at 18 degrees advance in those cells, I'll try 14.

you know you can set rpm and kpa max and min in mlv autotune...right?

Lean those cells and play with spark, its worked for me.

johndoe 08-09-2008 07:26 PM

1 Attachment(s)

Originally Posted by y8s (Post 294413)
if you datalog the 55-65kpa cells below 1800 rpm, what AFR do you get?

I did a short datalog of the idle after changing the advance to 14 like you advised. I was able to bring the VE down to 35 in the cells around idle and now the AFRs are hovering around 13 but the AFRs and RPM hunt a bit more as well. This is definitely a step in the right direction though! Anything of interest in the datalog or should I just keep playing with spark and ve? Thanks for the help thus far!

Mach929 08-09-2008 07:29 PM


Originally Posted by johndoe (Post 294376)
What the shit? You have bigger injectors running leaner? Mind sharing your idle settings?

i have my idle cells, (by cells i mean 4).. if you have different values it will cause it to be come unstable. i also have my idles cell at 20 degrees timing. turn off any kind of ego or clt air density and move the 4 cells down by 1 and burn to ecu or nothing will happen. see where idle is, don't let the car heat soak too much. with hi-res you shouldn't have much of a problem idling this lean.

btw, my injectors are 550cc rx7 injectors but flowed at 620cc when i sent them out, call them what you will

and after today i think i have it dialed in to idle 14.8-15.2 even with 123 degrees of iat heatsoak

johndoe 08-09-2008 09:28 PM

update: After the changes every so often after coming to a stop and idling for 5-10 seconds the car wants to die now. Idle dips and I have to give it some gas to save it.

Rafa 08-09-2008 09:39 PM

Hustler; I love when you start this kind of thread! I find myself learning through your questions. :bowdown:

Keep them coming! :bigtu:

y8s 08-10-2008 10:23 AM


Originally Posted by johndoe (Post 294457)
update: After the changes every so often after coming to a stop and idling for 5-10 seconds the car wants to die now. Idle dips and I have to give it some gas to save it.

i dunno how MS does idle so unfortunately someone else has to help now :)

you can add a few degrees to your timing map and maybe a little fuel BELOW your idle cells to generate more power during idle dips. or you can open the idle screw and decrease the idle valve pulsewidth so there's more air for "catching" the rpm drop.

johndoe 08-10-2008 10:55 AM

all good suggestions. I appreciate the help y8s

paul 08-10-2008 11:06 AM

MSI HiRes with 550s and 460s in my 2 Miatas and I can idle em both at 15, 16, or 17 AFR. WTF are you doing wrong? I run 18 degrees at idle for both. Using the correct Req Fuel value for each, not inflated for higher res. Idle cells are in the 40's for both cars.

Thought you were gonna make it down this way one day so mess with your MS.

Rafa 08-10-2008 12:04 PM


Originally Posted by Markp (Post 294341)
You don't need a dyno to tune the spark map of a car, but you do need a repeatable piece of road and someone in the car doing the tuning other than the driver. It is possible albeit more labor intensive to get a great map on the road, provided you have the right road and a car that is reasonably safe to drive.

You want to find a long uphill stretch of straight road in the middle of nowhere. Baker Grade in California is perfect for this but roads like this exist everywhere. Unfortunately you can't do the speed limited type of tuning that is possible on a dyno, but you can get really close, close enough not to matter.

Datalogs are your friend, stolen spark tables are your friend, remember your motor is likely to act in a VERY similar manner to most everyone else. Dyno time is really useful when you are looking for that last 5-10 HP, that's it. Everything else can be done on the road.

I would rent the dyno without any tuning support. Most dyno guys can't help themselves anyway, they'll likely jump in and help. Rent an hour, see how you do after you have really thoroughly road tuned it.

Mark

First of all; great post by Mark.

Would anyone care to explain this part: "You want to find a long uphill stretch of straight road" a little further?

What I mean is; why on an uphill and what grade?

Thanks

ZX-Tex 08-10-2008 12:22 PM


Originally Posted by paul (Post 294577)
MSI HiRes with 550s and 460s in my 2 Miatas and I can idle em both at 15, 16, or 17 AFR. WTF are you doing wrong? I run 18 degrees at idle for both. Using the correct Req Fuel value for each, not inflated for higher res. Idle cells are in the 40's for both cars.

Thought you were gonna make it down this way one day so mess with your MS.

I wish I knew what he was doing wrong, then I would know what I am doing wrong too. I have tried those settings with 550 RX7s and the idle is not stable. I have to idle at 13-13.5 with much lower timing.

y8s 08-10-2008 12:35 PM


Originally Posted by Rafa (Post 294585)
First of all; great post by Mark.

Would anyone care to explain this part: "You want to find a long uphill stretch of straight road" a little further?

What I mean is; why on an uphill and what grade?

Thanks

steep as possible. the reason is that you can't generate full boost in lower gears because there's not enough load on the motor

and more importantly, if you try to go flat out in taller (4th, 5th) gears to fine tune your high boost maps, you'll end up going very fast on public roads.

on a steep hill in 2nd you can keep it at reasonable speeds.

Rafa 08-10-2008 12:39 PM


Originally Posted by y8s (Post 294593)
steep as possible. the reason is that you can't generate full boost in lower gears because there's not enough load on the motor

and more importantly, if you try to go flat out in taller (4th, 5th) gears to fine tune your high boost maps, you'll end up going very fast on public roads.

on a steep hill in 2nd you can keep it at reasonable speeds.

Now I get it. So, you're saying it can be done in 2nd gear? I thought it had to be in 4th :bang:

y8s 08-10-2008 01:01 PM

if you can stay in 2nd gear for long enough, yup. dynos are done in 4th to measure best peak power with least drivetrain loss...

johndoe 08-10-2008 03:11 PM


Originally Posted by paul (Post 294577)
MSI HiRes with 550s and 460s in my 2 Miatas and I can idle em both at 15, 16, or 17 AFR. WTF are you doing wrong? I run 18 degrees at idle for both. Using the correct Req Fuel value for each, not inflated for higher res. Idle cells are in the 40's for both cars.

Thought you were gonna make it down this way one day so mess with your MS.

God knows what I'm doing wrong, I'm still learning. If that's an offer to lend a hand I might make a trip to Jersey soon. It's not too far from me.

coastertrav 08-10-2008 07:34 PM

Also if you are looking for a spot on tune contact Tony at T1 in Dallas, he is the man.

He tuned a buddy of mines Civic for under $600 and that included installing Hondata, and the car seriously behaves like stock.

Not only that, but you will go home with a baggy that has a lifetime supply of sparkplugs as he pulls them after every run to check for detonation and swaps in a new set.

ZX-Tex 08-10-2008 09:32 PM

So what is the deal with all of the spark plug consumption? Why not just use detonation cans? It is pretty easy to hear pinging.

coastertrav 08-10-2008 10:55 PM

If you do a pull, then pull the plugs immediately afterwards if there was any detonation, including any you wouldn't be able to hear, it will show up as shiny metal like flakes on the plug.

That is what I was told from Tony himself, who I would trust with any tuning based information.


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