N/A to Boost
 

Howdy yall

I've pulled the trigger on an FM DIY kit. Been running MS with factory 265cc injectors. I just installed a vishnu fuel rail along with 540cc Osidetiger injectors. My plan is to get the car running a little smoother with the new injectors before adding turbo.

Question: once I have the new injectors dialed in, whats the best way to extrapolate my map which has never seen MAP values greater than 100? In other words, how do I modify my map to safely predict the fuel required at boost levels? I realize it may be off a bit.. is it safe enough to slowly autotune it to perfection?

Thanks

https://cimg7.ibsrv.net/gimg/www.mia...07411af0f0.jpg

Are they are EV1 injectors from 1970?

Lol i think so. But they are flow matched which is nice

Should have gotten ev14.. i know..

I used my values from 70-100 kpa, extrapolated linearly up to 200 kpa, added 10% or so to boost areas, then was careful when using Autotune to complete the map. I was about 1-2 AFR rich everywhere before Autotune, so I feel it was a good safety margin before leaning out.

Okay that was my plan, richen everything out and pull fuel from there.

Brain, you mention my injectors and now I am second guessing my decision. Can you explain?

the large deadtimes associated with injectors twice as large makes it hard to get a nice clean stoich idle. it may be a non-issue, how about this angle: how much did you spend on them?

They were like 80 shipped. Dead time is ~.6ms

Right now the idle is high ~1300rpm , but perfect 14.7 afr and very steady

How did you determine this?

That dead time seems... ambitious.

1300 rpm isn't what I'd call stable either. I mean, if that's what the car starts off at then, yeah, awesome. But I'm hitting 800 rpm stable-ish afrs with stock NB1 injectors.

Lol value /= stability. 800 +/- 100 is less stable than 1300 +/- 50. I have a high idle because it is my preference, but also because this isnt my daily.

I wouldn't even know where to start determining dead time. I read this straight off the supplied datasheet.

I agree that .6 seems ambitious. I had never touched that setting before and it was at 1.7 with my old setup, stock 265cc

I'd define stable, in this case, as being close to oem. Oem idle is not 1300. 900-1000. Sure... whatever, but at 1300, you're likely getting away with a crummy idle because it's not going to stall on its face. It's like a shortcut to 'stable' idle without tuning things out properly. Imho.

-A noob.

Well when you add a 9lb flywheel and high amperage spal fans and still use AC, things are far from OE. I dont mean to bash your input, and I agree my base idle rpm is higher than stock. Working out a more stable, lower rpm would achieve absolutely nothing for me, except a few pennies on gas. This is also with the idle screw closed entirely, using only the IAC


But​​​​​​ now then, lets stay on topic.

Main subject is still "best way to predict / extrapolate maps for boost"

Sub topic is "do i need to sweat the ev1 style injectors?" From what I've read, atomization is superior on newer generations but nothing to really write home about. Sure the graphics are nice, but in HP gain% what are we talking?

i would have guessed like 2.0ms for them :P

Now that you know the dead time is shorter, do you still express concern? Im interested in learning but need data not opinions haha

Fair enough.

But, then I'd ask why you spent so much money and time on everything and skimped on injectors...

Haha good question, but a disappointing answer. Straight up ignance!

I read good things about osidetiger, and also good things about tested, flow matched injector sets. These are also high ohm, so no need to rewire anything. Nearly double the size of 265cc, so retuning was cake.

I highly doubt the number, and id just leave 1.7ms in my tune.

you'd probably do best converting your map by finding a good base with boost rows, then manually copying your non-boosted rows into it. then interpolating the boosted stuff so it's a smooth rich transition.

Ahh... good idea.

Ill leave the dead time where it is for now unless issues arise. The car runs quite smoothly after making the changes to tunerstudio.

But I will take your advice and compare a base boost map to my current map and try to translate it as best I can.
Thanks brain!