rd65

91, 1.6, 140k with a recently installed FM kit. I am currently running the kit as it comes at 6psi. Car currently has the stock cat and Cobalt cat back w/ resonator. The cat may be leaving this weekend. How will that effect my AFRs? Currently I run 11.8ish AFR under wot and 6psi.
Can I cheat the voodoo to keep the AFRs safe w/ different injectors, fuel pump so that I can add more boost? Not looking to run 15psi, just 8 or 10psi. I will likely go stand alone at some point but I have other places to put that cash right now.
I am in the Seatlle area so no crazy cold in winter, mostly sea level to about 500' elevation I daily the car, no autocross or track days, just some spirited back road driving.

18psi

iTrader: (76)

The last miata I owned, I bought the megasquirt before I bought the car. that's how important it is.

x_25

I have seen a stock ecu do mid 11 AFRs at WOT, so not great, but whatever.

Even a speeduino would be miles better than the voodoo box.

Only1Balto

Do you run 11.8 all the way up to redline? I'm on the same kit at 6 psi, and from 3k up I'm in the 10.5-11.5- but the closer I get to 6k the more the AFRs start to creep into the low 13s and I let off. Not sure if its supposed to be a steady AFR all the way up to redline, or if I have an issue somewhere.

rwyatt365

The Voodoo box is not "smart". There is no "feedback" for it to adjust the injector pulsewidth according to a boost map. All it does is to add fuel when it sees boost according to a setting that you dial in with a potentiometer. So, if you go beyond it's capability, your AFR's will begin to climb. Also, if you put in bigger injectors, you will "swamp" the stock ECU's ability to control them in non-boost conditions (depending on how big an injector you go to). In that case you could run the risk of running pig-rich everywhere (or not run at all) when out of boost.

I had a Voodoo kit on a NB1 1.8 and the "biggest" injectors I could run on that were the purple-top '01 injectors (I think those are 310cc injectors).

Only1Balto

I'm not trying to go beyond its capabilities, I just want it running right so I know what it is and isn't supposed to do. If FM designed it to perform a certain function with a certain turbo setup- I'd like for it to do just that, since as much of the variables are the same as possible with the kit they've given me.

I dont think there's a potentiometer on my box. I recorded a video to FM and I'm waiting for a response from them. I was just curious if the OP was holding mid 11s all the way up the rev range, because if so- I may have an issue somewhere.

DNMakinson

iTrader: (3)

If you don’t want massive power with lots of mods, you could add MS and larger injectors (FF640) and tune. Then, when you go for inspection, switch back to stock inj, stock ECU, and the Voodoo.

A thought to consider.

Only1Balto

FF640s, FF LS coils and MS3Pro are what I have waiting to install. I was just hoping I could enjoy the FM kit, taking my time while I study up on tuning.

But I guess, yea you're right. If all I need the voodoo box for is for driveability until smog- I may as well just swap it out until needed.

Lokiel

Correction (it was a long time ago when you probably did it and you've mixed the information, welcome to "The Old Farts Club" :P ):
Purple Tops were OEM 265cc and used on the MSM - can't confirm if they were OEM on '01 and up.
Many of us MSM owners initially upgraded to the green Supra 305/315cc injectors which were as large as the OEM ECU could handle (320cc ran too rich), then chucked them and all the dodgy power-mod hacks for an aftermarket ECU and larger injectors.

rwyatt365

Definitely did this from memory - ALWAYS a dangerous thing at my age!

x_25

For those not in the know on the VooDoo box changes, the older ones had a pot to adjust the amount of added fuel.

The current crop of CARB compliant ones do not, because to be carb compliant, the end user is not allowed to adjust the tune.

rd65

I believe I am mid 11's all the way to redline. There aren't many places around home to do 3rd and 4th gear pulls. Mine have mainly been 2nd gear. Too much traffic on main 55mph roads and too many turns/driveways on 35 mph roads around here. I am going to remove a wastegate washer and go do a few pulls to see where I am at. Maybe need to find some thinner washers to keep things safe. More power would be nice but I am not up to spending $3000 bucks on MS, injectors, rear end, radiator, coolant reroute right now. Will maybe piece that together as I go. I have a 400 Ford with a mega main seal leak so that will take the $3k.

rd65

Inspection? What inspection? We dont do that here. hehehe. Lucky me.

rd65

I believe I am mid 11's all the way to redline. There aren't many places around home to do 3rd and 4th gear pulls. Mine have mainly been 2nd gear. Too much traffic on main 55mph roads and too many turns/driveways on 35 mph roads around here. I am going to remove a wastegate washer and go do a few pulls to see where I am at. Maybe need to find some thinner washers to keep things safe. More power would be nice but I am not up to spending $3000 bucks on MS, injectors, rear end, radiator, coolant reroute right now. Will maybe piece that together as I go. I have a 400 Ford with a mega main seal leak so that will take the $3k.

Socals14

This is exactly what I did...640's, LS coils run in wasted spark, and Haltech Elite. When I need to smog, everything is plug and play.

x_25

Speeduino it and a GMIAT, under $300 and will be all you need, they added mapdot so you can even get away with a non variable TPS, just have to unplug the stock one or it will freak out. It also sounds like you already have a wide band. Tune to the limit of the stock injectors and leave it there. Add FF 640s or even 380s if you are on a budget later. Rerout and otherstuff unneeded on a street car. I have been at ~200rwhp for 2 years on my 1.6VLSD that has almost 170k on it at this point.