I'm rich!! Help me fix it!

Hopefully that got your attention....

Anyways, here's my problem. I just pulled the trigger on a 1990 MX6 GT Turbo for $1000. There are a couple things done to this thing that both make me excited and worried.

1) The stock turbo on these things are TINY, and run out of breath at about 4500. THIS one has a Supra CT26 turbo, pulls all the way to redline, and spools a little later. (A good thing, in my opinion.)

2) It has 440cc injectors. Stock is 330cc. The car runs beautifully, idles perfect, and doesn't seem to be running quite rich enough to blow big clouds of fuel. BUT, i'd like to find a cheap-ish way to control them to get the gas mileage, and just so it runs right. The fireballs it blows every once in a while are very entertaining, though.

I can chip the ECU to get rid of the boost cut for about $50. I already have a wideband on the way. What's the cheapest effective way to take some fuel out in a safe manner? SAFC II? I'd Squirt it, but i don't really have the necessary know-how, and i'm not comfy enough with it to trust it on a DD.

Any suggestions would be greatly appreciated. I'm not familiar with VAF-based cars besides my Escort, and i haven't had to do anything close to this on it.

THey're not real cheap, but a Rising Rate of Gain Fuel Pressure Regulator might be the low-tech solution for ya. You would drop the fuel pressure way down for idle/cruise, but when the boost comes on, the fuel pressure builds exponentially to compensate.

There might be cheaper ways to deal w/ the boost cut. On the turbo dodges you can build an adjustable zener diode to hook inline w/ the MAP sensor. It basically limits the voltage to the sensor to just below the cutout voltage. Dunno if that's possible on a VAF system.

problemaddict wrote: THey're not real cheap, but a Rising Rate of Gain Fuel Pressure Regulator might be the low-tech solution for ya. You would drop the fuel pressure way down for idle/cruise, but when the boost comes on, the fuel pressure builds exponentially to compensate. There might be cheaper ways to deal w/ the boost cut. On the turbo dodges you can build an adjustable zener diode to hook inline w/ the MAP sensor. It basically limits the voltage to the sensor to just below the cutout voltage. Dunno if that's possible on a VAF system.

Ah ok, so you're talking an FMU with a lower base pressure. I've used those on Hondas before, with mixed success. They always tended to run REALLY rich in boost, particularly during spool up. That was on a MAP, though.

As for the boost cut, the chip also smooths the fuel and timing maps in addition, it's an EPROM chip.

I'll look into the FMU, though....

Do you think that the SAFC II would do what i'm looking for, though? I have a line on one for $150, and i already purchased a wideband.

The forum guys when they max out the stock injectors like to do a 5th injector setup, and i'm not too cool on that. And with my larger turbo, i imagine i'd max out the stockers real quick if i tried to source those, too. I just want to effectively use the 440s that are in there. The extra 110cc can't be THAT bad, can it?

Last I heard, nobody had been able to get the safc to work on the 1gens. The chip adjusts the fueling towork with the tbird turbo hybrid where you put the comp wheel and housing on the stock exh/center section.

I can tell you from experience that engine does not like 15psi of boost in 5th gear on the highway, in the summer. I kept the main bearing fragments as a testament to my stupidity. But MAN that was a fun car!

Strizzo wrote: Last I heard, nobody had been able to get the safc to work on the 1gens. The chip adjusts the fueling towork with the tbird turbo hybrid where you put the comp wheel and housing on the stock exh/center section.

Ahh.... ok. So SAFC = no go probably.

I don't think i understood what you were talking about with the chip, though.... assuming we're talking about the same chip, people use them on stock turbos, and i have neither the stocker or the Tbird hybrid, running on stock ECU w/ 440s. I'm pretty sure mine is bigger than either, attached to a 3.0 litre engine stock.

The fireball might be from the use of a BOV. The fuel injection system doesnt know that a bunch of air was relieved back into the atmosphere and never made it to the engine since it was already measured.

RossD wrote: The fireball might be from the use of a BOV. The fuel injection system doesnt know that a bunch of air was relieved back into the atmosphere and never made it to the engine since it was already measured.

Yeah, you're probably right. From further research, these cars do better with re-circulated setups. I'm not real worried about it, it's not stumbling or anything. But definitely a good point!

But you're right. Fireballs are pretty cool, but not when it happens next to a crowded cross walk.

RossD wrote: But you're right. Fireballs are pretty cool, but not when it happens next to a crowded cross walk.

Hah, they aren't near that big to be a hazard to anyone other than the noise. I think with the way the exhaust is run, it'll always make the noises on occasion anyways. If i'm close enough to someone that the fireball hits them, they also have a sidemirror on the way to nailing them in the chest.

The car as a whole is quieter than my Celica with massive leaks in the exhaust, and the Celica has been known to blow flames, too.

slefain wrote: I can tell you from experience that engine does not like 15psi of boost in 5th gear on the highway, in the summer. I kept the main bearing fragments as a testament to my stupidity. But MAN that was a fun car!

This sounds like a controls & fueling issue and not a strength issue. That motor is pretty stout, since it's based on a diesel design and uses piston oil squirting, plus a main cap girdle to tie the whole lower end together. A properly managed F2 should have handled 15psi fine.

pres589 wrote:

slefain wrote: I can tell you from experience that engine does not like 15psi of boost in 5th gear on the highway, in the summer. I kept the main bearing fragments as a testament to my stupidity. But MAN that was a fun car!

This sounds like a controls & fueling issue and not a strength issue. That motor is pretty stout, since it's based on a diesel design and uses piston oil squirting, plus a main cap girdle to tie the whole lower end together. A properly managed F2 should have handled 15psi fine.

Ok glad you handled that.... i wasn't sure if this was exception or norm, but i have been reading of people putting 20psi with a good sized Holset on these motors internally stock and putting down some stupid power. If the stock block/head will run 11s, i think 15psi on stock turbo should be fine.

All of your issues could be fixed by a dedicated fuel control solution, instead of add-on band aids. I really think you should consider the squirt. Hell - given the wide usage on Miatas, there may be a solution that is already ready to go, or close.

DILYSI Dave wrote: All of your issues could be fixed by a dedicated fuel control solution, instead of add-on band aids. I really think you should consider the squirt. Hell - given the wide usage on Miatas, there may be a solution that is already ready to go, or close.

Yeah.... i'm sure it's the best solution, and there's a PnP setup right now on the forums for this car for like $350 i think. I just don't trust myself to set it up, and i'm completely lost when it comes to creating a map and all that jazz. Every time i try to read up on megasquirt, my friends find me in the corner in the dark in the fetal position rocking back and forth with my thumb in my mouth.

If you think that someone as idiotic as me could take care of it in a weekend, i'll probably do it, but then i'm still going to have to pay someone to tune it.

Or... you could come up and help me out?

DILYSI Dave wrote: All of your issues could be fixed by a dedicated fuel control solution, instead of add-on band aids. I really think you should consider the squirt. Hell - given the wide usage on Miatas, there may be a solution that is already ready to go, or close.

I've never laid hands on a Miata but the engine in his MX6 uses a lot of Mitsubishi sensors and is of a different family entirely.

Could be a nice chance to get a hot wire style mass airflow sensor in there and away from the flapping door sensor that's in there from the factory.

Ugh. I'm dumb. That one MS setup is for a KLZE turbo, anyways.

Looks like there isn't a PNP solution for the F2T as far as i've found. Poopy.

So what is my best piggyback band-aid solution that will actually work with the car? Seems like they tend to do the FMU/RRFPR solution. I guess that means more bling in the engine bay..... ugh.

93celicaGT2 wrote:

DILYSI Dave wrote: All of your issues could be fixed by a dedicated fuel control solution, instead of add-on band aids. I really think you should consider the squirt. Hell - given the wide usage on Miatas, there may be a solution that is already ready to go, or close.

Yeah.... i'm sure it's the best solution, and there's a PnP setup right now on the forums for this car for like $350 i think. I just don't trust myself to set it up, and i'm completely lost when it comes to creating a map and all that jazz. Every time i try to read up on megasquirt, my friends find me in the corner in the dark in the fetal position rocking back and forth with my thumb in my mouth. If you think that someone as idiotic as me could take care of it in a weekend, i'll probably do it, but then i'm still going to have to pay someone to tune it. Or... you could come up and help me out?

You said you've already got a wideband, right? Get the squirt, set it up to self-tune on the wideband. Load a baseline tune based on a similar motor, and let the self tune do it's thing.

DILYSI Dave wrote: Load a baseline tune based on a similar motor, and let the self tune do it's thing.

Careful with that self tune...let it go too long, and eventually it will educate itself into self awareness, and next thing you know, your mazda =

DILYSI Dave wrote:

93celicaGT2 wrote:

DILYSI Dave wrote: All of your issues could be fixed by a dedicated fuel control solution, instead of add-on band aids. I really think you should consider the squirt. Hell - given the wide usage on Miatas, there may be a solution that is already ready to go, or close.

Yeah.... i'm sure it's the best solution, and there's a PnP setup right now on the forums for this car for like $350 i think. I just don't trust myself to set it up, and i'm completely lost when it comes to creating a map and all that jazz. Every time i try to read up on megasquirt, my friends find me in the corner in the dark in the fetal position rocking back and forth with my thumb in my mouth. If you think that someone as idiotic as me could take care of it in a weekend, i'll probably do it, but then i'm still going to have to pay someone to tune it. Or... you could come up and help me out?

You said you've already got a wideband, right? Get the squirt, set it up to self-tune on the wideband. Load a baseline tune based on a similar motor, and let the self tune do it's thing.

That i could probably handle.... Now the next step is seeing if a PnP actually exists... i have a bad feeling that it doesn't, doesn't seem to be a very popular motor anymore.

93celicaGT2 wrote:

problemaddict wrote:

As for the boost cut, the chip also smooths the fuel and timing maps in addition, it's an EPROM chip. I'll look into the FMU, though.... The forum guys when they max out the stock injectors like to do a 5th injector setup, and i'm not too cool on that. And with my larger turbo, i imagine i'd max out the stockers real quick if i tried to source those, too. I just want to effectively use the 440s that are in there. The extra 110cc can't be THAT bad, can it?

I'm not sure I follow you, nor do I Know that much about Mazda pre OBDII stuff, but you said it has a custom burned EPROM?? Is that the EPROM in the ecm?

If so, you should probably be able to modify the tune yourself with the help of a chip burner (50-100 + a "few" hours of learn time). You could scale the tune for larger injectors and (guessing here as its an AFM) scale back fueling under light load. You will want to datalog with your wideband before you change anything so you'll know where to start.

If your still running the stock intercooler, upgrade. That thing is tiny. I have one in my garage.

If you can't burn a PROM yourself and don't want to step up to MS yet, what about progressive controlled alcohol injection? There are some pretty slick setups for reasonable amounts of money.

look.. just don't run lean.. cause then that "bargain" car you bought will have a nicely ventilated engine block.

93celicaGT2 wrote:

Strizzo wrote: Last I heard, nobody had been able to get the safc to work on the 1gens. The chip adjusts the fueling towork with the tbird turbo hybrid where you put the comp wheel and housing on the stock exh/center section.

Ahh.... ok. So SAFC = no go probably. I don't think i understood what you were talking about with the chip, though.... assuming we're talking about the same chip, people use them on stock turbos, and i have neither the stocker or the Tbird hybrid, running on stock ECU w/ 440s. I'm pretty sure mine is bigger than either, attached to a 3.0 litre engine stock.

i assumed you were talking about the zombie chip which is really optimized for the tbird turbo and adds timing and pulls some fuel around where the turbo would normally spool. the stock tuning pulls a lot of timing and adds a bunch of fuel in that spot for safety.

i know people run the zombie with the stock turbo, because it lets them run more than 12psi without hitting cut. supposedly the stock injectors are 330cc/min, which should be ok up to 200 hp with a walbro 190 pump. if you keep an eye on everything with a wideband, you should be ok.

a popular thing to do is to swap in an fe3 from the kia sportage. supposedly some of them came stock with about 170hp, then they put ms and a turbo on it for around 250-300hp.

FE3 from a Sportage + an appropriate turbo + a bunch of Megasquirt madness = a great transplant into a 2nd gen convertible RX-7, right? RIGHT?

I know if you want to track down a recirculating BOV, my Legacy GT (05+) uses one, and that there are some aftermarket ones that you can set to100% recirculating or 50/50, go fast bits has one that I am looking at for my car.

I'm rich!! Help me fix it!

You're a car guy, it'll fix itself.....