BPT bucking (missing?) in cooler weather

[Cpl_Bryant]

I drive an MX-3 with BPT (GTX) and front mount intercooler. I have the 255 fuel pump and stock GTX injectors.

I was driving in to work this morning cruising around 75MPH. I put the pedal to the floor to pass a car and I started to hear my turbo spool up and started to make some power, but all of a sudden the car acts like it just misfired or something.

I was thinking that it might be cramming so much air in there (with the colder outside temperature) that the fuel could not keep up or cut out for some reason. Anyone else run into this issue or something similar? What was the resolution?

[cyclonekid78]

What kinda VAF are you using. Sounds like fuel cut, it might be going bad.

[Franko]

If it felt like hitting a brick wall then that was the boost cut. A few ways to defeat it, the best one being to put a standalone in it and get it over with.

[cyclonekid78]

Ya Boost cut which cuts the Fuel to your engine so as not to go lean.

[Cpl_Bryant]

I see, kinda figured. There is no way to reprogram the fuel maps on the GTX ECU then? I know of some of the standalone systems, but I'm trying to avoid putting any more serious money into the MX-3. What would you recommend? Looks like I'm gonna pay $300 - $400 for the Apexi SAFC II. Looks like the cheapest way to go. I think I'm going to get some boost control and blow this damn thing up. Let her go out in a blaze of glory.

[cyclonekid78]

Look for a Rx7 VAF. It will let you rev to 7200 with no cut.

RX7 B code VAF is what you want. Have it on mine, runs good with it.

[wickedmx3]

I have the EXACT same problem...

looking at the different fixes now, mostly the standalone solution.

[inferno94]

Look for a Rx7 VAF. It will let you rev to 7200 with no cut.

RX7 B code VAF is what you want. Have it on mine, runs good with it.

I have a RX7 A code one and I suppose it makes it lean (stronger spring) the way its factory set but you can tune em.

[Sortin]

I had a boost controller on my 280zx, and the dial got turned a couple times around by accident (passenger had their foot on it maybe, dunno) I got on the interstate, got on the gas heavy, saw the dial jump around, and BANG! I thought something had broke. Was just way too much boost. Turned the dial down, and it was back to normal. Of course, I wasn't trying to over-boost it any, stock boost was plenty, and had no aftermarket intercooler. You'd laugh at the intercooler it has

[wickedmx3]

Would a SAFC Neo take care of this or do we need a full stand alone? I dont have $1100 to $1400 for a Haltech E6X right now.

[wickedmx3]

Would a SAFC Neo take care of this or do we need a full stand alone? I dont have $1100 to $1400 for a Haltech E6X right now.

Bump.

Can somone help me out with this question?

[10secSim]

I recomande A Megasquirt 2!!!

[wickedmx3]

Sorry, I am not really on the MegaSquirt band wagon. It is not like I can build it and for the cost of having someone else do it, I might as well get a Haltech E6X.

Besides, I just stated I don't have the cash for a standalone, I just want to know if the SAFC Neo will get me by for now, until I can do the standalone.

[Franko]

A SAFC will not fix your problem, In fact it will only make it worse. The boost cut is caused by the ecu deciding that its too much once it passes a certain airflow amount. The SAFC intercepts the signal from the airflow meter and changes the voltage so that the ecu will think that MORE air went in then what actually did. This will make the car run richer at that point and thus the piggyback. If you did that then your boost cut will happen SOONER than before because the ecu thinks its happening earlier.

So SAFC... No..

Now, about your setup. Give me some info. Gtx ecu I can only assume. What are you using for a boost controller? What does your boost go to? How are the vacuum lines routed?