3-Bar map sensor?
 

I got another question. When running the Power FC when do you need to get the 3-bar map sensor? You need it when you run over 15 psi right? I gonna be running the Greddy profec B spec II with the PFC. I plan on running around 18 psi high and about 14psi low. Where can I get this 3 bar map sensor for a good price and how does it wire in to the FD? As everyone can tell I'm new to this PFC deal. Thanks...Tony

You can get the map sensor from Jason @ the rx7store I believe. It's the Apexi SAFC soleniod if I'm not mistaken..

Thanks....so how do you install it? I'll have to check how much it is at the RX7store, anyone else know of any other sources?

Should be plug and play I believe...

It's not plug and play.

You need to goto to OPTION 2, set scale to 41800, and offset to 0. The wiring is:

GM 3bar | Function | Rx7 Factory Wiring
A | GRND | Black/Grey
B | MAP SENSOR VOLTS | Greeen/Yellow
C | 5V | Brown/White

R-magic....thanks for the help. So I will need to get this GM map sensor if I run more then 14 psi correct? Also where can I pick up one of these GM map sensors? GM dealer :-)

Thanks for clearing that up. :)

You can run up to 17 or 18 psi boost with the stock map sensor ... but if you overboost there is no way to compensate with more fuel or conservative timing. You will get whatever you program at 17/18 psi. Assume you overboost to 20+, you will be lean compared to 17/18 psi boost.

My stock 2 bar map sensor would not read above 16.8 psi. And i have a few junk motors to prove it! Also have the car tuned for the higher levels with race gas only. Anything above 15-16 psi for pump gas. At least not unless you run some real conservative timing and maybe water injection.

So is this they only option with the 3 bar GM MAP sensor? I have heard of someone else using option 3. Just doing my home work because I am going to a gm 3 bar map. Any and more input would be great.

Thanks

My stock MAP sensor tops out at 1.15 kg/cm^2 ~= 16.3 psi. You'll need a 3-bar sensor for running above that boost level for the reason that twokrx7 described.

-Max

I should have stated that I run the PFC w/ commander.

Correct me if im wrong but wasnt the max boost on the stock map sensor 16psi?

17 psi stock MAP sensor

option 2,3,&4 are all the same.
option 1 is for PowerFC boost kit

Hmmm - here's what I did for Apexi 3-bar
 

Well, I'm unsure about the GM 3 bar, because I ordered the Apexi 3 bar sensor only out of the Apexi boost kit. Swaped it with the stock one no problem. Changed to Option 1 on the PFC, but needed to use the datalogit to adjust the offset a bit to zero out boost with the car off. Stock setting is 43860 scale, 3289 offset. I used the same scale but and offset of 2820. Boosting to 15 lbs on a t04s very nicely right now, and have very briefly (as I adjusted boost settings with my controller) got it up to 18 lbs (very, very, very short burst) and it accurately reflected 1.29 on the 3-bar.

The nice thing about the Apexi unit is no hacking of the harness - it plugs in just like the 2 bar.

Beast

16.3 on a PFC is going to be around 17-18 on a gauge.

STEPHEN

hmmm, that apexi one seems nice, where did you get it?

Source for 3 bar
 

I purchased mine from Motorsports Dynamics in Sacramento. Cost was ~ 70 bucks, and it took a month or two to come from Japan.

I've got the GM 3 bar sitting in my garage, does anyone know how to hook this up? I see where R Magic posted the wire conversion BUT what do I splice it to? The map sensore just has holes where a plug would clip in. The stock plug doesnt work so I'll have to cut it off. What do I splice on in its place to plug into the GM sensor???

Anyway know?

Thanks,
STEPHEN

DId you guys see this one at rx7.com? what do you think about it? and does it work the same as a gm sensor or as a boost kit from the pfc


http://www.rx7.com/store/rx7/fdecu.html

MAP (manifold absolute pressure) sensor in a factory 3rd Generation RX-7 cannot see past 17psi. Using a 3 Bar MAP sensor will allow the computer to map engine management strategy up to 29psi. Note: to be used only with A’PEXi PowerFC or Haltech ecus. PowerFC requires special programming, call for details.

3 Bar MAP sensor
Price: $99.00


3 Bar MAP sensor connector and pins
Price: $12.00

That's not the Apexi 3 bar...
 

I think that's the Haltech 3-bar. I have no idea how to hook it up or what scale/offset to use. Looks like they'll supply the needed info and hardware if you buy it.

The Apexi 3 bar looks exactly like the stock unit - you can't tell the difference unless you look at the parts number.

My 3bar sensor that came with the Boost control kit didn't look like the stock sensor at all. There is a pic in the PowerFC forum of the kit.

Looks the same to me....
 

The component I'm talking about is the black 'tee' looking piece in the upper middle right side of your photo, right above the plastic baggie. The hose nipple attachment is where the vacuum hose plugs in, the two metal rings are where your screws tighten in to the mounting pedestal on the fire wall, and it even has the same three-pin plug for the harness. Plug and play for me.

Now, the boost controller pieces I don't know about. I don't use the boost controller from Apexi - I have the old dial-boost setup that Pettit sold some 5 years ago.

Am I missing something, Steven? Wouldn't be the first time....

https://www.rx7club.com/attachment.php?postid=798689

just to clear things up the stock map sensor reads to 1.15bar or 16.8psi. This is a FACT its not 15 or 16 or 17 or 18 or whatever you want. And what twokrx7 said is exactly true. Thats why when I boosted to around 30psi even though my car was tuned super rich above 16psi on the stock map sensor all it saw was the max it can read 16.8psi and it gave all the fuel it could but that wasnt near enough for 25-30 at 6500rpms...

steve is it the new or old # 3 bar sensor? its a good idea to buy the connector that goes with it but if you have the old sensor only its gonna be hard to find the old connector. Garfinkle told me he used a 3 wire weather pack instead of the connector which if you have the old sensor is a great idea. Then you just want to cut off the stock connector and splice those 3 wires with the wires that come out of the connector A B C on the sensor. Simple but it still took me about 3 hours to mount the sensor and wire/solder it and insulate it like factory. pretty cool mod for safety IMO...and for the soldering go pick up some Flux, you shouldnt do anything without it.

Yes we are talking about the same 3 bar MAP sensor in the photo. Every stock sensor I have seen is mounted to a metal bracket that attaches to the firewall with a M6 bolt. It does not have the side mounting wings like the 3 bar sensor. The electrical side is definately plug and play.