Like the title says, im wondering who is using there XFI to control boost? post up how your doing it!

 

What do you want to know? We have setup several cars using the XFI to conrtol boost.

 

How easy is it to setup?

 

Easy you will either need a VSS signal or driveshaft collar for MPH input to the XFI. The boost control solenoid. The fast will control the ground side of the solenoid. Then you go to the boost control table and larger numbers will net you more boost smaller numbers less. The table is based on MPH and TPS vs duty cycle. At lower speeds and tps you can have less boost and faster speeds more tps more boost. It's pretty easy.

 

I guess I didnt think it was that easy. I havent seen much on it and most ppl say jsut get a boost controller but recently weve been hearing from a few ppl that the FAST can easily do it. how accurate is it? where are you getting the solenoids from and is there any writes up showing how to wire it up? Also can you ramp into boost or can you do different boost levels in each gear?

 

For wiring it's easy, one side of the solenoid is wired to 12v switched power and the other goes to the XFI boost control wire. More info in the help menu under boost control.

For the solenoid you could almost any three way solenoid. Fast offers one that we usually use.

You can ramp the boost based on mph and tps very easily. There is no gear based boost control though. It does work very well, I just used this on a single turbo corvette street car that made 535 rwhp and we had a 5 psi spring then used the boost control to raise it to 10 psi.

 

The only disadvantage is boost vs speed. If you spin the tire, it can be counter-productive for traction. The power adder section does offer a boost over-ride function to make "staged" boost possible. You can run it w/o the speed input and configure the 0mph only column for a single stage of electronic boost control.

 

So am I correct in assuming that the XFI just controls duty cycle of a control solenoid with never actually knowing the boost levels... How does this react on days that are colder or hotter? Im just wondering how consistent it is...

 

Is the only way based on boost vs. speed?
If so I'll keep my AMS.
I have XFI and was hoping it maybe able to do the same at the AMS 500 I have.
-J

 

There is a closed loop feature in the Boost Control Parameters in the XFI.
You can also control boost with the nitrous stage features as a timer controller to control pre set stages with solenoids.

More to come one this. I am taking a trip to Comp in the next month to play on their dyno and work out the details of the new Fast XFI class. EFI University will have this class available the first part of the year.

 

Brian do you have any updates on this subject?

I think a lot of people would like to control boost with the Fast without the VSS.

 

I would imagine the xfi using the staged nitrous control to control staged boost would work about the same as using the staged boost control for the bs3. I have been researching it to control my boost so I can ditch my external boost controller and have a staged progressive boost function. I have a few links I can post informing how to setup the bs3 so it should be helpful in setting up the xfi just the same for the most part.
So either try searching for bs3 boost control or nitrous control as it may help you figure this out. If you want the links I have let me know I'll gladly post them.
Other than that I'm here just watching trying to get some pointers on setting my system up.

As for a quick rundown of it on the bs3(should be about the same with xfi). You can control boost staged with C02 on the top of the gates or with boost controlling the top of the gates. You can have three stages plus the wastegate spring. Each stage requires a solenoid and a valve to control boost to the gate.
As said above each solenoid is controlled by the ecu grounding it, so the solenoid must be supplied a 12v key on power source.
There is a timer enabler wire that controlls the start of the timer. This will be key on powered and a relay from the transbrake to cut power to the wire so once the transbrake is released the timer will start.
As I said this is how the bs3 is and the fast may differ slightly.
Each stage is activated on top of the other stage, so the first stage stays active the whole time as the other stages activate. 1,2, then 3 they will all be on. This is all simple to double check with an ohm meter in case the xfi differs in control.

 

Here is a link with diagrams for routing should clear things up a little on the non electrial part of the setup.https://www.theturboforums.com/smf/index.php?topic=49967.0

 

There are a bunch of ways you can control boost.

The boost control table can be used with any speed sensor, VSS, driveshaft or even a GPS.
You can also set the boost control table to all the same MPH values if you want just boost by TPS% this will change duty cycle of the solenoid only per amount of throttle. This will allow only one column though.

The closed loop features are Closed Loop Aux 8 which makes the boost table a percentage of "ANY 0-5 volt sensor" so this does not have to just be a map sensor it can be anything. A 50 in the table will be 50% of what ever the range is so 50% would be 2.5 volts of what the sensor is reading. Think outside the box on this one, it does not have to be a map sensor.


The regular closed loop feature is a percentage of the existing map sensor so if you are using a 3 bar map sensor and you put 50% in the boost table you are asking for 15psi. The ECU will correct and try to keep a 15psi boost level.

Open loop is just a duty control, no correction on the ECUs part only duty cycle vs MPH and TPS%


I will post the print of how to use the nitrous control for a 4 stage boost control later today.

 

Cool, I'm looking forward to seeing this as well as it will probably help me out with my setup as well. I hope I didn't get anybody lost with my bs3 rant of info.
Thanks

 

Here is a schematic I put together for running the Fast XFI nitrous control as a 4 stage boost control, that will be boost based on time instead of MPH. You could use 1-4 stages on top of in addition to the spring in the wastegate. You will have to plug port #3 in the Mac solenoid.

 

I'd imagine you can use the NOS setup pictured on any system really....I'm curious if anyone has used the Gen 7 output, I dont think its as friendly as the XFI, but I have no idea....I'm using a Gen 7 and would like to do something similar, but I'm not running super boost or anything, I just like to tinker around.

 

You could use this for any stage output on any EFI system

 

what about simply using the PWM output on the Gen 7? Since you seem fairly knowledgeable with this setup....

 

For a PWM output you would use a solenoid like the MAC type pictured and pulse it x% duty cycle to achieve the boost you desire. The time based one I posted above is just an on/off type switch.