ZeroBanger

I have done alot of research to learn the power FC and how it controls boost. I have realized that its alot of trial and error. I have run 18 times at the track and hit the fuel cut 8 of those times. over the last few weeks I have done alot of testing. I would set the boost , then the duty cycle and test my car. My point was to get my car as close as possible to my target boost, but not go over and get the fuel cut. I found that I usually hit the cut in 3rd gear at high RPM.

Anyway, I would look at my intake temp and set the boost and duty cycle accordingly. I think I have it down based on air temp where I should keep my power FC setting to acheive appropriate boost. Now my question is about a boost controller and will it work better?

For example, right now I set it for 12.5 PSI. I know for sure that I may get 10 PSI in first gear, 11 in 2nd, 12 in 3rd and probably 12.5 in 4th. If I get a boost controller, will it keep me at a solid 12.5 in every gear?

Last question what is the best controller to use with the twins?

Thanks!!!

David

Kahren

iTrader: (13)

if u are using the pfc to controll the stock wastegate and prespool solenoid with your mods u might spikea little. also check the lines that go to wastegate and prespool actuators and the ones that go from the actuators to the solenoids and also check if your solenoids are not leaking. if all ehck s out ok you need some other method of contrrolling boost. for example https://www.rx7club.com/forum/showth...hreadid=115089

3isacharm

so if you have the power fc do you also have to run a boost controller?

Kahren

iTrader: (13)

you can purchase the additional servo-solenoid that they sell, to controll boost. but u coudl also go with teh home depot valves. worked great for me and NO spikes
check this out
https://www.rx7club.com/forum/showth...hreadid=115089

RotaryKnight

I ran a PFC with a HKS EVC IV....ran great. Of course it was dyno tuned at XS.

ZeroBanger

hi...

thanks for the response. I don't get spikes on my power FC. I got mine professionaly tuned and installed. My question is concerning boost control. If I was able to do the install myself i would consider the home depot thing, but I will be having it professionaly installed.

So again, anyone have an answer to my question concerning the consistency of a boost controller in every gear vs power FC?

Kahren

iTrader: (13)

the consitancy of teh boost controller and spikes come from the boost controller itself, if it spikes you will have to change to somethign else. your power fc just controlls teh stock solenoids, the stock solenoids will not give u a reliable boost pattern once u upgrade.

Badog

I think the stock setup with the PFC works.

Here is a shot of a dyno run I did with an Apexi AVC-R set at .80 controlling boost (hit 337 RWHP) :


Here is a shot of another Rx-7 (sameday) with PFC set at .80 controlling boost (he hit 300 RWHP) :


I have been trying to get the AVC-R to the same goals as you, David. I want to set and forget and always have the same performance within -/+.05 bar.

I have dis-connected my AVC-R and have the PFC controlling boost. Now, I get VERY solid performance with the settings:
Primary: .95 Bar Duty 76%
Second: .95 Bar Duty 80%

The most spike I have seen is +.05Bar. I have been tuning with a wideband the last few days, and only have seen this under 4th amd 5th gear WOT.

Until you chart the actual perfromance of what is going on with your boost, you're still in the dark.

Hope this helps.
Tony

ZeroBanger

Wow badog...

Great info. After spending every day at lunch writing down my intake temps and and my boost/duty cycle settings I was slowly figuring out how to get my boost right. Its a pain that I have to change it when it gets cold. I kinda set up a "cold" and a "hot" setting but it doesn't always work that way. My latest its

.85 .68
.85 .64

This gave me .84 Bar in 89 degree weather for my 13.1 @ 106.5 run. I did not hit the fuel cut and was pretty happy. My feeling is if the weather was in the 60's I would have over boost and hit a fuel cut. It happens all the time when I drag race, once sometimes two times a night. Last week was the first time I did not happen. I hope I'm figuring it out.

Thanks for the dyno info. My car was dynoed a few weeks ago, it looks like my turbos are very strong even at 149K miles.

David

Badog

Get a Datalogit.
Get a DIY-OZ wideband.



The best $500-600 you'll spend on your car.

I think those duty cycles are about right. I like rock solid boost on the first turbo with a quicker spool up, and a little more overshoot on the 2nd turbo, personally. I have traction issues, even with 17x10s on the back