Dual Manual Boost Controllers?

[FieroGTFan]

I tried searching for this but I was unable to find anything, possibly searching the wrong terms.

1989 Conquest TSi wondering if I could possibly use the factory two stage boost control and three port waste gate with a manual boost controller to each port. Perhaps do something like like 10psi under 4k rpm, and 13 above 4k rpm.

Has anyone tried this in the past? Curious if it would be possible.

17C turbo and TBI installed on the car.

Thanks

Edited June 24, 2022 by FieroGTFan

[tux]

I think my old profec a-spec was able to do this but using the standard wastegate

[FieroGTFan]

That's what I was wondering if using the factory setup of the 3 port waste gate and the boost "crossover" at 4000RPM if I could add manual boost controllers into the lines to the wastegate to increase my pressure in each stage. It seems to make sense in my head at least.

I had never heard of a ProFec before but it seems to be a powerful little tool.

[tux]

For the time period, it was the bees knees.  It was a rather expensive Greddy/Trust electronic boost controller.  I found it complicated to set up.  Can do way more with a standalone.

 

They have a newer Profec but the thing looks weird and doesn't have any input for rpm

Edited June 24, 2022 by tux

[Turbo Cary]

I have an old TurboXS dual stage boost controller if you're interested. It's a manual style with two knobs and an electronic switch. Basically wire it up so you can swap between high or low boost on the fly.

[Caliber308]

I hear about upping the boost, but I haven't heard a thing about modifications except for a 17c turbo?

Edited June 24, 2022 by Caliber308

[TexasQuest]

What injector size are you running? Adjustable fpr? Wideband o2 sensor to monitor afr's? These are crucial items needed before raising the boost pressure.

[FieroGTFan]

Sorry didn't feel like going through the whole list (used to be in my signature before the server got wiped out). Walbro 255, upgrade injectors, Trilogy Turbos FPR, Mallory ignition coil, wideband, 1G MAF, and a few other supporting mods. I have made sure the car is running 100% before trying to push any further. 

I am talking about trying to place a MBC on the 7.5psi part of the wastegate, and another MBC on the 10.5psi part of the wastegate. Curious if anyone has experimented with this in the past as an interesting way to keep the factory "two stage" operational but up the boost on such.

-Jeff

[Turbo Cary]

Yes you can run two separate MBC's like that. The ECU is going to switch the solenoid no matter what and if you're interrupting the flow to the wastegate then boost will be changed accordingly. 

[Caliber308]

13 hours ago, FieroGTFan said:

Sorry didn't feel like going through the whole list (used to be in my signature before the server got wiped out). Walbro 255, upgrade injectors, Trilogy Turbos FPR, Mallory ignition coil, wideband, 1G MAF, and a few other supporting mods. I have made sure the car is running 100% before trying to push any further. 

I am talking about trying to place a MBC on the 7.5psi part of the wastegate, and another MBC on the 10.5psi part of the wastegate. Curious if anyone has experimented with this in the past as an interesting way to keep the factory "two stage" operational but up the boost on such.

-Jeff

Personally I think that going from 7.5 to 10.5 psi boost on a 17c is a total waste of time. Why? a TDO5 17C is efficient from 10 to 20 psi boost, if your looking to go from 10 to 15 psi it might be worth it. Turbosmart makes a dual boost controller that can be activated with the flip of a switch in cabin. They come with complete instructions and run about $220.00 dollars. If you choose to go this way make sure you install a aftermarket  boost gauge, as the stock one is known to be inaccurate.

[Caliber308]

Here are some other things to think about. With aftermarket fuel injectors, most are Delphis, they need to see at least 44.5 to 45 psi fuel pressure. So. if you are using a fuel pressure gauge under the hood, you can adjust them to 45 psi at idle. Now comes in the fun part. With 45 psi at idle you will need to see 55 psi at 10 psi boost. So, if you do not have a electronic FPG in cabin how do you know what your FP is on boost? I learned this from a long time member on this site. You will need to run a hose from you FPR to a accurate FPG and tape it to the windshield. At WOT read what your FP is. If it is not at 55 psi, you have a problem with your FPR. Better safe than sorry when you turn the boost up.

Edited June 26, 2022 by Caliber308

[FieroGTFan]

Thanks for the replies anyone. I do have a boost gauge and fuel pressure gauge inside the car to help ensure the car is running as expected.

The car is currently running the factory boost setup of 7.5psi below 4k rpm and 10.5psi above 4k rpm, I am looking to install boost controllers in each line to increase this perhaps to something like 10psi below 4k rpm, and 13psi about 4k rpm, sorry if I didn't make this clear from the start.

Thanks again for all of the good insight on this topic. I have one Hallman MBC and have a friend willing to lend me another for a basic trial run on this to see if I can change the boost independently as Turbo Cary mentioned should be possible.

[Caliber308]

Let the members know how this worked out for you. It might help others.

[FieroGTFan]

Hi all, finally got around to trying a bunch of different variables. As we all know you can only change one thing at a time to make it a valid experiment

It seems that anytime I interrupt the boost signal from either the 7.5psi or 10.5psi line off of the solenoid the boost instantly spikes much to high (20+psi). I even tried this with a Hallman Pro RX boost controller (ceramic ball supposed to react quicker to boost changes) and had the same result. For the time being I am going to keep my Hallman boost controller in the car and move the three lines around if I ever want to target a higher boost level. Most of the driving I do with the car I am not driving hard so the factory boost levels keep it in a happy range that will help longevity as well I hope.

Thanks for all of the help and let me know if you guys have any other ideas you think I should try before fully writing this off!

[BlueCuda]

I ran into that trying a few different home brew boost controllers back on my first car in the 90s.  It seemed adjustments made either no difference, or you got ALL the boost. I think I finally ended up with a regulator from an air compressor that got me about 12PSI on a super 16G. 

 My first 87 wouldn't cut fuel or spark no matter the boost, I have no idea how it didn't die.  I haven't pushed my current one past stock yet because I enjoy how trouble free it has been.