Manual Boost Control Advantage

[BrianM]

Besides the obvious of being able to crank the boost up above stock levels are there other advantages of running a manual boost control? I have a JoeP that I have yet to install. I may dabble in cranking the boost up just a bit to 16-17 but if i were to just keep at stock levels there an advantage over using manual over a properly functioning stock electronic boost control?

[blueboss]

Like you stated. You can "dabble" with the boost and it's serviceable. That's about it.

[MikeFleming]

The flip side is there are some serious other issues that now need to be addressed.

When the engine reaches detonation, and it will, the only remaining control for the EEC is to retard ignition timing as it can no longer lower boost pressure. The stock system will back off timing first, then lower load, then re-advance timing to reduce chamber temps.

When the EEC can no longer lower load (aka boost), it leaves only reducing timing more. Which will dramatically increase chamber temp and EGT values. Over the long run this often results in severely reduced service life of exhaust valves, exhaust valve seats, and all other up-front exhaust components.

Be sure to budget accordingly.

[BrianM]

So sounds like a manual boost controller is less desirable if maintaining stock boost levels.

Is there no truth to references I have seen to a slightly faster spool up and more steady hold of boost level with the manual??

[MikeFleming]

There will be no change in boost startup (RPM) - the engine still has to start the air moving to get boost in any case. And, assuming your wastegate diaphragm spring is proper, there will be no decrease is spool time to get to 10 PSIG. And once you're at 10, getting that extra 4-6 PSIG is very short indeed. All the lag you see is getting to 10 PSIG.

Yes, boost can be more "steady" but the timing (and power/surging level) may still continue if there is any detected knock.

[BrianM]

Thanks for the knowledge Mike. I will probably leave it as is at least for now. The only mods I have done to the car are what you see in my signature. I have all of the parts for my 3" downpipe and midpipe eliminating the cat then into dual 2.5" Magnaflows and tails but have not done the install yet. I hope that mod will give me something. Should have the car breathing and exhausting about as good as can be with stock motor and head and E6 unless I want to start porting which I probably don't. And although I have toyed with the idea I also dont really want to go to a FMIC either. I really don't want to get into pushing things although a little more boost would be nice.

I'll get the exhaust on and see how it goes. The car runs and drives excellent so I don't want to screw anything up.

[SVOBoyd]

The flip side is there are some serious other issues that now need to be addressed.

When the engine reaches detonation, and it will, the only remaining control for the EEC is to retard ignition timing as it can no longer lower boost pressure. The stock system will back off timing first, then lower load, then re-advance timing to reduce chamber temps.

When the EEC can no longer lower load (aka boost), it leaves only reducing timing more. Which will dramatically increase chamber temp and EGT values. Over the long run this often results in severely reduced service life of exhaust valves, exhaust valve seats, and all other up-front exhaust components.

Be sure to budget accordingly.

Hey Mike sorry to bring up an old thread but I was having issues with wild flucatuations in boost with my stock BCS so I went with a manual controller. I would have replaced the stock BCS with a new one but they are unobtanium. Are there any electronic BCSs that can be used in place of the stock BCS?

[MikeFleming]

Almost any later model solenoid BCS will work about the same. Look for an electrical load in the 50-80 Ohm range. It gets a PWM square wave in 10Hz from the EEC (ground side) and ignition +12 VDC (actually 14VDC with engine running). DO NOT exceed 1 Amp electrical load on the BCS driver in the EEC.

[SVOBoyd]

Almost any later model solenoid BCS will work about the same. Look for an electrical load in the 50-80 Ohm range. It gets a PWM square wave in 10Hz from the EEC (ground side) and ignition +12 VDC (actually 14VDC with engine running). DO NOT exceed 1 Amp electrical load on the BCS driver in the EEC.

Thanks for the info. It seems like most of the newer BCS's are 3-port, like the Ford Ecoboost, that bleed off pressure. It looks like some of the Subaru's use a two port BCS (most seem to be Denso's) but so far I haven't been able to find any specs. I'll keep searching.