I've noticed that boost tend to be higher in the higher gears than it is in the lower gears due to the higher load. I've also noticed that the car is more knock happy in the higher gears than the lower gears. So, the increased boost in the higher gears is actually the reverse of what you want (I think).

When I went to the strip yesterday, I used my electronic boost controller to bring up boost in the low gears and bring it down in the upper gears and it seemed to help significantly in maximizing performance down low and staying out of knock up top. If I had been working with a MBC, I would had to have set boost based on 4th gear and just live with running lower boost in the lower gears.

This seems like a rarely mentioned advantage of an electronic boost controller over a MBC.

Thoughts?

 

Yeah couple of thoughts. Why would you ever want to lower the boost at the track. I think it would be more beneficial to put a splash of race gas or add more fuel or remove some timing rather then lower the boost where you need the power the most.

 

As far as race gas, it still has its limits, especially unleaded race gas, so that wouldn't really change the fact that you can always run more boost in the lower gears than up top without detonation, provided that fuel and timing is constant through the gears.

Adding more fuel or pulling timing would give up power in the lower gears, unless you have a way to tune by MPH or gear, which I don't have with the UTEC. I don't know if this is possible with a standalone. The benefit of lowering the boost in the upper gear is that you can do so without sacrificing power in the lower gears.

EDIT: Another thought. Mapping by load doesn't completely solve this issue because the load on the motor is still greater in the upper gears, even at the same boost pressure, and therefore you can't just adjust timing/fuel based on boost because the knock threshold will be different in every gear.

I'm not rock solid confident that I'm on the right track here though. I'd appreciate any expert feedback on this. I could be way off base.

 

The whole basis of going to a standalone is to give you the ability to switch to speed density fuel calculations which in an indirect way calculates the load and VE of the engine at that specific point.

You might get more boost in the lower load situation yes, so this might seem like it makes more power but in theory if you are not getting knock in those lower gears then you are not maximizing the combustion process either and then the higher boost is really not accomplishing that much more. This is all based on what I remeber from an IC engines class I took a couple of years ago, so I might be way off base also.

Now there is another theory that since you are not in the lower gears for very long the knock in the higher gears might actually be a product of heat rather then boost pressure. Higher gears allow more time for heat to build up in the intercooler and thus the intake charge starts to elevate.

It would be interesting to see a back to back dyno runs to see what if any improvement is seen with your boost program.

 

Interesting? I wanted the EBC but ended up with the MBC. I just couldent see spending that much more for something that does the same thing. Now that I see it your way it makes sence. But how much time are you shaving off your E.T. with the EBC boost settings vs MBC? A dyno test would be great proof.

 

I couldn't run this boost program on the dyno since it is MPH dependent rather than gear dependent. At the strip with consistent shift points, there is no distinction, but on the dyno where you cover the whole RPM range in one gear I'd have to basically set boost at the setting that I would use at the track from about 60-80 mph (i.e., 3rd gear). If I dynoed in 4th, then I'd have to lower the boost to my 80+ mph setting, which would show very low numbers in the low RPMs. Tuning for the track and tuning for the dyno just aren't the same thing in this case.

 

Ah yes I had a brain fart and forgot about that whol fact of single gear tuning. Although a datalog of a 1st gear through fourth gear run would be helpful, that is if the UTEC can log MPH.

 

I would say that in theory EBCs should perform better period. But the fact that they can be inconsistent and difficult to set up at times causes people to deal with the lesser performance of an MBC.

 

An EBC hands down is 10x better when setup correctly. it runs in closed loop boost to compensate for weather changes. Especially in the cold winter months, you don't have to pop your hood, jump out, and adjust your boost to compensate for the cold mornings and hot afternoons. The EBC also has overboost protection to protect your car as well. The only hard part is most people wont take the time to learn how to set one up correctly.

 

I am very surprised with the responses here. I feel like I must be missing something. Otherwise, why would the top racers be using MBCs? Maybe this is really only an issue when you are octane-challenged?

 

I am making assumptions here but I would presume that racers use a MBC because of the following:

- EBC control valves are expensive to replace when they go bad and they will
- Most EBC will not allow more then 36ish psi of boost and I know most pro racers run more then that.
- Less to go wrong and less to wire with a MBC.
- Why the heck do they need to change boost on a daily basis. 1 psi of change due to the weather is really not that huge of a difference unless you are on the ragged edge of the pump gas tune on the street.