roger smith

iTrader: (4)

This should help you,

https://www.evolutionm.net/forums/sh...d.php?t=276674

fastforward1

^thanks!

Pd1

iTrader: (38)

The Hallman Pro with the heavy spring and non-ceramic ball is a good MBC. Is that what was used here? If it was the RX version (ceramic ball IIRC), then that's really the wrong MBC to use on this car to begin with. If it was the right Hallman, I'm surprised to see that boost curve as the ones I've had/seen are much flatter than that.

Evolessfornow

iTrader: (28)

Is this the right solenoid?

tephra

iTrader: (6)

yup.

but you can get it from rockauto if you want

Jim in Tucson

iTrader: (3)

I'm not trying to **** on anyone's bonfire, but this seems like a lot of work compared to a simple MBC. The graph would indicate that most likely this car saw an increase in HP, but a decrease in torque.

For someone tracking their car, or even auto-X, I can understand the desire for a flat and consistent boost curve. And I can see that a dyno queen would make more HP on this graph. But, what about the average street car, where torque is king?

I think I'm an average EVO daily driver and I spend most of my time in the 3,500-5,500rpm range, not the 5,500-7,500rpm range. My dream setup would be a 30psi spike tapering to 18.

So, what does ECU boot control really offer over an MBC?

RazorLab

iTrader: (8)

Like stated in the first post, this boost curve is not finished. Yes it will match the boost of the MBC at peak boost. I kind of wish I hadn't posted this boost plot until it was finished now. I simply wanted to show how ecu-boost can hold more boost through the midrange and up top.

Here are some examples of finished ecu-boost curves:












I've seen major gains in the torque and horsepower curve through the midrange with ECU-boost compared to a MBC. Most of the time, ecu-boost will hold more boost through the midrange and above.

Here is a good example, MBC vs ECU-boost:



Other advantages of ECU-boost vs MBC have been explained here before. In a nut shell, the system has error correction so it will do it's best to hit it's target if it's over or under it. Simply put, it will add or decrease boost to hit it's target. Holding boost up top is another advantage. I've seen 10-20whp gains from moving from a MBC to ecu-boost on the same car, with the same mods. Another advantage is 16 points of RPM tuning for the boost. You can basically make any boost curve you want.

I've also seen a GM solenoid spool larger turbos (FPgreen +) quicker.

Here is a comparison between a Evo 9 turbo with stock solenoid using ecu-boost and a FPgreen with a GM solenoid using ecu-boost. Solid line is FPgreen, as you can see you can get a FPgreen to basically spool exactly the same as a stock 9 turbo:

RazorLab

iTrader: (8)

Yes.

tephra

iTrader: (6)

ecu boost will also mean you can run my altmap stuff (**TBA) so you can have different boost profiles for different fuels or whatever..

sllt1776

iTrader: (1)

great stuff. I will have to think about doing this soon. I have a MBC right now, Of course, I bought it before I got into all this cool stuff. the MBC does it's job but why use an abacus after they created computers?

codgi

iTrader: (22)

Slightly OT, but have you been able to get VIIIs to spool the FP similiar to the stock turbo as well? The green will probably be the last engine mod I do but if it can spin like the stock turbo .

RazorLab

iTrader: (8)

I've seen 20psi around 3400 in 3rd with FPgreens on Evo 8's. Some do better than others, to be honest, we have had more FPgreens on 9's than 8's for some reason.

scheides

iTrader: (10)

I don't have any real logs, but here's some video of my car with GM BCS on stock 05 VIII turbo w/ alky. Holds 26psi pretty flat up until 6300rpms or so. This was just the beginning of my tweaking with the GM BCS.

roger smith

iTrader: (4)

This is just to reiterate Brian's argument why ECU-controlled boost is nice and the GM 3-port.

It's possible to do reverse taper - something not possible on manual boost control I believe.

Note this is from an unfinished tune. Also this is using GM 3-port.

sllt1776

iTrader: (1)

Ah, Like an intentional and controlled boost creep.