Boost control for an SE?

[Nevyn72]

Hi all, yet another question from me..*ducks*..... Oi who threw that!

So as part of the modifications I plan there is the inevitable question of how best to handle the level of boost from the factory IHI turbo.

Based on my reading there are two issues here, firstly that the boost is limited to 7.5 psi from the factory and secondly that the boost is further restricted in the first three gears by the ECU.
The solution is to bypass the factory boost control using either a manual or electronic boost controller but each of these options had it's own issues.

Now to put this in context I will also be upgrading the injectors and doing something about the ECU (reflash, add a piggyback or replace entirely) as part of the same process.
I'm just wondering what is going to be the best solution for boost control as part of this process?

Manual boost control appears to be the cheapest and simplest but is it the best?

Electronic boost control would need to work in conjunction with the ECU solution somehow.... In this case;
- Does this mean a more complicated, and presumably expensive ECU solution?
- Does this require a new/aftermarket EBC or can it use the factory unit?
- Will I get a 'better' result using an EBC over a MBC? (ie. gives the ECU another parameter to control so you end up with a better tune overall)

Another question on the side, if I'm only going for ~10-12 psi boost on factory internals & turbo, what size/brand injectors would be optimal?
Are there issues going for an overly large injector over something just big enough?

Cheers,
Nev

[Lokiel]

EBCs will produce a better result than MBCs but just aren't worth the hassle IMO. I had the Gizzmo EBC and it was a pain in the butt to install and the interface was rubbish - I had to keep the manual on hand all the time because I could never remember how to set it up which was necessary each time I disconnected the battery - that got old real quick. The Gizzmo unit was a standalone system that controlled the boost.

Aftermarket ECU's, the Adapatronic at least, can interface with external EBCs, but can also control it themselves which is far simpler and requires less hardware connectivity.

Toyota 321cc injectors are the largest/best injectors for modified SEs that the stock ECU can idle nicely but they're impossible to find so Toyota 305cc (also sold as 315cc) injectors are more commonly used with the stock ECU.

Larger injectors won't idle well and run rich.

[NitroDann]

Standalone EBC that reference only the boost pressure are SLIGHTLY better than good quality, 30 dollar MBC's.

However ECU controlled EBC, referencing rpm, throttle position and boost, is amazing. You will not go back from ECU controlled EBC which is set up properly. There are various issues referencing boost only or shooting for a boost target.

If you set to 12 psi target, and you use half throttle, the turbo setup and boost controller don;t care that you want half throttle, they will work together and make 20psi if necessary to get 12psi past the throttlebody and into the cylinders, because thats what they are targeting. So half throttle just became full throttle.

This is the EXACT thing that people who say they dont like the power delivery of turbo cars are complaining about.
The guys who will never run a turbo car because its hard to drive are complaining about this exact issue.

Run EBC controlled by the ECU with a 3d target map referencing rpm and throttle position.

Dann

[A.Chen89]

As per Dann and Lokiels reply as above.

Most if not all aftermarket ECU's should have an output to drive an EBC (just a solenoid).

A trick manufacters/tuners use to increase drive ability is to increase boost as the torque falls off (e.g XR6 turbo). Gives you flat torque useable torque curve.

[timk]

I have a Turbosmart eBoost I was using on my SE which was removed when I went Adaptronic. It seemed to do what it said on the box, if you are keen I can dig it out.

[Nevyn72]

Thanks for the replies guys, so basically the best result for handling boost level will be achieved by letting an aftermarket ECU control boost level in conjunction with other mapping perameters..... As I expected, the most expensive option!.....

I have a Turbosmart eBoost I was using on my SE which was removed when I went Adaptronic. It seemed to do what it said on the box, if you are keen I can dig it out.

Thanks for the offer mate, I'll think about it but will probably get the Boost control, Injectors, ECU solution and tune done in one hit as an integrated upgrade by a specialist tuner who, unlike me, actually has some idea about what they're doing!

[NitroDann]

You have to get an aftermarket ecu anyway, and then either use the solenoid valve the car comes with stock, or a new GM MAC valve is around 70 bucks so it's super cheap.

Dann