dizzyj

Here is my thought for implementing an effective and cheap scramble boost (hit a button to increase boost pressure for a short period of time. i.e. on the straights at the track). Wondering what others would think.

I have a LR duel port wastegate and an mbc. My understanding is that the more air that the MBC lets through, effectively the heavier the spring pressure the wastegate sees and the more boost you get. if I were to disconnect my mbc, and plug it. then the wastegate would operate via spring pressure.

given that. I could simply add a solenoid controlled valve inline to the MBC. if that valve simply went from 100% open to 100% closed based on a momentary button on the steering wheel, then I could selectively pick between wastegate spring pressure, or mbc selected boost. the mbc would limit the high range on the boost.

in addition, if I could find a valve that had a trim on the close side (think I have seen these) then I would not be limited to spring pressure, but I could dial in the amount of boost at the low end as well.

Finally, if I wanted a click of the button, I could add a TDR to control the solenoid (I actually have one of these from a previous project).

Anyone done anything like this?

MarkRobinson

Many current EBC's offer this: exactly what you want. The only downside I can see from your thought is how you monitor the amount of time you're at the higher boost levels.

On my AEM TRuBoost setup, you attach a spring-loaded button to the wiring to enable the scramble boost, set the interval of time you want the higher setting to run for, and set the higher level of boost: done. I run a very low spring pressure so I can run my boost controller at off (4psi), Setting A (6.5psi), a7 setting B (8.5psi) where the Scramble toggles between A & B.

When racing I'll lower my A to 5psi, & Keep B at 8 or so: a nice ~100hp increase in boost

toddk911

If EBC what about a program to tie in scater boost with TPS? Then there is no need for toggle switches or bottons, etc.

So at 50% TPS X boost and 75% or 100% Y boost.

dizzyj

Would either be a momentary switch, or a TDR = time delay relay. set to relay to how long you want the boost to be higher in seconds.

personally I think I like the momentary switch. Just hold it down.

Paulyy

Turbo Smart Dual Stage

This is what you want. set 2 different boost levels, and switch between them.

OR if you want to use your spring rate and a MBC Turbo Smart Single Stage this is what you want!

dizzyj

Thats perfect! anyone have any experience with one of these?

Paulyy

mate, all the Aussies use this brand down here. And we all swear by it!

This brand just specialised in Controlling boost nothing less nothing else.


one of my mates have the dual stage in his R33 GTR and loves the thing.

p5th

Ok,perfect timing!! Went to check on car, and low and behold.......I have a scram switch. I also have a truboost,they installed 2 switches(1 scram;2 high/low/valet 3-way toggle). I have to deliver some parts/test drive tomorrow and will asked to move switches though. Will give further info if you like. Right now it's ticked for 30 seconds. Yes,spring loaded toggle.

MarkRobinson

That's what I did: both momentary buttons on my OMP steering wheel actuate the Scramble on my race car.

Also, CPU controlled EVC's help bring boost in faster by not allowing blow-by (the WG) during spool: one of the reasons I've always used EVC's: 928 turbo(s), 911 turbos, 944 turbo.

JohnKoaWood

Now THAT I would considder buying, just to say I had fitted my car with a rocket launcher switch!

V2Rocket

you could make this really simple:

WOT switch > "overboost switch" > solenoid valve > WG

just like on a nitrous/meth system, turn it on when you need/want it but it doesnt come on til WOT

i am considering the same type of thing for my supercharger - on/off switch for the bypass valve

OP: what kind of boost pressure are you looking for for scramble? if you close the boost signal to the WG wouldn't you need a really stiff spring to keep it from opening?

Paulyy

neat huh!