Manual Or Electronic Boost

[Manuel Kasko]

Hey guys,

So what would choose for your car?

Is it worth the money spent of the electronic compared to the manual?

I think this is a good topic and im looking at possibly buying an electronic one.

Lets go

[zebra]

Yes! Especially with an internally gated turbo

Works much better.

[zebra]

Actually I have one you can have cheap if you want to dabble

It's a hdi spec r thingy

Not sure if it still works so you can try before you buy

[zebra]

there was a really good write up on EBC's on here from a few years back...but I cant for the life of me find it

Basic gist was that a good EBC was worth 30 odd kws through the mid range over a bleed valve and full boost about 500rpm earlier.

[ARTZ]

what about no boost controller..just running off gate alone??

[Manuel Kasko]

I been reading heaps about them.

The electronic are way more reliable as they dont have as much boost spike and overboosting issues.

Zebra is yours the one with no screen and just the push in push out button?

Currently running a boost t and find it seems okay but just never seen the difference of it compared to electronic

[zebra]

Yeah the one with the single knob

[Manuel Kasko]

Sweet how much we talking?

[zebra]

No idea tbh. Send me an offer lol

[Manuel Kasko]

1 BILLION DOLLARS!

[zebra]

For that price I'll give you 50% off a 2nd item of equal or lesser value

[Manuel Kasko]

Hahaha ill look into their prices and throw you an offer next pay day

[zebra]

No worries

[bored33]

Yeah the one with the single knob

lol knob

[J'son]

Currently mine has a manual one installed. It has the switch in the cab for high and low boost.

Apparently the low boost cant go below 6psi, it is as low as it will go (on the unit i have)....and the high is set around 11psi.. However, it is easily bumped and changed... I bumped it the other day cleaning under the hood, so now need to see where it is sitting at and make sure it is not too high......

I definitely get boost spikes atm, and I am pretty sure that is not really a good thing... On low, it spikes near 10 then averages back to 6 or 7 psi... on high, it spike to 14/15 and then averages back to 11 or 12 psi normally.

The prob is either of these things are not technically rego legal, at least not in the ACT.... I cant see why if they not legal if they are done properly and safely and dont ventilate to the atmosphere though.... An electronic would be even more awesome, but that would prob take a lot more setting up and costs to get..

Also, what is the deal if i ever need to take either out.. (the manual or an electronic) to pass rego? Wouldnt that mean i have no boost limiter at all?? And would it even be easy to remove... esp an electronic... the manual one seems to just splice in to one of the lines? I need to look at it better some time and learn more about how these work....

Edited November 14, 2011 by J'son

[zebra]

to take it out, just run the boost source straight into the actuator, will give you 5-6psi max (actuator pressure)

For those who arent quite sure about boost controllers, wastegates, actuators etc

It is quite simple.

internally gates turbos (like the standard RB units) have an actuator

looks like this

inside the can (big round thing on the end) is a spring and a diaphragm

the spring holds the flapper closed

looks like this

via the rod on the actuator (long bit with a hole in the end)

There is a nipple on the can that is feed pressure from either the intercooler piping or the intake plenum.

When the air pressure in the pressure in the can is greater than the spring prssure it opens the wastegate flap and bypasses exhaust from the turbos exhaust wheel which stops the turbo from spinning faster and faster (which if happens you have unlimited boost...well unlimited until either the engine or turbo goes bang)

But as the air pressure increases the valve slowly starts to open, as both the spring is effectively loosing tension as the pressure builds up on the diaphragm and the exhaust gas pressure builds up behind the flapper it isnt a straight hits 7psi and snaps open

A Manual boost controller or bleed valve simply reduces the amount of pressure the can receives by bleeding off though a needle valve (if you looks at the bleed valve there will be a little hole in it somewhere) and tricking the diaphragm into thinking there is less pressure there so the spring holds the flapper closed more than normal, allowing more exhaust gas to go through the turbine wheel and thus increasing boost.

Electronic boost controller works in the same way, but has an electronic solenoid which pulses to let the air out.

They bring boost on faster buy leaving the valve full open (hence the can not receiving any pressure and holding the flapper fully closed). Until it gets close to the target boost pressure and then starts to allow the wastegate to open by bleeding off less air and sending more pressure to the can.

The cheapest manual boost controller out there is to simply poke holes in the vacuum line going to to the can.

(we used to do this at dyno comps on the 2nd and 3rd runs in events where you werent allowed to change the state of tune between back to back runs)

We would "check for leaks" and poke a few holes in the boost controller hoses with a pin and hello 4-5psi more with out changing anything

NB* I dont recommended doing that though as quite a few engines went pop because it got too much extra boost as it cant be controlled lol

Wow I need a break....will explain boost spiking in a few mins

[zebra]

HHHokay

Boost spikes:

Manual controllers a notorious for it (especially the Turbo Smart ones)

Basically, turbo ramps up to max boost faster than what the actuator can open to slow the turbo down usually caused by vacuum lines that are too long and delaying the pressure the diaphragm gets to open the flapper, or a bleed valve that bleeds off to much air in a big rush when the pressure goes up before settling down.

EBC's can do the same, which is why most have a gain setting which is basically a frequency controller for the solenoid, turn gain down allows more air to reach the can earlier.

Boost drop off:

Caused by lots of things,

1. a weak actuator spring which means the flapper is blown open by the exhaust gas

2. Restrictive exhaust, as pressure builds in the exhaust the turbine slows down, think of a desk fan, spins pretty freely in fresh air yes. put it underwater and see how fast it spins. exhaust back pressure does the same thing

3. too small turbine housing, pretty much same as above.

4. Bad tune, too rich and too much timing means exhaust gas temps are low and the exhaust gas doesnt have the energy to drive the turbo hard enough (common with really big turbo setups on small engines)

5. Gasket/intercooler piping leaks, speaks for itself really...leaks are bad mmmkay

6. compressor out of flow, the turbo simply cant pump enough air into the engine as revs rise.

Boost creep (boost keeps rising)

Also cause by a few things

1. wastegate too small, cant bypass enough air, turbo spins faster and faster (often found with Gt30 turbos with the .63 A/R exhaust and cheap ebay turbos with internal wastegates)

2. Tune, not enough ignition timing means a very high exhaust gas temps which spin the turbo harder...usually goes hand in hand with a too small wastegate.

3. Bad boost control - bleeding off too much air

4. Wastegate flap being stopped by the dump pipe, usually found with cheap split dump pipes, the flapper gets jammed and cant open any further due to a bad design

[Manuel Kasko]

You can of course get a different spring which is set to a higher pressure.

But this means pull it all apart and can get messy/expensive. (not to mention its not worth the time)

Zebra thanks for all the info I wish I could rename the title so people can get access to this info.

[zebra]

Ye didnt mention that.

HKS and Blitz Sell 1Bar/14.7psi actuators for the RB25 turbos, as does Hypergear turbos

[Manuel Kasko]

Nice so then you know your running 1 bar all the time?

I would prefer the 2 stage electronic one to be frank