MBC - What is the difference?
 

Turbo Boost Controller Kit Blue Altima 200SX Protege XB:eBay Motors (item 330334283298 end time Jun-01-09 19:54:47 PDT)

boost controller, Car Truck Parts, Turbos, Nitrous, Superchargers - buy and sell on eBay Motors

They are both cheap MBCs but is one better than the other? And what is the extra piece that comes with the first one, with 3 ports?

The second link you posted does not go to a specific listing, just a general search.

The first one is a knockoff of a unit made by TurboSmart of Australia. The smaller part (with the three nipples) goes in series between the boost source and the wastegate actuator, with a third line going off to the larger unit. That one goes inside the car, with the second nipple left unconnected as a vent to atmosphere.

By turning the knob you are adjusting a variable bleed. This has the effect of adjusting the setpoint of the smaller unit.

Here is a link to the fitment directions for the original unit: http://www.turbosmartonline.com/inde...ownload&id=200

IMO, this sort of design (along with all the rest of the adjustable and multi-stage boost controllers) is a gimmick. There's nothing wrong with the good ole' ball-n-spring MBC under the hood.

I've used a bunch of the turbosmart ones, and it is really nice having a measured "click" when adjusting it. When on the dyno, can ease up the boost since each click is equal.

Oops, this is the link I meant to post for the second unit.
High Quality Manual Boost Controller VW BMW Mazda SRT4:eBay Motors (item 320377748405 end time Jun-01-09 22:08:11 PDT)

Most people buy a boost controller because they got the wrong wastegate. Or want more boost then the factory wastegate can provide. Unless you need one just go without it. I have seen many cars explode after the boost was raised with no adjustments to fuel and timing.

Like yourself, the OP is running a MegaSquirt. I expect he's familiar with the tuning requirement of a boosted engine, and has adequate capability to deliver fuel appropriate for his boost level.

I have a related question so hopefully this doesn't look like a thread jack.

How do you know what spring tension to use when building an MBC? My spring seems to be too stiff in that it boosts the 12 pounds I want when cold, but as the spring gets hot it goes down to 9 because the spring is obviously less stiff. You can see the issue here.

One would expect that everyone is familiar with tuning there ECU's, Boost vs. Load, Steady state cruising, timing and fuel vs. knock/detonation and WOT tuning. but i know several cars in the local area with standalones and they have no idea of what the ECU is or does except it makes there car run stronger and faster. So as a known fact not everyone tunes the own car. Im guilty of this also, as i did the rough tune and drove up to Church's in LA which is about a 100 miles away and they finished the final tune for me on there dyno.

Sorry to go off topic, but the MBC is just a way to bleed off signal pressure to the WG actuator to increase the boost. both work off the same concept of reducing the signal to the WG. the first one bleeds off pressure, the second one restricts the pressure. I dont like either, but with MS just get the boost mod kit, and a solonoid and now you will have a EBC. Same concept as the MBC, but controlled by the ECU with a stepper motor:)

Thanks, but I built my MS and have tuned it myself at the boost levels for which I am shooting, so I am well aware of the risks.

I currently have a MBC I made from parts I got at home depot, and it simply does not perform how I need it to. I couldn't find the parts to build a precision unit so I cobbled together something I thought would work and it does not. (fwiw, I used the spring out of a ball point pen and it is right in the range I needed. I've heard many others having success with these springs also, so you might try that)

At this point I am leaning toward the second one because it's a ball and spring type, unless somebody has some reason why I should buy the bleeder type.

I get rock solid boost control with a cheap ball and spring MBC. EBC sounds like a pain in the ass to me.

I just bought the EBC kit for my MSpnp. I figured if i have the feature, why not utilize it? Was affordable (40 dollars) compared to standalone EBC (200 dollar range)

The EBC on the MS is awful. Most of the people here who convinced me to use it have since stopped using it themselves, myself included. We are all just waiting for somebody to fix the code so closed-loop control works.

oops well i guess thats 40$ in the toilet. Dir

MSPNP EBC sucks balls, search and you will find more discussions on this.
I had this one:
Turbo Boost Controller Kit Blue Altima 200SX Protege XB:eBay Motors (item 330334283298 end time Jun-01-09 19:54:47 PDT)

and it sucks. With a 14psi can you cannot set it lower than 16-17psi and it will overshoot.

I don't really understand how it works with the two components.

This one looks much simpler:
High Quality Manual Boost Controller VW BMW Mazda SRT4:eBay Motors (item 320377748405 end time Jun-01-09 11:36:06 PDT)

but not sure if that works any better?

Bullshit, there is nothing mechanically wrong with a boost controller, and difinitive advantages over a basic wastegate. A boost controller will make more power even at it's base pressure since it isn't cracking open early.

Either electronic or mechanical controllers are proven to be reliable and safe, like anything else in FI, it has to be understood and tuned.

MBC are cheap, easy to install, reliable and easy to tune relative to EBC (I'm running MS EBC), if you can't tune a MBC, you'll pop your motor tuning MS EBC.

Stepper motor? It's a solenoid.