DaveW

I promised that i would post my results with this system.

Over the winter I installed an Autometer stepper-motor boost gauge, an HKS DP, and dual (both WG & pre-spool) home-made ceramic-ball-spring boost controllers (both the WG and PS lines to the solenoids are plugged just after the actuators). Other significant mods are in my signature.

Today I went out at lunch-time and adjusted them. It was ~48F outside. It took me about 5 iterations, starting with no pressure on the springs, and I now have a 9.0 - 8.0 - 9.5 psi boost pattern with absolutely no spiking. The Autometer gauge reacts VERY quickly (it is plumbed into a Tee off the line to the MAP sensor). I have purposely left the boost a little low until I get a feel for how this system will react under all conditions.

So, bottom line, this system works very well!

DaveW

I forgot one thing. Thanks to Damian for posting this method!!!!!

TwinTurbo_SE7EN

Im doing the same thing.

do you have any pictures?

Thanks.

DaveW

No pictures. Sorry. It's not a work of art or anything, and it's pretty simple, so I didn't take pictures.

JTurtonRX_7

Ive done the same thing and It works perfectly.

jpandes

I've been using a MBC for the last three years without issues.

TwinTurbo_SE7EN

right on. how about a place that sells a 1/32" drill bit? havent been able to find one for the wastegate side of the boost controller.

cloead

There's my setup.

DaveW

TwinTurbo_SE7EN

QUOTE: right on. how about a place that sells a 1/32" drill bit? havent been able to find one for the wastegate side of the boost controller.
************************************************** *****

I used an 0.020-inch bit for the boost-control vent.

McMaster-Carr has it. Here's the part # for their 0.0197 HSS bit: 2951A38

TwinTurbo_SE7EN

^^Thanks for the picture.

and thanks for the part number, Dave.

LemonR1

What size are those exactly and what are they called? Im about to go to home depot and i want to replace the old M.B.C on my car and dont know exactly what to look for.

DaveW

"Home Depot" is just a way of describing home-made boost controllers. Home Depot doesn't actually have anything like that, but they do have some of the fittings, etc., used to make them.

The ones I described are the ball-spring type, as opposed to the needle-valve type which still rely on the stock WG and PC solenoids.

I don't have time to describe them in detail now, but if you search, there are quite a few threads describing how to make them.

Here's one "how to:"

http://www.geocities.com/chmwatson/FAQs/mbc.html

bolo_fd

iTrader: (2)

where do u get parts for the home-made ceramic-ball-spring boost controllers

edit: hahaha u posted right b4 me thanks for the link

Gadd

My home brew MBCs

DaveW

I used generic 1/8" brass pipe fittings vs the 1/4" fittings shown in the link. 1/4"-dia ceramic ***** and the ~7/8"-long x 0.21 dia x .02 wire stainless steel springs were from McMaster-Carr (I used 2 springs in series connected by a brass insert per controller). I used an 82-degree countersink to make seats for the ***** on the inlet end. I used 1 ball on each end of the spring. A 1/4-28 bolt worked better for me than the 5/16 bolt shown in the above link.

DaveW

OK. Now that I've had these running for a few days, I went out to tune them again. With a few more iterations, I now have a "perfect" 10-8-10 boost pattern.

scotty305

iTrader: (2)

I can't think of the physics of it right now, can someone explain if these will cope with altitude changes? Say if I drive up and down a 2,000-4,000 ft mountain?

-s-

DaveW

Since the input pressures to the actuators are controlled directly by the controllers, they should give the same boost pressure (gauge pressure, which is the amount above atmospheric pressure) at all altitudes. However, the absolute boost pressure would be higher at low altitudes, and lower at high altitudes, due to atmospheric pressure changes.

jayk

What is the difference between "absolute boost pressure" and just "boost pressure"?

jayk

I guess what I'm asking is whether it is possible for the gauge to show 10psi while the engine is actually getting less or more than 10psi?

DaveW

JAYK, to answer your question, your boost gauge should always read 10 psig (gauge) if that is what the controllers are set to. However, that 10 psig is the pressure a normal gauge will read (i.e., relative to atmospheric). At sea level atmospheric pressure is ~14.7 psia (absolute, i.e., relative to a complete vacuum). So at sea level the absolute boost pressure is 10psig+14.7psia=24.7psia. At a higher altitude, or at lower barometric pressure, atmospheric pressure will be lower, say 14.0 psia. Therefore, the absolute boost pressure will be 10psig+14psia=24.0 psia.

So even though the controller may be giving the exact same gauge boost pressure, the actual absolute pressure will change. Unless the controller works on absolute pressure (again, relative to a complete vacuum), the actual pressure in the intake will vary as I explained above.

There are systems that work on absolute pressure, but these simple manual controllers do not. I don't know about how the electronic controllers measure pressure (gauge or absolute).

I hope that answers your question.

damian

iTrader: (2)

ur welcome :-)

damian

iTrader: (2)

thats what I like to hear!!! :-)

scientist68

can i double check your set up DaveW...i plan to do this for myself.

You have the boost controllers plumbed in between the manifold and wastegate, no pills and the lines to the solenoids capped off ?

My car has boost trouble, runs 8,7,5. I'll put these controllers in to remove all the solenoid control and asscociated lines. I seem to have wastegate /pre control problems.

i wanna to feel that boost !!

DaveW

I have controllers installed in the lines that originally had the pills on both the pre-control and WG actuators with the lines from the actuators to the solenoids blocked with solid (no holes) pills. The pills in line with the controllers were removed.

A low-boost pattern like yours may indicate a problem that might not be solved by installing boost controllers. There is a link in the stickies and many other posts (search) related to solving boost issues.