RX-7 Pilot

Has anyone tried using a mechanical boost controller? How did you like it? Debating right now on whether to use an electronic one or not for my single turbo.

thanks
Kelvin

RETed

EBC's give better and more consistent control.&nbsp I don't recommend MBC's unless you're going cheap...



-Ted

RICE RACING

I must agree 100% with RETed, MBC are very inaccurate, EBC are good but expensive.

I run a HKS WG and simply made a round disk to go under the top hat, then with a siple bolt I can adjust the boost from 1bar to 1.5bar, totaly repeatable and accurate with no failure.

Just hard to adjust in the cabin

DANKAHOLIC

What are you guys talking about?? MBC's are the MOST accurate..... Ball and spring ones anyway...... Not bleeder styles. A good mbc (i.e. Hallman) will have faster spool and less chances of boost creep than most ebc's out there. They will hold consistent boost even under the most hot temps, unlike ebc's that use solenoids that are very sensitive to heat.

Chris
Just my 2 cents.......

btw ...... I run a avc-r

RX-7 Pilot

thanks for the info guys

surfpac

I agree with Chris (DANKAHOLIC)!!
I made a MBC for by friends TII and it works perfect!! I used the ball and spring design and NOT the bleeder type one. The ball and spring AKA "pressure relief valve" is much better than the bleed types in that it allows the turbo to spool much faster because it only allows air to get to the wastegate actuator once the desired boost setting is reached. In essence, the wastegate is completely shut allowing full exhaust to go through the turbine, hence a fatser spool up. The bleed type setup is allowing air to get to actuator at all times which allows some exhaust gases through the wastegate. My friend's 400+ TII is currently set for 15psi and he only raises it to 20 when he runs race gas. It is totally adjustable and very very accurate with no boost creep. It is very simple to make (not rocket science) or you can buy one already made for around $35. Check out these these sites.
http://www.gtfour.com/article.asp?ID=AAAAEI
http://pages.cthome.net/gus/mike.html
http://www.boostvalve.com/index2.html

surfpac

Hey Chris!
If they say it costs "a pennny for your thoughts" and you "put your 2 cents in"
what happens to the other penny? :o)

RETed

Come on...you gotta be kidding me...

Can you adjust boost ramp with an MBC?&nbsp NO.
Can you adjust boost levels easily on an MBC in the cockpit?&nbsp NO.
Can you run multiple boost levels at a touch of a switch with an MBC?&nbsp NO.
Is the MBC consistent over ambient temps and humidity?&nbsp NO.

Sure, it's $20 in parts from Grainger/McMaster - I'm not going to argue about bang-for-the-buck, but when you get serious you go with an EBC, period.



-Ted

DANKAHOLIC

How often are you really going to change the boost on you car when its a single anyways...? You will probably just set it @ one level and leave it there on the street/daily driving. You would need higher octane to turn the boost up so you would just change it when you have race gas.... Just get off your *** to change the boost. What are you talking about? EBC solenoids are THE MOST sensitive to ambient temps. They are less accurate when temps change. NO ebc, not even the HKS EZ is as accurate as a mbc, period.

Chris

RETed

What?&nbsp Coming from a Supra owner?

The A'PEXi AVC-R is a closed-loop EBC with it's own dedicated MAP sensor.&nbsp The old HKS EVC III ATM did the same thing.&nbsp The GReddy PRofec (A) also has it's own MAP sensor.

With dedicated MAP sensors, it runs boost levels from feedback.&nbsp They are the MOST STABLE boost controllers period.

Your MBC will change just as bad as a non-closed-loop EBC.&nbsp WTF you crowing about?&nbsp You telling me the MBC will change boost levels LESS than a non-closed-loop EBC?&nbsp BULLSHIT.


-Ted

Dan Balassi

Does anyone have any "hard data" to support your theory? I'm in the process of deciding on a boost controller for my 88 anniv turbo. I have the Racing Beat complete exhaust, fuel cut defender and Bonex intake. If I install a boost controller, will I need more fuel? ie.. new fuel pump and/or larger sec injectors?

RETed

I used to run an HKS MBC on my FC.&nbsp I now have an A'PEXi Super AVC-R (Gen I).&nbsp I don't have numbers to support the steeper boost ramp, but I know the AVC-R is a lot more consistent day-to-day.&nbsp The HKS MBC used to range anywhere from + or - 2psi depending on ambient temps and humidity.&nbsp Now, I know what's coming - these guys are going to jump on me for using a "bleeder valve" rather than their precious ball-and-spring valve...

Speed takes money.
Performance takes money.
How fast you want to go?

$20 check valves have no place in a high performance vehicle, unless you're cheap.&nbsp That's the bottom line...



-Ted

cewrx7r1

iTrader: (2)

You can run two boost levels with a MBC by using an electronic controled two way solenoid. Each of the two outlets have a different size jet that affect the pressure buildup in the WG actuator by bleed of. They even sell such a complete MBC device for dual boost controlled. Some front wheel drive cars use it to run lower boost when coming off the line in first gear then switch to higher boost in second gear. This came out over 2 years ago. If you use it with a ball and spring MBC, it works the same allowing faster spollup.

My friend Rick has run the AVC-R and it is sensitive to outside temp changes. Not stable at all! I have read their advertisments on their sites. They say that it has actuator loop back control but not map sensor to actuator closed loop control.

While I was a tech in the USAF, we had many systems with full closed loop control that kept systems completely stable.

If any current EBC had a real map sensor closed loop system controlling the WG actuator, then once you set you desired boost, it would remember the map sensor output voltage and controll boost to keep that voltage as constant as posible under all conditions. This boost would be the same no matter if it was 100F or 30F as long as the tubo could produce that boost.

There is no such system available to us right now that I have heard of. If it was I would buy it even if it costs over $1000.

RETed

$20 says it's a FD running stock twin turbos with an exhaust system...
Anything that will creep on you will NOT be controlled by an EBC, period.

I've had my AVC-R for over 5 years, and it has never wavered on me.&nbsp I set it at 1.00kg/cm&#178, and it stays there...humid 90% heat at 85&#176F ambients temps in Hawaii, blazing 105&#176F temps in Sac summer, 30&#176F Sac winters, 30&#176F Vegas winters with 20% humidity, or 110&#176F Vegas summers with 10% humidity.&nbsp All reading backed up by a GReddy 60mm P/H electronic boost gauge.&nbsp This is all on an FC3S - stock turbo, ported wastegate.


-Ted

crispeed

One area the MBC will always out perform the majority of EBC units on the market presently(except the EBC from innovative turbo systems) would be the ability to run extreme boost levels for eg. 35psi +

crispeed
87 Rx-7 TII
9.204@150.47mph
2600lbs

HWO

the best boost controller in those instances chris is called HEAVY WASTEGATE SPRING, who needs valve or whatever in the piping, put a heavy **** spring in there and plumb a boost line straight to the wastegate

crispeed

Actually most of the people I know running 40psi + of boost, only connect a hose to the top and not to the side of the wastegate!

crispeed
87 Rx7 TII
9.204@150.47mph
2600lbs

RETed

HKS EVC Pro - up to 44psi and $1,500



-Ted

Cheuk in Seoul

44psi!!! Do you even need a wastegate?

Anyways, In my personal experience.

I have found manual wastegates difficult to get exactly where you want them to be and some variability in holding a certain psi.

I actually do play with my AVC-R quite often while in the car. I have the very low boost street setting and the low boost street setting. I just reprogram for higher boost for the track.

A manual wastegate will work fine but I prefer the electronic controllers.

Dan Balassi

What are the preffered manual and electronic boost controllers for the 2nd gen Rx7 turbo? and if I have RB's exhaust and Bonex intake, should I be concerned about not enough fuel from the stock system , if I install a boost controller?

JScott

Ummm, YES, you should be very concerned. Making boost too early or exceeding 10-11psi on the stock fuel system is asking for it.

You need a perfect stock fuel system(clean injectors, filter's) to be where you are now.

Scott

Dan Balassi

Which pump is the most cost effective upgrade?
I am making 12 psi peak in 3rd, 4th gears. My Aif/Fuel gauge is still showing good under full throttle.

SnowmanSteiner

How often do you change boost with a single? Well quite often. Not all of us go full out high boost when we drive around town. We actually care about saving our engines and turbos. And if someone wants to spur of the moment race on the street, are you going to say hold on a minutes let me go change my boost real quick? Or if you find yourself on a road that suddenly gets curvy and you want to have some fun, are you gonna pull over and reset the boost. That's probably the most common for me at least. Since our cars are made to handle well. Just my thoughts on the subject. With an EBC you can control more aspects of boost, which for my money is worth it. You can do better tuning if you can set where the wastegate opens etc. from inside the car. I'm with you RETed, my only question is has anyone tried the new Profec E-01? Is it worth the cash or is it just overkill if you're not going to use it for tuning.

- Steiner