Installing a Manual Boost Controller ("MBC")
a.k.a. "How to bring out the Esprit in your Elan!"

WARNING !!
If you choose to change the stock configuration of your Elan, you do so at your own risk! In short, if you damage your Elan or endanger your life as a result of something you read here, it is your responsibility.  Please use common sense.

Now, all that said, installing a manual boost controller is not a complex task. It will likely be the most significant performance upgrade you will do to your Elan! The "manual boost controller" is merely a "bleed valve" that is installed between the turbo and the wastegate.

From: Jade:  I decided to build the killer bleed valve this weekend. I have been using a fish tank bleeder for the last 6 months and it works okay, but I was always afraid of the loose fit. Home Depot has the answer. Here are the parts and they are all very heavy duty brass parts for air guns. The company that make the parts is Amflo, #235D Throttle Valve 1/4" NTP, #344TD Solid Brass Tee 1/4" female, & #410D 1/4" hose repair Kit. This gives a large adjustment range, the only problem is that if you put it past 2 on the Throttle Valve you will hit your boost limiter fast, so go slow in opening it. It looks great and seems to work great. The total cost for the 3 parts is $15.

Background:

With no or low boost the wastegate is "closed" and all the exhaust from the exhaust manifold is sent to the turbo's turbine to spin it up. Under stock conditions, as the turbo produces boost pressure, it is transmitted to the wastegate via a small hose. When the pressure rises to a point which is set inherent to the manufacturing of the wastegate, the wategate "opens." This allows exhaust gases to bypass the turbo and keeps the turbo from spinning faster and creating more boost. Without a wastegate, the turbo would keep spinning faster and faster as the exhaust gases increase, until the turbo bearing gave out and the turbine self destructed--this would hopefully be before the pressure ruined your engine!!

The wastegate on our Elans is set to 0.65 Bar--this setting is inherent to it and NOT changeable. Thus at this pressure the wastegate opens and no more boost will be created. The purpose of the manual boost controller is to create a "controlled leak" in the feedback line to the wastegate. This effectively "tricks" the wastegate into sensing a lower pressure than actually exists.

The MBC is a valve that bleeds off some of the pressure out to the atmosphere away from the wastegate. The size of the leak is controlled by your adjustment of the manual boost controller. With the MBC active, as the boost rises to 0.65 Bar, the wastegate is sensing less pressure than this. The boost will rise higher as some pressure is vented and a new equilibrium will be created at a higher boost--this will be sensed as 0.65 Bar by the wastegate, and it will open. This is how your "free, increased boost" is created!

The Elan also has within its internal program an "absolute boost limit"--this is approximately 0.95 Bar. This is a check by the omniscient factory designers to keep us from damaging our engines. It is my understanding that the Elan has inherent to it the programming and fuel mapping needed to deal with the increased boost properly up to this limit. (Please see the above warning as I will not guarantee the accuracy of this knowledge!) If you raise the boost to the absolute limit, you will hit the car's "cut-off" switch which will momentarily stop the fuel injectors. This will feel like a big surge and is the same effect of the "rev limiter" which you can experience on your own time.

I will also point out that if you increase the boost on your Elan, I highly recommend installing a bypass valve--without it you will increase the wear on your turbo and subject it to the rigors of the increased boost. I also recommend installing a replacement "drop-in" type high-flow air filter OR an open filter element to give the engine ready access to all the air it will need for the boost increase. Also be sure the engine is well tuned and the timing is set properly. Use your common sense!

Now let's get to the point!!

How to install this MBC

Here is a scan from the Service Manual which shows the area in question the best (I put "Front", "Rear," and "Left" to help orient you if needed). Go to your Elan and study this area well.

Look for the small hose that connects the turbo over to the wastegate diaphragm (I put an arrow pointing at it).

This short hose is to be REMOVED and REPLACED by a new hose of EQUAL diameter which will be a bit longer and will include the "Bleed Valve" spliced into it.

Look below for my crude rendition of the "AFTER" situation. Make a "U-shape" with the new hose and be sure to not let it touch any metal surface that could melt it! You may want to get some nylon "zip-ties" to secure the hose to something so it doesn't flop around as well. Be sure the hose connections are tight as they will be subjected to the pressures within.

I drew a black line representing the new hose with a blob in the middle representing the bleed valve. That is how I have my MBC configured. The valve is a simple turn-screw type valve. You can look for this type valve through your local speed shop, hardware store, or even aquarium store! It is simple and cheap.

It's this simple to set up!

Now you have to adjust your "controlled leak" to get a situation where the boost maxes out where you want it! So at the limits of valve adjustment: with the bleed (valve) closed 100%, the line is like normal and you will have 0.65 Bar max boost; if the bleed (valve) were "wide open" you could in theory have infinite boost because the wastegate would NEVER sense enough boost to open (it would all leak out the valve). Your job is to set the valve so it lets the turbo "max out" where you want it. BE CAREFUL because you will easily hit the max "cut-off." Also remember that the dash-mounted boost gauge (or "fun gauge" as I call it and you will learn why!) will likely not be very accurate. You will want to start with the valve closed and SLOWLY turn it open (with test drives inbetween) until you get the desired limit. Remember too that the new max boost will only be created under driving conditions that will develop max boost--in other words, your Elan's boost characteristics will only change in the max position with this MBC in place.

Have fun and be safe and careful. Let me know if you have any more questions.

Happy Elaning !!--Doug