Installing a Manual Boost Controller

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.

- From: Dave: I used the same Amflo parts as Jade did, just mounted it differently (used a 3M velcro-type material for easy removal if I need to). I used thread seal tape on all pieces and about 10" of hose on each side of the valve (it is mounted on the flat painted surface behind the hood prop stay).

- From: Scott: I have also made my own MBC. I work for a manufacturing company and we have a corporate account with the B2B supplier named Grainger. I found a compressor control valve for $8. This plus a brass "T" and 2 hose nipples from a local hardware store had me complete. It has a a threaded control and a LOCK NUT. The area where the pressure leaks out is protected by a brass screen. Nice setup.

With no or low boost, the wastegate is "closed" and all the exhaust from the exhaust manifold is routed through 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--a positive-feedback loop. 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 therefore keeps the turbo from spinning even 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 0.40 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 actuator 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 actuator. The size of the leak is controlled by your adjustment of the manual boost controller. With the MBC in place and active, as the boost rises, the wastegate actuator is sensing less pressure than than it should since some pressure is escaping from the feedback line before reaching the wastegate actuator. The boost will therefore rise higher as some pressure is vented and a new equilibrium will be created at a higher boost level--this will be sensed as 0.40 Bar by the wastegate, and it will open. This is how your "free, increased boost" is created!

The Elan also has within its internal computer 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 beyond 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 EITHER 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!

Why am I quoting the wastegate at 0.40Bar when the car goes up to 0.65Bar max boost in factory form. Well this is because the Elan already has installed into it a form of electronic boost control. This is the Boost Solenoid Valve (BSV) which is a unit directly behind and under the air filter garbage can. The computer pulses this BSV open under boost conditions to create its own "leak" in the feedback line and raise the boost to 0.65Bar max. Thus the car is using a similar system to trick the wastegate actuator and create higher boost.

Therefore to properly install a MBC you should disconnect the electrical connector going to the BSV. Otherwise you will have 2 separate leak systems trying to raise the boost, which can result in boost fluctuations, creep, and overboost.

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 actuator (I put an arrow pointing at it and made it red).

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" (MBC) 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 or warp 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.

There are examples pictured at the beginning and end of this write-up. As mentioned above, you need to disconnect the electrical connector going to the BSV. Otherwise you will have 2 separate leak systems trying to raise the boost, which can result in boost fluctuations, creep, and overboost.

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% and BSV disconnected, the line is like normal and you will have 0.40 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 between) 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.

Through the use of ElanScan computer interface with your Elan, you can monitor and record the boost the car computer is sensing thru the MAP sensor. This can help you better fine tune the boost to your desired set-point.

"I recently purchased a Bailey Motorsport dump valve from Aldon Automotive Ltd, Birmingham UK (www.aldonauto.co.uk). They sent me a fitting kit labeled "for Escort RS Turbo" and upon enquiry (the alloy 'T' piece looked on the small side) assured me that it would fit the Elan also.

"However, having cut the pipe coming out from the throttle body, I discovered that the pipe is much bigger than the alloy T piece most of the way along it's length. This resulted in much chopping of the pipe and lateral thinking and I ended up with the pipe in 4 pieces, swapped around so that one end would fit into another, and jubilee clipped together in 4 places! Not deal or pretty! Suffice to say I was not best pleased about the advice I received.

"The photo of the "Top End Unit" on the website is what prompted me to purchase, and I also copied what seemed to have been done in that photo (the valve and fitting kit all look the same as mine). So I would caution those 'would be' upgraders visiting the page that the right fitting kit is essential - and check it before cutting!

"That said, the noise is great, and there is absolutely no Turbo lag anymore with boost coming straight back in smoothly under hard acceleration. I also fitted an adjustable boost valve at the same time (£21.70 from same supplier) and that works an absolute treat.

"Removing the stock pipe and fitting a new slightly longer length with the valve spliced in took about 20 minutes. I recommend using clips at each joint. I also recommend fitting clips to the vacuum pipes coming off the left had side of the throttle body (boost gauge and one other) since one of these blew off when I was road testing with increased boost, resulting in the ECU cutting the engine and the warning light flashing at me in an alarming way!

"Having spent a couple of hours road testing and setting the valve correctly (to about 0.8 on the boost gauge), there is now a very noticeable increase in urge at maximum boost and overtaking acceleration is now quite neck snapping--it really flies!"

Doug, here's a picture of an installed Joe-P (ball-spring) MBC, available for $48 (complete price incl. shipping) from WWW.BOOSTCONTROLLER.COM. If you add it to the write-up, be sure to tell them NOT to order the "deluxe" kit that comes with hose, it is 3/16" and too small, our cars use 1/4" hose. (therefore, notice the hose-clamp to securely fit the 1/4" hose to the smaller Joe-P)

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