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2001 S Turbo Auto
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488 Posts
Discussion Starter #1
read a bit about these - they sound a bit dangerous on their own above 1bar. What is stock boost pressure of SF5 turbo??

and if I can reduce this via MBC would I need to adjust anything else (all stock at present)?

cheers
mike
 

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99 UK S-turbo
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8,590 Posts
Stock boost is around 0.55 bar.

Overboost fuel cut is at 0.8bar (99/00MY, 01-> not sure).

I disconnect the pipe from the BCS to the intake pipe (at the intake pipe) and block (both sides!) when doing a long mway run to restrict me to wastegate boost (around 0.3bar) for economy, takes about 1 minute to do and 1 min to reverse!

Simon
 

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JDM Foz [sold]
2016 Mercedes E220 AMG Auto
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4,389 Posts
do a search for hdi sbc or click the link in my sig. its an electronic boost controller. dont know how you'd get on with an s-turbo, but I have mine set to .5 bar for motorway and regularly get over 30mpg. press of a button and you get full boost for any overtaking, etc...
 

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2009 JDM XT Forester Auto
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682 Posts
I disconnect the pipe from the BCS to the intake pipe (at the intake pipe) and block (both sides!) when doing a long mway run to restrict me to wastegate boost (around 0.3bar) for economy, takes about 1 minute to do and 1 min to reverse!
Could i have more info on this ?
 

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99 UK S-turbo
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8,590 Posts
Sure......I'll take some pics when I can but.....

Follow 'vacuum' piping from BCS to where it joins the intake piping (hard plastic where it goes under the manifold) pull pipe off and plug with a bolt (m4 from memory) fiteither a cap if you have it, or a short piece of pipe (with another M4 bolt) onto the intake pipe et voila - wastegate boost only!

Simon
 

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129 Posts
Sure......I'll take some pics when I can but.....

Follow 'vacuum' piping from BCS to where it joins the intake piping (hard plastic where it goes under the manifold) pull pipe off and plug with a bolt (m4 from memory) fiteither a cap if you have it, or a short piece of pipe (with another M4 bolt) onto the intake pipe et voila - wastegate boost only!

Simon
I to would like more info! i have an 03xt. Thinking about the Controller though.
 

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Emeritus Forum Staff
2015 Triumph Tiger XCx 1 Down. 5 Up.
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5,242 Posts
do a search for hdi sbc or click the link in my sig. its an electronic boost controller. dont know how you'd get on with an s-turbo, but I have mine set to .5 bar for motorway and regularly get over 30mpg. press of a button and you get full boost for any overtaking, etc...
I like the principle of this - one mode for power, one mode for economy.

However, am I right in thinking that the MBC takes away the ECUs control over boost and therefore would render a remap redundant?

If so, I wonder if there is some way of creating an electronic version of the Rookie's solution so you could effectively disable boost when you wanted a few more MPG and at the flick of a switch, you get your boost back and still have it controlled by the ECU?
 

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JDM Foz [sold]
2016 Mercedes E220 AMG Auto
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4,389 Posts
I like the principle of this - one mode for power, one mode for economy.

However, am I right in thinking that the MBC takes away the ECUs control over boost and therefore would render a remap redundant?

If so, I wonder if there is some way of creating an electronic version of the Rookie's solution so you could effectively disable boost when you wanted a few more MPG and at the flick of a switch, you get your boost back and still have it controlled by the ECU?
yeah your right but so would any method you use, even manually. if you use simons method then you are still taking control from the ecu. The only way of doing this is to use your right foot in a more controlled manor.

There is a version of the HDI which uses the standard boos controller
http://www.subaruforester.org/vbulletin/f75/sbc-d-rx-36321/
 

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Emeritus Forum Staff
2015 Triumph Tiger XCx 1 Down. 5 Up.
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5,242 Posts
yeah your right but so would any method you use, even manually. if you use simons method then you are still taking control from the ecu. The only way of doing this is to use your right foot in a more controlled manor.

There is a version of the HDI which uses the standard boos controller
http://www.subaruforester.org/vbulletin/f75/sbc-d-rx-36321/
True, but only for short periods of time such as on motorways and then when I'm back on the twisties, I can hand back control to the ECU and the EKUTEC map (courtesy of Bob Rawle).

Will have a look at the other HDI controller.

As far as my right foot goes, I've never found it easy to resist temptation! ;o)
 

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2001 S Turbo Auto
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488 Posts
Discussion Starter #11
Stock boost is around 0.55 bar.

Overboost fuel cut is at 0.8bar (99/00MY, 01-> not sure).

I disconnect the pipe from the BCS to the intake pipe (at the intake pipe) and block (both sides!) when doing a long mway run to restrict me to wastegate boost (around 0.3bar) for economy, takes about 1 minute to do and 1 min to reverse!

Simon
Cheers Si. Wish I'd had this option for the m1 today! Although seem to be getting high twenties even when FULLY loaded averaging 70-75.

Myk, I am jealous of this mod on the T/tb and still wishing I'd gone for the JDM model :( Looks good but too pricey for my tastes this month!

Gigsy, i can only dream of a remap. Although once the basics get sorted it's something I can save for after subtle mods.

cheers all, good thread and info!
 

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Emeritus Forum Staff
2015 Triumph Tiger XCx 1 Down. 5 Up.
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5,242 Posts
Quick update on this... I spoke to Bob Rawle on a slightly different subject as I am going to fit a TD04 which will then require a remap. Bob, being Bob, is in huge demand and won't be able to remap my car until the end of July:icon_frown:

As I'm not sure when I'll be able to fit the turbo - due to wife and children, I may need to fit it some time before. In order to prevent overboost from the larger turbo, Bob suggested connecting the turbo outlet directly to the wastegate actuator, limiting the boost to about 0.6 bar according to Bob.

See the diagram on Boost control system

In other words, connecting Line 1 and Line 2 in the diagram together without the T piece in the middle.

I had a think about this and it is, in effect, this is doing the same thing as Simon's fix... the only difference is that Simon blocks the pipe after the boost control solenoid (BCS). Both methods prevent the BCS (controlled by the ECU) from bleeding pressure away from the wastegate actuator and thus the wastegate opens on it's spring pressure (c. 0.6 bar).

So, my theory is to get a 2nd BCS and fit it after the 1st BCS. The 1st BCS will still be controlled by the ECU and will open and close to as per normal to control boost but the new, 2nd BCS will be controlled via a switch so that it will either be open (leaving the 1st BCS to control the wastegate) or closed (preventing the 1st BCS from venting pressure and therefore the wastegate will open at it's default spring rate).

First off, I'm going to try Simon's method and monitor how the engine copes with just running on wastegate pressure (I now have a ODBII cable and ECU logging software! :woohoo:).

In theory, the ECU should read the manifold pressure (@ 0.6 bar boost) and then fuel/advance ignition accordingly with no big drama. If this goes OK, then I'll attempt the switchable version!

Will let you know how I get on.
 

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Emeritus Forum Staff
2015 Triumph Tiger XCx 1 Down. 5 Up.
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^ Ah yes, but somewhat more expensive than a switchable solenoid ;o)
 

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Emeritus Forum Staff
2015 Triumph Tiger XCx 1 Down. 5 Up.
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Progress Update:

I've blocked off the BCS vent now so I'm running with just wastegate boost which is giving me 0.39 bar (feels soooo slow ;o).

I will run this setup for the next couple of days (approx. 200 miles) which should give me a good indication of how it affects fuel economy. Early signs are good though as I've managed to get roughly 100 miles from 1/4 tank (normally I hit the 1/4 full mark at about 70 - 80 miles).

I'll also be taking data logs during this time to make sure all is OK with the ECU etc. Everything seemed fine on the logs this morning apart from a peak of -5 degrees knock correction for one instant which is a bit worrying... however, that was the only knock correction I saw so may just have been a blip but will be keeping an eye on that for sure.
 

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03 Audi
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238 Posts
Simon,

Are you talking about blocking the pipe & connector circled in red within the image attached or don right as per his thread response here: http://www.subaruforester.org/vbulletin/f75/service-but-pipe-missing-70863/index2.html i.e. second attachedment engine bay image - just trying to get my head around the plumbing>

Original comment:

Stock boost is around 0.55 bar.

Overboost fuel cut is at 0.8bar (99/00MY, 01-> not sure).

I disconnect the pipe from the BCS to the intake pipe (at the intake pipe) and block (both sides!) when doing a long mway run to restrict me to wastegate boost (around 0.3bar) for economy, takes about 1 minute to do and 1 min to reverse!
 

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Emeritus Forum Staff
2015 Triumph Tiger XCx 1 Down. 5 Up.
Joined
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5,242 Posts
Simon,

Are you talking about blocking the pipe & connector circled in red within the image attached or don right as per his thread response here: http://www.subaruforester.org/vbulletin/f75/service-but-pipe-missing-70863/index2.html i.e. second attachedment engine bay image - just trying to get my head around the plumbing>

Original comment:

Stock boost is around 0.55 bar.

Overboost fuel cut is at 0.8bar (99/00MY, 01-> not sure).

I disconnect the pipe from the BCS to the intake pipe (at the intake pipe) and block (both sides!) when doing a long mway run to restrict me to wastegate boost (around 0.3bar) for economy, takes about 1 minute to do and 1 min to reverse!
Yep, its the one circled in red.
 

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03 Audi
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238 Posts
Gigsy,

What did you use to block the open ends? I'm guessing there must be some connector fittings which can be used to cap the holes!!
 

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Emeritus Forum Staff
2015 Triumph Tiger XCx 1 Down. 5 Up.
Joined
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5,242 Posts
On mine, I have a step up pipe as the pipe from the BCS is smaller than the fitting on the air intake. I just used a screw whose head what the correct size to block the step up pipe which I then put back on the the air intake pipe... I'll take a photo tonight if you like.

Blocking it off works though... I gained about 6 mpg.
 
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