How to check Boost readings

[SIG60 0]

I have been using this forum for tips for nearly two years now but still am cr@p at using the search facility :oops: Can anyone point me in the right direction of (ie idiot guide) on how to check what boost im getting from the MFA.

[stevemac 0]

MFA boost check is very inaccurate. Only way to get a true reading is to fit a boost gauge.

[exturbo2003 0]

wouldnt agree with you steve. my MFA reading is only 1/2 psi out from my boost gauge

i think its still usefull if not totally accurate

[stevemac 0]

How to test your boost levels - UK spec cars

 

1. Start Engine

 

2. Move the MFA selector to "2"

 

3. Press and hold the MFA end button (keep holding)

 

4. Stop engine

 

5. Start engine

 

6. Release the MFA end button.

 

7. Press the MFA End button one time.

 

 

You should now see 450-800 readings fluctuating with idle. Anything higher than 800 is not right (vacuum leak). Much less than 450 is probably too much timing advance.

 

Go run your car!!! 3rd and 4th gear to REDLINE. Carefully note the highest #'s you've got.

 

A pullied charger should not make less than 11.6psi, and even so, thats weak. A Stock charger should make ~~11psi in perfect shape!

 

EURO Hg(#'s of boost/vacuum) Comments

200 -23.7

400 -17.8

600 -11.9

800 -5.9

1000 0 (Atmosphere- ala no boost, charger is bypassed)

1200 2.9 psi (Your charger is dead or big boost leak)

1400 5.8 psi (Your charger is about dead or big boost leak)

1600 8.7 psi (Your charger needs new apex strips or big boost leak)

1800 11.6 psi (Great for stock pulley, Probably needs new apex strips if 68mm pulley)

2000 14.5 psi (Great for 68mm pulley on stock charger)

2200 17.4 psi (Great for 68mm pulley on heavily ported charger, hold on to your ass fast!!) :rambo:

 

2000 and up folks need to be careful with fueling, as the programming maps end at about 2000 on the ecu :) Dynotuning, and air/fuel/egt gauge, and custom chip recommended

[stevemac 0]

Bit more MFA info :-

 

 

For G60's the extra MFA functions are:

 

MFA switch, position 1:

1: Engine map code.

2: Country code.

3: Speedo drive ratio.

4: Upper RPM limiter.

5: Lower RPM limiter.

6: Deceleration fuel shutof pressure.

7: Segment test.

 

MFA switch, position2:

1: Test sum of programmed bytes

2: Intake manifold vacuum/pressure. (boost check)

3: Engine RPM.

4: Momentary fuel consumption.

5: Signal from speed sensor.

6: Oil temp.

7: Ambient temp.

[SIG60 0]

Thats what I was looking for!!! You guys have not failed me yet!!

[stevemac 0]

No worries m8 - all info was taken from http://www.snstuning.com - some good stuff on there, in the DIY section.

[Ronan 0]

Bit more MFA info :-

 

 

For G60's the extra MFA functions are:

 

MFA switch, position 1:

1: Engine map code.

2: Country code.

3: Speedo drive ratio.

4: Upper RPM limiter.

5: Lower RPM limiter.

6: Deceleration fuel shutof pressure.

7: Segment test.

 

MFA switch, position2:

1: Test sum of programmed bytes

2: Intake manifold vacuum/pressure. (boost check)

3: Engine RPM.

4: Momentary fuel consumption.

5: Signal from speed sensor.

6: Oil temp.

7: Ambient temp.

 

How do you see these extra readings?

[W3RKD 0]

Please note (again) that these are only manifold pressure readings... **what the engine cant use at any given time** If anything has been do to increase the efficenty of your engine dont expect these figures to be anything like the same as listed above..

[markmcie 0]

When fitting a boost gague were is the best place to tap into to get the boost readings ??

[stevemac 0]

Ronan,

 

1. Start Engine

 

2. Move the MFA selector to "2"

 

3. Press and hold the MFA end button (keep holding)

 

4. Stop engine

 

5. Start engine

 

6. Release the MFA end button.

 

7. Refer to the above guide

 

8. MFA will return back to it's normal mode once the engine is switched off

 

 

markmcie - usually spliced into the vac pipe between the inlet manifold & the fuel pressure regulator (on the driver's side of the inlet manifold).