9 replies to this topic

[Westyturbobusa]

Hi all, not had the 220 for long & need to take it to Courtney for final mapping.

From the documents included with the sale i believe when it went for mapping previously, there was a problem with low boost.

 

I'm sure this has been sorted but wanted to check the boost before taking it on the long trip to CMS. So, could anyone confirm that my basic maths is correct .

 

Map @ current rpm limit: 0.15 ATM (15KPa)

15KPa - 100KPa(gauge offset) = 85KPa

85KPa = 12.32psi

 

After speaking to CMS they reckoned it should be 9-10psi, so looking ok?

[TFD]

Depends on where you start from.

100 kpa is atmosphere pressure = 1 bar. OBD-tuner calculates pressure from this point of view. So idle vacuum = 30 kpa = -0,7 bar

 

But if you say atmosphere is 0 (wich mostly is whit a boostgauge), then idle should read -70kpa = -0,7 bar

So if you read 15kpa at max.boost this either means: 0,15 bar of boost or -0,85 bar of boost (vacuum).

 

Must say... I dont get your gauge-offset correction ?

 

If you read 85kpa @ max boost = 0,85 bar = 12,5 psi (when gauge says atmo is "0").

[Exmantaa]

 

I assume you log(ged) the MAP sensor and that has an absolute reading:

- Should log ~100KPa with engine off. = 1 bar = atmospheric pressure. (check this!)

- @ idle normally around 30-40KPa (-0.6/-0.7bar vacuum), depending on idle rpm and fittted cams.

- Stage 2 SC at full boost; around 180KPa = +0.8 bar boost (~12psi)

 

The SC max boost pressure reading depends on exhaust/head restrictions and the fitted pulley diameter. A low reading at higher revs could indicate possible belt slip or a boost leak. (but then you normally also get a vacuum leak) 

 

Edited by Exmantaa, 29 February 2016 - 08:54 AM.

[Westyturbobusa]

Bit more info:

 

Stage 2

3.35" pulley

Standard cams

Standard exhaust system (pre cat removed)

68mm TB.

 

Using "OBD Doctor Free" software on tablet to log MAP sensor is getting these results:

 

@Engine off:

MAP = 54KPa (7.8psi)(0.5atm)

 

@Engine idle:

MAP = 22KPa (3.2psi)(0.2atm)

RPM = 940

 

@Current RPM limit(base map) ~5.5K:

MAP = 15KPa (2.2psi)(0.15atm)

[stu8v]

Just put a temporary gauge on it for test purposes.

[Exmantaa]

Bit more info:

 

Stage 2

3.35" pulley

Standard cams

Standard exhaust system (pre cat removed)

68mm TB.

 

Using "OBD Doctor Free" software on tablet to log MAP sensor is getting these results:

 

@Engine off:

MAP = 54KPa (7.8psi)(0.5atm)

 

@Engine idle:

MAP = 22KPa (3.2psi)(0.2atm)

RPM = 940

 

@Current RPM limit(base map) ~5.5K:

MAP = 15KPa (2.2psi)(0.15atm)

 

Ehh, what ecu software is this running?? The Courtenay Stage 2?

Looks like it, as that works with a "faked" 2 bar MAP sensor instead of the 1 bar OEM version, therefore you see readings of only half the real MAP pressure. (It's simply logging a sensor voltage and translating this into a pressure reading for the original 1 bar sensor specs.)

So with the CS mapping and 2 bar sensor you should multiply your logged MAP pressures 2x.

 

So:

@Engine off:

MAP = 54KPa (7.8psi)(0.5atm)  [color=#ff0000;]x2 = 108KPa [color=#ff0000;] [/color][/color]

 

@Engine idle:

MAP = 22KPa (3.2psi)(0.2atm)   [color=#ff0000;]x2 = 44KPa  [color=#ff0000;] [/color][/color]

RPM = 940

 

@Current RPM limit(base map) ~5.5K: 

MAP = 15KPa (2.2psi)(0.15atm)   [color=#ff0000;]x2 = 30KPa???   [color=#ff0000;]  [color=#ff0000;][color=#ff0000;] [/color][/color][/color] [/color]

[color=#ff0000;]What's this? Is that full throttle logged with a working loaded (whining) supercharger??[/color]

[color=#ff0000;]Should read something like 80-90KPa full throttle => x2 = 160-180KPa.[/color]
 

[TFD]

44kpa @ idle = -0,56 bar = 

Idle should see around -0,7 bar (~30 kpa).

 

To low vacuum at idle and strange boost#'s. Sounds like a leak somewhere.

[Exmantaa]

Well, it runs 940rpm at idle and at that rpm I'm somewhere around 40KPa.

Lower it to 800 (throttleplate more closed) and it should read around your 30-35KPa.

 

But that full throttle reading has more vacuum than @ idle, so probably something wrong with the logged value. (maybe it's logged the MAP value on decelleration?) 

[TFD]

Correct.

[Westyturbobusa]

Holy thread resurrection! Finally got round to looking at this again, Max MAP = 81KPa x 2 = 162KPa (8.9psi boost pressure) So all looks good with Courtney's expected value (9-10psi). Am I right in thinking the additional rpm of the final map should increase the Boost slightly to bring it up to near 180KPa. Cheers for the help.