Jaguar Club SG

zenkinz · Senior Member

2.2 diesel turbo question

icebear · Senior Member

it goes to 1.6 bar according to my OBD reader... thats not LPT le.. lol..

zenkinz · Senior Member

icebear wrote:
it goes to 1.6 bar according to my OBD reader... thats not LPT le.. lol..

obd reading of map? That's atmospheric value so must minus 1bar leh. Or do you mean turbo pressure of 1.6bar?

icebear · Senior Member

zenkinz wrote:
icebear wrote:
it goes to 1.6 bar according to my OBD reader... thats not LPT le.. lol..
obd reading of map? That's atmospheric value so must minus 1bar leh. Or do you mean turbo pressure of 1.6bar?

lemme go confirm the idling reading. not sure where its Gauge(atmospheric) or Gauge(absolute)

zenkinz · Senior Member

Thanks ! Want to find out the low end lag is due to full turbo or not

icebear · Senior Member

zenkinz wrote:
Thanks ! Want to find out the low end lag is due to full turbo or not

uhm.. i believe its the characteristic of turbo, there's always a lag (the bigger the turbo, more lag, especially with fixed vane turbos; not sure ours is fixed or variable). as usual i asked wearnes, and they said its like that, the characteristic of the car. lol..

zenkinz · Senior Member

icebear wrote:
zenkinz wrote:
Thanks ! Want to find out the low end lag is due to full turbo or not

uhm.. i believe its the characteristic of turbo, there's always a lag (the bigger the turbo, more lag, especially with fixed vane turbos; not sure ours is fixed or variable). as usual i asked wearnes, and they said its like that, the characteristic of the car. lol..

yes, except that for LPT it'll not be obvious at least for my SAAB.

icebear · Senior Member

zenkinz wrote:
icebear wrote:
zenkinz wrote:
Thanks ! Want to find out the low end lag is due to full turbo or not

uhm.. i believe its the characteristic of turbo, there's always a lag (the bigger the turbo, more lag, especially with fixed vane turbos; not sure ours is fixed or variable). as usual i asked wearnes, and they said its like that, the characteristic of the car. lol..
yes, except that for LPT it'll not be obvious at least for my SAAB.

small turbo boost faster ma.. lol..

zenkinz · Senior Member

icebear wrote:
zenkinz wrote:
icebear wrote:
zenkinz wrote:
Thanks ! Want to find out the low end lag is due to full turbo or not

uhm.. i believe its the characteristic of turbo, there's always a lag (the bigger the turbo, more lag, especially with fixed vane turbos; not sure ours is fixed or variable). as usual i asked wearnes, and they said its like that, the characteristic of the car. lol..
yes, except that for LPT it'll not be obvious at least for my SAAB.

small turbo boost faster ma.. lol..

yup, so I want to know if 2.2is using full turbo or not lor .:P

zenkinz · Senior Member

I think if you are reading from OBD, it should be reading manifold absolute pressure. so boost should be just whatever you read - 1 bar.

inteeresting to know our car uses variable geometry turbo .. soit should be a full turbo with the ability to adjust the turbine housing to create 'light pressure turbo' effect at low end... learn new thing!

PS: so our engine shares the same platform as landrover and ford?

-- Edited by zenkinz on Wednesday 24th of July 2013 10:51:15 AM

icebear · Senior Member

zenkinz wrote:
icebear wrote:
zenkinz wrote:
icebear wrote:
zenkinz wrote:
Thanks ! Want to find out the low end lag is due to full turbo or not

uhm.. i believe its the characteristic of turbo, there's always a lag (the bigger the turbo, more lag, especially with fixed vane turbos; not sure ours is fixed or variable). as usual i asked wearnes, and they said its like that, the characteristic of the car. lol..
yes, except that for LPT it'll not be obvious at least for my SAAB.

small turbo boost faster ma.. lol..
yup, so I want to know if 2.2is using full turbo or not lor .:P

here's the info on our engine and type of turbo. its a variable geometry turbo, so this is already boost faster. :) unfortunately, it didnt state the boost pressure.. lol. will try to let u know soon from my OBD.

http://en.wikipedia.org/wiki/Duratorq#2.2_2

http://en.wikipedia.org/wiki/PSA_EW/DW_engine#DW12

http://en.wikipedia.org/wiki/Variable_geometry_turbocharger

icebear · Senior Member

zenkinz wrote:
I think if you are reading from OBD, it should be reading manifold absolute pressure. so boost should be just whatever you read - 1 bar.

inteeresting to know our car uses variable geometry turbo .. soit should be a full turbo with the ability to adjust the turbine housing to create 'light pressure turbo' effect at low end... learn new thing!
PS: so our engine shares the same platform as landrover and ford?

-- Edited by zenkinz on Wednesday 24th of July 2013 10:51:15 AM

i got the OBD reading. its slightly under 1.6 bar boost. prob is 1.5 bar. As mentioned, diesel has no TB, so its not under vacuum like petrol. this is taking into account atmospheric liao. else it'll be 2.6/2.5 bar.

-- Edited by icebear on Wednesday 24th of July 2013 05:02:16 PM

icebear · Senior Member

chiaster wrote:
The lag is very prominent on corner exits... As experienced by myself recently... How do we go about creating LPT at low end?

the only way to reduce/prevent turbo lag is to keep the revs up.. don't let the revs drop below 1.8k.. abit hard to do for diesel IMO cos the power range is kinda narrow.. lol....

-- Edited by icebear on Wednesday 24th of July 2013 05:01:32 PM

chiaster · Guru

The lag is very prominent on corner exits... As experienced by myself recently... How do we go about creating LPT at low end?

zenkinz · Senior Member

icebear wrote:
zenkinz wrote:
I think if you are reading from OBD, it should be reading manifold absolute pressure. so boost should be just whatever you read - 1 bar.

inteeresting to know our car uses variable geometry turbo .. soit should be a full turbo with the ability to adjust the turbine housing to create 'light pressure turbo' effect at low end... learn new thing!
PS: so our engine shares the same platform as landrover and ford?

-- Edited by zenkinz on Wednesday 24th of July 2013 10:51:15 AM

i got the OBD reading. its slightly under 1.6 bar boost. prob is 1.5 bar. As mentioned, diesel has no TB, so its not under vacuum like petrol. this is taking into account atmospheric liao. else it'll be 2.6/2.5 bar.

-- Edited by icebear on Wednesday 24th of July 2013 05:02:16 PM

ok I'm not familiar with diesel engine, but OBD reading usually reads MAP, not turbo boost. an MAP reading - 1 bar is usually equivalent to turbo boost. I'm not exactly sure what you mean by diesel has no TB, no turbo boost? If no turbo boost, then how the variable geometry turbo is able to control the turbine at different engine rev?

chiaster · Guru

His "TB" refers to throttle body...

chiaster · Guru

icebear wrote:
chiaster wrote:
The lag is very prominent on corner exits... As experienced by myself recently... How do we go about creating LPT at low end?

the only way to reduce/prevent turbo lag is to keep the revs up.. don't let the revs drop below 1.8k.. abit hard to do for diesel IMO cos the power range is kinda narrow.. lol....

-- Edited by icebear on Wednesday 24th of July 2013 05:01:32 PM

I tried to keep it between 3-4k and it was really really tough... :(

zenkinz · Senior Member

chiaster wrote:
icebear wrote:
chiaster wrote:
The lag is very prominent on corner exits... As experienced by myself recently... How do we go about creating LPT at low end?

the only way to reduce/prevent turbo lag is to keep the revs up.. don't let the revs drop below 1.8k.. abit hard to do for diesel IMO cos the power range is kinda narrow.. lol....

-- Edited by icebear on Wednesday 24th of July 2013 05:01:32 PM
I tried to keep it between 3-4k and it was really really tough... :(

but it shouldn't be the case (of keeping the rev), because of the variable geometry turbo. I do think that the lag is not as pronounce as some of the full turbo I have experienced, although not the most responsive. Guess we can't have cake and eat it too.

chiaster · Guru

Can you further explain "variable geometry turbo"?

kennethtancy · Senior Member

zenkinz, you are worried of low end turbo lag...

firstly the 2.2D does not suffer from low end turbo lag... it has a mid range turbo lag.

2.2D has a econ rpm range of approx 1750-2250rpm

auto gear changes are at approx 1500-2500rpm

red line is at 4200rpm.

THIS IS NORMAL FOR DIESEL.

so the lag you feel is at approx after passing 2000rpm... this is mid range rpm already...just when the full turbo is just kicking in... prior to full turbo the variable geo vanes should minimise the lag by directing sufficent air for the turbines to have a good spin up speed.

also this is turbo is also to help maintain power at mid to higher ranges so manufacturers can use smaller engines.... most after market turbo set ups are for boosting the engine for even higher performance.

the initial torque you feel from approx 0-2000rpm is all diesel engine torque 450Nm.

so if you want more vroooom vrooom... after market ones are what you looking for... don't expect too much from the in house ones UNLESS.....

you go for the XFR... those turbos are totally diff... thats the performance ones.

-- Edited by kennethtancy on Thursday 25th of July 2013 02:09:37 PM

zenkinz · Senior Member

chiaster wrote:
Good insight

But as always, theory and reality is different... The words above makes sense but I've realised (last weekend) the practical part and the low end (below 2k rpm lag) is evident...

yup, there is a alittle retard at low end (from 0-1000+ rpm), although it's less obvious than a Saab Aero (using full turbo), but compared to my current LPT turbo it's quite obvious.

maybe the answer to my question is the eco-mode ... i shall try the sports mode to see how it feels :)

-- Edited by zenkinz on Thursday 25th of July 2013 03:50:22 PM

zenkinz · Senior Member

chiaster wrote:
Can you further explain "variable geometry turbo"?

I'm not an expert at this, i am just deducting based on the link that icebear pointed out earlier.

I think the gist is various size of turbine (in terms how this is achieved I am not very familiar) is being used at different engine rev necessary to build up the boost to induct air into the engine.

http://www.youtube.com/watch?gl=SG&v=CbdY1rymBJg&hl=en-GB

XFS · Senior Member

zenkinz wrote:
chiaster wrote:
Can you further explain "variable geometry turbo"?

I'm not an expert at this, i am just deducting based on the link that icebear pointed out earlier.
I think the gist is various size of turbine (in terms how this is achieved I am not very familiar) is being used at different engine rev necessary to build up the boost to induct air into the engine.
http://www.youtube.com/watch?gl=SG&v=CbdY1rymBJg&hl=en-GB

With pics..

http://paultan.org/2006/08/16/how-does-variable-turbine-geometry-work/

A Variable Turbine Geometry turbocharger is also known as a variable geometry turbocharger (VGT), or a Variable Nozzle Turbine (VNT). A turbocharger equipped with Variable Turbine Geometry has little movable vanes which can direct exhaust flow onto the turbine blades. The vane angles are adjusted via an actuator. The angle of the vanes vary throughout the engine RPM range to optimize turbine behaviour

chiaster · Guru

Wow... Good stuff...

chiaster · Guru

Good insight

But as always, theory and reality is different... The words above makes sense but I've realised (last weekend) the practical part and the low end (below 2k rpm lag) is evident...

kennethtancy · Senior Member

well the numbers are approx... but i really want to know is how will it affect our warranty if we swap to after market turbos... cos in all honesty... in house turbo is only average at best.

i also hope to get some better after market ones where the lag is minimum through out our limited rpm range of 0-4200rpm.

Lorenzo · Veteran Member

wah v chim u guys are sexpert.

chiaster · Guru

Even if you switch off the Eco mode and drive in "S", the low end lag remains... Eco mode doesn't affect the drive at all and it only kicks in when the car comes to a standstill...

zenkinz · Senior Member

Oh yeah, its probably just hold the gear longer..m haiz..

icebear · Senior Member

kennethtancy wrote:
well the numbers are approx... but i really want to know is how will it affect our warranty if we swap to after market turbos... cos in all honesty... in house turbo is only average at best.

i also hope to get some better after market ones where the lag is minimum through out our limited rpm range of 0-4200rpm.

minimal lag= smaller turbo loh.. i dont think there's gonna be a way out of this.. turbo is exhaust gas driven.. without sufficient rpm for turbo to spool, there'll always be a lag, thus smaller turbo can spool earlier, but still need some revs..

kennethtancy · Senior Member

hmmmm its like asking for the cake and wanting to eat it too...lolx

chiaster · Guru

So now the trick is to keep it in the optimum rpm for minimal lag...

icebear · Senior Member

i am reminded of VTEC! hur hur..

Lorenzo · Veteran Member

or mivec

kennethtancy · Senior Member

knn... buy a jag drive like jap