[Mpower]

22 psi does sound really high. I guess we will confirm that when remano fit a boost gage into his Scrpio.

[Sideways]

Originally Posted by Mpower

22 psi does sound really high. I guess we will confirm that when remano fit a boost gage into his Scrpio.

I'd like to see it too. If it aint right the turbo energy guys are defineately gonna hear from me.

[renamo]

Is it possible to fit any pressure guage to measure turbo boost ? for eg: hospital oxigen pressure guages which are claimed to be accurate.

Or any special guage is required for turbo applications ?

[nitrous]

Renamo, u can get an engine-boost guage which is available with autoguage/autometer. And make sure it can read till 24-25 psi...
Sideways can comment more on this since he used to have a Turbo Lancer

[porsche_fan]

Firstly, no 3K application runs at pressure ratios above 2.2, that means that the max boost pressure that the turbo could produce would be limited to abt 1.2 bar.

secondly, an EGR valve and a BOV are 2 totally different things.

BOVs are used in turbo petrols to prevent surge, as has been explained in great detail.

petrols, being low CR and spark ignited engines, operate at or near abt the stoichimetric AF ratio. to attain this they have a throttle valve, which controls the amount of air metered into the engine. the fuel input is adjusted likewise. this is why, when load is reduced, it causes the throttle valve to close and this is where the BOV comes in. the BOOM noise is heard in turbo petrols for this very reason.

An EGR valve merely recirculates the exhaust air from the exhaust manifold and mixes it with the fresh inlet charge. this causes the oxygen content to reduce and hence limits the NOx formation. there is no 'blow off' anywhere in the inlet route.

diesels are more fuel efficient because they can operate at higher AF ratios (usually abt 20+).As there is no throttle valve in diesels hence no BOV is required.

[jat]

Originally Posted by porsche_fan

Firstly, no 3K application runs at pressure ratios above 2.2, that means that the max boost pressure that the turbo could produce would be limited to abt 1.2 bar.

secondly, an EGR valve and a BOV are 2 totally different things.

BOVs are used in turbo petrols to prevent surge, as has been explained in great detail.

petrols, being low CR and spark ignited engines, operate at or near abt the stoichimetric AF ratio. to attain this they have a throttle valve, which controls the amount of air metered into the engine. the fuel input is adjusted likewise. this is why, when load is reduced, it causes the throttle valve to close and this is where the BOV comes in. the BOOM noise is heard in turbo petrols for this very reason.

What a silly mistake . Thanks a lot for reminding about throttle valve. I should have remembered it in first place while giving funda on surge. Thanks again.

Regarding pressure ratios of turbo, technology exists for pressure ratios of 3.5 that is turbo pressure of 2.5 bar. But for many constraints the technology is not provided to end user. For example see the pete's tuning box to produce more power.

[Mpower]

Originally Posted by porsche_fan

Firstly, no 3K application runs at pressure ratios above 2.2, that means that the max boost pressure that the turbo could produce would be limited to abt 1.2 bar.

3K meaning KKK? A 2004 Porsche 911 turbo runs 1.8 bar boost stock. I believe the STI_300 is even higher. You would think they are using a german turbo supplier

[Mpower]

Originally Posted by Sideways

Tifosi, he means bosst pressure as in the case of the turbo. I know the non CRDE runs 1.4 to 1.6 bar which is about 22 to 23 Psi. i know it sounds a lot but I have verified this with Turbo Energy who make the turbos for the Scorpio.

Sideways, Im wondering if what he's refering to is the absolute pressure at compressor outlet. So the boost would be 22 - 14.7 = 7.3 psi (gage pressure which is commonly quoted).....but it still works out to 1.5 bar.

[porsche_fan]

Lets not compare a
1.) 3.6 L 6 cyl gasoline boxer which uses cutting edge technology and makes 444 HP and a 2.6L 4 cyl diesel which makes 115Ps
2.) a turbo manufactured by BW systems germany and one by TEL, India which only has 31% BW stake in it.

Petrols have poor volumetric efficiency as compared to diesels.

therefore to achieve the same volume of air flow, higher boost pressures are reqd.

Of course all this greatly depends on the engine design and the rated speed , but this a basic thumb rule.

[MB-Sting]

Originally Posted by nitrous

Yes,Renamo.

We're sure its 22 psi.
Infact, we were searching for a Scorpio's waste-gate actuator when the one in the EVO-VI gave up. The EVO was spooling somewhere around 18-22 psi.

Has someone maybee got a picture of a boostgauge on a Scorpio showing the actual maximum boost, my boostgauge shows my Scorpio boosts about 0.9bar max. If there is something wrong I would like to get it fixed, but if 0.9bar is what its supposed to be I'm fine. Everybody says it should be 1.5bar???