Menu toggle

Measuring boost level?

Scott, great explanation, thanks.

Is it just me, or does the 944t vacuum/boost system seem to be fiendishly complicated compared to other turbo cars of the same era?
 
I think I see where my confusion came from: If you use a single-port wastegate then a boost enhancer or a boost controller perform exactly the same function. It's only with a dual-port wastegate that you hook up a boost controller differently and thus it does a different job.
 
Not quite Poprock. In a single port wastegate installation the boost enhancer (BE) will completely block the pressure signal to the wastegate altogether so the wastegate valve will be held shut with the spring pressure. Inside the BE there is a pop valve which will pop fully open once the desired boost pressure is reached thus exposing the wastegate diaphram to the full boost pressure which should immediately open the wastegate. Because the pressure signal is completely blocked until max boost is achived it doesn't matter if your wastegate spring has weakened off over the years as long as it is strong enough to hold the valve closed against the exhaust manifold pressure.

An MBC doesn't block the pressure signal at all. The wastegate diaphram will be exposed to the full boost pressure which will continue to rise until the preset max boost pressure is achived. After which the output from the MBC will remain at a constant pressure. This setup to me is pointless because it is still the wastegate spring that regulates the boost and not the MBC (assuming you set your MBC to a higher boost pressure than your spring).

When I installed my DPW and set the boost pressure to stock I immediately got 20bhp, so the single port wastegate was costing me at least 20bhp.
 
You must log in or register to reply here.

Posts made and opinions expressed are those of the individual forum members

Use of the Forum is subject to the Terms and Conditions

Disclaimer

The opinions expressed on this site are not necessarily those of the Club, who shall have no liability in respect of them or the accuracy of the content. The Club assumes no responsibility for any effects arising from errors or omissions.

Porsche Club Great Britain gives no warranties, guarantees or assurances and makes no representations or recommendations regarding any goods or services advertised on this site. It is the responsibility of visitors to satisfy themselves that goods and/or services supplied by any advertiser are bona fide and in no instance can the Porsche Club Great Britain be held responsible.

When responding to advertisements please ensure that you satisfy yourself of any applicable call charges on numbers not prefixed by usual "landline" STD Codes. Information can be obtained from the operator or the white pages. Before giving out ANY information regarding cars, or any other items for sale, please satisfy yourself that any potential purchaser is bona fide.

Directors of the Board of Porsche Club GB, Club Office Staff, Register Secretaries and Regional Organisers are often requested by Club members to provide information on matters connected with their cars and other matters referred to in the Club Rules. Such information, advice and assistance provided by such persons is given in good faith and is based on the personal experience and knowledge of the individual concerned.

Neither Porsche Club GB, nor any of the aforementioned, shall be under any liability in respect of any such information, advice or assistance given to members. Members are advised to consult qualified specialists for information, advice and assistance on matters connected with their cars at all times.

Porsche
Lockton
Pirelli
Officially approved
Oracle Finance
WEX Esso
Collecting Cars
Archant Dialogue
Back
Top