I went to the dyno with my New Vararam System. 465 Hp 465 TQ
The same as I got with the Blackwing Dynoed a few months ago!
The Manifold Pressure at full throttle during the pull was 102 KPA
the same as Barometric Pressure 102KPA. I left the Dyno
and went for a blast 100 MPH 104 KPA at the MAP 125 MPH I hit
105 KPA That is 3 KPA increse in MAnifold Pressure readings on the
Tech II . 3kpa is equal to 30 Millabars or approximately 1 psi of Positive
Pressure. I have never seen this much pressure on a Naturally Aspirated
Engine. (No Turbo or Blower). Just for the hell of it I made a big leak
in the Vararam system and ran again. Best KPA was 102 Equal to
Barometric Atmospheric Pressure. It proves the Vararam when installed
properly Works! I made 3kpa on 415 cid It would be more on a
stock 346 cid (harder to fill a big hole) FYI The guys a Vararam do the
Indy Car IRL air boxes. Ever wonder how the Naturally Aspirated Chevy's and Infinity Engines have the same speeds as the old cart Cosworths
with turbo"s Technology and Natural Charging did at Indy! You cannot
get enough air in on a Dynojet to do proper testing. You can however
utilize your scan tool and see if your system what ever it is shows the
map, manifold pressure exceeds the BAro reading. If it does you are
making some positive pressure in the manifold Which is awesome.
You can feel the kick at 100MPH. Not like NOs , but you can feel it!
Try it You will Like It and better yet do not knock it till you try it!
TEST DON'T GUESS!

 

The one problem tho is the Barometer is only read during key on from the MAP sensor. There is no seperate barometer sensor, its all the same sensor.

Note: I am not knocking the vararam, mabey its the best out there, who knows. Just pointing out a fact about the control systems on the C5.


[Modified by kewlbrz, 5:23 PM 8/22/2002]

 

...you forgot to end with the statement "no flames, please.".;)

RG


[Modified by RG in Dallas, 5:24 PM 8/22/2002]

 

With the key on The computer reads Baro.

The split second you turn your key on the computer notes Barometric
Pressure. It takes Baro Presssure and subtracts manifold pressure to
get vacuum. Baro - Map = Vacuum kpa ( metric) Hg" (English)
Everyone seems to think the Baro reading is not accurate. The computer
does both air flow calculations Volumetric ( grams per second from the
Mass AIr Flow) and Adaptive Speed Density (Manifold Pressure, Rpm
Intake Air temp, Volumetric Effic.) It runs both computations Mass
Air Primary and Speed Density as a back up. They must be within 50 %
of each other or codes will set . The Baro./ Map is very reliable on the
LS1 and other g.m. products. Years ago back in the days of Computer
Command carburetion we had a separate Map and Baro sensor. It is
not necesssary as the computer sees the baro reading before rpm
(crankshaft sensor) Not to be a smart butt, but I train Engine Management
Systems to Independent and Dealer Technicians and have been doing it
for the past 19 years. The only inaccuracy will be the computer reupdating
the baro reading from what the map sees ( it finds it hard to beleive that
there is positve pressure and readjusts the baro until the next key cycle)
key on, no rpm - look at map (which is baro now) What I mean is after the
computer sees the map higher than the baro it will adjust the baro
to the higher number Cycle the key and your back to the actual baro reading. You can compare it to an actual barometer if you still don't
believe! Unless you are climbing a mountain or entering a hurricane
or major thunderstorm during your testing the Baro is accurate.


[Modified by vetetech, 12:48 AM 8/23/2002]

 

You state your reading 105kPa. Im baffled that the techII you have is showing that. My autotap maxes at 102 kPa I beleive last I checkd. Also according to the delphi white paper regarding the MAP sensor, its stated range is 20 kPa - 102kPa. Looking at the transfer curve with respect to voltage it ends at 102 kPa also.

It also states an allowable pressure error which rises to 1.7 kPa at 102 kPa.

Also you state: "3kpa is equal to 30 Millabars or approximately 1 psi of Positive Pressure."

I'm getting, 3 kPa = 30 millibars = .029 atmospheres = .435 psi




[Modified by kewlbrz, 11:16 AM 8/23/2002]

 

I got that covered :D

 

:lol:

 

That's why you da' man.:D

RG

 

Thanks for the info vetetech :yesnod:
:cheers:

 

Blackwing and Z06 Cold Air Screens. The surface area of the BW is HUGE and location is behind the cold air openings. Hydro lock should be extremely rare!

 

Hydrolock should be very rare with any box, stock too, if you don't swim with it.:)

RG