OK SO Any1 Done This???

[lkfldredneck]

Inchalota. I'm american damnit.

Touche. Well still, i could go for a taco.

 

[98chevyz71]

i thought this was the chat thread

 

[lkfldredneck]

i thought this was the chat thread

Meh, nothin better to talk about in here!

 

[gmcyukondriver]

Tisk tisk. Manifold ABSOLUTE Pressure. Easy mistake.

Absolute? So does that mean the it gives the sme reading for vacuum as it does for boost?


In other words, it only senses pressure. Not whether it is pushing or pulling?

 

[Sampuppy1]

Absolute? So does that mean the it gives the sme reading for vacuum as it does for boost?


In other words, it only senses pressure. Not whether it is pushing or pulling?

Someone's gears are turning to find out if a gauge can be hooked to this......


Sent from what is likely a government flagged smartphone. Tyler/T-Unit

 

[TerryD]

Thought I didn't want the Weiand Action+ b/c of it being Dual Plane Design. I thought thats what I go. The part # will matter tho right?
http://www.carshopinc.com/product_info.php/products_id/74246/8121?gclid=CMnFsMvZwroCFejm7Aod1k0ArQ VS http://www.carshopinc.com/product_info.php/products_id/74244/8120?gclid=CL3ogILawroCFWxo7AodnAcALg

First: Can you post pictures of the intake manifold you have please?

Secondly: What you have should have if it is a strip dominator is a single plane intake. It has no divider between the two halves of the engine and isn't designed for the low RPM. The Action+ (which I cannot find a EGR version of now) is a dual plane which improves lower RPM port velocities and cylinder fill.

Here are some suggestions on intakes you could use:

Edelbrock Performer 86-95 w/ EGR:
http://www.summitracing.com/parts/edl-3706/overview/

Holley Street Dominator 86-95 w/ EGR: (not the same as a Strip Dominator btw)
http://www.summitracing.com/parts/hly-300-64/overview/make/chevrolet

Edelbrock Performer EGR for TBI:
http://www.summitracing.com/parts/edl-3704/overview/make/chevrolet

 

[TerryD]

Absolute? So does that mean the it gives the sme reading for vacuum as it does for boost?


In other words, it only senses pressure. Not whether it is pushing or pulling?

No, Absolute refers to the pressure scale it reads out in. There is PSIA (Pounds per Square Inch Absolute) and PSIG (Pounds per Square Inch Gauge). Normally we use PSIG for everyday life because accounting for the ~14.7psi (depending on where you are) of static pressure the atmosphere exerts on us isn't useful. 0psia is the same a -14.7psig or -29.9"hg (inches of mercury) which vacuum is measured in. You cannot reduce pressure below 0PSIA or -14.7PSIG. So the MAP sensor reads vacuum in most instances. I do not think that the earlier MAP sensors on GM stuff will read pressure, just vacuum since a NA engine will never see intake pressures above 14.7psia or 0psig.

 

[someotherguy]

I had the change to buy the Edlebrock performer for $80 on CL but guy never returned my emails, maybe b/c how I type.....lol

Dude if I could, I would mod you up for this.

Richard

 

[someotherguy]

I do not think that the earlier MAP sensors on GM stuff will read pressure, just vacuum since a NA engine will never see intake pressures above 14.7psia or 0psig.

Pretty sure you're right about that; a MAP sensor swap is needed when boosting.

If you want a gauge just hang a mechanical one off a vacuum tee.

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Richard

 

[great white]

Well, its a little deeper than what we need to be discussing here, but all map sensors read pressure. They are measured in bar. 1 bar equals 14.7 psi.

So a 1 bar map sensor reads from 0 to 14 .7 psi.

1 bar is normal atmospheric pressure which is what a naturally aspirated engine sees.

if the PCM sees pressure less than 14.7 psi then it is seeing what we are referring to as vacuum, or pressure less than 1 atmosphere or one bar. What it actually reading is pressure below 1bar, not a vacuum.

If you're going forced induction then you will be reading more than one bar as boost means pressure above one atmosphere.

For example; my turbo diesel has a 2 bar map sensor. This means I'm good to a total about 29 psi. my stand alone boost gauge uses a 3 bar map sensor so it's good to around 32 psi.That's all psia.

Most boost gauges are calibrated from the manufacturer to read 0 at 14.7 psi because that's easier for people to understand then a reading of say 18 or 20. it's much easier for the average gear head to understand the meaning of 4 or 6 psig instead of 18 or 20 psia so thats how aftermarket boost gauges are built.

if you look at the fuel calibration tables in the PCM you will see they are marked in bar and they start at zero because the PCM reads absolute pressure not gauge pressure.