zad5

I am trying to research something and wanted to know how much pressure does the turbocharger need before it starts spinning. the basic turbo or ball bearing turbo or big *** turbo's if u have any info that would be cool thanks.

H22isnotabigblock

air pressure dosent spool a turbo, it is expanding exhaust gasses, your question is too vague, and there are too many variables involved i dont think that i can answer it any better than that...

zad5

ive never said air pressure. i know there too many variables bigger motor compression wut kinda turbo but i just want a ball park answer. of how much gas pressure is needed.

99B16Si

u did say air pressure! look at your post title.
but either way its not about pressure its about air flow. if you blow on the blades of a ball bearing turbo it will usually spin. do u think that air is pressurized??? of course not. its all about air flow/volume which in turn creates pressure but is not the depenedent variable that gets a turbo spinning

DaX

iTrader: (1)

It is mostly about mass of the gasses and velocity...but turbo's also work on a pressure differential [this is why you want a large down pipe...to create a larger difference of potential].

ZoRG

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DaX &raquo;</TD></TR><TR><TD CLASS="quote">It is mostly about mass of the gasses and velocity...but turbo's also work on a pressure differential [this is why you want a large down pipe...to create a larger difference of potential].</TD></TR></TABLE>

True, pressure is also the idea behind VNT technology, flow is the same but the nozzles increase the pressure and "speed" of the gas, which adds super fast spooling.

You sort of get a feel for prediction on what turbo will boost where by reading on what it does on other peoples cars, so if you can list your static CR, what exhaust manifold, what inlet manifold, what engine, and what turbo, I am sure someone can help you out on a close prediction on what lag you will see.

squirrel

OT: but can someone explain, why a car needs to be under load in order to boost?

zad5

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by H22isnotabigblock &raquo;</TD></TR><TR><TD CLASS="quote">air pressure dosent spool a turbo, it is expanding exhaust gasses, your question is too vague, and there are too many variables involved i dont think that i can answer it any better than that...</TD></TR></TABLE>

my bad for going off i didnt c the title.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ZoRG &raquo;</TD></TR><TR><TD CLASS="quote">
You sort of get a feel for prediction on what turbo will boost where by reading on what it does on other peoples cars, so if you can list your static CR, what exhaust manifold, what inlet manifold, what engine, and what turbo, I am sure someone can help you out on a close prediction on what lag you will see.</TD></TR></TABLE>

i was just wondering wanted to better my understanding if it wasn not going to be used on a car could it still work with a lot of air pressure or something... but by just blowing air the blade will spoon, interesting. umm ah dont worry about im kinda retarded and just wanted to know a few things thanks

G"UNIT

damn couldnt get it out fast enough.. everyone done anwsered ur question

zad5

the more the ideas the better..

1316130057

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 99B16Si &raquo;</TD></TR><TR><TD CLASS="quote"> if you blow on the blades of a ball bearing turbo it will usually spin. do u think that air is pressurized???</TD></TR></TABLE>

Actually the air in the turbine housing is pressurized. It's usually about 40% of the psi on the cold side. No joke.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">OT: but can someone explain, why a car needs to be under load in order to boost?</TD></TR></TABLE>

It dosen't. Your car could hypothetically be in boost at idle. As a matter of fact, I remember the first day I got my WRX (what a joke that POS was) I was sitting in the gas station parking lot and revving it and watching it climb up to 1psi. Also consider that the average turbo can't ingest enough CFM while sitting till to really build much pressure. Compare this to rolling along the highway and revving the car, and you WILL see boost at the gauge while the car is in neutral and coasting.

Finally..the timing maps while in gear are actually designed to make power and inherently spool a turbo. The timing maps out of gear are not. This will ultimately have a massive effect on how much boost you'll make.

MachAF

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1316130057 &raquo;</TD></TR><TR><TD CLASS="quote">
It dosen't. Your car could hypothetically be in boost at idle. As a matter of fact, I remember the first day I got my WRX (what a joke that POS was) I was sitting in the gas station parking lot and revving it and watching it climb up to 1psi. Also consider that the average turbo can't ingest enough CFM while sitting till to really build much pressure. Compare this to rolling along the highway and revving the car, and you WILL see boost at the gauge while the car is in neutral and coasting.

Finally..the timing maps while in gear are actually designed to make power and inherently spool a turbo. The timing maps out of gear are not. This will ultimately have a massive effect on how much boost you'll make.
</TD></TR></TABLE>

Whether the car is sitting still or moving has no affect on how much air the turbo it can ingest.

Timing is controlled by the ECU which gets its information from engine load and engine rpm. There isn't a in gear map and an out of gear map. Reving the engine in neutral provides no load, this is why the turbo is not fully spooled.

1316130057

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MachAF &raquo;</TD></TR><TR><TD CLASS="quote">

Timing is controlled by the ECU which gets its information from engine load and engine rpm. There isn't a in gear map and an out of gear map. Reving the engine in neutral provides no load, this is why the turbo is not fully spooled.</TD></TR></TABLE>

Lemme rephrase: The timing map is vehicle speed based, much like a speed limiter is. When no vehicle speed is sensed the timing is considerably mild.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">Reving the engine in neutral provides no load, this is why the turbo is not fully spooled.</TD></TR></TABLE>

So what do you see as the reason for load being the deciding factor??

EE_Chris

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1316130057 &raquo;</TD></TR><TR><TD CLASS="quote">Lemme rephrase: The timing map is vehicle speed based, much like a speed limiter is. When no vehicle speed is sensed the timing is considerably mild.</TD></TR></TABLE>

Speed-Density fuel and timing maps are referenced by MAP and RPM inputs. They are then modified by the other sensor inputs. Is this a particular standalone you have dealt with that uses the VSS to determine timing?

Honda-Pilot

When on the 2 step rev limiter I can build 13lbs of boost standing still. This is because the throttle plate is all the way open for a longer period of time. When you blip the throttle it doesn't allow enough airflow to spool the turbo well enough.

When running down the quarter mile I can build 25lbs of boost because of the long duration the throttle plate is open AND the dynamic compression which creates heat is higher.

There are other factors more minor not mentioned.

I hope this helps.

oscarmayer

maybe you shoudl EXPLAIN what your trying to accomplish???

zad5

basically i need the input shaft to spin less then 9k which should be really easy to do rite because it spins at insane speeds 125k-200k rite what im trying to do is a big *** secret it some stunt that wont even work im trying to do a project that will most likely take more then 10 years just starting it soon thanks for all the info. id rather not get into wut im doing but any info is greatly apreciated

1316130057

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EE_Chris &raquo;</TD></TR><TR><TD CLASS="quote">

Speed-Density fuel and timing maps are referenced by MAP and RPM inputs. They are then modified by the other sensor inputs. Is this a particular standalone you have dealt with that uses the VSS to determine timing?</TD></TR></TABLE>

Stand alones (like Motecs since the early M40's and Pectel T6's) and stock ECU's alike. If you contend that this is not true, then how do you propose that drag-style antilag systems function? They retard timing so far that you run small amounts of throttle and have your rotational idle take care of the rest. Fuel combusts in the manifold and the turbo spools. They're activated (in most cases anyway) with a switch that tells the ECU "how to idle" so to speak. Wouldn't work while in gear (if you were powerbraking for example) because there are seperate maps for each.

That brings up another point. Most stock ECU's in the world don't have an antilag on/off switch and certainly don't have rotational idle capabilities already programmed in. If it did, we'd all be launching at (insert your desired psi here) amounts of boost and people would swear we all had big block's under our hoods.

1316130057

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Honda-Pilot &raquo;</TD></TR><TR><TD CLASS="quote">When on the 2 step rev limiter I can build 13lbs of boost standing still. This is because the throttle plate is all the way open for a longer period of time. When you blip the throttle it doesn't allow enough airflow to spool the turbo well enough.

When running down the quarter mile I can build 25lbs of boost because of the long duration the throttle plate is open AND the dynamic compression which creates heat is higher.

There are other factors more minor not mentioned.

I hope this helps.</TD></TR></TABLE>

Although this may be true (some standalones allow for timing and/or fuel alterations while out of gear) a stock car with a turbo kit attached even if held at WOT will not see considerable boost.