Reply With QuoteExcuse my ignorance but I thought it happened at a certain rev range not throttle position.
2 Grand Master
A turbo question, does boost only occur at WOT?
Does an engine only produce boost at wide open throttle or does it occur at part open throttle also? Corky Bell (Maximum Boost), p9 thinks the former.
I was thinking the latter but I'm unsure.
Grand Master
Excuse my ignorance but I thought it happened at a certain rev range not throttle position.
Cheers
Wingman
'89 525i/A Exec 193000kms
'94 Subaru Liberty AWD Wagon
Looking for Merc 300TE
NSW, Australia
Don't have to be WOT to produce boost... unless maybe you have an insanely enormous turbo. Case in point... listen to any SRT-4 owner when they're backing out of a parking space... tiny turbo=that car is boosting under light throttle at about 2krpm's. Boost will be created if there is enough exhaust being created by the engine (with enough force) going through the turbo to spool it up...
I'm no F/I expert by any means but that is my take on it... F/I guys can tear me apart and correct me please.
Last edited by e34nication; 12-21-2005 at 05:06 AM.
5-10 Grand Master
that about covers it
Originally Posted by e34nication
all america wants is cold beer warm cat and a place to take a poop with a door on it
Super Moderator
Corky Bell is correct, you're only going to produce useable boost when the
throttle is open far enough and the rpm's are high enough to spin the turbo up to the point at which it will produce useable boost. Part throttle openings as he stated won't allow enough exhaust gas pressure and volume to spin the turbo up enough to produce useable boost. You gotta remember the engine is just a big air pump and if the throttle plate isn't open enough you can't pull enough air through.
Grand Master
boost, will occur whenever your exhaust can push the turbo to suck air in, and force it into your intake. so the amount of rpm it takes to make boost is entirely dependant on the size of the turbo, and the size of the engine
big engine, small turbo, boost will occur at low rmp, NOT WOT
small engine, big turbo, you might get closer to WOT to get boost.
Big, Big Time Poster
under pressure......................
Very true.......although there is a baseline of different displacement in which the cars "IDLE" draw of cfm's is X and then there is the number of Y which begins the pressure increase above X.
All turbos must spin in order to not be a full restriction during start up and idle of course.....but a boost signal or climb is recognised at the gauge/meter long before its felt and the electronics and fuel do their part.
Pardon any redundant statements here.......
Vinny
AC Schnitzer | S-5 | Stainless exhaust | Bodykit | wing| 3pc. wheels | badges | springs | mirrors | steerwheel |
Schwarz on Blk
Big Time Poster
All depends on the size and efficiency of the turbo, the size of the motor, he efficiency of the intake tract, the exhaust, and gearing.
On my Z with stock T-25 turbos, I can be cruising along on the highway in 5th gear, and if I breathe on the throttle, I'm in boost.
Grand Master
sounds nice
Big, Big Time Poster
This is why the new 530 Diesel has two turbos. A little one and a big one.
All the best
Bob
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