[Diy_efi] New to list, have a question about speed density and turbos

[A6intruder]

Why is speed density any better?  I would think particularly in your case, a
properly sized MAF before the turbo would simplify your computations.  You
would have accurate info on what is going into the turbo and only have to
correct for air charge temp after the turbo.

Speed density could be a lower parts count.  If you use a multi-bar MAP
sensor you could have 100% power at 21 psi boost or where ever you set it on
your custom ECU.

Just my initial thoughts.

Daniel R. Nicoson
Equipment Exchange Company
Phone:  (814) 774-0888
Fax:      (814) 774-0880

-----Original Message-----
From: diy_efi-admin at diy-efi.org [mailto:diy_efi-admin at diy-efi.org]On Behalf
Of Startled Jackrabbit
Sent: Tuesday, October 22, 2002 8:54 PM
To: diy_efi at diy-efi.org
Subject: [Diy_efi] New to list, have a question about speed density and
turbos

Hi everyone!

This is my first post to this list, and I've only just
recently become very interested in EFI.  I'm
considering building a setup to replace my current ECU
(I have a '90 Talon Tsi AWD).  I will probably base it
off of an Atmel AVR.

Anyway, my car is turbocharged and is equipped with a
Karman vortex type mass airflow sensor.  From what
I've read, speed density is a better set up overall,
especially for turbos, and I would like to use it in
my design.  I am fairly knowledgable about how both
systems work.

My question is this:
My car can reach full boost before I am at full
throttle, IE, I might reach it at 80% throttle.  The
ECU will think that this is the maximum airflow,
although I know much more will enter the engine at
100% but the pressure will not increase, thus I will
lean out.  What is the best way to compensate for
this?  I would prefer to be able to do this without
needing a wideband O2 sensor.
Should I just use an acceleration enrichment table
that is active above a certain boost level and
correlate it with throttle position and tune it with
my EGT gauge?  That would be tedious but doable.  Is
there a better way (calculations are nice...)?

Thanks in advance!

Over and out,
JeremyB.





__________________________________________________
Do you Yahoo!?
Y! Web Hosting - Let the expert host your web site
http://webhosting.yahoo.com/

_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi


_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi