GM Map sensor for 15lbs boost

[Dave Morrill]

Steve,
	Thanks for the reply.  We should def. compare notes.  I too am running
NHRA (have been the past 2 seasons at Oxford ME and New England Dragway
in NH.)

	Would love to get that 30lb MAP sensor number from you.  We've been
running carbs with added power jets to increase fuel for boost, and it's
been a nightmare, thus EFI.  I've lean burned down twice, and a 3rd time
via detonation.  Learn from me, you absolutely MUST run 116 octane fuel
at all times if you run more than 8lbs boost.  Also, spend the 75 bucks
to ceramic coat your pistons, another absolute must have if you don't
like swapping pistons with holes in them.  Other MUST haves are EGT
sensors in each pipe, a good boost/vacuum gauge, and fuel pressure
guage.  For me burn down occurs at 1250 degrees, with ceramic I've been
over 1400 with no damage.  

	At the time I started the turbo project, Aerocharger had not come out
with a turbo large enough for a ZRT800 at 8400rpm.  I'm using a
mitsubishi TE04H with custom oiling system.  I've run up to 15lbs boost
no prob, but the fuel system is so finicky right now I cant run there
for long.  I custom build the exhaust and intake manifolds, and am
running the stock pipes.

	I am building a closed loop system with feedback originally based on
EGT sensors.  They are exposed tip K type thermocouples from OMEGA. 
I've decided to add MAP for coarse adjust, and use EGT as a secondary
feedback for safety.  

I've build a Pulse width modulation circuit that runs at about 150hz, or
period of 6.8ms.  I can adjust the duty cycle of the injectors from
.45ms to 6ms, based on an input voltage of 0-8.3V which will allow one
injection cycle per revolution at 9000 rpm or so..  I am building the
EGT interface now, and as soon as I choose a MAP sensor I will combine
the two with a summing amplifier.

Questions
1.	Are you removing your carbs completely, or just piggy packing the EFI
on top of these?  

2.   	What type/where are you getting your injectors and bosses/throttle
bodies?  

3.	Have you done the VE airflow calcs yet?  I have some data on this
from when I sized the turbo. what size injectors you've selected.

4.	What size injectors you've selected (lb/hr)?
	
Also, If your keeping your carbs, throw away that junk fuel pressure
system (red dome/ gold dome) Aerocharger gives you and get a boost
controlled regulator from CB Performance in Californa (they sell VW hop
up parts).
	
	Your project is well worth the effort, when the boost comes up it is
awesome!!!

Lets talk further,
		Dave.

sorry about the double mailing, wanted to be sure you got this.


Steve Leonard wrote:
> 
> Dave,
>    I don't the part number here with me, it's at the
> shop. But I get it later today. GM has 2-bar(15psi
> boost) and 3-bar(30psi boost)sensors. Have to to be
> careful with choosing the sensor you want. The 2-bar
> sensor is only trust worthy upto about 10 psi
> where as the 3-bar is good upto about 20psi (boost)
> in actual applications. So be careful in your
> selection.
>    Turboing a snowmobile? We should compare notes. I
> am
> working on a 1998 Ski-Doo Mach Z, 800cc three
> cylinder.
> We are turboing this unit also, We are installing an
> AeroCharger Turbocharger, with MAP controlled fuel
> injection. We are setting it up to run in the NHRA
> asphalt drag racing class.
>                               regards,
> 
>                             Steve Leonard
> 
> ---Dave Morrill <dmorrill at gore.nsc.com> wrote:
> >
> > Hello,
> >       I took a quick look through the archives and found
> nothing.  I'm
> > looking for a GM style MAP sensor that can respond
> to up to 15lbs of
> > boost.
> >
> > I'm in mid design of an analog piggyback EFI system
> for my turbocharged
> > snowmobile.  I am using exhaust gas temp to control
> pulse width and have
> > decided that I want MAP also to help fine tune the
> pulse width.  The PWM
> > circuit is test and complete.
> >
> >
> > thanks,
> >       Dave.
> >
> 
> _____________________________________________________________________
> Sent by RocketMail. Get your free e-mail at http://www.rocketmail.com