i am doing a secondary delete tomarrow for.... - Page 2 - ZR-1 Net Registry Forums

GOLDCYLON · 04-25-2011

Quote:

Originally Posted by VetteMed

First time around I had some lean codes, even with the Haibeck chip. However, those disappeared after new FIC injectors and new fuel pumps were installed. Not a peep out of the ECM since then

Andrew

Cool. Lean codes? Now thats a Hoot. Would not be codes I would expect

VetteMed · 04-25-2011

Quote:

Originally Posted by GOLDCYLON

Cool. Lean codes? Now thats a Hoot. Would not be codes I would expect

Well, think about it - you're doubling the airflow to each cylinder - if fuel delivery is not up to par, due to a clogged injector, low fuel pressure, etc, then the mixture will be lean. The Haibeck chip changes the injector programming so that both injectors fire any time the throttle is off idle, but obviously that's only as good as the quality of the injector performance, and fuel delivery to the injectors!

A26B · 04-25-2011

"Doubling the air flow" is not exactly accurate. Without the secondary throttle system operating, "impeding" or "restricting" is more accurate. An engine is essentially a positive displacement air pump. It's only going to take in so much air, directly proportional to the displacement. In operation, the secondary throttle system is like a supermax port job.

VetteMed · 04-25-2011

Quote:

Originally Posted by A26B

"Doubling the air flow" is not exactly accurate. Without the secondary throttle system operating, "impeding" or "restricting" is more accurate. An engine is essentially a positive displacement air pump. It's only going to take in so much air, directly proportional to the displacement. In operation, the secondary throttle system is like a supermax port job.

Jerry, perhaps in the interest of brevity I over-simplified. When the secondary system is either removed, or latched open, it's allowing all 16 intake runners to feed air to the cylinders. This is double the air compared to what is delivered when the secondary throttle plates are closed. If the secondary fuel injectors are not delivering fuel (due to faulty injectors, poor fuel pressure, or an ECM command to not fire), but the secondary throttle plates are open, there's bound to be a lean mixture.

In my situation, the immediate lean mixture led to a code being set, which then caused the ECM to completely disable the secondary injectors, while the throttle plates were still open (nonexistent).

I am not under any false illusion that simply removing the secondary system doubles the potential airflow through the secondary intake ports.

Hope this clarifies what I was getting at.

PhillipsLT5 · 04-25-2011

No secondaries here! Love it!
Ditto

Kevin · 04-25-2011

i really need to drive a no secondary car, and I don't mean romp on it type of drive, but just a cruise around town to see how it deals with every day driveablity

PhillipsLT5 · 04-25-2011

Hard to tell the difference with or without them except more power now and less junk in the way

XfireZ51 · 04-26-2011

Gentlemen,

The motor is going to use X amount of air and fuel at a given throttle opening. Simply activating the secondaries doesn't "make" the motor use more air/fuel. At part throttle cruise, the amount of air/fuel charge is going to be delivered either by one port and one injector OR split between two runners and two injectors. The fuel tables in the cal only deal with total VE at a given MAP, fuel delivered either by one or two injectors. Wth proper tuning, the difference in single or double runner cruising should be not very discernible especially if mods are done to move more air through the system(i.e. headers, freer exhaust)

VetteMed · 04-26-2011

Quote:

Originally Posted by XfireZ51

Gentlemen,

The motor is going to use X amount of air and fuel at a given throttle opening. Simply activating the secondaries doesn't "make" the motor use more air/fuel. At part throttle cruise, the amount of air/fuel charge is going to be delivered either by one port and one injector OR split between two runners and two injectors. The fuel tables in the cal only deal with total VE at a given MAP, fuel delivered either by one or two injectors. Wth proper tuning, the difference in single or double runner cruising should be not very discernible especially if mods are done to move more air through the system(i.e. headers, freer exhaust)

Agreed 100%, makes perfect sense.

sammy · 04-26-2011

guys first off thanx for all the responses/help. . this really was an easy job to do .we used aircraft wire to wire the secondaries open. we pulled all the vacum tubing and pieces . i also had to replace the starter motor as the dealership that he bought the steamed cleaned the motor before he too k delivery . it sure is one nice 90 the metalic rad paint with manual air and polished stk 90 wheels . the grin on his face was worth the 230 mile trip one way to help him . he was so frustrated he wanted to sell the car .but i told him our cars make us earn the right to own them and this was just a test.lol also told him his new mistress liked it rough, that the more you beat on her the happier she is . the look on his face was priceless

04-25-2011	#13
A26B Join Date: Dec 2003 Location: Arcadia,OK Posts: 3,394	Re: i am doing a secondary delete tomarrow for.... "Doubling the air flow" is not exactly accurate. Without the secondary throttle system operating, "impeding" or "restricting" is more accurate. An engine is essentially a positive displacement air pump. It's only going to take in so much air, directly proportional to the displacement. In operation, the secondary throttle system is like a supermax port job. __________________ Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 *ZR-1*, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed.

04-25-2011	#15
PhillipsLT5 Join Date: Aug 2005 Location: Scottsdale, AZ Posts: 2,452	Re: i am doing a secondary delete tomarrow for.... No secondaries here! Love it! Ditto

04-25-2011	#16
Kevin Join Date: Jun 2005 Location: pittsburgh Posts: 4,632	Re: i am doing a secondary delete tomarrow for.... i really need to drive a no secondary car, and I don't mean romp on it type of drive, but just a cruise around town to see how it deals with every day driveablity __________________ It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B"

04-25-2011	#17
PhillipsLT5 Join Date: Aug 2005 Location: Scottsdale, AZ Posts: 2,452	Re: i am doing a secondary delete tomarrow for.... Hard to tell the difference with or without them except more power now and less junk in the way

04-26-2011	#18
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,709	Re: i am doing a secondary delete tomarrow for.... Gentlemen, The motor is going to use X amount of air and fuel at a given throttle opening. Simply activating the secondaries doesn't "make" the motor use more air/fuel. At part throttle cruise, the amount of air/fuel charge is going to be delivered either by one port and one injector OR split between two runners and two injectors. The fuel tables in the cal only deal with total VE at a given MAP, fuel delivered either by one or two injectors. Wth proper tuning, the difference in single or double runner cruising should be not very discernible especially if mods are done to move more air through the system(i.e. headers, freer exhaust)

04-26-2011	#20
sammy Join Date: Jun 2010 Location: back in lone pine Posts: 591	Re: i am doing a secondary delete tomarrow for.... guys first off thanx for all the responses/help. . this really was an easy job to do .we used aircraft wire to wire the secondaries open. we pulled all the vacum tubing and pieces . i also had to replace the starter motor as the dealership that he bought the steamed cleaned the motor before he too k delivery . it sure is one nice 90 the metalic rad paint with manual air and polished stk 90 wheels . the grin on his face was worth the 230 mile trip one way to help him . he was so frustrated he wanted to sell the car .but i told him our cars make us earn the right to own them and this was just a test.lol also told him his new mistress liked it rough, that the more you beat on her the happier she is . the look on his face was priceless