Batch fire TPI question
Thread Starter
Instructor
Joined: Jul 2007
Posts: 181
Likes: 0
From: Boise ID
Batch fire TPI question
On a batch fire system 4 injectors fire at the same time right. If that's the case what does the fuel do once it's been shot or injected? does it sit in the runners? Or does is it still suspended in air because the event happens so quickly? I have always wondered about this because the ignition doesn't batch fire so what does the fuel do while it's waiting to be drawn in it seems to me that this would not be very efficiant. Do all EFI systems do this or just TPI? could a person put a delay on the injectors for the cylinders that are not quite ready for fuel and gain performance through efficiancy?
Burning Brakes
Joined: Aug 2006
Posts: 1,061
Likes: 99
From: Seattle WA
I think all TPI's were batch fire as well as the first LTx. Later in the LTx production (95?), they went to sequential fire. It's not a big deal because the fuel is in vapor form. Under certain circumstances, the fuel can condense out and puddle (really cold engine with cold-start enrichment), but in normal operation you shouldn't see this happening.
The bigger benefit of sequential-fire is more control over individual cylinder mixture rather than the fuel timing itself.
The bigger benefit of sequential-fire is more control over individual cylinder mixture rather than the fuel timing itself.
Melting Slicks
Joined: Feb 2006
Posts: 2,753
Likes: 15
From: backwoods upstate ny
we have used CONSTANT flow injectors (hilborn, algon, kinsler,etc) on drag and circle track racing engines for many years with NO electronics...top end performance is great, idle is ok...for emissions, a true ''sequential'' system helps at ''idle'',batch flow is a ''half measure'' at reduced complexity/cost/emission reduction.
Pro
Joined: May 2006
Posts: 583
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From: Pittsburgh PA
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From: Covington GA
Team Owner
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From: sw Ohio
Le Mans Master
Joined: Feb 2006
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From: Louisiana
Read the sticky's
Fuel Injection Definitions
Tuned Port refers to the L98 setup. It alludes to the long runners of the intake manifold.
Sequential Injection fires an injector in time with the spark plug.
Batch fire is when all 4 injectors on one side fire at the same time, followed by the other side.
The advantage to batch is at high rpm operation - ie, racing.
The advantage to SFI is all other times... better MPG, better idle, better drivability, and better tunability.
Tuned Port refers to the L98 setup. It alludes to the long runners of the intake manifold.
Sequential Injection fires an injector in time with the spark plug.
Batch fire is when all 4 injectors on one side fire at the same time, followed by the other side.
The advantage to batch is at high rpm operation - ie, racing.
The advantage to SFI is all other times... better MPG, better idle, better drivability, and better tunability.
Former Vendor
Joined: Nov 2006
Posts: 2,482
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From: Carmichael ca
. Still its the most fun you can have with you Corvette
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