Comparisons to various EFI systems?

filmjay

Well-Known Member
I'm looking around for EFI info..which there is a TON here.
But, I'd like to know if there was a breakdown of advantages/disadvantages to the various types of systems.

TPI? TBI? MPFI? SFI?

What kind of power is possible? mileage? reliability? ease of installation and maintenance? etc....

I'd like to go EFI on my budget build, but want a minimum of sensors and electronics if possible. I'm thinking TBI is probably gonna be my best bet.

Thanks! :)
 
ok IVE got so much info that could easily take a book, but heres the cliff notes version, you face both clearance issues and finding an intake designed to match the rpm range and flow rates necessary to meet your goals
Ive tested a bunch of IMPROVE TPI REPLACEMENT style intakes on my cars, one of the best is the ported HOLLEY STEALTH RAM, but theres CLEARANCE ISSUES on some cars as its 10" tall and a corvette for examole has only 9" of hood clearance so a CUSTOM PLENUM or a HOOD SCOOP is MANDATORY TO RUN ONE on a corvette for example !

viewtopic.php?f=69&t=433

http://www.eecis.udel.edu/~davis/z28/wi ... 21105.html

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viewtopic.php?f=55&t=60


TPI? good torque, good fuel control, slightly restricted air flow in the peak hp ranges

most of the factory intakes even the larger runner and base versions are a restriction to flow at between 4500rpm where the stock intakes basically quite and about 6000rpm where the best one
PDRM1966.JPG

the FIRST FUEL INJECTION INTAKE

http://www.firstfuelinjection.com/products.htm

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http://www.speedwaymotors.com/RHS-1...MIxaWg5tXZ1gIVA6ppCh09DgVzEAYYAiABEgINIfD_BwE


http://www.westcoastoffshore.ca/Fue...ke-Manifold-w-Fuel-Rails-12903-KIT-P5412.aspx

rhs_sbc.jpg


it states it comes with the fuel rails , it fits standard 23 degree heads and fits vortec heads ,
and at $514 thats not a bad deal,for a high fow single plane SBC intake



viewtopic.php?f=55&t=1052

http://ncarboni.home.att.net/NCtpi.html

TPI is designed for max low and mid rpm torque, not peak hp

TBI?...cheap, easy to install wet flow , in theory it beats a carb but generally its not as good as either MPFI or TPI in either low or peak hp,

basically a computer controller carb replacement, and like a carb fuel is mixed with airflow in the tbi venturies , but in theory with more precise control

http://store.summitracing.com/egnsearch ... toview=sku

http://store.summitracing.com/partdetai ... toview=sku

hly-950-24s_w.jpg



MPFI?

http://store.summitracing.com/partdetai ... toview=sku

hly-9102101_w.jpg


http://store.summitracing.com/partdetai ... toview=sku


hly-91504201_w.jpg


the advantage of MPFI is that the throttle body controls mostly air flow and the intake runners flow only air, the injectors generally spray a fine mist of fuel dirrectly into the heads intake port so they control the fuel distribution to a far greater extent than the wet flow TBI systems
SFI?

http://static.summitracing.com/global/i ... _60505.pdf


three types of fuel control

early systems were constant flow,

http://www.kinsler.com/page--Constant-Flow--14.html

http://www.hilborninjection.com/category.asp?Id=187

http://www.kinsler.com/page--EFI--4.html


fuel flow was controled by a pump responding to engine rpm and a bye-pass jet and fogger nozzels in each intake runner, this could only be efficient over a fairly narrow rpm range but once tuned correctly it produces excellent power in the intended rpm band
s281_large.jpg


BATCH FIRE MPFI, slightly lower cost than sequential fire,good mid and upper rpm power
then electronic controls were added with a o2 sensors and other sensors that traced air temp, coolant temp,air flow rates, vacume levels and oxygen content in the exhaust, but fired all 8 injectors , generally twice per crank rotation, the pulse duration controled by a cpu, reading the sensor input, this worked great on the mid and upper rpm ranges but left a good deal of wasted fuel at idle speeds
later systems fired 4 injectors in each bank alternately

sequential fire systems

http://www.hilborninjection.com/category.asp?Id=174
0307htp_holleystealth04_z.jpg


best responce, most efficient, decent hp, most expensive

as computers got faster sequential MPFI, ideally pulse durration and timing matched valve opening in the runners
 
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