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06-22-2018
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#11 |
 Join Date: May 2007
Location: Addison IL
Posts: 250
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Re: Plenum & Injector Housing Porting
Mercury Marine corrected the port mismatch problem in '93. It was part of the 405 hp upgrade. They CNC blended the injector housing ports 1.5" down the port. They also increased the plenum port diameter from 33 to 34 mm. That's why porting an early engine well will add 35 hp. Only 20 hp can be gained on the '93 and up engines.
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06-22-2018
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#12 |
 Join Date: Aug 2015
Location: Magnolia, Texas
Posts: 884
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Re: Plenum & Injector Housing Porting
Here's a couple of pictures to illustrate.. note that using the gasket as a reference, the head ports are concentric, while the injector housing ports are shifted, dramatically on the primary runners..[ATTACH][ATTACH]
Sent from my XT1585 using ZR-1 Net Registry mobile app |
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06-22-2018
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#13 |
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Join Date: Aug 2015
Location: Magnolia, Texas
Posts: 884
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Re: Plenum & Injector Housing Porting
As point of reference, these are the original injector housings from this engine..
Sent from my XT1585 using ZR-1 Net Registry mobile app |
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06-22-2018
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#14 |
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Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,709
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Re: Plenum & Injector Housing Porting
Steve,
One thing I did when I first ported the top end is to use a double fluted burr (I think that’s what its called) and then I finished things off by bolting everything together and using a 38mm ball hone to smooth out the transition.
__________________
[SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX |
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06-22-2018
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#15 |
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Join Date: Aug 2015
Location: Magnolia, Texas
Posts: 884
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Re: Plenum & Injector Housing Porting
Thanks Dominic.. I'm using three different burrs depending on where I am in the runner.
I need to know if this is sufficient removal of the primary injector boss.. hesitant to get deeper, but certainly still have room.. Yes, I touched the face with a burr! Very, very minor.. [ATTACH][ATTACH] Sent from my XT1585 using ZR-1 Net Registry mobile app Last edited by jss06c6; 06-22-2018 at 05:22 PM. |
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06-22-2018
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#16 |
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Join Date: Aug 2015
Location: Magnolia, Texas
Posts: 884
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Re: Plenum & Injector Housing Porting
Took a bit more off.. better transition now..
Sent from my XT1585 using ZR-1 Net Registry mobile app |
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06-22-2018
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#17 |
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Join Date: Aug 2015
Location: Magnolia, Texas
Posts: 884
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Re: Plenum & Injector Housing Porting
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06-22-2018
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#18 |
Join Date: Jul 2017
Location: West Chester, PA
Posts: 378
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Re: Plenum & Injector Housing Porting
Just had my original injectors replaced, 4 of them are no good. Happy to donate a couple to the cause.
Sent from my SM-N920V using Tapatalk
__________________
1990 Black/Black ZR-1 #1155 1993 White/Red coupe (Regrettably sold) 
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06-22-2018
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#19 | |
 
Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,493
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Re: Plenum & Injector Housing Porting
Quote:
More later...
__________________
Good carz, good food, good friendz = the best of timez! 90 #1202 "FBI" top end ported & relieved Cam timing by "Pete the Greek" Sans secondaries Chip & dyno tuning by Haibeck Automotive SW headers, X-pipe, MF muffs Former Secretary, ZR-1 Net Registry |
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06-22-2018
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#20 | |
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Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,709
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Re: Plenum & Injector Housing Porting
Quote:
__________________
[SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX |
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