Plenum questions - ZR-1 Net Registry Forums

VetteMed · 01-04-2010

I picked up a spare plenum many months ago, and haven't really looked at until today. It is identical to the plenum in my '91, with the exception of 2 holes - one on each underside of the runner pairs, for the 2 passenger side rearmost cylinders. It is smooth, about 3/8" diameter. Any idea what this might have been for? Also, how far up do the "walls" between the runners normally go, from the mating surface for the injector housings?

01-04-2010

Pictures?

Runner wall goes up maybe 1.5" into the port.

VetteMed · 01-04-2010

Pics:

GOLDCYLON · 01-04-2010

Pre production test Plenum?

01-04-2010

Extremely raw casting, as the mating surfaces have not been machined. I would not figure those to be casting holes, but they are unfinished. A drill would have left a nice smooth surface.

tccrab · 01-04-2010

Seems to have imperfections on the bottom left side.
Might just be shadows, but kinda looks like a dent above the A and another just to the left of the 4.
My guess would be that it's a prototype with holes for special sensors (can't imagine why) or a failed casting that didn't get thrown away.

The holes are too far up the runners for "NOS" nozzles, but it would be a cool way to hide 'em away from prying eyes...

TomC
'Crabs

billybaloneey · 01-05-2010

Quote:

Originally Posted by VetteMed

Pics:

Re: Plenum questions
Somebody started to drill for 'Fogger' nozzles, I'm guessing. Only thing that makes sense.
__________________
1976 Stingray,RED on RED/1990 ZR-1, Bright RED on RED,1706,factory stock/1993 ZR-1,Ruby Red,283, factory stock/1995 ZR-1, Torch RED on RED,116, factory stock

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That hole looks like it was cast...not drilled.

VetteMed · 01-06-2010

Quote:

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That hole looks like it was cast...not drilled.

That's what I thought.

bdw18_123 · 01-06-2010

Quote:

Originally Posted by billybaloneey

That hole looks like it was cast...not drilled.

Or it was drilled first, and then had the crap sandblasted out of it which made it look like a cast hole.

A26B · 01-04-2010

I think its a used plenum that has had the crap sand-blasted out of it. A raw casting wouldn't make the coolant & vacuum tubes look like that too.

01-04-2010	#1
VetteMed Join Date: Mar 2009 Location: Orlando, FL Posts: 1,816	Plenum questions I picked up a spare plenum many months ago, and haven't really looked at until today. It is identical to the plenum in my '91, with the exception of 2 holes - one on each underside of the runner pairs, for the 2 passenger side rearmost cylinders. It is smooth, about 3/8" diameter. Any idea what this might have been for? Also, how far up do the "walls" between the runners normally go, from the mating surface for the injector housings?

01-04-2010	#2
Jeffvette Guest Posts: n/a	Re: Plenum questions Pictures? Runner wall goes up maybe 1.5" into the port.

01-04-2010	#3
VetteMed Join Date: Mar 2009 Location: Orlando, FL Posts: 1,816	Re: Plenum questions Pics:

01-04-2010	#4
GOLDCYLON Join Date: May 2007 Location: Peoria, AZ Posts: 9,120	Re: Plenum questions Pre production test Plenum? __________________ GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V

01-04-2010	#5
Jeffvette Guest Posts: n/a	Re: Plenum questions Extremely raw casting, as the mating surfaces have not been machined. I would not figure those to be casting holes, but they are unfinished. A drill would have left a nice smooth surface.

01-04-2010	#6
tccrab Join Date: Oct 2004 Location: Folsom CA Posts: 1,657	Re: Plenum questions Seems to have imperfections on the bottom left side. Might just be shadows, but kinda looks like a dent above the A and another just to the left of the 4. My guess would be that it's a prototype with holes for special sensors (can't imagine why) or a failed casting that didn't get thrown away. The holes are too far up the runners for "NOS" nozzles, but it would be a cool way to hide 'em away from prying eyes... TomC 'Crabs Last edited by tccrab; 01-04-2010 at 10:18 PM.

01-04-2010	#10
A26B Join Date: Dec 2003 Location: Arcadia, OK Posts: 3,394	Re: Plenum questions I think its a used plenum that has had the crap sand-blasted out of it. A raw casting wouldn't make the coolant & vacuum tubes look like that too. __________________ 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.