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#11 |
Join Date: Nov 2018
Location: Washington
Posts: 98
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Thanks guys. So I take it there are no videos or DVD's. I am sure I can figure it out with the info I have. Just thought it would be easier with more pictures.
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#12 |
![]() Join Date: Aug 2004
Location: Spring Grove ,Pa.
Posts: 254
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My car came with Marc's 510 package and the secondary delete. I have some questions about it. I was going to call and talk with Marc about it. I usually think of something later that I want to ask. Like how do the fuel pumps work? Normally the car would run on the primary pump until all the injectors come in play and the secondary pump comes on. So how do the pumps work when you are running on all 16 injectors all the time? How or what is done concerning the pumps?
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91 Turquoise Metallic Haibeck 525 #0134 |
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#13 | |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,696
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[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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#14 |
![]() ![]() Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,493
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That's what YOU think!
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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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#15 |
![]() ![]() Join Date: Aug 2009
Location: South Dakota/California
Posts: 3,791
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My Secondaries are in super shape and my FULL POWER switch is working fine.
I did replace all secondary vacuum system for $100. New Secondary Port Throttle Vacuum System Yes........that is what I think ![]() I think it is a bit foolish to eliminate one of the most unique and selectable and functional options for the LT5 (The Full Power switch on the console)..... And just because you do not want to do a simple fix but rather do a more complex "fix" eliminating the secondaries ![]()
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Left Clickable links ![]() -Solutions- LT5 Modifications/Rebuild Tricks Low Mileage ZR-1 Restoration 1990 Corvette (L98) Modifications LT5 Eliminated Systems LT5 Added Systems LT5/ZR-1 Fluids 1995 LT5 SPECIFIC TOP END REBUILD TRICKS Last edited by Dynomite; 06-18-2020 at 02:58 PM. |
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#16 |
![]() Join Date: Aug 2004
Location: Spring Grove ,Pa.
Posts: 254
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Xfire, thank you I wondered if anything was changed with the delete. I read Marc's article about going with a single pump if your sending unit is in bad condition. I saw a nice reconditioned ZR1 sending unit recently on eBay for around $475.
https://www.ebay.com/itm/90-95-ZR-1C...0/264751696997
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91 Turquoise Metallic Haibeck 525 #0134 |
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#17 |
![]() Join Date: Jul 2007
Location: Bartlett, IL
Posts: 7,153
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No, I know they work fine. They will work fine until they don?t work fine
Same with my fuel pumps
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1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978 |
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#18 |
![]() Join Date: Jun 2005
Location: CenCoast California
Posts: 899
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With a 350, I've never been a fan of deleting the secondary port throttles because it degrades dirivatility and decreases torque output on the low end.
During the 20 years I owned Barney, my purple '95, the two times I had trouble with the SPTs, I repaired them rather than eliminated them. For a 368...maybe, bigger than that, yeah, I'd get rid of them along with appropriate cal changes.
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Hib Halverson Technical Writer former owner 95 VIN 0140 current owner 19 VIN 1878 |
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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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Couple of things from 11 years and counting, driving w/o SPTs...
Drivability:
Far as the intact SPTs vs. secondary delete practice goes, for the more aggressively ported 350 cid or one with 368+ cid, I have no primary/secondary comparison data to share. That said tho, apart from this "delete" discussion, I do have the stock LT5 and (aggressively) ported "before and after" (Dynojet) data on my 350 cid LT5. The pick-up in torque at WOT in the "after" scenario clearly mitigates or negates entirely the ever smaller (below 4000 rpm) torque advantage present in the NORMAL switched position. All in all tho, aside from the unnecessary complexity of the SPTs AND the uniqueness OR "NCRSness" AND the advantages of deleting the SPTs, you'll have to decide. My wife's ZR-1 does not have SPTs, but is not ported to the point where reinstalling them wouldn't be practical if someone wanted to do so. But, I like the reliability and drivability that having deleted the SPTs provide. So, I'd never consider reversing the delete procedure. Below is a Dynojet graph of an LT5 slightly modified by Lingenfelter (specific mods unknown). From this graph one can get an idea of the differences between the NORMAL and FULL ENGINE POWER settings. Also I included the "before and after" graph results of an Excel spreadsheet showing the FULL ENGINE POWER plots for rear wheel torque for my ZR-1 in stock and fully ported configurations. ![]()
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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 Last edited by Paul Workman; 06-23-2020 at 11:55 AM. |
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#20 |
Join Date: Nov 2018
Location: Washington
Posts: 98
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I removed the plenum yesterday and replaced all the injectors along with Jerry's improved fuel pressure regulator. All the secondary vacuum lines, reservoir, solenoid, actuators, etc. were also removed. I am going to wire the secondary linkage open after I determine the best way to do it. Any suggestions there? I was figuring to wire or use plastic ties to tie the linkage lever to the original canister mounting bracket. Is that how you guys have done it? I will reinstall the plenum today while waiting for my recalibrated prom from Marc which will be here tomorrow.
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