ZR-1 Net Registry Forums  

Go Back   ZR-1 Net Registry Forums > C4 ZR-1 > C4 ZR-1 Technical Postings

Reply
 
Thread Tools Display Modes
Old 07-28-2020   #1
Paul Workman
 
Paul Workman's Avatar
 
Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,493
Default Update: Secondary delete: Decel stall on 2ndary delete

A work in progress...

Some experience occasional stalls on deceleration (engine braking) from @ or slightly above 3k rpm in certain conditions.

One theory is a faster action sensor may be the answer; perhaps the NTK (A8D1B1 21003 from Rock Auto).

Well, they're cheap enough, so I installed a pair of them and put the Z through several ~3500ish to ≈ 1200 rpm decels and experienced NO stalls. Encouraging, but too soon to declare success, just yet. ("One example does not a trend make!")

In my case, the issue gets worse with altitude; e.g., happens more frequently as the height above sea level increases.

It's been said that the issue stems from the SPT being eliminated results in too much air getting in and upsetting the mixture on decel. Yeah-but...I ain't so sure 'bout that! After all, it's the throttle body controlling the amount of air flow - not the SPTs. And, it only happens on decel/engine braking from higher than normal driving rpm.

Well, it is an intriguing quirk, and I'll leave it to the experts to solve. It isn't a big deal except when aggressively romping at higher altitudes especially. But, it would be nice if there was a solution...and initial results with the NTKs IS encouraging!
Attached Images
File Type: jpg NKT (2).jpg (132.7 KB, 26 views)
File Type: jpg NKT .jpg (68.1 KB, 25 views)
__________________
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; 07-30-2020 at 07:30 AM.
Paul Workman is offline   Reply With Quote
Old 07-29-2020   #2
-=Jeff=-
 
-=Jeff=-'s Avatar
 
Join Date: Jul 2007
Location: Bartlett, IL
Posts: 7,164
Default Re: Update: Secondary delete: Decel stall on 2ndary delete

RockAuto PN to look up is 21003. it shows to be for the 90-95 Corvette as well
__________________
1990 Corvette ZR-1 #1051
Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback
Late Model IH - Plenum
Coilovers - 4.10s
Custom Interior
NCM Lifetime Member #978
-=Jeff=- is offline   Reply With Quote
Old 07-29-2020   #3
Jagdpanzer
 
Jagdpanzer's Avatar
 
Join Date: Apr 2007
Location: Northern VA
Posts: 2,659
Default Re: Update: Secondary delete: Decel stall on 2ndary delete

According to the NTK web site 21003 are for the ZR-1 DOHC engine and the 21006 are for the base OHV engine.

https://partcat.com/ngk


Sent from my iPhone using ZR-1 Net Registry
__________________
Phil Wasinger
1994 Torch Red ZR-1
WAZOO Member
George Braml Intake
Jagdpanzer is offline   Reply With Quote
Old 07-30-2020   #4
Ccmano
 
Ccmano's Avatar
 
Join Date: Jun 2006
Location: Sparks, NV
Posts: 2,852
Default Re: Update: Secondary delete: Decel stall on 2ndary delete

It's the tune. Mine was doing that and a hesitation at times until Dom and I tuned it out. Smooth as silk now.
H
__________________
90'ZR-1 #1461 Red/Black
Ported Intake, Degreed Cams, OBX Headers & Exhaust, Fidanza FW, Secondary Delete, Custom tune, C6 GS Wheels. Sold
08 C6 Z51 Crystal Red Metallic Sold Vararam Intake, Tune, Sold
05 C6 Z51 Red/Black Sold
90'ZR-1 #1723 Black/Gray Sold but not forgotten
91' Z51 L98 White Vert. My First, you always remember your first. Sold.
Ccmano is offline   Reply With Quote
Old 07-30-2020   #5
-=Jeff=-
 
-=Jeff=-'s Avatar
 
Join Date: Jul 2007
Location: Bartlett, IL
Posts: 7,164
Default Re: Update: Secondary delete: Decel stall on 2ndary delete

Quote:
Originally Posted by Ccmano View Post
It's the tune. Mine was doing that and a hesitation at times until Dom and I tuned it out. Smooth as silk now.
H
what was done to tune it out?
__________________
1990 Corvette ZR-1 #1051
Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback
Late Model IH - Plenum
Coilovers - 4.10s
Custom Interior
NCM Lifetime Member #978
-=Jeff=- is offline   Reply With Quote
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 05:46 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright ZR-1 Net Registry 2020