Snap, Crackle and Pop
Thread Starter
Staging Lane
Joined: Jan 2018
Posts: 57
Likes: 8
From: Ottawa, Ontario
Snap, Crackle and Pop Hello Forum Members. I have a question that I hope you can help with ...
2000 Corvette with M6 transmission.
First round of mods included Vararam CAI, XSPower LT headers with high flow cats and x-pipe, Corsa eXtreme axle back, LS6 intake and a street tune using HPTuners. On deceleration (closed throttle) the motor made a wonderful (I loved it anyway) popping, snapping and crackle. Made the car really fun to drive. Most entertaining ...
Second round of mods added a cam 228/232 .613 .601 111+3, 243 casting heads (not ported), Cometic 0.040" head gasket, 36 lbs injectors, new timing chain, oil pump, harmonic balancer and a retune on the street (same tuner). Car pulls strong, has a few drivability issues yet to be resolved (hot start won't stay running without throttle and hunts for idle for 30 secs, some surging up to 1700 rpm, cold start hanging idle) but the sad part is all the snap, crackle and pop is gone!
Question 1: Can I expect the tuner to be able to mostly resolve the drivability issues listed?
Question 2: Is there a way to restore the snap, crackle and pop? I really miss this part of the driving experience.
Thanks for your help!
2000 Corvette with M6 transmission.
First round of mods included Vararam CAI, XSPower LT headers with high flow cats and x-pipe, Corsa eXtreme axle back, LS6 intake and a street tune using HPTuners. On deceleration (closed throttle) the motor made a wonderful (I loved it anyway) popping, snapping and crackle. Made the car really fun to drive. Most entertaining ...
Second round of mods added a cam 228/232 .613 .601 111+3, 243 casting heads (not ported), Cometic 0.040" head gasket, 36 lbs injectors, new timing chain, oil pump, harmonic balancer and a retune on the street (same tuner). Car pulls strong, has a few drivability issues yet to be resolved (hot start won't stay running without throttle and hunts for idle for 30 secs, some surging up to 1700 rpm, cold start hanging idle) but the sad part is all the snap, crackle and pop is gone!
Question 1: Can I expect the tuner to be able to mostly resolve the drivability issues listed?
Question 2: Is there a way to restore the snap, crackle and pop? I really miss this part of the driving experience.
Thanks for your help!
It's possible that your tuner turned of DFCO.
If you could post a copy of the tune, we could check it to see what was done. DFCO will make the engine very lean on deceleration and cause that "snap, crackle, pop" as you put it sound. Also, since you changed the cam, your VE table, and possibly your MAF, table, are off.
Your other cold start, hanging idle, issues need to be fixed in the tune. These are signs that the two tables I mentioned are incorrect, in addition to many of the idle tables such as proportional, EOIT, RAF, and several others. Most importantly here is that you changed injector sizes. Before you do anything else, you, or your tuner, needs to verify that the correct injector data is in the tune. Don't try to change, or modify, any other tables until the injector data is correct.
If you could post a copy of the tune, we could check it to see what was done. DFCO will make the engine very lean on deceleration and cause that "snap, crackle, pop" as you put it sound. Also, since you changed the cam, your VE table, and possibly your MAF, table, are off.
Your other cold start, hanging idle, issues need to be fixed in the tune. These are signs that the two tables I mentioned are incorrect, in addition to many of the idle tables such as proportional, EOIT, RAF, and several others. Most importantly here is that you changed injector sizes. Before you do anything else, you, or your tuner, needs to verify that the correct injector data is in the tune. Don't try to change, or modify, any other tables until the injector data is correct.
Thread Starter
Staging Lane
Joined: Jan 2018
Posts: 57
Likes: 8
From: Ottawa, Ontario
Thank you for replying. The injectors are Ford Racing 30 lbs Red Top (FRPP M-9593-BB302, Bosch PN 0280155759) which are rated at 36 lb when run at 59 psi. At WOT they are at 79% duty cycle. I purchased these injectors before learning how difficult it is to get accurate injector data. I did get an old (2009) baseline data set on this forum from Calibrated Success Inc. (CSI) that was good enough for the car to run. My tuner says resolving the issues may be impossible without better injector data, so I am hoping to find something better. If that is not working I might be forced to buy different injectors. If anyone out there can help with injector data it would be appreciated! I will ask my tuner for the file as it stands right now. Thanks again for your help.
Bad injector data = bad tune every time.
You can spend a lot of time and money chasing odd drivability problems in your tune when you have bad injector data.
My suggestion is either find complete data for the injectors you have in the format you need or buy known good injectors that come with solid data.
You can spend a lot of time and money chasing odd drivability problems in your tune when you have bad injector data.
My suggestion is either find complete data for the injectors you have in the format you need or buy known good injectors that come with solid data.
