Sti Would Exhaust Hitting the Diff Cause False Knock Reading
05-22-2007 #ane
Advanced Tuner
Will a restrictive exhaust cause knock
i was running 10psi with wot afr of xi.vii and was getting intermitent but rather constant knock from around 4400 to 5000 rpm usally i degree or so but i have seen every bit much as 3 degrees. today i droped heave down to 8psi and ready afr to 11.5 and im all the same getting knock of around 1-2 degrees at wot. IAT temps were around 37 degress c and commanded timing is eleven degress.
when i installed my dump pipes i had to crush a section of the pipes to clear the chasis rails (might have reduced pipe size past ane/four max) could this lower the knock threshold from increased dorsum force per unit area and not allow me to run equally much timing??
im running a full 2 ane/2in exhaust with high menses cats, pvc is blocked off and ive cleaned my manifold from all oilive looked at a few other 2bar tunes and people are running as much as 17 degres at wot!! Part of my exhaust is sometimes hit the body of the automobile so i guess that could be causing false knock and i will be fixing that this weekend simply i would like to hear your thoughts on dorsum pressure and timing
04 VY Commodore ute M6 ls1, 918 valve springs, TR6 plugs, genttrbb twin turbo kit, 60lb seimiens injectors, Bosh 044 fuel pump, SX fuel reg, PLX wideband,Total Castle Hill Exhaust with 2 1/2in dump pipes, 4in cats into twin 3in cat back (no merge), Ripshift, oz700 clutch and iii.73 unequal gears
05-23-2007 #vi
Advanced Tuner
thank you for the replys guys
here is some scans i did today
motorcar details:
internally stock ls1 with 918 valve springs
gentt twin turbo kit
M6 with three.46 diff gears
two 1/two high menses cats and catbackdump pipes are far from pinching in that location a nice oval shape like a daytona track
the driver side dump pipage is sometimes buzzing on the chassy rail espically at take off but im non registering whatever knock then so im not sure it it would causing false knock at pinnacle torque
Car even so pulls pretty hard and it dosnt experience like its trying hard to push the exhaust out, the turbos spool up apace and so i dont know if that whatever indication of backpressure?
Last edited by sikhabib; 05-23-2007 at 01:29 AM.
04 VY Commodore ute M6 ls1, 918 valve springs, TR6 plugs, genttrbb twin turbo kit, 60lb seimiens injectors, Bosh 044 fuel pump, SX fuel reg, PLX wideband,Full Castle Hill Exhaust with 2 i/2in dump pipes, 4in cats into twin 3in true cat back (no merge), Ripshift, oz700 clutch and 3.73 diff gears
05-23-2007 #8
Advanced Tuner
this is a log i did yesturday when i was running 12psi (same tune as in a higher place) i didnt have the wideband continued for this one simply afr were good (i was looking at wb brandish at the time)
im noticing that my command timing at wont isnt what i should be eg look at frame 13725 im only getting 6 degress of timing with good iat and no knock but just after that frame on the same wot run i still getting knock even with such depression timing numbers ??????
04 VY Commodore ute M6 ls1, 918 valve springs, TR6 plugs, genttrbb twin turbo kit, 60lb seimiens injectors, Bosh 044 fuel pump, SX fuel reg, PLX wideband,Full Castle Hill Exhaust with 2 1/2in dump pipes, 4in cats into twin 3in cat back (no merge), Ripshift, oz700 clutch and 3.73 diff gears
05-23-2007 #9
Advanced Tuner
hey russOriginally Posted past Russ K
cheers for the advise mate im gonna get log a scan now with the decay rate muliplyed by 4 and i'll upward the base of operations attack like yous said. What should i lower my fan temps to? ive got stock thermo atm merely will look at getting a 160*
im running tr6 plugs which should be cold enough for FI.
04 VY Commodore ute M6 ls1, 918 valve springs, TR6 plugs, genttrbb twin turbo kit, 60lb seimiens injectors, Bosh 044 fuel pump, SX fuel reg, PLX wideband,Total Castle Hill Exhaust with 2 1/2in dump pipes, 4in cats into twin 3in cat back (no merge), Ripshift, oz700 clutch and 3.73 diff gears
05-25-2007 #12
Avant-garde Tuner
final nighttime i fixed up my dump pipes and now the exhaust isnt hitting anywhere. i logged a few runs afterward and im nonetheless getting knock just nowhere near as often then i guess the dump pipes striking on the rails where causing some fake knock.today i fix all of my timing from 0.84 and up to 8 deg and got no knock at all (i attached logs and melody)
does that mean i was getting existent knock earlier?whats else could be stopping me from running more timing if it is high cyl temps how can i check that
04 VY Commodore ute M6 ls1, 918 valve springs, TR6 plugs, genttrbb twin turbo kit, 60lb seimiens injectors, Bosh 044 fuel pump, SX fuel reg, PLX wideband,Total Castle Hill Exhaust with two 1/2in dump pipes, 4in cats into twin 3in cat dorsum (no merge), Ripshift, oz700 clutch and 3.73 diff gears
05-25-2007 #14
Advanced Tuner
i am running stock cr and when it does knock i deceit hear any pinging at all. is it possible for false knock to appear but when more timing is added?i dont think information technology is bad fuel cause i filled up yeterday with crush five-power 100 octane after fixing my dump pipes and i was still knocking in the 4000-4800 expanse with x degres. (car was well-nigh out of fuel when i filled upwardly and i drove for like 30mins before i started loging once more). As this is my work ute i carry about 400kg of tools etc in the back and i besides carry ladders on the curl bars, could these take an effect on how much timing i can run?
chris have you got a log from your motorcar yous could put up or ship me? our cars have pretty similar mods and id dearest to compare a few things
thanks
Last edited by sikhabib; 09-01-2009 at 07:55 AM.
04 VY Commodore ute M6 ls1, 918 valve springs, TR6 plugs, genttrbb twin turbo kit, 60lb seimiens injectors, Bosh 044 fuel pump, SX fuel reg, PLX wideband,Total Castle Loma Frazzle with 2 1/2in dump pipes, 4in cats into twin 3in true cat back (no merge), Ripshift, oz700 clutch and 3.73 unequal gears
05-25-2007 #sixteen
Advanced Tuner
Wow 14 deg and no knock i hate you!!! what exhaust are you running? do yous ever become intermitent knock running that much timing? Even though my afr are expert and im not running out of injector at wot would it make whatever difference if i connect a heave/vac line to my fuel reg (its at the dorsum of the ute next to the fuel tank)
04 VY Commodore ute M6 ls1, 918 valve springs, TR6 plugs, genttrbb twin turbo kit, 60lb seimiens injectors, Bosh 044 fuel pump, SX fuel reg, PLX wideband,Full Castle Hill Exhaust with 2 1/2in dump pipes, 4in cats into twin 3in cat back (no merge), Ripshift, oz700 clutch and 3.73 diff gears
05-25-2007 #eighteen
Advanced Tuner
geez chris you must exist really busy with all this hpt stuff it you dont even have fourth dimension to change gears anymore lol and you only but got a new clutch
did you have to modify your gentt dump pipes to make them articulate the chassy runway and exhuast manifolds?
04 VY Commodore ute M6 ls1, 918 valve springs, TR6 plugs, genttrbb twin turbo kit, 60lb seimiens injectors, Bosh 044 fuel pump, SX fuel reg, PLX wideband,Total Castle Hill Exhaust with ii 1/2in dump pipes, 4in cats into twin 3in cat back (no merge), Ripshift, oz700 clutch and three.73 unequal gears
05-25-2007 #20
Advanced Tuner
update
ive been running lean the pigsty fourth dimension!! i decided to log my afr through the widebands software and my bodily afr is almost i unit leaner than what hptuners is showing. the weird thing is around stoich hptuners is showing exactly what my wb is reading merely as you come away from stoich it becomes more and more than inaccurate
Instead of playing around with the offset im simply gonna await till my plx arrives (ls1tech gb) then start tuning over again. for now i just added x to every cell from the 110kpa row downwardly and im now able to run 12 deg with no knock (i tin can probably run more timing but i didnt desire to push it without an accurate wb)Car pulls really difficult at present even with all my work stuff in the back i tin can break traction in 2nd by rolling on the throttle
thanks to everyone who helped
04 VY Commodore ute M6 ls1, 918 valve springs, TR6 plugs, genttrbb twin turbo kit, 60lb seimiens injectors, Bosh 044 fuel pump, SX fuel reg, PLX wideband,Total Castle Hill Exhaust with ii 1/2in dump pipes, 4in cats into twin 3in cat back (no merge), Ripshift, oz700 clutch and three.73 diff gears
Source: https://forum.hptuners.com/showthread.php?12334-Will-a-restrictive-exhaust-cause-knock
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