When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Ive had these ngk br7ef (025 factory gap)in for quite a few wot runs now, after some reading up on "reading spark plugs", it would suggest iam too rich and could add some more timing? thoughts?
setup - lsx b15 create- comes with a ls7 cam from factory (9.0.1 CR), twin turbo, borg warner 62's, 93 pump gas, with intercooler, but no meth etc, 15psi of boost at present, 11.3/11.4 afr at high rpm wot and timing is 27 to start with at 100kpa, then ramped down to 16 at 205kpa(15psi), using holley dominator to control everything
If plugs have been exposed to idle and drive time, you really only get general idle and cruise fuel info. Idle and/or cruise fuel is rich based on pics provided. If you want good WOT info on plug temp, fuel and timing info, do not expose plugs to idle/cruise time. Install new plug(s), make WOT pull, shut down, pull plug to inspect/capture pic. Cutting off threads is the best way to see fuel ring on upper insulator. It's best to install a new plug after each WOT tuneup change, just before WOT pull.
If plugs have been exposed to idle and drive time, you really only get general idle and cruise fuel info. Idle and/or cruise fuel is rich based on pics provided. If you want good WOT info on plug temp, fuel and timing info, do not expose plugs to idle/cruise time. Install new plug(s), make WOT pull, shut down, pull plug to inspect/capture pic. Cutting off threads is the best way to see fuel ring on upper insulator. It's best to install a new plug after each WOT tuneup change, just before WOT pull.
Running low 11.x F/A ratio on pump 93 is too rich. You are on the downside of the fuel burn rate by then, and are sacrificing power just as you would be if your timing was too low. I like to set the F/A ratio at the fastest burn rate (which is NOT the hottest burn rate), then match up the timing. The rest is up to the hard parts that you are working with. Can't change CR or swirl rates or any of that with a keyboard. Before you ask what the fastest burn rate is according to my opinion, it entirely depends on the fuel available to you. It varies dramatically based on region, time of year, and whether your gas station is actually pumping what they claim. As for your plug readings, good luck. They need to be taken on a fresh set directly after a WOT run. Except that tells you less than you think. Carbs will be pretty consistent, but you have the power to totally fubar every individual cell in an EFI tune. You could have 99% of your tune perfect, and still blow the motor over 1 tiny overlooked area. That being said, most builds are not nearly so close to the ragged edge, and some mistakes will be forgiven if the hard parts don't have to live with them too long.
.
Running low 11.x F/A ratio on pump 93 is too rich. You are on the downside of the fuel burn rate by then, and are sacrificing power just as you would be if your timing was too low. I like to set the F/A ratio at the fastest burn rate (which is NOT the hottest burn rate), then match up the timing. The rest is up to the hard parts that you are working with. Can't change CR or swirl rates or any of that with a keyboard. Before you ask what the fastest burn rate is according to my opinion, it entirely depends on the fuel available to you. It varies dramatically based on region, time of year, and whether your gas station is actually pumping what they claim. As for your plug readings, good luck. They need to be taken on a fresh set directly after a WOT run. Except that tells you less than you think. Carbs will be pretty consistent, but you have the power to totally fubar every individual cell in an EFI tune. You could have 99% of your tune perfect, and still blow the motor over 1 tiny overlooked area. That being said, most builds are not nearly so close to the ragged edge, and some mistakes will be forgiven if the hard parts don't have to live with them too long.
.
Thanks for your great post, "Before you ask what the fastest burn rate is according to my opinion" if say i had perfect 93 pump gas, was 93, what would be the perfect 12.5afr?
Thanks for your great post, "Before you ask what the fastest burn rate is according to my opinion" if say i had perfect 93 pump gas, was 93, what would be the perfect 12.5afr?
Do that on a boosted engine...and you're going to melt **** fast.
Thanks for your great post, "Before you ask what the fastest burn rate is according to my opinion" if say i had perfect 93 pump gas, was 93, what would be the perfect 12.5afr?
Somewhere around 12.2 gives the fastest burn rate. This, combined with perfect timing could give you the most efficient use of your gas. You may think that does not agree with your power results on a dyno, and you may be right. The benefits of richer mixtures, or more or less timing, or water injection, or a meth mix all play into this. My only real point was don't shove so much fuel down your engine's throat that you get negative gains.
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.
Spark Plug question 
