looking for spark plug advice.
Thread Starter
Instructor
Joined: Apr 2013
Posts: 114
Likes: 4
From: Lititz Pa
looking for spark plug advice.
I am running an LS2 ,Edlebrock super charger, AR Headers, Dual Clutch, Corsa Sport. I have a conversion unit installed to read alcohol percentage and adjust timing as needed. Also have the unit that monitors fuel supply and adds voltage when needed. Have hi cap injectors and fuel pump. Dyno result is 760 HP at the wheels. I run Flex Fuel on a daily basis and find milage suffers. Using premium 93 Gas on a highway trip I get 31-35 MPG (Truth!) Using Flex it drops to 24-26 MPG Highway. In town Flex gives17-20 MPG......Gas.....24-26MPG. Anyway I need advice on the plugs I should run for Flex Fuel. Even with the drop in milage I make out well since Flex is running about $2 a gallon right now compared to $3.57n for 93 premium. Reading about this I see some suggest a cooler plug.. Also I am noticing a rougher idle than I like. Also some suggest sidegapping at -.010 " from factory spec. I need suggestions on plugs AND I have one other symptom I can't figure out. RPM's do not drop quickly when the gas peddel is released. I feel like I'm almost flat shifting as I drive normally around town. RPM staus at 2-3,000 and SLOWLY drops.....like 10 or so seconds to normal idle at 700. I'm wondering if I am having a problem from the Flex Fuel or am I seeing a throttle housing problem???
Any reasonable suggestion would be greatly appreciated.
Cordially
Rick S
Any reasonable suggestion would be greatly appreciated.
Cordially
Rick S
Le Mans Master
Joined: Dec 2005
Posts: 6,999
Likes: 1,685
From: Southeast TX
You might ask this on the forced induction forum. You'd get more help. I'd run the AC plugs specced by GM for the LS9/LS7 engines on my supercharged engines. That's one step colder than the stock LS3 plug. Same heat range as the TR6, but an all around better plug. I had issues with the TR6 plugs and lots of others have too. Lots of stuff will come up on those plugs if you do a search. They have their place, but I wouldn't fool with them on the street.
If you need a colder plug, look at the TR7IX. I ran them for a while, but, at my power level (660wheel), they were probably colder than needed. They were noticeably rougher on the street than the LS9/Z06 plugs.
Edit; jonjoy mentioned the TR6ix's. The IX version may be OK, but the cheap copper TR6's, I'd steer clear of.
If you need a colder plug, look at the TR7IX. I ran them for a while, but, at my power level (660wheel), they were probably colder than needed. They were noticeably rougher on the street than the LS9/Z06 plugs.
Edit; jonjoy mentioned the TR6ix's. The IX version may be OK, but the cheap copper TR6's, I'd steer clear of.
Last edited by old motorhead; Apr 27, 2019 at 11:54 AM.
