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Spark plug for mod. 12a
I have an '83 gsl with 12a with weber side draft 45, lake city manifold, no emissions, smog pump or rats nest, exhaust is straight pipe with main cat and a stock or after market muffler. Runs good, bogs at about 6500 rpm, sometimes more, sometimes less. If I bring it up to "bogging rpm" it may bog a bit into the next gear until it cleas up. Consensus is too rich at high rpm. Currently has nippendenso plugs. I want to switch to NGK. Any recommendations between the BR8EQ14 or the BR9EQ14? eventually I will look at recalibrating the carb, but want to see if plugs make a difference. Dave
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Search about the nippendenso, I think they loose their electrode or wahtever easy and it does fun things to your engine.
Always run NGK man, I'd run the stock for a 12a, I don't got ours here so no idea, if those are the stock for a 12a you're gonna want two different ones. The #'s are the heat ranges, trailing/leading is different temps |
I had major problems the one time I tried running Denso plugs. Swapped them for NGKs and all was good...
Are you sure you're too rich at high rpms, and not outrunning the fuel pump or filter? |
You didn't mention anything about your ignition system either. You may need to upgrade your coils also.
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Good points, I don't know if I am out-doing my fuel pump, I bought the car with the current set up, and I don't know if it has the stock pump or not. I could change filters easily enough. Ignition is all stock, as far as I can tell. Maybe I should get the NGK stock plugs, see how she does, then check the fuel system. How might I check to see if the pump is up to the task of flowing the weber?
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Here is the path i'd take:
1. Fuel filter. ~$5. Easy. 2. NGK BR8EQ-14. ~7/per. Pricey, but they work great. 3. 2g direct fire. ~$20. I've read that it's easy. I've read that it works great. 4. New fuel pump to keep up with your Weber's requirements. |
Racing Beat only recommends going to 9's if you will be doing majority high-speed driving; 8's are more suitable for city driving as at lower rpms the 9's don't get hot enough to stay clean.
And they recommend NGKs exclusively. For "performance non-ported" engines, they list BR7EIX for city driving, and 8's for highway Specifications: NGK BR7EIX B= 14mm Thread Diameter 7= Heat Rating * E= 19mm Thread reach I= Iridium X= Booster Gap (Firing End Construction) Note: The use of spark plugs other than the "factory recommended" plugs requires the use of a "thin wall" socket. Installation and removal of these plugs requires the use of the Racing Beat Spark Plug Socket. *A spark plug's heat range has no relationship to the actual voltage transferred though the spark plug, Rather, the heat range is a measure of the spark plug's ability to remove heat from the combustion chamber. The heat range measurement is determined by several factors; the length of the ceramic center insulator nose and its' ability to absorb and transfer combustion heat, the material composition of the insulator and center electrode material. The insulator nose length is the distance from the firing tip of the insulator to the point where insulator meets the metal shell. Since the insulator tip is the hottest part of the spark plug, the tip temperature is a primary factor in pre-ignition and fouling. Whether the spark plugs are fitted in a lawnmower, boat, or a race car, the spark plug tip temperature must remain between 850-1500 degrees F. If the tip temperature is lower than 850 degrees F the insulator area surrounding the center electrode will not be hot enough to burn off carbon and combustion chamber deposits. These accumulated deposits can result in spark plug fouling leading to misfire. If the tip temperature is higher than 1500 degrees F the spark plug will overheat which may cause the ceramic around the center electrode to blister and the electrodes to melt. This may lead to pre-ignition /detonation and expensive engine damage. The firing end appearance also depends on the spark plug tip temperature. There are three basic diagnostic criteria for spark plugs: good, fouled and overheated. The borderline between the fouling and optimum operating regions is called the spark plug self-cleaning temperature. The temperature at this point is where the accumulated carbon and combustion deposits are burned off. Bearing in mind that the insulator nose length is a determining factor in the heat range of a spark plug, the longer the insulator nose, the less heat is absorbed, and the further the heat must travel into the rotor housings' water journals. This means the plug has a higher internal temperature, and is said to be a hot plug. A hot spark plug maintains a higher internal operating temperature to burn off oil and carbon deposits, and has no relationship to spark quality or intensity. Conversely, a cold spark plug has a shorter insulator nose and absorbs more combustion chamber heat. This heat travels a shorter distance, and allows the plug to operate at a lower internal temperature. A colder heat range can be necessary when the engine is modified for performance, subjected to heavy loads, or is run at high rpms for a significant period of time. The colder type removes heat more quickly, and will reduce the chance of pre-ignition/detonation and burn-out of the firing end. (Engine temperature can affect the spark plug's operating temperature, but not the spark plugs heat range). The NGK heat range is from Hot (2) to Cold (10). Reprinted from the NGK Product Catalog. For full-on race engines, they recommend BR10EIX for street-ports, and R6725-11.5 for peripheral ports (at $40 each!) |
Originally Posted by whitey85mtu
(Post 9116862)
Here is the path i'd take:
1. Fuel filter. ~$5. Easy. 2. NGK BR8EQ-14. ~7/per. Pricey, but they work great. 3. 2g direct fire. ~$20. I've read that it's easy. I've read that it works great. 4. New fuel pump to keep up with your Weber's requirements. Sounds like a plan. But.....what's a 2g, sounds like an ignition upgrade, at $20 can't go wrong. I'll do a search on weber fuel pump. I'm guessing a regulator is in the mix, too. I don't think my car has one. |
I run a carter 4-6lbs fuel pump for my weber with a regulator and have never had a problem feeding my 13B-PP. I also run BR10EIX in the engine and it seems to like them. Car is majority drag racing with very little street driving.
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Originally Posted by blown7
(Post 9116984)
I run a carter 4-6lbs fuel pump for my weber with a regulator and have never had a problem feeding my 13B-PP. I also run BR10EIX in the engine and it seems to like them. Car is majority drag racing with very little street driving.
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sorry my above post i screwed up. i do not use a fuel regulator, i just let the pump flow and it doesn't over fuel the weber
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Originally Posted by blown7
(Post 9117186)
sorry my above post i screwed up. i do not use a fuel regulator, i just let the pump flow and it doesn't over fuel the weber
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-Holley Blue fuel pump.
-NGK BR8EQ spark plugs -New plug wires -check timing -check vacuum advance (if not installed, install it) Or lock the distributor so it doesn't advance too far while in the high RPM range. -spray a little lube on the cams so the throttles open up all the way and don't stick. |
Originally Posted by NCross
(Post 9122299)
-Holley Blue fuel pump.
-NGK BR8EQ spark plugs -New plug wires -check timing -check vacuum advance (if not installed, install it) Or lock the distributor so it doesn't advance too far while in the high RPM range. -spray a little lube on the cams so the throttles open up all the way and don't stick. Thanks for the input. |
curious on this as well again lots of great info specially for a newb like me/
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You will need a fuel regulator with the Weber. Do not run it more than 3 to 4psi. The second gen direct fire leading coil is a great inexspensive upgrade. It will make a huge difference in performance.
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Holley 7 PSI. Comes with a 4-9 PSI adjustable regulator. Find a cheap fuel pressure gauge for it. Set it at 4 PSI. Run factory NGK 8 heat plugs for the 81-85 engine. Upgrade to electronic ignition (best upgrade ever). It's very easy, I can walk you through it if you need help. Takes 20 minutes to do. Costs about $50 - 60 or so depending on your used parts sources. That's it. Your car will never have run so good after you put these upgrades on.
Jeggs is a great Holley dealer. |
Originally Posted by NCross
(Post 9127559)
Holley 7 PSI. Comes with a 4-9 PSI adjustable regulator. Find a cheap fuel pressure gauge for it. Set it at 4 PSI. Run factory NGK 8 heat plugs for the 81-85 engine. Upgrade to electronic ignition (best upgrade ever). It's very easy, I can walk you through it if you need help. Takes 20 minutes to do. Costs about $50 - 60 or so depending on your used parts sources. That's it. Your car will never have run so good after you put these upgrades on.
Jeggs is a great Holley dealer. |
Dave,
Here's a link to a writeup on upgrading the fuel system, installation, part numbers, and a long discussion. You might want to check it out before you begin. Hope this helps... https://www.rx7club.com/1st-gen-archive-71/fuel-how-install-carter-fuel-pump-holley-fpr-529605/ And yes, the 2nd gen coilpack is a cheap/worthwhile mod.... |
Ncross, shouldn't he already have electronic ignition? This is an 83, isn't it?
Nevermind, I see what you mean. Direct Fire is the term for the 2nd gen mod, because you end up with your spark plug wires running directly from the coil to the sparkplug (bypassing the distributor cap). This saves a lot of spark energy that would otherwise be wasted. I think the coils are a bit stronger than stock too, plus you end up with one coil per plug rather than sharing a coil. It's a simple install if you don't overcomplicate matters. |
Originally Posted by Kentetsu
(Post 9127900)
Ncross, shouldn't he already have electronic ignition? This is an 83, isn't it?
Nevermind, I see what you mean. Direct Fire is the term for the 2nd gen mod, because you end up with your spark plug wires running directly from the coil to the sparkplug (bypassing the distributor cap). This saves a lot of spark energy that would otherwise be wasted. I think the coils are a bit stronger than stock too, plus you end up with one coil per plug rather than sharing a coil. It's a simple install if you don't overcomplicate matters. |
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