Do race plugs make more power? Well, not really
03-18-11, 01:56 AM
#26
The BUEs were originally designed for outboard engines witch are primarily CDI ignitions. Since the plug is such a cold heat range they will not be brought up to self cleaning temps by combustion. They have to rely on the spark it'self to remove deposits from the porcalin. If the spark is not strong enough deposits will build until they short the electrode to the shell. IIRC the older 6a series MSDs are inductive and do not have a powerful enough spark to clean the plug. Also i think the gap on the BUEs is around .050".
03-19-11, 12:05 AM
#27
Electromotive coils are inductive, I thought all the MSD were CD?
On a side note I put a bit more thought into the horsepower gains relative to plug changes. What are the chances that everyone seeing a 10hp gain or reduced time in the quarter mile is using a carb? If A/R ratios were not always perfect.... lets say 12.0 for example when the engine liked 13.0.... then the race plug was able to burn the mix better?
On a side note I put a bit more thought into the horsepower gains relative to plug changes. What are the chances that everyone seeing a 10hp gain or reduced time in the quarter mile is using a carb? If A/R ratios were not always perfect.... lets say 12.0 for example when the engine liked 13.0.... then the race plug was able to burn the mix better?
03-19-11, 06:07 PM
#29
Electromotive coils are inductive, I thought all the MSD were CD?
On a side note I put a bit more thought into the horsepower gains relative to plug changes. What are the chances that everyone seeing a 10hp gain or reduced time in the quarter mile is using a carb? If A/R ratios were not always perfect.... lets say 12.0 for example when the engine liked 13.0.... then the race plug was able to burn the mix better?
On a side note I put a bit more thought into the horsepower gains relative to plug changes. What are the chances that everyone seeing a 10hp gain or reduced time in the quarter mile is using a carb? If A/R ratios were not always perfect.... lets say 12.0 for example when the engine liked 13.0.... then the race plug was able to burn the mix better?
03-19-11, 06:23 PM
#30
Old [Sch|F]ool
Guys that can tune spot-on will pull six-figure salaries to do nothing but tinker with carbs all day for race teams. The rest of us have to deal with imperfect tunes.
Now, the same is also true for EFI, although EFI is a lot easier than carbs there is a smaller pool of tuners.
03-20-11, 05:21 PM
#31
[QUOTE=peejay;10525749]Probably 75% of the guys running carbs don't know how to tune, and 99.9% of them don't know how to tune spot-on. This is assuming that the carburetor in question is even capable of a proper tune in the first place, as most of them are not.
Guys that can tune spot-on will pull six-figure salaries to do nothing but tinker with carbs all day for race teams. The rest of us have to deal with imperfect tunes.
Now, the same is also true for EFI, although EFI is a lot easier than carbs there is a smaller pool of tuners.[/QU
If you have a good AFR and EGT guage and understand some carb tunning basics, it's pretty easy to tune a carb. Just like anything else, it takes practice and some know how. Same holds true for EFI and I don't think it's any easier to tune than a carb in fact I think it's harder.
The only advantage I see using EFI that's any easier when tunning is after the tune is done and going to different altitudes and weather, the EFI is much quicker/easier to compensate for those things and some do it automatically.
Guys that can tune spot-on will pull six-figure salaries to do nothing but tinker with carbs all day for race teams. The rest of us have to deal with imperfect tunes.
Now, the same is also true for EFI, although EFI is a lot easier than carbs there is a smaller pool of tuners.[/QU
If you have a good AFR and EGT guage and understand some carb tunning basics, it's pretty easy to tune a carb. Just like anything else, it takes practice and some know how. Same holds true for EFI and I don't think it's any easier to tune than a carb in fact I think it's harder.
The only advantage I see using EFI that's any easier when tunning is after the tune is done and going to different altitudes and weather, the EFI is much quicker/easier to compensate for those things and some do it automatically.
03-20-11, 06:07 PM
#32
Old [Sch|F]ool
All I will say on the subject is that the more I learn about carb tuning, the more I know that I know nothing. There is a lot more to it than just jets and air bleeds. 75% of people can maybe swap a jet or two, 99.9% can get things running decently well. A properly tuned carb is as good as or better than EFI, and to get there you're going to be playing with a lot more than just jets and air bleeds. Things like the shape and height of the booster, the design of the emulsion tube/well, will alter not just the fuel curve but also the fuel preparation, so you can get an "identical" fuel curve as with much different jetting, but one way will make more power because the fuel is prepared better, which brings into light the questions made about ignition systems' effect on power, and the specific comment I made about how with some carburetors "you can't get there from here".
As I said, the more I learn, the more I realize that I know nothing
As I said, the more I learn, the more I realize that I know nothing
03-21-11, 09:51 PM
#33
Most certainly not. But rather that the mechanics of a carb are tied directly to airflow performance, so cannot always get the most perfect air fuel ratio desired at all rpm points and loads. And the more radical the engine setup the more advantage EFI will have. Advantage is not to be mistaken for power production. In fact carbs have a certain advantage at very high rpm, where a fuel injector is not able to atomize fuel as effectively. So hopefully everyone realizes what I was trying to say.
03-21-11, 09:59 PM
#34
Most certainly not. But rather that the mechanics of a carb are tied directly to airflow performance, so cannot always get the most perfect air fuel ratio desired at all rpm points and loads. And the more radical the engine setup the more advantage EFI will have. Advantage is not to be mistaken for power production. In fact carbs have a certain advantage at very high rpm, where a fuel injector is not able to atomize fuel as effectively. So hopefully everyone realizes what I was trying to say.
03-21-11, 11:10 PM
#37
Old [Sch|F]ool
That, and the fuel mass actually helps VE, added inertia to the slug of air/foam in the intake tract.
And there's a bit of an "air door" effect when you are injecting across or tangential to the airflow, as well.
Oh yes, I have a list of things I want to play with for my next intake manifold, I really do...
03-23-11, 12:34 AM
#39
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a couple of us have been using the Rx8 plugs, which are very similar in design to the race plugs but in a 6 or 7 heat range (the trailing rx8 plugs are a different length)
ive tried em in 3 different cars. my old gsl-se, which liked em, it definitely gained some low rpm response.
the stock FC, which didn't like em, the FC felt rich, and if i pulled a bunch of fuel out with the SAFC, it would run like normal, but i just put the stock FC plugs back in.
the P port likes em too. they wanted more fuel vs the autolites which is fine cause they were getting it. they come out of the p port looking great too
ive tried em in 3 different cars. my old gsl-se, which liked em, it definitely gained some low rpm response.
the stock FC, which didn't like em, the FC felt rich, and if i pulled a bunch of fuel out with the SAFC, it would run like normal, but i just put the stock FC plugs back in.
the P port likes em too. they wanted more fuel vs the autolites which is fine cause they were getting it. they come out of the p port looking great too
03-23-11, 05:17 AM
#40
I love the Rx8 leading plug. I've done back to back runs with FCplugs vs FB plugs vs Rx8 plugs and they all made the same power. I run the Rx8's plugs because they seem to miss less around town and they last forever. Is go through FC plugs in 3000 miles, where as the Rx8 plugs last well over 10k. Mind you I do run 2 Crane HI6 boxes. One running a FC leading coil directfire and the second with a lx92 coil through the cap for trailing. I love my ignition setup. Even with my IDA my car always starts 15-115* she starts. (knocks on wood)
Oh and thanks to amazon one click shopping. Those BUE's should be here soon...
Oh and thanks to amazon one click shopping. Those BUE's should be here soon...
04-05-11, 03:33 PM
#43
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i think i found out why the race plugs didn't make more power on the TEC3 vs a stock based ignition.
the answer is CHARGE TIME.
all of the stock pre rx8 (leading in the case of the FC and FD) ignitions fire TWICE each revolution of the engine. if the stock coils need 4.5ms to charge and another .5 ms to fire, then the coils are only getting fully charged up to 6000rpms.
so anything over 6000rpm ignition energy is going DOWN, and in a stock car so are chamber pressures, so it seems to even out.
this would explain why the engines like to be so lean up top, AND why the race plugs make more power, because they take less energy to fire.
the TEC3 on a 20B can't be wastesparked, so its one coil per plug, although i guess you could do one coil per rotor, either way, it fires less than a stock 2 rotor mazda ignition
the answer is CHARGE TIME.
all of the stock pre rx8 (leading in the case of the FC and FD) ignitions fire TWICE each revolution of the engine. if the stock coils need 4.5ms to charge and another .5 ms to fire, then the coils are only getting fully charged up to 6000rpms.
so anything over 6000rpm ignition energy is going DOWN, and in a stock car so are chamber pressures, so it seems to even out.
this would explain why the engines like to be so lean up top, AND why the race plugs make more power, because they take less energy to fire.
the TEC3 on a 20B can't be wastesparked, so its one coil per plug, although i guess you could do one coil per rotor, either way, it fires less than a stock 2 rotor mazda ignition
04-21-11, 03:59 PM
#47
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oh yeah how about spark plug gap vs power? i mean as long as you've got nothing better to do than dyno stuff....
