Question about gapping plugs (like B10egv plugs)
I run the B10egv plugs that require you to gap them. I was hanging out at the local dyno yesterday and a piston guy was talking about gaining almost 10rwhp just from changing the gap on his spark plugs.
Can someone explain the theory behind this and also how can you tell if you can safely use more or less gap. Thanks, STEPHEN |
10 RWHP? from gapping? I kinda doubt that. But I've been wrong before. You have to gap most plugs when you get them according to specs. Obviously the larger the gap the bigger the spark - but you also can run into problems of it not firing. Maybe someone could help me out and explain how you want to gap your plugs... for a hotter short spark, or a longer one. -JinX
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Yea, see thats the info I'm looking for. I know you can change the spark by running different gaps but I'm not sure how you can tell what a good gap is or if you should make it bigger or smaller.
STEPHEN |
Damn, maybe I need to check out a piston forum for this info haha
STEPHEN |
If you have the plugs gapped too big it will misfire. You hypothetically would like to run as large of a gap as possible wthout misfiring. But there are exeptions to every rule!
Nick |
yes you can get more power from bigger spark plug gaps. The problem is you better have an ignition system capable of doing it or it will misfire.
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I have been running those plugs in my car for almost 2 years and have never gapped them. If the car was tuned with the plugs straight out of the box I wouldn't bother touching them.
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I have seen people do it before, but whats point??
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Originally posted by CTHIS RX7 I have been running those plugs in my car for almost 2 years and have never gapped them. If the car was tuned with the plugs straight out of the box I wouldn't bother touching them. Maybe I should just try using them right out of the box since its working for you and its a little more gap that way. I'm running a MSD6a on the leading coils so I SHOULD be ok, its not like its a big difference in gap.....course that might be considered a big differance, I really dont know Anyway, thanks guys, STEPHEN |
I use them for both my pump gas and c16 tunes straight out of the box. I reckon it should be ok.
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How much boost you running on pump gas?
STEPHEN |
Then you also get into indexing plugs for those really obsessive. -- SPAuto - you sound like you are using piston plugs with words like "bending them down" to regap. My rx7 plugs don't have the electrode hook, but are flat.
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Originally posted by SPOautos How much boost you running on pump gas? STEPHEN 12psi on pump gas and 19psi on c16. |
Re: Question about gapping plugs (like B10egv plugs)
Originally posted by SPOautos I run the B10egv plugs that require you to gap them. I was hanging out at the local dyno yesterday and a piston guy was talking about gaining almost 10rwhp just from changing the gap on his spark plugs. Can someone explain the theory behind this and also how can you tell if you can safely use more or less gap. Thanks, STEPHEN The good ol b10ev's are no longer avaialble. they are called something else now. I just cant remember what it is. |
I had a lotus 1600cc twin cam engine. I did a lot of experimenting by indexing / gapping the plugs and was able to get 6 RWHP more out of it by indexing the plugs. Gapping 2 RWHP. This was a full race motor - Nothing below 4200RPM.
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basically, the larger gap allows for a larger surface area for the spark to jump across, allowing for a more powerful spark. however a lot of boost can extinguish the spark in an excessively gapped plug. you need to take into account your boost and a/f ratios in determining your gap. low boost and lean a/f ratios can be ignited much easier, hence you can gap your plugs more. w/ more boost and richer a/f ratios you have to be careful not to misfire, so you have to gap them down a bit.
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Originally posted by Brentis Then you also get into indexing plugs for those really obsessive. -- SPAuto - you sound like you are using piston plugs with words like "bending them down" to regap. My rx7 plugs don't have the electrode hook, but are flat. |
Re: Re: Question about gapping plugs (like B10egv plugs)
[i] The good ol b10ev's are no longer avaialble. they are called something else now. I just cant remember what it is. [/B] The one I've been using of late would be the BR10EIX's. Those are Iridium plugs made by NGK. So far the results have been very good. They do offer advantages over the regular EGV's. They last much longer in a daily driver and offer much smoother operation during idle and cruise conditions which I believe is due to it's ability to operate at wider gaps and because the Iridium tip is much smaller and conducts voltage easier. I've been running them between 0.022 to 24 with no misfire problems so far. crispeed 87 RX-7 TII 9.204@150.47mph 2600lbs un-tubbed |
I think you should be able to find a lot of information on this subject from all over the net. This forum is a bit behind on things as far along in tuning as plug indexing and gap. perhaps there is a 1000 HP race engine or nascar forum out there that spends all day on 3HP things like this.
Im sure the information on plugs will apply to all combustion engines not just piston engines. if you do find any good information, by all means report it back here. |
Re: Re: Re: Question about gapping plugs (like B10egv plugs)
Thanks for that info Chris!!! I'll try those next and see how they do.
Thanks for the info guys, STEPHEN Originally posted by crispeed The newer ones are called EGV's. The one I've been using of late would be the BR10EIX's. Those are Iridium plugs made by NGK. So far the results have been very good. They do offer advantages over the regular EGV's. They last much longer in a daily driver and offer much smoother operation during idle and cruise conditions which I believe is due to it's ability to operate at wider gaps and because the Iridium tip is much smaller and conducts voltage easier. I've been running them between 0.022 to 24 with no misfire problems so far. crispeed 87 RX-7 TII 9.204@150.47mph 2600lbs un-tubbed |
Yeah I ordered up a set of BR10EIX for use in my single turbo FD. I have 4x BUR9EQP in there now, and they are doing OK (no misfires and they are a nice medium brown color) but I want to try out something new to see how it works out.
Brian |
Originally posted by Wargasm Yeah I ordered up a set of BR10EIX for use in my single turbo FD. I have 4x BUR9EQP in there now, and they are doing OK (no misfires and they are a nice medium brown color) but I want to try out something new to see how it works out. Brian crispeed 87 RX-7 TII 9.204@150.7mph 2600lbs un-tubbed |
There is a guy here on the forum that sells a socket for $20 shipped. I think he goes by Metalman. If you search the for sale section for socket you should find him. If not pm me and I'll check my super old pm's and get his exact name
STEPHEN |
indexing is irrelevant on a rotary as the plugs have symmetrically arranged electrodes.
The idea in piston engines is to get all the plugs facing the one way with the electrode opening up to the flame front. In a rotary the manner in which the flame promulgates from the tip will not really differ according to the direction it faces, as they look the same from each direction. Only the EV/EGV series need to be gapped, the rest can't/shouldn't/aren't. |
But as far as indexing goes would it be better for the plugs to face inward toward eachother and toward the center of the combustion area? Since the plugs are on the outer edges of the combustion area it would make sense to me that the "opening" in the gab should face the middle with the "bar" facing the bottom and top of the engine.
Does that make any sense at all. I doubt any of this would matter to a street car but I'm just wondering. Hell since I'll be putting the plugs in I might as well do it in the best direction possible STEPHEN |
Thanks for the tips Crispeed and SPOautos! I was not aware that a special socket was needed, but I'm sure I can pick one up no problems or take the grinder to a spare one around here somewhere :)
Are there any issues with "spacing" on those plugs? For example leaving out/putting in more washers to adjust the depth of the plug in the rotor housing? Brian |
For the B10EGV plugs I just screw them in as is. I dont know about the ones Crispeed was talking about though, I havent used them. I'm under the impression they are the same plug but just in Iridium so they should be ok....hopefully he'll check the thread again and clarify
STEPHEN |
I took a 2 dollar Sears 13/16 spark plug socket and used a grinder on the tip of it to make it fit. I tested it for strength by inserting/removing an old plug in a junk housing and tightening it to 50 ft*lbs which is obviously WAY over what I would on a good housing.
I also examined the depth of the BR10EIX compared to a stock plug. They both sit in the hole about the same amount and end up about the same distance from the trochoid surface. I think i'll throw them in tomorrow and see how they run. Brian |
Wargasm - Where did you get the BR10EIX from? Were you able to get them from a local place like Auto Zone, ect or did you have to get them online?
I'm going to get some in the next couple weeks STEPHEN |
I got them from http://www.carshopinc.com/ for 7.95 per plug. The shipping was a little steep at something like 9 dollars, but they came pretty fast :) You will find more reasonable shipping elsewhere, but then the plugs end up being like 10 bucks each so it balances out.
I didn't try any local shops because I'm massively lazy and would rather pay a few bucks and wait a couple days to have them arrive at my doorstep. You might try some motorcycle or ATV shops as those seem to be what the plugs are for. Brian |
I put the BR10EIX in the trailing positions today (gapped to about .022) and left my BUR9EQP for the leadings since the color of those seemed about right. I took the car out for about a two hour drive and didn't notice too much difference which is a good thing.
The car idled fine, drove fine... It almost seemed to pick up off the throttle a tiny bit snappier, but I'm pretty sure that was my imagination :) Air/Fuel ratios stayed about the same as before... no big changes there. Brian |
Originally posted by Wargasm I put the BR10EIX in the trailing positions today (gapped to about .022) and left my BUR9EQP for the leadings since the color of those seemed about right. I took the car out for about a two hour drive and didn't notice too much difference which is a good thing. The car idled fine, drove fine... It almost seemed to pick up off the throttle a tiny bit snappier, but I'm pretty sure that was my imagination :) Air/Fuel ratios stayed about the same as before... no big changes there. Brian crispeed 87 RX-7 TII 9.204@150.47mph 2600lbs un-tubbed Travieso Racing 73 RX-3 10.57@124.97mph 2190lbs un-tubbed 13B PP--All Motor |
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