Now I am really confused. In haynes it says 1.1mm for all the 234 engines: B234L, b234E, b234R, b234I, B204I.
1.0mm is only for B202L, which as I understand is a 2L.
0.8mm is for B202I.
Sorry, didn' get it, is that you reccomend to gap it for 1 not to go over 1.1? Just for safety?
Also, I have question, if I am running aftermarket ECU and more boost, should I try making the gap smaller, 0.9 for example?
I buy my plugs pre-gapped to 1.1mm.. as many suggest.. and then regap them myself if I can be bothered
BUT... is it possible to buy the plugs gapped to .9mm from factory? I've never really seen them, well haven't looked all that hard either.
You usually end up gapping them down a little when you start running more boost and you can get mis-fires when the gap is too large and I have solved my mist-fires under heavy boost many times by gapping the plugs down to .9 or .8.
I have gone as low as .26" when I run my car on WM injection and a lot of fuel and if you don't gap em down, they will get quinch and that is when the flame front is spark is no longer making the gap and firing. Too much fuel, not enough spark. You have to gap down to make sure the firing crosses the gap.
I have heard you make the most power with the widest gap that you can have good spark across and that is limited by you're ignition system. If you can up you're ignition system, you can run a wider gap even with more boost and fuel.
Alright, I just regapped my plugs to 0.9mm and my boost went WAAAAY down. So, I don't know for whom this works, but apparently not for me. Tomorrow morning, Ill regap them back to 1.1 and see how is the boost. If it will be back up, then that will be quite a clear cut proof that for my set up at least, 1.1 is the proper gap.
And I do have the stock, proper plugs, got them from the dealer.
It works for anyone running more boost. Like I said, you want the largest gap you can get away with without any mis-fires! If you are not getting any missing, you will make more power with a wider gap. If you ever start upping the boost, you will see that mis-fires and at some point and you have to gap the plugs down to keep the fire across the plug gap.
When I went to 28-30psi, I had to gap down to .26" to keep the mis-fires from occuring under heavy boost and many others have done the same thing...
Another point. You want to run the ngk bcpr 7es-11 plugs. They are the known good plugs for our cars with good boost.
Well, today I regapped them all back to 1.1mm. The boost is MUUUUCH better.
Yesterday i would get a peak to the middle of the red zone COLD and then it would be imiddiately reduced to almost the stock boost.
Now, when cold, the boost goes off the scale, and in 5th gear at about 80mph, (adequate IC cooling) under WOT it goes to the 2/3 of the red zoen and stays there.
I don't know what's wrong with my car, but that's what works apprently.
With 0.9 i would get boost reduced to almost base boost at 45ambient. I know it wasn't heatsoaking...
Sounds like you might have a sticking bpc and having it boost a lot or a little intermittently is one cause. You can also clean out the bpc with wd40 and shop compressed air. I have had many of them stick on me. They can stick or fail wide open where you get too much boost or stick half way closed where you get less boost. I have not experienced what you say on the plug gap.
I would double check base boost and blow out my bpc if I where you.
Also, how old are the plugs, are they new? If the wider gap is working for you, just run that. You will know it if the gap is too large because you will start to get mis-fires under heavy load and boost. If its working at the gap you have them set at, I would not worry about it.
The spark plugs are relativly new, and they have the special "electric" grease on them.
I would think if it is a BPC valve or something, then I would never get a lot of boost. However, with 1.1mm, I get VERY nice boost, and I see it reduce only cause of the IC. When cold(car warmed up, but the first boost run in the morning, ambient 40, I can perform WOT 1-3rd run, with turbo gauge being off the scale all the time. And as I said, on the highway, I get constant 2/3gauge.
With 0.9mm gap, on the highway, I would get spike to the middle of the red zone, and then it would go all the way almost to the base boost. With 1.1, it never goes this low, the lowest it went is the begining of the red zone.
I didn't adjust the base boost though yet, on the stock gauge it looks like it is in the same place as stock, but I know, I need to adjust it.
How would it affect it thugh?
The bpc can stick either way like I said... They can stick open and cause over-boost!
If its running well at the current gap, don't worry about it.
The base boost will effect how high in boost you spike to. Stock is around 5.5-6.5psi with the bpc unplugged and then wot in third gear. You have to have a boost gage to know what it really is. The apc gages are not that accurate and are a map in the ecu.... You can make them read whatever you want no matter what the boost is.
Put a real boost gage on it and set you're base boost. If its too high you will get spikes to higher boost levels and this can heat soak the ic and then the boost will drop off dramatically.
Its always a good idea to blow out you're bpc in my opinion. I have had them stick right out of the box brand new and have seen 3 of them stick open with too much boost and a buch of them sticking closed and not giving enough boost. I have had them work fine one pull and stick the next, then be fine for a few pulls and then stick again.
If you clean it out and you get much more consistant boost levels, you know it was sticking
Thanks a lot!
Damn it, I got misfire now!!! Regapped to what it was before, and now, the boost is fine, but as soon as I get into the red zoen, I get misfire...
I didn't put the boot grease onto the plugs, so i will do that now, maybe this casued it. If it won't help, then ILl try reducing the gap to 1mm...
Thanks for the tips on the BPC. So, just disconnect it and spray some WD40 in it? I don't have air compressor
Ok, just added the grease on to the sparkplugs and it fixed the misfire. I would never would have thought that some grease could do this sort of thing. Now I get off the scale with no misfire...(well at least for the 15 minutes i tried it out).
So, I would strongly reccomend you guys buy it, it is the stuff sold at PepBoys in small packets ofr like a dollar, say "Avoids stuck boots, displaces water, reduces arching". It did the trick))
Ill still cleacn the BPC valve, just in case.
Is it the valve which sits on driver's side of the radiator?