ok we have someone who knows alil something here!

 

Compression Spark Plug Gap
Up to 10.5:1: 0.050" - 0.060"
10.5:1 - 13.0:1: 0.040" - 0.050"
Above 13.0:1: 0.035" - 0.045"

Straight from msd themselves. It's just a start though. The bkr7es i think they are, its what the boost guys run, i had a set from that, and the gap was good for my 13:1 compression... just an fyi.

http://www.msdignition.com/pdf...s.pdf

page 3

 

MSD ignitions are capable of much wider gaps than OEM Honda Ignitions.

I would personally do something less than 0.040

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GetawayInMoscow &raquo;</TD></TR><TR><TD CLASS="quote">MSD ignitions are capable of much wider gaps than OEM Honda Ignitions.

</TD></TR></TABLE>

I always hear negative things about MSD in Hondas.

 

I have seen a MSD system catch fire one time on a stock setup. That setup could of been wired wrong, its been awhile though.

I have the digital 6a w/ blaster 2 and I have nothing but good things. Good options.

 

where you having problems with the stock ignition system, & thats why you added the msd?

 

I never had a problem w/ my stock ignition on any my cars,just the the igniter and rotor and stuff. I just wanted some more spark for my new motor (sig). The motor that caught on fire was a friends.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 00Red_SiR &raquo;</TD></TR><TR><TD CLASS="quote">From what I've learned over the years, the wider the gap (that the ignition system can sustain) the more power will be made. The only reason for closing the gap down was if you were running high compression, boost or nitrous because the extra dense mixture and higher cylinder pressures could "blow out" the spark/flame. That's where enhanced ignition systems like MSD allow you to run larger gaps on higher compression/boosted engines which usually translates into more power and responsiveness.

I don't claim to know all of the theory behind how it works, I can only pass along information that I have both read and experienced. Jacobs Electronics had some interesting articles years ago on this topic.</TD></TR></TABLE>

yea thats what i thought

 

soooo for 12.5 CR motor. 0.038 is good?

 

anywhere from .040-.050 would be be a decent. just keep in mid stock honda b series motors are gapped at .044

 

As stated previously, you generally tighten the gap up with high cylinder pressure--like high compression or alot of boost. I have been running 0.035" with Champion C61cx plug (equal to an NGK r5671a-8)--kind of by default because it has a cut back ground elctrode and you can't really tighten the gap up on them. 12:1 comression d16.

When the cylinder pressure is very high, an ignition system has a tougher time jumping 0.045" than say 0.030"--and sometimes the ignition simply can't put ou the necessary power and you get a misfire. That spark actually has to punch a hole through the dense air/fuel mixture, and the denser it is the harder it is to punch that hole. By closing the gap up, you reduce the voltage requirement the ignition has to produce to jump the gap.

I think the theory behind using the largest gap you can get away with comes from the fact that you are exposing more of the air-fuel mixture (for a longer time) to the spark which can initiate a healthier burn.

 

really close.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by d16dcoe45 &raquo;</TD></TR><TR><TD CLASS="quote">As stated previously, you generally tighten the gap up with high cylinder pressure--like high compression or alot of boost. I have been running 0.035" with Champion C61cx plug (equal to an NGK r5671a-8)--kind of by default because it has a cut back ground elctrode and you can't really tighten the gap up on them. 12:1 comression d16.

When the cylinder pressure is very high, an ignition system has a tougher time jumping 0.045" than say 0.030"--and sometimes the ignition simply can't put ou the necessary power and you get a misfire. That spark actually has to punch a hole through the dense air/fuel mixture, and the denser it is the harder it is to punch that hole. By closing the gap up, you reduce the voltage requirement the ignition has to produce to jump the gap.

I think the theory behind using the largest gap you can get away with comes from the fact that you are exposing more of the air-fuel mixture (for a longer time) to the spark which can initiate a healthier burn.</TD></TR></TABLE>

thats a darn good explanation...i could'nt agree more

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DonF &raquo;</TD></TR><TR><TD CLASS="quote"> really close. </TD></TR></TABLE>
Take us to close

 

thats weird... everytime i buy my plugs the gap on the stores screen says .52 which buy what im seeing is to much. im running 12.5 cr on a fullybuilt b20vtec. im gonna try and gap em to prob .42 at the most... maybe even lower...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtecobsession &raquo;</TD></TR><TR><TD CLASS="quote">thats weird... everytime i buy my plugs the gap on the stores screen says .52 which buy what im seeing is to much. im running 12.5 cr on a fullybuilt b20vtec. im gonna try and gap em to prob .42 at the most... maybe even lower...
</TD></TR></TABLE>


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by itr1244 &raquo;</TD></TR><TR><TD CLASS="quote">soooo for 12.5 CR motor. 0.038 is good?</TD></TR></TABLE>

 

D16Dcoe45

The gap size has a direct affect on the spark plug's tip temperature

NGK site is a good read.


Modified by FST GSR 1 at 8:04 AM 9/10/2008

 

Since the gap size has a direct affect on the spark plug's tip temperature
and on the voltage necessary to ionize (light) the air/fuel mixture, careful attention is required. While it is a popular misconception that plugs are pre-gapped from the factory, the fact remains that the gap must be adjusted for the vehicle that the spark plug is intended for. Those with modified engines must remember that a modified engine with higher compression or forced induction will typically require a smaller gap settings (to ensure ignitability
in these denser air/fuel mixtures). As a rule, the more power you are making, the smaller the gap you will need.

A spark plug's voltage requirement is directly proportionate to the gap size. The larger the gap, the more voltage is needed to bridge the gap. Most experienced tuners know that opening gaps up to present a larger spark to the air/fuel mixture maximizes burn efficiency. It is for this reason that most racers add high power ignition systems. The added power allows them to open the gap yet still provide a strong spark.

With this mind, many think the larger the gap the better. In fact, some aftermarket ignition systems boast that their systems can tolerate gaps that are extreme. Be wary of such claims. In most cases, the largest gap you can run may still be smaller than you think.

 

so what is the advantage to having a larger gap for spark?

The only reason I can think of is that the larger the gap... the bigger the spark distance so better the cylinder mix will burn? so you are trying to get the biggest spark you can that can break the cylinder presure that you are running? (every time)?

Van

 

Thank You, +1 for R5's, they were suggested by a friend, who knows somebody in the industry and thats all I have ever run.