Plug gapping make more HP in my application????

[reeber]

I recently had a new VT Engine installed with PI heads, PI intake manifold and changed the blower pully from 3.60 to a 3.33 as well as 60# injectors, long tubes (ceramic coated) and off road H-Pipe. Now, look at "my garage" to see the rest, but when we first dynoed the car with a .036 plug gapping, the spark blew out at about 5500 RPM, but made 467 RWHP. Now, the temperature in the dyno room was 65 degrees. We regapped the plugs to .028 and that solved the spark problem. However, we could only get 437 RWHP at 5500 RPM after that, but the dyno room temp. was 96 degrees. Did I lose the HP from the heat? Or was it from the plug gapping? Remember, I do not have an intercooler or methanol injection. Could it be a combo of both. Will a smaller plug gapping hurt HP because it won't ignite all of the gasses? So, I ordered the Boost-A-Spark which should be here in a few days. I'll install that and reset the plug gapping to the original .036 or higher and see what kind of increased power I make. Anyone else have this issue?

 

[cougar694u]

Well, for a blower car and high compression engines, it's best to run a smaller gap like that. If not, it blows out the spark, so to speak.

I think your loss in HP is due to the 30* difference in temp. Blower cars are more affected by ambient air temps than N/A cars because it's raising the heat as it's forcing it in there.

 

[reeber]

i know that and I have a copy of the Dyno sheet. Anyone know a place that hosts it? So, I can put it on this thread?

 

[reeber]

Here's the two Dyno Runs... You can see the spark blowing out on the first run..

 

[reeber]

Here's a clearer printout. Don't know what happend to the other one.

 

[LJ30]

Well, for a blower car and high compression engines, it's best to run a smaller gap like that. If not, it blows out the spark, so to speak.

True, but, you always want to run the largest gap you can without getting spark blowout. The bigger the gap you have, the more complete burn you are going to get on each combustion. The smaller the gap, less complete of a burn happens. So yes, a lot of your power loss would be from the smaller spark plug gap. I would do everything possible to make sure you get the largest gap possible (within spec).

 

[VPStang]

maybe u can experminet with side-gapping???

 

[reeber]

When I install the Boost-A-Spark, I am going to regap the plugs to spec. and make a few pulls on the dyno to see the results. I am very curious to see if plug gapping could make that big of a difference in HP. I know the heat had some sort of contribution to the power loss, but I have a hunch that the smaller plug gapping also is responsible.

 

[RyanSG]

How can you tell if a spark plug is "blowing out" AKA how does it sound or feel?

 

[tomustang]

try a colder plug and drop the gap .05 from .036, should be better

 

[Dan_Soprano]

try a colder plug and drop the gap .05 from .036, should be better

 

[Kilgore Trout]

I do not think side gapping is the answer. HOWEVER, I do think plug indexing could be used to make the electrode block the "wind" from the intake valve if done properly... This would be 90 degrees off of what indexing usually tries to accomplish...