hey just got the car out for the first race this year.while we waited out rain i put a new set of plugs in the motor (acdelco cr45ts)after 3 runs i pulled one to check it and it was still like new with the acception of the ground strap turned blue and purple.i noticed in the burnout right before i turn the line lock off it pops like its on the limiter. runs the 1/4 like nothings wrong. so i tested the fuel pump with the lines off the carb,took 31seconds to fill a gallon jug. then i tryed it again with the bowls off the carb and the lines attached,took 55 seconds to fill it. it an areomotive ss pump and bg deadhead regulator 1/2 line. the carb has 78jets inthe front and 86s in the back.what do u guys think is the pump not enough or do i need to go up in jet sizes?oh yeah we are 500ft above sea level.

 

I wouldn't get too worried that the plugs look like new. The WOT mixture line in way down at the bottom of the porc. Very hard to see without turning off the threads with a lathe. The top won't get much color unless you drive slow or lots of idling. I would make sure there is nothing shiny on the porc. Look for very light dried soot on the outer ring of the threads that might not even go all the way around. The colors on the strap, if they go to the curve of the strap, you have the right heat range. I have a very similar motor except a 355 with a 800 DP and 77P and 86S. If you are worried why not go up 2 on the jets and see what happens. My porc looks white after just a few runs and just barely colored after 20 or so. Also take a look at what the outlet of the hedders have to say.

 

Mount a fuel gauge some where outside the car and watch it while you go down the track. Aslong as you don't dip below 7psi your pump is fine.

 

There are a lot of things to look at when looking at a plug.

The line down inside on the porcelain. The color line location on the ground strap. The color around the bottom ring are just a few things.

Changing plug gap, timing, jetting, fuel etc can all effect what a plug looks like. A plug that looks too hot can be just right if the jetting or timing is changed.

Your fuel can test is a little low. Sounds like the engine isn't getting enough fuel. Barry Grant recommends a 1 gallon can should be filled in a specific amount of time based on how fast it runs. Actually it's how much fuel in weight is required to feed a specific HP engine.

A 10 second car needs to fill 1 gallon in 25 seconds
11 second car, 30 seconds
12 second car, 35 seconds
13 second car, 40 seconds
14 second car, 45 seconds etc

If your free flow is capable of an 11 second car but through the needle and seat is capable of feeding a 16 second car, I'd say your float bowls are emptying before the end of a run. Install larger needles and seats and try again.

I never did see how fast my old system could fill a can through a float bowl but free flow, it would fill 1 gallon in about 15 seconds through a 1/2" line. That was with a BG400 pump rated at 400 GPH and it was feeding 4 float bowls.

 

i will get another set of needle and seats and try it again and see if its any better. its got 0.110 in it now i think u can get up too a 0.150 with a steel or titanium tip. how big should i get? any sealing problems with the steel and titanium ones? i also have a crappy professional products fuel filter i going to order a good one and throw that away.

 

just an update. i got the .150 steel tip ones and tryed the can test again.....32 seconds to fill a gallow through the bowls! that sure beats the 55 seconds with the .110s .

 

Well that should correct any problems with draining the bowls dry during a run. Keep the fuel pressure below 7psi.