GotTheFever

bsc,
The inside of the engine is stock. This means that I have at the most 8.75/1 compression ratio. I was told by numerous people that I should not have detonation problems, since the Procharger is intercooled. I even went out of my way to re-plumb the coolant system so that the intercooler gets its water from a location before the oil cooler. Was your Wieand intercooled? I’ll try less timing and see if it helps. I hope it’s not detonation. Would octane booster help? That will be a lot of octane booster for a 130 gallon tank. Nickerson feels that the secondary jets are too large and recommended that I go down 4 sizes. They re-worked the carbs, so I’ll try this as well.
Thanks
Dan

robyw1

You should not have any problems firing the plugs at only 7-PSI. The stock ignition will be good to 16-PSI w/o a MSD box. However your timing does sound a little too advanced. I would back it off to 20-degrees total and test. A couple of things on your statement tripped an alarm in my head. You stated on 2 occasions then as soon as you nail the throttle it cuts out. You also stated that you have to ease it to 4700RPMs. That indicates to me that you may have an enrichment problem. Check the accelerator pumps on those Holley carbs. Make sure that you get a steady stream of fuel flow when someone moves the throttles. You should see a healthy stream of fuel come from the center squirters with even the slightest increase in throttle movement. Keep us posted.

Roby

robyw1

Also I forgot to ask. You are running carburetors correct? Why is the fuel pressure set at 14-PSI? I don’t know how you have it set up but how are you getting 7-PSI at idle and 14-PSI at full throttle boost? Is this a special regulator setup from Procharger? Is the fuel pressure more than 10-PSI at the carburetors? If so you need to back off to 7-PSI. 14-PSI will push the float down and flood your engine.

Roby

Kanookstr

GotTheFever, I am running a procharged 502 mag as well. I am at 6 lbs of boost. every 4 weeks or so I experience the same problem as you. It won't climb over 4400 rpm. it gets there like a bat out of hell, but then it just flattens out!!!!!I don't know if you tried this, but I was reluctant to believe it was that simple, and tried everything else!!!!! Then I finally gave in and checked the inside of my distributor cap!!! sure enough the contacts were covered with a greenish white corrosion, kinda like what you find on a battery.. It wasn't much, and didn't think for a sec that it could cause the power and rpm loss at high rpm's. I decided to clean the contacts anyway with a nail file the wife had in her purse, and sure enough....BANG!!! WOW~ she climbed to 5200 rpm and kept pulling I now keep a cleaned up spare cap on board, and swap them every time I notice the upper rpm power loss... Good luck, and sometimes it's the simple things that cause the biggest problems

fstboater

Take a spark plug type Hei tester and put it on a spark plug wire and snap the throttle it needs to keep a good blue spark. At all times and never blink off the OTC too is a st125 spark tester. You can do this test at home to rich will make it very flat on top end.Look at the heat line in the spark plug electrode it should be in the area where it bends what do the plugs look like? Black white burned up ect. Good luck looks at this stuff before you take it to the lake.

GotTheFever

robyw1,
I think that the accelerator pumps are ok. If I’m at WOT, I can re-gain my power by pulling back on the throttles to about ¾ throttle where I am out of boost. About the fuel psi. According to Nickerson, I should be getting 14 psi. This is how he explained it. In order to get 5 lbs of boost, there needs to be 7 lbs of boost in the carb box. There will be 2 lbs of boost different between the carb box (above the ventures) and the intake manifold. If I start with 7 lbs of fuel pressure at idle, then I add 7 lbs of boost in the carb box, the referenced fuel pressure should be 14 psi.

Kanoosktr,
I don’t want to rule anything out at this point, even the simple things. I’ll check over the entire ignition system. The weird thing is that it happens to both engines under exactly the same conditions. Thanks.

fstboater,
It has been a little bit since I’ve looked the plugs over. I was originally looking at the plugs to dial in the carbs, but they never really revealed anything. If I did a full throttle pass, then removed them, they looked brand new. They had no sign of heat damage, but they also had no sign that they had carbon on them. After a day of boating I would look at them and they appeared brown to black in appearance. My intent is that the next time I’m out I’ll change out the plugs again, and get some more readings. It’s just a ***** to replace all 16 of them.

Thanks again everybody for your input.
Dan

Gary Anderson

Just worked on a cruiser this weekend that would lose power over 3000 rpm. Anti-siphon valve in tank was almost completely clogged. Another easy/cheap thing to check.
Gary

BAJADAVID

If your anti-siphion valve is still in your tank you would be starving the engine for fuel @ wot. You must remove it if your running a procharger.


David

Kanookstr

Absolutely!!!!

And if your using Aeromotive 1000 pumps. you should be running Minimum of 1/2'' lines feeding the pump. Brett at Aeromotive recomends 5/8". Anything less than 1/2" will result in certain pump failure.