Motor choices

[gnarley]

Originally posted by cstraub69
The 540, my neighbor asked me to get a quote on a blower for his 496 while I was at PRI. I was told with 6 psi he would need a new set of pistons in 25 hours of use.
Chris
Why after 25 hours and not 28 or 99 or even 200 hours? Is that assuming the user is on the juice for that entire 25 hours @ 6 psi? What if the user was only on the juice 25% of the time during the 25 hours? This does not seem realistic.
Please explain if possible.

[cstraub]

Charlie, I would say he meant hard running. What has been done by the OEM's to combat emmmissions is to raise the top ring in the piston. . .this reduces the area where gasses build up. By doing this you get a cleaner burn. Down side is when boost is added the extra heat builds up and torches the thin area of aluminum at the top of the piston above the ring lands. Hence the new engines are not bost friendly.
I spoke with Vortec and a fellow from Warlock Marine. . .I have the business cards around here somewhere. The older motors would take it even with cast pistons, but these newones you need to beware.
Chris

[gnarley]

OK so if you went with a 496 and added 6 psi boost and did a comp test and leak down prior to running for a baseline then continued to check you would probably know when something started going south, and might well exceed the estimate. On the other hand if this is a known problem would you want to even take that chance or just opt for the motor that would be boost friendly?
This sounds like a candidate for water injection, which would keep temperatures down since fuel dumping isn’t an effective coolant.
What are your thoughts Chris?

[Havasu47]

Originally posted by gnarley
OK so if you went with a 496 and added 6 psi boost and did a comp test and leak down prior to running for a baseline then continued to check you would probably know when something started going south, and might well exceed the estimate. On the other hand if this is a known problem would you want to even take that chance or just opt for the motor that would be boost friendly?
This sounds like a candidate for water injection, which would keep temperatures down since fuel dumping isn’t an effective coolant.
What are your thoughts Chris?
LMFAO
Not the water injection thing again
Thin area above the ring, thin block deck, thin cylinder head deck, all add up to "no like boost"

[DogHouse]

I heard somewhere that a Magic will run pretty good with a Peto built 598 in it...

[cstraub]

From what I have gathered, this new Gen. BBC needs alot of aftermarket parts to make it HP friendly. If I was to "boost" this engine I would put pistons and rods in it.
Chris

[gnarley]

Originally posted by Havasu47
LMFAO
Not the water injection thing again
Thin area above the ring, thin block deck, thin cylinder head deck, all add up to "no like boost"
Actually I wouldn't do it myself if the 496 is not boost friendly. But my point was if someone really wanted to could this be an option for increasing the longevity in that situation?
Havasu47, you seem to be the only person I've heard dis'n WI. Maybe that’s due to a failure of your own? You said you had used it extensively in the past. You said few pistons melted @ 6000 RPM under 15lbs boost due to a bad water pump? Maybe you didn't use quality parts for your WI like the good parts you used in the motor? Maybe you have an extremely biased opinion due to your own failure?
There are other things that could also cause you to lean out or detonate and blow holes in pistons the size of golf balls. The point is you had a failure.
You also previously said “The cylinder temps with the 110 was in the 1300 deg range. With 91 and water injection they would climb over 1500 and would have to back off the throttle”.
I would say that wasn’t to bad considering you used 91 octane @ 15 lbs boost! Did you bother to take any measurements with the 110? I bet the temps would have been even less.
To many major auto manufactures have used WI and professional race teams like current World Rally Cars and in aviation for there not to be any credibility, so why not in boats? Most people don’t understand WI and would rather not be bothered by it, but if more did understand I bet more would try it.
Hell runin a fuel motor is being on the edge every run and if the tune up is off just slightly its going to melt down and you see those guys having parts failures here and there but they don't stop using something that worked because it failed, they try to fix the problem so it won't happen again.
Winners never quit and quiters never win
You gave up

[cstraub]

Only experience I have with water injection was on a turbo application. . . 140Lbs of boost. It was scarey....
Chris

[Havasu47]

Originally posted by gnarley
Actually I wouldn't do it myself if the 496 is not boost friendly. But my point was if someone really wanted to could this be an option for increasing the longevity in that situation?
Havasu47, you seem to be the only person I've heard dis'n WI. Maybe that’s due to a failure of your own? You said you had used it extensively in the past. You said few pistons melted @ 6000 RPM under 15lbs boost due to a bad water pump? Maybe you didn't use quality parts for your WI like the good parts you used in the motor? Maybe you have an extremely biased opinion due to your own failure?
There are other things that could also cause you to lean out or detonate and blow holes in pistons the size of golf balls. The point is you had a failure.
You also previously said “The cylinder temps with the 110 was in the 1300 deg range. With 91 and water injection they would climb over 1500 and would have to back off the throttle”.
I would say that wasn’t to bad considering you used 91 octane @ 15 lbs boost! Did you bother to take any measurements with the 110? I bet the temps would have been even less.
To many major auto manufactures have used WI and professional race teams like current World Rally Cars and in aviation for there not to be any credibility, so why not in boats? Most people don’t understand WI and would rather not be bothered by it, but if more did understand I bet more would try it.
Hell runin a fuel motor is being on the edge every run and if the tune up is off just slightly its going to melt down and you see those guys having parts failures here and there but they don't stop using something that worked because it failed, they try to fix the problem so it won't happen again.
Winners never quit and quiters never win
You gave up
Charley, you, unlike Chris, myself and many other posters have no "hands on" experience with many of your opinions. You choose to take everyone who takes the time to help by answering questions in these forums and say stupid things like "you gave up". You have no idea of the extent of testing that I or anyone else you flame has done.
I have read many of your posts and every time someone answers with something you don't agree with you flame them.
Read my post, I was joking with you.
By the way, please enlighten us with all those auto manufacturers that have decided to use water injection on their production cars in 2004?
There are other things that could also cause you to lean out or detonate and blow holes in pistons the size of golf balls. The point is you had a failure.
That's correct, but in this instance it was a failure in the water injection pump.
You gave up
Yep, I gave up on water injection. As I said before, after much testing. You should try it sometime.
Winners never quit and quiters never win
That's original. Spoken like a true armchair quarterback. As far as winning goes. We do it, you read about it, then tell us how it should be done.
Hey, here's an idea, bring your "Blown Fourwinns" to the BBSP at Havasu, turn up the boost, add water injection, and kick everybody's ass. Then you can speak from experience.

[Foggerjet]

140 lbs of boost? HOLY SHITE. good god I thought 30 was alot.
WOW
fog