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[miller killer]

Maybe I am wrong,but eveytime I go to buy parts for sale that wre run on dyno time only,my motor man says no no!I've talked to alot of people that say the same thing.if you guys want to buy parts from these dyno runs let me know,i find them all over cheap.

[RiverDave2]

Dude, what are you talking about? Buying parts that have been dynoed? What??
People buy the parts, then put the in the motor, then dyno them, then run them in the boat.. A dyno is how you test your HP/Torque as well as prove out your setup.. After it's proved out you stick the motor DIRECTLY in the boat..
Your making it sound like people dyno there motor then rip everything out of it and rebuild it.. That would then not be a true HP as everymotor will be a little different.
As far as buying used parts, there's a reason your motor builder doesn't want you to do that. He wants to sell you new parts! The other reason is with used parts you never know where they've been, hairline cracks etc... Your better off buying new then going to a Dyno.
RD

[Cas]

ya know what? I'm absolutely busting a gut over here. Miller, you're killing me! Are you saying you're going to build a 100+ mph jet boat using used parts and you're not going to dyno it?

[miller killer]

The only used part on my motor is my rev kit.yes im am building a 100 mph plus jet boat.I see alot of used parts that were used for dyno testing only,didnt say im putting those parts in my motor.No i am not going to dyno my motor,I will tune motor myself!not saying im better than a dyno because im not.

[flat broke]

Originally posted by miller killer:
The only used part on my motor is my rev kit.yes im am building a 100 mph plus jet boat.I see alot of used parts that were used for dyno testing only,didnt say im putting those parts in my motor.No i am not going to dyno my motor,I will tune motor myself!not saying im better than a dyno because im not.
I don't know who does your pump work... Oh yeah how could I forget Tom is the only guy allowed to touch the Aggressor, but most of the time the initial impeller choice/cut is made based on a dyno sheet. If you go and tell your pump guy "I think it'll do about 800hp, come up with some hunch based torque and hp curves, and you're wrong, guess what... your boat isn't going to run as well as you had planned. The bottom line, if you are planning on running 100, and not putting the motor on the dyno, I'd be willing to bet you're 1. not going to make your goal the first time out. 2. going to spend money on re-doing engine and pump setup work that were initially based on guestimates. I'm not trying to cut on you, but if you're building the HP to go 100, you can afford the dyno run. If not I hope you can afford the potential broken parts on the lake.
Good luck,
Chris www.liquidaddiction.net (http://www.liquidaddiction.net)

[attyjas]

I agree...lets all take a break. If anyone knows of someone looking for a great deal on a boat check out http://home.earthlink.net/~attyjas/

[Costello]

The only parts I ever know of for sale after dyno time is maybe valve springs. These springs would have had even fewer real passes than dyno pulls before they were changed trackside anyhow. I mean really, are guys changing rods after a dyno session? The answer is no. The botttom end bearings may be changed for good measure after time on the dyno depending on how many pulls etc. but would you buy used main or rod bearings? Of course not. The only guys that spend enough time on the dyno to have a steady stream of dyno run parts are Pro Stock racers. When you're in the game at that level you don't even want the hassle of a bunch of screwballs like us constantly hassling you for used parts. Just my observations. Incidentally I've done some work for an NHRA Pro Stock team and someone from within tells me 1 track pass and 2 dyno pulls is about comparable in parts abuse.

[Jetboatguru]

Miller killer, I think it is great that you are putting together a fast boat and are going to race it. It sounds like you are working with Jim Brock and he defintely knows his way around the block. The point here with the dyno issue is to help you. It seems like a lot of money to just dump on a big machine loading your motor. Your concern is probably that it will break. I assure you that the dyno is less strenuous on your motor than racing it. The test will probably be run between 5000rpm- 6500rpm. Your motor is barely working at these RPMs. Jet boat motors are built for low RPM big torque. (Except if you run a Pro Stock deal like Zellmer) A pro gas Flat or Pro stock car pulls to 9500 on the dyno. Years of testing by Pro stock racers have help determine that 2 pulls on the dyno equal 1 pass down the track. If your engine is gonna break, would you rather it break on the dyno or at the track 150 miles away from home after you paid entry fees and Hotel?
[This message has been edited by Jetboatguru (edited January 30, 2002).]

[RiverDave2]

If your worried about breaking your motor on a dyno, then you really ought to look at the quality of parts you put in it and start over..
Real world conditions are much harder on a motor.
RD

[schiada96]

I think it would be safer for it to break on a dyno than at speed on water. Right?