Reply With QuoteNo, I think you will be classified as a "cheerleader" in this thread... http://free.***boat.net/ubb/biggrin.gif
"Man, I don't EVEN have an opinion on this"
Marvin- Pulp Fiction
Why is there an east coast west coast thing here? The shops don't seem to have that vibe. Several years ago I went to Jack at MPD to have my pump redone. He recommended I use Don's inducer. Jack said Don was a brilliant pump guy and the inducer would help me. I called Don to get his input on using the inducer in my situation, and he asked who suggested it. I said Jack at MPD. Don said that Jack was a brilliant pump guy and I should do whatever he suggested. Maybe I am the farmer and got taken--but my boat has never run better--hole shot, top speed, etc have all shown nice improvements. Both guys gave me advice the same, and both said the other guy was brilliant. Am I a farmer?
[This message has been edited by Caribbean19' (edited November 22, 2001).]
No, I think you will be classified as a "cheerleader" in this thread... http://free.***boat.net/ubb/biggrin.gif
"Man, I don't EVEN have an opinion on this"
Marvin- Pulp Fiction
I agree, Don and Jack both do some good work. I can speak from experience from Jack, and from word of mouth about Don. I don't have any problems, just ones when people say us west coasters don't know what we are doing, and that I should send my pump do Don's when I'm one street away from Jack's...
I'm done responding to Chet, this thread proves his stupidity cut and dry. So to me everything else Chet posts reads BLAH BLAH BLAH, YADDA YADDA YADDA...
HBjet
[This message has been edited by HBjet (edited November 23, 2001).]
I must have missed something along the way, because I still can't figure out why Chet is asking for dyno numbers on a mild 502 with a 14-71. Surely he could afford the dyno time with the money he is going to save by running one of those newfangled bronze impellers. ;-)
Chris
PS, if you're going to quote pump makes on boats, you might want to think 2x about using the 8 second class as the end all be all of proof. Then again I guess you can't use the 6 second class because you might have to site a certain MPD prepped boat. :-)
RD2 & JM,
I hate to be a pisser here but I think the main problem with the industry is that NONE of the manufacturers truly understands impeller design. I'm sure they have a good working knowledge from years of association, but there is "the original design" -and then (pretty much) tweeking of that. You guys could make a great changed impeller but what do you change? We need to find a hydrodynamics engineer that can examine this thing to give you guys the direction to go in.
Let's face it, R&D costs $$$ and if the projected units sold is not right, the project never leaves the message board.
The reality is that if you don't create a revolutionary product,(i.e. Place Diverter) a real "gotta have" you can't sell enough parts to justify the exercise.
Soooo, if we can find a pump designer with your level of enthusiasm, we have it made.
sorry..a bit of a rant there...
RiverDave, if you get a tour of SoCal jet'ers together let me know, I would love to see this stuff 1st hand. Had heard about it before but assumed it must be FM (F&@^'n Magic)
What is mild about a 502 with a 1471 ??
Chet,
I mocked up a 502 on my dyno program for you heres the specs: 502,8:1 compression,rectangular port heads,ported with 2.365 In. valve and 2.038 Ex. valve,2 850 cfm carbs,14/71 BDS competition blower,no intercooler,a mild 20% underdriven @ 8 PSI boost(for reliability),hydraulic roller cam;610 in. .632 ex. 112 lobe center,.234 in. dur. .242 ex. dur. gets you 746 HP @ 6000 RPM and 733 ft.lb. torque @ 4500 RPM adding an intercooler bumps it up to 830 HP @ 6000RPM and 816 ft. lb. torque @ 4500RPM.
Hope this gives you a good idea of where your at. Of course more boost would get more HP as would smaller valves get less. http://free.***boat.net/ubb/biggrin.gif
Hey customcruiser,
thanks on a second opinion, at least someone could at least give me that. HBJet is too busy basking in his glory thinking he's got one up on me. I really wanted him to answer. Anyways, i was guessing closer to 850hp(the blower is the variable here) but that's neither here nor there. It's just that there is a boat for sale on the ***boat classified with a 502 with a 14-71 and guess what impeller he has???? HBJet??..., Flatbroke care to add?? I'll let you tell the folks here in cyberland. K? Better email him so you can say he made a misprint..should have been SS (Only chet would be dumb enough to run bronze). BTW, we're not here to compare pumps (flatbroke where ya been?) so dont snowball the thread.
One last thing...where did i say the west coast shops have no idea what they are doing Mr. Superslueth HBJET??? WHERE? All i said was people in socal need to open your eyes to the rest of the world we live in. That was specifically meant to the cheerleaders on this board who mention one shop and one pump over and over again. Keep basking in your self made glory HB buddy because you just love to snowball stuff!
Wouldnt it be great if all the pump guru's visited this page occasionally to put there two cents in??? I think so. HBjet, how would this ever going to begin to happen the way you go about things eh??
as you said HB..blah, blah, blah.
CHET
I think the real stress to the impeller comes from the shock of coming out of the water and reentry.If a smooth application of power is applied without cavition a bronze would probably work.I think rpm may be a factor as well.If a large cubic inch motor is used,the torque curve should be in the 6000 rpm and under range.If I chose to use a bronze impeller with a big blown motor I would go as large as possible to keep it from spinning too fast.The RPM may have as much of an influence on durability as horsepower.I don't think it would be worth the chance of wrecking the pump,so I would spend the extra money on a stainless unit.DEL51
Del51 has a good point, which I think Froggystyle mentioned also...shock factor.
If you only consider steady state loading (hp) and don't consider shock or transient loading for a lake jet, then you may well end up paying big $$$ in a trashed housing...amoung other things. I know in the heat of a "lake" race, I rarely lift and the Dragn gets airborne plenty off the rollers. The comfort of knowing my impeller's SS is worth the extra $'s. Especially for a part so critical to pump life and safety.
jer
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