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Discussion Starter #1
Now that the smoke has cleared on that other bad deal,.... (most of you know what im talking about) I visited Don Hampton a few weeks back and gave him a deposit to build me a brand new 14-71!

Why a hampton 14-71?

1) Hampton is THE O.G. blower guy

2) Out of all the blower manufactures I called,.. Don was the coolest guy to speak with. Lee at littlefield was a close second, but the straw that broke the camels back is #3....

3) IMO Don Hampton has the best looking blower on the market.

4) Hampton dosent make a 10-71 to replace my old one. If im going to change my distibutor to a crab anyway I might as well go straight to 14-71. Plus a 14 will be better for a future build ;)

Ive got a blown 496 BBC, eddy rpm rec heads (soon to be darts), isky #rr-652 cam on a 112 grind set up on a 108 center, 8.5 to 1 comp, bds comp manifold, Twin holley dominator # 8896 stage three carbs with 96 jets square, 32 degree timing.

I know that nothing is linear, but here is my thinking: I ran my teflon stripped 10-71 @ 10% under. Im not sure what the boost was but accourding to mooneyham it was on the edge for pump gas. It ran great. The new blower is not going to be stripped. These are just rough calcs but...

10-71 is roughly 469cuin X .10 under = 469-46.9= 422.1 cuin
14-71 is roughly 522cuin X .18 under + 533-93.9= 428 cuin

For LAKE bench racing purposes only, lets say the above calcs are close.

Here are my questions:

1) If I back down timing to say 28 degrees, could I turn the 14-71 a smidge faster than 18 % under?

2) The motor is already pig fat...but how much more boost can you get away with by setting it up fat for pump gas?

NO!... I WILL NOT BUY A SMALLER BLOWER:)devil

-Whiskey
 

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This must be a low rpm deal..??

I ran a 565 @ 12% over with a stripped 14-71 and a 200hp shot of niitrous all on 92 pump gas and a water meth kit coming on at 6psi..... rann killer and zero problems!! 88-92 jets in a pair of 1250's and 27 on timing!!
 

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Discussion Starter #3
This must be a low rpm deal..??

I ran a 565 @ 12% over with a stripped 14-71 and a 200hp shot of niitrous all on 92 pump gas and a water meth kit coming on at 6psi..... rann killer and zero problems!! 88-92 jets in a pair of 1250's and 27 on timing!!
I wouldnt say low rpm.. maybe mid to upper. I had it in a runner bottom. It pulled like a MF'er to 6500 but is dosent like to go past that. I assume the heads are holding it back.

The cam card says Bracket racing: jet w/B-impeller, flat bottom, hydro RPM-Range (4500-7400) Lift (.650 .654) Valve Lash hot (.028 .030) Duration (318 330) .050 Duration (274 286).

Were your carbs boost ref? JMO but seems small on the jets. What rpm were you at?

 

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Carbs were not boost ref, I was refering to a low rpm because you want to under drive it so much. Why have all that blower and not use it? They really wake up when you get them spining some.
 

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Now that the smoke has cleared on that other bad deal,.... (most of you know what im talking about) I visited Don Hampton a few weeks back and gave him a deposit to build me a brand new 14-71!

Why a hampton 14-71?

1) Hampton is THE O.G. blower guy

2) Out of all the blower manufactures I called,.. Don was the coolest guy to speak with. Lee at littlefield was a close second, but the straw that broke the camels back is #3....

3) IMO Don Hampton
has the best looking blower on the market.

4) Hampton dosent make a 10-71 to replace my old one. If im going to change my distibutor to a crab anyway I might as well go straight to 14-71. Plus a 14 will be better for a future build ;)

Ive got a blown 496 BBC, eddy rpm rec heads (soon to be darts), isky #rr-652 cam on a 112 grind set up on a 108 center, 8.5 to 1 comp, bds comp manifold, Twin holley dominator # 8896 stage three carbs with 96 jets square, 32 degree timing.

I know that nothing is linear, but here is my thinking: I ran my teflon stripped 10-71 @ 10% under. Im not sure what the boost was but accourding to mooneyham it was on the edge for pump gas. It ran great. The new blower is not going to be stripped. These are just rough calcs but...

10-71 is roughly 469cuin X .10 under = 469-46.9= 422.1 cuin
14-71 is roughly 522cuin X .18 under + 533-93.9= 428 cuin

For LAKE bench racing purposes only, lets say the above calcs are close.

Here are my questions:

1) If I back down timing to say 28 degrees, could I turn the 14-71 a smidge faster than 18 % under?

2) The motor is already pig fat...but how much more boost can you get away with by setting it up fat for pump gas?

NO!... I WILL NOT BUY A SMALLER BLOWER:)devil

-Whiskey
Lil E, just one question. We're you hitting the bottle last night?
 

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steelcomp was here
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You guys can't compare a 565 to a 496 here. They're not even close.

Lil E, just one question. We're you hitting the bottle last night?
LOL...:shock:
 

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Discussion Starter #8
Carbs were not boost ref, I was refering to a low rpm because you want to under drive it so much. Why have all that blower and not use it? They really wake up when you get them spining some.
Hopefully when I scrape up the money for a future build the 14 will be right at home.

thank you for the advise
 

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Nope just thinking about boats instead of doing something more productive like sleeping.

Were you hitting the bottle last night?

p.s. sorry I wasnt able to come by the BBQ
We hung around the house after Joe and Chelsey left....BBQ was fun....today, I'll work around the house and start playing with the new stuff for the motor
 

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Discussion Starter #11
You guys can't compare a 565 to a 496 here. They're not even close.

LOL...:shock:
This is the point of the thread. If you run a big blower on a small motor like mine what can you get away with? I have seen where guys back off the timing, fatten up the carbs and get away with turning the blower faster.

My uncle had a 468 with a hi helix 14-71, 7.5 to 1, dart heads, and its lived for over 10 seasons. The new owner saw over 15lbs on pump gas and no intercooler. The only explaination Ive recieved of why it works is the motor has no timing and its way rich.

My question is ,..I know Im running another point of compression compared to the above example, but how much boost can you get away with by backing off the timing and giving it some extra fuel?

thank you :)
 

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steelcomp was here
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This is the point of the thread. If you run a big blower on a small motor like mine what can you get away with? I have seen where guys back off the timing, fatten up the carbs and get away with turning the blower faster.

My uncle had a 468 with a hi helix 14-71, 7.5 to 1, dart heads, and its lived for over 10 seasons. The new owner saw over 15lbs on pump gas and no intercooler. The only explaination Ive recieved of why it works is the motor has no timing and its way rich.

My question is ,..I know Im running another point of compression compared to the above example, but how much boost can you get away with by backing off the timing and giving it some extra fuel?

thank you :)
There's a big difference between 7.5:1 and Dart heads and your 8.5:1 and the Eddys. You can't say "I know I'm running a point more compresion BUT..." Yes, you are, and that's significant.
Boost is only a reference to restriction and you're going to make a lot more bost a lot sooner with your set up than Danny did. 6# boost on your engine will not be the same as 6# on his. You're basically trying to put a 1471 on a street engine with w big lazy cam. The cam is going to help bleed off some cyl pressure but you're still going to have to underdrive the heck out of the blower. Timing and fuel are all part of the game but totally dependant on the combination.
You're taking on a bit of a challenge here. It's usually a good idea to learn to swim a little before jumping in the deep end. I dunno...call me crazy...
:notsure:
 

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This must be a low rpm deal..??

I ran a 565 @ 12% over with a stripped 14-71 and a 200hp shot of niitrous all on 92 pump gas and a water meth kit coming on at 6psi..... rann killer and zero problems!! 88-92 jets in a pair of 1250's and 27 on timing!!
That 27* deal.....any particular reason? I was taught that number 30+ years ago on several completely different set-ups and have heard that number from several different sources over the years. They only thing i have noticed is pistons seem to begin to rattle a little at idle in a street car/decent muffs situation.
Sorry for the thread jack....not really:p
 

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Like most lake/river boaters the wow/bling factor is a big thing. I am not going to comment on the boost #s or anything mechanical..I also have a hampton blower. It meets my needs and I would be really be happy with it if the case would not grow fur every time it gets a little water on it. Water spots are a bitch to remove. Don't even think about putting your cover on the boat...out of all my prep to go to the water, I spend more time cleaning the case. The end plates and covers are easy to maintain. I thought the case oxidizes from the alloys that are used. For me I would never use a hampton again in the marine enviorment..just my 2 cents...I still have it, I just don't like it for the reason I stated.
 

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Discussion Starter #15
There's a big difference between 7.5:1 and Dart heads and your 8.5:1 and the Eddys. You can't say "I know I'm running a point more compresion BUT..." Yes, you are, and that's significant.
Boost is only a reference to restriction and you're going to make a lot more bost a lot sooner with your set up than Danny did. 6# boost on your engine will not be the same as 6# on his. You're basically trying to put a 1471 on a street engine with w big lazy cam. The cam is going to help bleed off some cyl pressure but you're still going to have to underdrive the heck out of the blower. Timing and fuel are all part of the game but totally dependant on the combination.
You're taking on a bit of a challenge here. It's usually a good idea to learn to swim a little before jumping in the deep end. I dunno...call me crazy...
:notsure:
Thank you for the advise. I will have to underdrive 18-20% for my application.

Im not trying to jump off the deep end with my build. And if it wanst for challenge, non of us would be doing this. I was just wondering what some guys have gotten away with and how they did it.

once agian scott thank you for the help.

p.s. the eddys are coming off as soon as I save the coin for new heads.
 

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You should run it closer to 25% under. A 1471 moves a lot more air than a 1071. I used to run a 1071 12.77% over and switched to the 1471 and make same boost running it 10.4% under.
 

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565 I've run the same motor with a 10 and now the 14, for the 14 I did more port work on the heads and bigger valves, less restrictive intake and more efficient intercooler, bigger cam and dry exhaust. My 565 breathes like a 600 if you go by the blower shops boost chart.... Before with the 1071 it was right on the money for a 565.
 

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This is the point of the thread. If you run a big blower on a small motor like mine what can you get away with? I have seen where guys back off the timing, fatten up the carbs and get away with turning the blower faster.

My uncle had a 468 with a hi helix 14-71, 7.5 to 1, dart heads, and its lived for over 10 seasons. The new owner saw over 15lbs on pump gas and no intercooler. The only explaination Ive recieved of why it works is the motor has no timing and its way rich.

My question is ,..I know Im running another point of compression compared to the above example, but how much boost can you get away with by backing off the timing and giving it some extra fuel?

thank you :)
Put it on a Dyno.
 

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Like most lake/river boaters the wow/bling factor is a big thing. I am not going to comment on the boost #s or anything mechanical..I also have a hampton blower. It meets my needs and I would be really be happy with it if the case would not grow fur every time it gets a little water on it. Water spots are a bitch to remove. Don't even think about putting your cover on the boat...out of all my prep to go to the water, I spend more time cleaning the case. The end plates and covers are easy to maintain. I thought the case oxidizes from the alloys that are used. For me I would never use a hampton again in the marine enviorment..just my 2 cents...I still have it, I just don't like it for the reason I stated.
20 bucks says your Hampton is a mag blower. Oh well, sucks to be you. Do you really believe Don is using some "Unique" aluminum alloy that is more susceptible to corrostion than everybody else? Some propritory "special" Hampton aluminum? Yeah, your right, using a Hampton in a boat is a Hampton problem, not an owner problem. :)sphssToo freek'n funny!


Put it on a Dyno.

He doesn't need a dyno, all he needs is a boost gauge. You could dyno thing till the cows come home and leave HP on the table. It might detonate like a bitch on the dyno, and drive right thru it on the lake. Ever been able to hold a fully boosted boat to 3000 Rs? I haven't. But I could EASILY do it on a dyno and blow chunks thru the wall. Doesn't mean it would ever happen in the boat. You would be amazed at what we get away with in the boat that would never survive a dyno session.



Ive got a blown 496 BBC, eddy rpm rec heads (soon to be darts), isky #rr-652 cam on a 112 grind set up on a 108 center, 8.5 to 1 comp, bds comp manifold, Twin holley dominator # 8896 stage three carbs with 96 jets square, 32 degree timing.

I know that nothing is linear, but here is my thinking: I ran my teflon stripped 10-71 @ 10% under. Im not sure what the boost was but accourding to mooneyham it was on the edge for pump gas. It ran great. The new blower is not going to be stripped. These are just rough calcs but...
1) If I back down timing to say 28 degrees, could I turn the 14-71 a smidge faster than 18 % under?

2) The motor is already pig fat...but how much more boost can you get away with by setting it up fat for pump gas?

NO!... I WILL NOT BUY A SMALLER BLOWER:)devil

-Whiskey
Whiskybent. Steel is right. First thing, never compare apples with oranges. You end up rods off the bottom of your boat. Never compare blower speeds and compression ratios combined with engine sizes of somebody else deal and try to determine your blower speed.
Steel posted something I misread at first. At least I hope I did, or he needs a clubbing.
All roots blowers hit maximum, or very close to it, in about 2 engine revolutions. Its a positive displacement pump feeding a positive displacement pump, geared together. Its not a turbo or a centrif.

BUT the same engine, with different size blowers running different pulleys, to hit the same boost at full throttle, can have different boosts at part throttle and less than max RPM because of the drive ratio difference. It is almost always the larger blower that will make the most boost at part throttle mid RPM running. Its why they tend to use small 144 qnd 177 inch blowers on the street. They stay out of boost longer up the throttle postion range, and keep the STREET engine out of boost, and low RPM detonation caused by low RPM boost.

You're right about your old blower. It was right on the very edge FOR A STREET engine! Not a boat. Ever been able to hold your boat engine to 3000 RPM full throttle? Ever had it PULL up threw the RPM from 1500 under full throttle/full boost? Or did it simply blow right by that and land around 4500 or higher almost instantly? Ever see a street enigne that NEVER went above 140-150 degrees. Does your boat? Also, Mooneyham's numbers were conservative, and assumed things like iron heads. You have iron heads?

Your numbers for the 14 are pretty damn claose. I assume you got them from Don. Again, they are conservative. START THERE!!!! It will get you close to 6-7 LBS boost. You MIGHT get away with 8 maybe even 9 lbs at 30 to 32 degrees. It depends on the boat weight, and the gearing, and the prop, and the weather, and the .......get the idea? You CANNOT duplicate that on a dyno!

I will leave you to think about this. If you want a seat of the pants BAM effect from the thing, stay with the higher timing and less boost. If you back off the timing, it becomes a pig in a poke lazy when it isn't in boost. If your looking for a top end blast and all the power you can muster on the top end, lower the timing to 28 and crank up the boost. But I guarantee you'll hate the power off boost. NOBODY can tell you what boost and pulleys you can get away with. You have to do that yourself. Start with the numbers you have. They are safe, but not necessarly the most you can get away with.

Remember, you CANNOT hold you fully boosted fully loaded boat to some insane low RPM that would demand street timing. This thing is NOT in boost, the throttle is MAYBE 25% open, and its already at 5000 and .barely moving. How do you get something like this to hold 2500 at full throttle and full boost and full load. You can't!!!!!



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