ISO Sensenich Q to try out

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radtech
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ISO Sensenich Q to try out

Postby radtech » Sat Jul 14, 2018 11:00 am

I have a 16 ft alumitech with a 70 Cad 500, 10.5-1 compression, 120 RV cam. I was told by a Man I trust (Marshall Jones from Mack's Fish Camp) That a Sensinich Q would give me the push to get this big rig rolling on dry ground. I have looked into it several times since then and haven't been able to get a chance to try it out. I'm currently swinging a 74" water walker sig and it will jump out of the water but once I'm on dry ground it wont get me moving. Any help would be appreciated. I would be glad to buy the blades, but I'd like to see how they perform before spending the money. Would only need blades as they will fit my hub.

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Re: ISO Sensenich Q to try out

Postby Slidin Gator » Sat Jul 14, 2018 6:13 pm

I'd be happy to help you out if you ever want to make a trip to S. Fla. I am currently running a Q blade and I have a set of NGQ's on order now. So I am obviously interested to find out how the new prop compares. It would be even better to add the Sig into the comparison mix.

Once I get my present buggy project out of the way, I have a new load cell and materials sitting in the shop to make my new thrust test contraption for direct comparisons. I hope to have that sorted out late August, keep in touch.

In the mean time, what RPM are you turning that prop at now? Do you know the weight? What do you have on the bottom to make things slippery?

Those Caddys make torque, but you don't have the lightest set up, so it's going to take making everything to get what you are looking for.
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: ISO Sensenich Q to try out

Postby radtech » Sat Jul 14, 2018 7:38 pm

Sounds like an awesome opportunity. I'd love to make it happen...get an idea of how all 3 props do. Definitely keep in touch. I'll PM you my contact info and all. Missed out on my Mack's Fish camp trip this year, so it would be cool to get to take a shorter trip down to see everyone.

As far as my set-up, I have new poly on it as of last year and not very many rides on it. Not sure of the weight, but it is pretty heavy. When she sits on dry ground it's really hard to push the nose. Usually takes 2-3 people to slide the nose around enough to break it free. Prop is turning about 3100 on the trailer.
Tim

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Re: ISO Sensenich Q to try out

Postby radtech » Sat Jul 14, 2018 9:07 pm

Where do you ride at, brother?

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Re: ISO Sensenich Q to try out

Postby Slidin Gator » Sat Jul 14, 2018 9:08 pm

Central Florida and south, but always open to opportunities.

That's a little high on the revs, what is your pitch setting?
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: ISO Sensenich Q to try out

Postby radtech » Sat Jul 14, 2018 9:26 pm

Hard to say. There are no marks on a sig. Just a ridge that marks the starting point. It is maybe 1/2 cm past the starting notch. Much further than that and it bogs down and doesn't want to plain out. I know it is supposed to run no higher than 2800, but it seems to perform much better where it's at. I've run Lake O before, but I wasn't very impressed. Seems like too much deep water. I ride 2a and 3a and b when I'm down that way, usually stay at Mack's fish camp in the motorhome. Love it down there. It's lots of shallow water trails.

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Re: ISO Sensenich Q to try out

Postby Deano » Sat Jul 14, 2018 9:27 pm

Tim, I don't know that it would make any difference in your specific case, but my situation is a very similar to yours.

I'm also running a set of Signatures with my 472 on a 15' Rivermaster which is also a good bit of boat for a DD.
I have found that in this case, I get a little more bottom end dry push with the blades pitched to turn 2850 or so.

That may or may not correlate to your specific rig, but with your stronger engine and additional weight factored in,
the comparison may in fact be a good one. Don't know if you've already tried increasing the pitch a little, but if not, it
may be something else to try.

It may sound counter intuitive, but adding pitch worked for me. I tried adding more, but this engine is much closer
to tired than it is to fresh, and simply lacked the grunt to stand anymore. Yours may in fact be able to.

Can't help with the Q comparison as I've never run them. Almost did at one time, but another brother beat me to them.
"The suppression of uncomfortable ideas may be common in religion and politics,
but it is not the path to knowledge; it has no place in the endeavor of science."
- Carl Sagan

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Re: ISO Sensenich Q to try out

Postby radtech » Sat Jul 14, 2018 9:37 pm

Deano, yes I tried it pitched to run around 2800, but it was so sluggish that it took forever to get on plane. We pitched it back to 3100 the other week on Seminole, and now it literally jumps out of the water when you kick it. It seems to work better pitched a little more. Still got some other problems to deal with now as I hit a submerged stump gator hunting last year and flew the boat, twisting and bending the bottom. I think I'm just gonna order a new hull built when I can and rebuild completely and add a gear box in the future. For now, I just wanna see if the Q will make a difference or not. I hate to spend the money only to find that it doesn't help or is even worse.

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Re: ISO Sensenich Q to try out

Postby radtech » Sat Jul 14, 2018 9:59 pm

I have jacks in the bottom and we got the bottom straight when we put the new poly on, but the hull is also twisted and now the center jack is bent and messed up at the center stringer due to jumping a submerged stump. Not sure if anything will fix it, but gonna try to work it out til I can afford a new hull

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Re: ISO Sensenich Q to try out

Postby radtech » Sun Jul 15, 2018 4:17 am

:thumbleft:

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Re: ISO Sensenich Q to try out

Postby SWAMPHUNTER45 » Sun Jul 15, 2018 6:34 am

The Q blades like to run at 3,000 to 3,100 it's the wider NGQ that likes to be choked to 2,800 rpm.

My experience with them was the Q didn't have quite as much push on dry but gave a bit more running speed on the water.

If you want a prop for a DD Caddy 500 that is lightly modified a 74 innch NGQ pitches 2.5 would be something to try. The Branch 514 we set up in 2014 spun a 76 inch NGQ pitched at 3 but it was a fully ported roller build. It pushed a heavy 16 ft glass boat with rod boxes and poly dry with 3 people and a cooler in the boat. It was a labor to get it to break loaded on the summer grass but she would it just took effort or a push of the "little red button."
Last edited by SWAMPHUNTER45 on Sun Jul 15, 2018 6:50 am, edited 1 time in total.

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Re: ISO Sensenich Q to try out

Postby mojoe » Sun Jul 15, 2018 6:46 am

1) ladyblackwater is 100% correct. A hull that will rock will ride dry better

2) I have never seen a prop change turn a boat that keeps getting stuck into a hill burner

3) As you said, less pitch gives you snap, but you are complaining about dry push. Deano is correct here that pitch = push... but you will lose snap. It’s a trade off.

4) Want both push and snap? Get a 12’ hull and a 6cyl ac motor :cheers:
Mark 7:9

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Re: ISO Sensenich Q to try out

Postby SWAMPHUNTER45 » Sun Jul 15, 2018 6:56 am

If you want push and snap in a big boat try a Branch 542 Cadillac bolted to a 2.37 gear drive with 4 "S" blades.


I agree a hull set up is critical to your ride and running the hill. That and weight are huge factors.

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Re: ISO Sensenich Q to try out

Postby radtech » Sun Jul 15, 2018 6:58 am

LOL I think I'll stick with the ol CAD. I'm debating on what I want to end up with, but I'm starting to lean towards a 13 1/2-14ft hull, 1.76/1 gearbox, etc. I will do this slowly over time as soon as I figure out how I wanna do it, and continue to ride the ol John Deere til I'm ready to swap it to the new boat. In the meantime, I wanna see if I can get the hull worked over where it rides better and check out the difference in props, as I've only ever had a wood prop and the sig. I've been looking for a stock quadrajet as well, but so far I haven't managed to find one. The old 2 barrel that came off my original engine (a 220 GPU) doesn't seem to give the ol cad enough juice and that may be one of the problems. I'm sure there are several issues that need to be dealt with in order to gain performance, but I'm working on it

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Re: ISO Sensenich Q to try out

Postby radtech » Sun Jul 15, 2018 7:01 am

Swamphunter, I'm not too sure that kind of set-up is in my budget at present, though it does sound good. That sounds like around 20 grand or more for just engine, box, and prop. I'm just a poor fella. lol

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Re: ISO Sensenich Q to try out

Postby SWAMPHUNTER45 » Sun Jul 15, 2018 8:07 am

You could probably over the next 6 months get a used 2 or 3 blade S and gear drive for around 4K then upgrade the rockers for around a grand to a shaft system. Maybe less but think I am close on budget.

Not sure if you have room to make it work but my rig was converted over from DD or GD. No going back. A gear drive Caddy is wonderful. You don't even need to spin it hard. Think about a 2.11 drive taking and almost doubling your torque. The 1.7 ratio was made for the Caddy boats back before the modern upgrades. From time to time you see them for sale here.


Just a option for you to consider if power becomes a need.

As far as aircraft engines go that's for those $$$$$ guys I just run up to Advance Auto and use my coupon.

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Re: ISO Sensenich Q to try out

Postby SWAMPHUNTER45 » Sun Jul 15, 2018 8:31 am

Tuff to beat a 13 1/2 Jimmy White with the wide beam for a Caddy.

That's the best hull we have found for both speed and dry ground. So much so that Mr Branch is in the very slow process of putting his own JW boat together. He has been busy this year and had a death in the family that forced him to close the shop a few weeks so no time now to build his own stuff. I'm hopeful in 6 months we may see the first 570 cubic inch direct drive Cadillac sliding around.

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Re: ISO Sensenich Q to try out

Postby radtech » Sun Jul 15, 2018 11:04 am

I'm a little skeptical about the glass hulls. I started off with one and loved it because it rode well, slid well, etc, but after a few pucker moments hitting submerged stumps on Seminole, I more or less split the hull in half. When I got rid of it, there was a clear crease in the hull straight up the middle where the hull was ready to split open. As for power, mine has plenty, just doesn't get to the full power being DD. Definitely want to build the new one with a gear box.

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Re: ISO Sensenich Q to try out

Postby SWAMPHUNTER45 » Sun Jul 15, 2018 11:51 am

Start watching the classifieds.
I had a super clean 1.53 that I got years back from Dutch. It went from me to Blu to now Kwan has it.

If you get a drive that's been cared for they last upwards of 1500 hours. If you need tech advice pm but plan to get a rocker upgrade and try to find out if you engine has had the valves upgraded to one piece.

When you see parts you need jump on it.

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Re: ISO Sensenich Q to try out

Postby radtech » Sun Jul 15, 2018 1:07 pm

I've certainly been keeping my eyes peeled for a deal on one. It will mean having to eventually buy a new prop and all, but it'll be worth it in the end when I have it all together on a new hull.

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Re: ISO Sensenich Q to try out

Postby Slidin Gator » Sun Jul 15, 2018 5:28 pm

radtech wrote:Hard to say. There are no marks on a sig. Just a ridge that marks the starting point. It is maybe 1/2 cm past the starting notch. Much further than that and it bogs down and doesn't want to plain out. I know it is supposed to run no higher than 2800, but it seems to perform much better where it's at.


radtech wrote:Deano, yes I tried it pitched to run around 2800, but it was so sluggish that it took forever to get on plane. We pitched it back to 3100 the other week on Seminole, and now it literally jumps out of the water when you kick it. It seems to work better pitched a little more.


What you say makes sense if the motor is lacking torque in the lower RPM ranges and you kind of hit the nail on the head on a later post:

radtech wrote:... As for power, mine has plenty, just doesn't get to the full power being DD. Definitely want to build the new one with a gear box.


Your motor is probably just starting to get to max torque at the prop limit, so you have to drop the pitch just to spool the motor up enough to jump on a plane. But in doing so the max prop speed could be beyond it's optimum range and not making max thrust at the top end (and probably loud as h@@L I bet).

I would focus on fattening up the torque curve below 3,000 RPM before considering prop options, that will yield the most improvement in your situation, unless you change your mind and decide to go the gear box route. I come up with 434 CFM for a 500 in^3 motor at 3,000 RPM. Your present carb may be a hair too small and I am a quadrajet fan. They are more difficult to tune, but once set they are solid. Definitely no bigger than a typical 500 CFM unit.
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: ISO Sensenich Q to try out

Postby radtech » Mon Jul 16, 2018 2:03 am

Yes, it is certainly loud, Slidingator. Everyone on Seminole who knows me, Knows it's me when I kick it and can hear me all over the lake. lol

I am 100% looking for a quadrajet to put on my engine. Just haven't run into the right opportunity yet. Also, yes, I am planning to eventually go gear box, but I'm gonna build a fresh hull and rigging and do it up right the first time. Thanks for the input

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Re: ISO Sensenich Q to try out

Postby Slidin Gator » Mon Jul 16, 2018 6:56 pm

I guess it depends on where you are looking, I have a couple of 5 gallon buckets full of Quadrajet parts from carbs I've worn out, it is a place to look for a core anyway. $250 for a rebuild, $350 if you don't have a core.

http://www.carburetion.com

I buy a lot of parts from this site.
https://quadrajetparts.com/
I grew up thinking I-10 was the Mason Dixon line.
1986 Airboat Engineering Inc., 14' Marsh Master. Refreshed narrow deck, SV O-540, 72” NGQ. A Bob Stossel original.

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Re: ISO Sensenich Q to try out

Postby radtech » Tue Jul 17, 2018 6:40 am

Thanks, Slidin gator! I'll take a look for sure

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Re: ISO Sensenich Q to try out

Postby radtech » Tue Jul 17, 2018 7:26 am

I have been given the advice to try a edelbrock 650 cfm annular carb and have found one quite reasonable. I'm thinking of going that route rather than spending almost as much for a q-jet and having to rebuild it. Not a lot of difference price wise in a manual or electric choke, but I have an HEI distributor, so manual may no longer be an option. Any thoughts?


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