continued conversation on aqua and super tigre engines

[camaroboy383]

Camaro,

Can you tell me what it was that you did not like about the engines. It might be good to get this from another modelers view.

Always looking to make a better product!

Was it performance, or maybe a specific aspect/s of the engine?

Grim

Futaba

Odonnell

OS Engines

AquaCraft

GrimRacer

VS1

UL-1 Superior

Nemesis

HTV/Aeroslot

Ninja

Futaba Sport 20

Super Sport 45

1963 Miss Bardahl

U-55 Oboy Oberto

FASST.. no data needed.. just RESULTS!

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#22 camaroboy383

National Racer

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25-February 08 Posted Yesterday, 01:01 AM

no problem mike,,,, ...remember this is just my honest opinion,, and nothin but opinion... well my first impression is that there is some unnecesary wieght,,,the cooling cap i think is just way over kill and ads a mint to the overall wieght...the case casting seems a little extra beefy around the exhaust outlet and the larger case fins to add.. so there is some more wieght... i understand you can get a standard back plate,,,which is a nice option for sure... so that will cut some down obviously...

my main peave with these engines is the lacking torque,,, they seem to want the smaller props and almost refuse to perform when loaded up... on the other hand i noticed these engines seem to spin the smaller props faster,,,so it almost evens out...now im speaking as in all around use,,, seems dang fine for a hydro,,,,(which they come in),, but slap it in the sv and it seems to have trouble getting to the pipe with a prop my mod aqua just spun the heck out of.... they just seem more prop picky...... im sure the timing numbers are different from the aqua, along with other factors of course, i.e button, head space.... so i would assume this is where the lack of torque occurs.... keep in mind i never tried any different timing configurations,, or different pipes and headers,,, bone stock the way they come in the duece...

im not a fan of the composite carbs,,,dont get me wrong,,, i know they perform just fine,,, im just not a fan,,(personal preference)...

plus sides------- i was impressed with the internals,,, the sleeve,the rod, the crank,and piston,,, super nice machining,,way nicer than the internals of the aqua...

so it boils down to this,,, my dis-likes are...

1) the wieght

2) the lacking torque

3) the composite carb

again,,, these are just my observations and opinions... and hats off to you mike for putting alot of effort where its needed,,(getting people into the hobby with rtr)....im like bill,,seems i have the most fun with the cheap rtr stuff... the rest of the fleet is just white knuckle racing....

Alden

Alden cost

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#23 Grimracer

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27-December 01 Posted Today, 04:57 PM

Ok.. good info..

Best is that you qualified that as your opinion..

Cus to me...

In "testing" the weight is/was a non issue. If one could qualify that the extra weight (say.... Aqua vrs SuperTigre) witch by the way is a difference of 1.4oz on a typical 4 pound boat) dampens the performance that would be good to know. I have not seen this to be an issue. (Proven)

The “Difference” in torque is a setup issue as you know and even if the motor makes good power some just have a hard time propping a boat that way.. You have a valid opinion on that and its well understood.. Thanks. I wish I would have had more time to work on that head button.

Composite carbs got a bad wrap in the past. They have really gotten much better over the last few years. Truth is its really hard to ware out a composite carb.. Overall they just last longer.. Not really an issue with boating but worth noting. To date I have yet to fail the carb on the ST 18.. (fact).

Thanks again and rock and roll the RTR class.

Grim

Futaba

Odonnell

OS Engines

AquaCraft

GrimRacer

VS1

UL-1 Superior

Nemesis

HTV/Aeroslot

Ninja

Futaba Sport 20

Super Sport 45

1963 Miss Bardahl

U-55 Oboy Oberto

FASST.. no data needed.. just RESULTS!

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well mike i wanted to bring this to a new thread to be respectful of larcor.... i wanted to clarify a couple things....

i understand your point of the 1.04 oz. not being an issue,,, but when it boils down to it i beleive it just makes the engine more bulky large.. maybe somone wants to slap one in a small rigger and possibly that extra wieght makes a diff,, or the overall size of the engine just doesnt allow it to be reasonable application...

now as far as the whole torque thing,,,this is the part i mainly wanted to clarify.... as far as the issue being the set up,, im not so sure i can agree with you on that... i tried every possible strut position,,rudder position,,, corrected the cg for the "heavier" engine...(all fact) im tellin ya that engine will not swing the same props as the mod aquas i have...

i will give you specific examlpes and i hope you could possibly try for your self .... (like i said this was testing in the sv hull) ....

props that i can swing with the mod aqua and gives the greatest speed are as follows,,(keep in mind,,as you know the set up changes per prop)

x440 3 blade,,, this prop swings fairly easily and gives the greatest speed of all this prop has shown me in the 45 mph range,,,does the hull take it no,,, blows off almost every time...fact is the engine will produce good power on this prop my testing with a array of set ups showed me the super tigre would not and absolutely refused to swing that prop

x640 this prop is the one i run faithfully and produces 41-42 mph speeds every pass consistantly... its an absolute good all around prop from a dig to full steam... the super tigre again had issues with this prop,,,and again on an array of different set ups...

these are two specific examples... there are a couple others i had issues with but these stand out the most...

now the composite carbs................ i beleive you that the carbs are hard to wear out...... the breakage error im expressing is human......... im sure they last a long time with just the barrel opening and closing,,,but 9 1/2 out of 10 composite carbs are ruined by human error,,, seen it all to many times.....oops i over tightened the needle assembly,,o.k stripped threads,,toss it....oops i over tightened the pinch bolt and damaged the neck....oh well,,toss it... i think you understand the point im getting at... aluminum is just a little more forgiving thats all im sayin,it kinda lets you know its tight when you thread somthin into it,,and for those who modify carbs for themselves might not like the idea of maching the composite...

i also want you to remember that im comparing the stock super tigre to a modified aqua.,...

alden

 

[Sean Bowf]

Alden, with all the AQ engines you have to have lying around...you should put a stock one in a hull and do a comparison....just to be fair to the ST engine...

I agree with most of what you are saying, just seems like you are comparing apples to oranges if you are comparing a stock ST to a modifed AQ.

As to weight, I would be curious to run a boat with a GPS in it, then drop 1.4 ounces in it and see how much the speed changes. This is about how much weight I had to put in the nose of my MV to keep it from blowing off with the CVRM in it...so I know it will change the handling, just don't know how much it will change the speed.

If I get enough time this weekend, I will tear down the ST I got a few weeks ago in our second deuce and see how the timing numbers, etc, compare to the AQ. Never really got the first one running right...as soon as we think we have it tuned, it does not do well the next run. And this is with just a Y535 on it.

From the fooling around I did with the GO engine, it seems like carbs are an important area folks miss. I think because a lot of our engines start out as car engines, they come with smaller bore carbs than what would be optimal in boats. Just my 2 cents. More testing will tell. I am waiting on a non-windy day to try out a bored out GO carb to see how much difference it makes. Just seems like I hit a brick wall with other mods to the engine (can't seem to get any more out of it no matter what I do).

Sean

 

[Mike Starrett]

It seems your comparisons are done between a modded AQ .18 and a stock ST .18

If that's the case why are we not comparing stock vs. stock? Will a stock AQ .18 turn an X440/3 or an X640? I'm not sure since I've never owned one but I'd bet they won't. I know (and agree) my stock ST.18 won't. I run a Y535. Anything bigger is a waste of time. They love RPM's. As far as weight goes, I added 3oz. to the front of my Deuce to get it to settle down. I don't think the extra ounce made any difference.

I raced a stock Deuce last year and I wish everyone else ran a stock AQ.18.

They could sure use a better collet though. I believe that collet is responsible for a lot of shaft failures. As well as the motor being misaligned with the stuffing tube.

Mine still has the starter on it but I start it with a belt. It's just easier to start when it turns faster.

It's a tough little engine. I never tried to break it in. From the time i got it I ran the crap out of it. One time something plugged up the water lines during a run. I kept running and it got slower and slower. I finally brought it in and it stopped short of the bank. The thing sounded like a bowl of Rice Crispy's. I thought that was the end of it but to this day it has great compression with little or no bleed off.

Just my 2 cents worth.

 

[camaroboy383]

It seems your comparisons are done between a modded AQ .18 and a stock ST .18

If that's the case why are we not comparing stock vs. stock? Will a stock AQ .18 turn an X440/3 or an X640? I'm not sure since I've never owned one but I'd bet they won't. I know (and agree) my stock ST.18 won't. I run a Y535. Anything bigger is a waste of time. They love RPM's. As far as weight goes, I added 3oz. to the front of my Deuce to get it to settle down. I don't think the extra ounce made any difference.

I raced a stock Deuce last year and I wish everyone else ran a stock AQ.18.

They could sure use a better collet though. I believe that collet is responsible for a lot of shaft failures. As well as the motor being misaligned with the stuffing tube.

Mine still has the starter on it but I start it with a belt. It's just easier to start when it turns faster.

It's a tough little engine. I never tried to break it in. From the time i got it I ran the crap out of it. One time something plugged up the water lines during a run. I kept running and it got slower and slower. I finally brought it in and it stopped short of the bank. The thing sounded like a bowl of Rice Crispy's. I thought that was the end of it but to this day it has great compression with little or no bleed off.

Just my 2 cents worth.

mike,,,to answer your question about the props and the aqua...... yes the aqua would turn them in stock form.... it would actually spin the 640 perdy darn good.... the 440 would swing also just not as well as wih the modded engines..... i agree with you on the collet thing,,,, i use the octura ones and they seem to last me,,,,,well,, i actually have never replaced one yet....

Im not bashing the st engines,,,they just werent for me... mike asked what i didnt like about them,,and well i brought my opinion to the table...... i have a very hard time trying to understand the methods used by the manufacturers and i guess i will never fully understand.... to me it just seems so simple for them to make a already existing product better,,, instead they choose to start over with a new product and discontinue the last.... new product is good,,,but to me a improved product is better... ....

alden

 

[camaroboy383]

Alden, with all the AQ engines you have to have lying around...you should put a stock one in a hull and do a comparison....just to be fair to the ST engine...

I agree with most of what you are saying, just seems like you are comparing apples to oranges if you are comparing a stock ST to a modifed AQ.

As to weight, I would be curious to run a boat with a GPS in it, then drop 1.4 ounces in it and see how much the speed changes. This is about how much weight I had to put in the nose of my MV to keep it from blowing off with the CVRM in it...so I know it will change the handling, just don't know how much it will change the speed.

If I get enough time this weekend, I will tear down the ST I got a few weeks ago in our second deuce and see how the timing numbers, etc, compare to the AQ. Never really got the first one running right...as soon as we think we have it tuned, it does not do well the next run. And this is with just a Y535 on it.

From the fooling around I did with the GO engine, it seems like carbs are an important area folks miss. I think because a lot of our engines start out as car engines, they come with smaller bore carbs than what would be optimal in boats. Just my 2 cents. More testing will tell. I am waiting on a non-windy day to try out a bored out GO carb to see how much difference it makes. Just seems like I hit a brick wall with other mods to the engine (can't seem to get any more out of it no matter what I do).

Sean

that would be excellent info for sure sean on the timing numbers... i no longer have the st's here to phisicaly see the difference....i never had tuning issues with the two i had,,, they ran perdy consistant all the time...

i agree with the carb theory.. there is alot to be gained in the carb area's,,, mr. charles perdue will agree there along with many others... there is always a fine line that once you cross the performance will go down,down,down.. only thing you can do is apply what works and watch her scream,,after that,,, your brick wall has arrived...lol... :lol:

alden

 

[f16man]

Alden, with all the AQ engines you have to have lying around...you should put a stock one in a hull and do a comparison....just to be fair to the ST engine...

I agree with most of what you are saying, just seems like you are comparing apples to oranges if you are comparing a stock ST to a modifed AQ.

As to weight, I would be curious to run a boat with a GPS in it, then drop 1.4 ounces in it and see how much the speed changes. This is about how much weight I had to put in the nose of my MV to keep it from blowing off with the CVRM in it...so I know it will change the handling, just don't know how much it will change the speed.

If I get enough time this weekend, I will tear down the ST I got a few weeks ago in our second deuce and see how the timing numbers, etc, compare to the AQ. Never really got the first one running right...as soon as we think we have it tuned, it does not do well the next run. And this is with just a Y535 on it.

From the fooling around I did with the GO engine, it seems like carbs are an important area folks miss. I think because a lot of our engines start out as car engines, they come with smaller bore carbs than what would be optimal in boats. Just my 2 cents. More testing will tell. I am waiting on a non-windy day to try out a bored out GO carb to see how much difference it makes. Just seems like I hit a brick wall with other mods to the engine (can't seem to get any more out of it no matter what I do).

Sean

that would be excellent info for sure sean on the timing numbers... i no longer have the st's here to phisicaly see the difference....i never had tuning issues with the two i had,,, they ran perdy consistant all the time...

i agree with the carb theory.. there is alot to be gained in the carb area's,,, mr. charles perdue will agree there along with many others... there is always a fine line that once you cross the performance will go down,down,down.. only thing you can do is apply what works and watch her scream,,after that,,, your brick wall has arrived...lol... :lol:

alden

Has anyone modded a ST sleeve and case yet? and how much nitro are you using with the stock engine?

 

[M@MRacing]

Mike i have a 440/3 blade on my wifes stock aqua in her super veee runs with the best of them.

 

[Sean Bowf]

SV will have an easier time turning a larger prop than an MV. I think it has to do with the depth of the prop in the water. If the MV could be made to be surface drive (which it isnt stock) this might change.

Alden, Not sure if you have your prop numbers switched around or if I missed something, but it should be easier for the engine to turn a X440 than an X640, unless the 640 is a two blade and the 440 is a three blade. Is that what is going on, an X440/3 compared to an X640/2??

Sean

 

[camaroboy383]

SV will have an easier time turning a larger prop than an MV. I think it has to do with the depth of the prop in the water. If the MV could be made to be surface drive (which it isnt stock) this might change.

Alden, Not sure if you have your prop numbers switched around or if I missed something, but it should be easier for the engine to turn a X440 than an X640, unless the 640 is a two blade and the 440 is a three blade. Is that what is going on, an X440/3 compared to an X640/2??

Sean

you would be correct sir...... x440/3,,, x640/2 ..... both engines in the sv hull...

f16,,,, the case machining looked dang good to me,,,, im not sure you will gain anything from the case... the sleeve timing can be changed but have heard nothing about it,... really trial and error is going to show the best results... start cuttin different timing configurations till you find where it runs well and run with that cut..... i dont know how many sleeves i cut for the aqua when i first started messin with them... :blink: ... the first one i cut till it dropped power then worked back from there,....time time time,,,perdy much what it boils down to...

alden

 

[misshydro]

dont know why they tigerdrive the ST.. more drag on the motor too me..be nice if somebody mod a ST and do some compairson...or just run a stock aquacraft.18 mv against a stock .18 ST but in a second gen hull ,orbetter yet both motors in the duce hull...

 

[camaroboy383]

actually missy,, the tiger drive imposes very little to no drag on the engine when its running.... the crank is set up exactly the same as the hpi nitro star units... the crank pin is hollow and has a spring and a hardened steel pin that slides in and out nicely.... the pto shaft has a slight recess in it that ramps down gradually but quickly... when the engine is running the pin just slides around the pto shaft as the machined ramp only goes in one direction... essentially the pto shaft wont spin at all when its running so the drag is very minimal if any.... its a loud design,,, but its a very effective design....

alden

 

[Bill Gibson]

actually missy,, the tiger drive imposes very little to no drag on the engine when its running.... the crank is set up exactly the same as the hpi nitro star units... the crank pin is hollow and has a spring and a hardened steel pin that slides in and out nicely.... the pto shaft has a slight recess in it that ramps down gradually but quickly... when the engine is running the pin just slides around the pto shaft as the machined ramp only goes in one direction... essentially the pto shaft wont spin at all when its running so the drag is very minimal if any.... its a loud design,,, but its a very effective design....

alden

Alden, im just curious.. does the ST appear to be any better built than the Aqui? How about the rod? I wonder how the ST would hold up to modds compared to the Aqui? Ive never seen the ST, so i was just wondering....hope to get to the pond with your motor (and pipe!) soon...must resist the urge to lean er out and pull the trigger when i do!! :lol:

 

[Sean Bowf]

Bill...it looks like they spent more time on the rod than OS did when they made the AQ engine. I won't claim to be any sort of expert when it comes to engines, but it looks a lot better...more rounded edges...has a little knifing to it (does not come to an edge, but is tapered). In a few more minutes I will post come pics and numbers...

At least one thing seems odd...the top of the two transfer ports in the engine are .004 different (top of port to top of liner). Does not sounds like a lot, but that makes their timing 2 degreed different. Not sure if this was done on purpose...or just their "tolerance" for the ports.

Sean

 

[Sean Bowf]

This first picture shows the rods, pistons, and the exhaust port. The engines from left to right are AQ (worn out), ST (new), CVR (new P/L I have had sitting around for awhile). Timing numbers I got for them is 158 171 158



This picture is of the transfer ports, same order. Timing numbers I got are (used the higher ST port) 113 119 109



This picture is of the boost ports, same order. The boost port does not have a channel in the AQ engine (not used). 112 120 101



I have not measured the head volume of the ST yet...so will have to edit that in here later. But the Compression ratios I got are 7.1 to 1, EDIT: 6.4 to 1 (I need to double check my measurements later...because I am getting a HUGE head clearance right now), 7.5 to 1. These are stock numbers out of the box (shims still in).

Numbers are subject to whatever errors I can/could/did make...

Something to note is the size of the ports and bore of the carb. The AQ seems to have port sizes and carb bore near the size of a .12 CVR engine...something to keep in mind when comparing the other engines' port sizes to that of the AQ engine.

The timing numbers of the ST look a lot better (more toward an RPM engine...ie Boat engine). But to me, it does not seem to have the torque of the other engines. Maybe the CR is too low for the higher port timing numbers??

Couple other measurements I took...the mount of the carb seems to be the same size as the AQ carb. Of course the AQ carb uses a couple mounting screws, so it would be hard to make the ST carb work on the engine. Point I am trying to get at, is the carb of the ST has a larger bore than the AQ. I am getting .215 for the AQ, .255 for the CVR, and .254 for the ST.

Of course the rest of the variable for the intake would be the bore in the crank. .246 AQ, .280 ST, and .314 CVR

Intake duration are 189, 185, and 210 degrees.

Sean

 

[Sean Bowf]

Well...I measured it about three times...and unless I am messing up the math somehow, I am getting a head clearance of .033 with shims installed that are about .017. So...the compression numbers I edited into the post above should be real close.

Now I need to figure out where the crank pin went...heh.

Sean

 

[TERMINATOR]

actually missy,, the tiger drive imposes very little to no drag on the engine when its running.... the crank is set up exactly the same as the hpi nitro star units... the crank pin is hollow and has a spring and a hardened steel pin that slides in and out nicely.... the pto shaft has a slight recess in it that ramps down gradually but quickly... when the engine is running the pin just slides around the pto shaft as the machined ramp only goes in one direction... essentially the pto shaft wont spin at all when its running so the drag is very minimal if any.... its a loud design,,, but its a very effective design....

alden

i like the pin and spring, cuz when i pulled trevor's "my 6yo" boat apart and put the endplate on it..that pin wasa perfect for for my savage 25 ss motor that i had lost and could not find a replacement for,, like kiling 2 birds with a brick..lol , i think once we had his out and the junk stock tank was leaking , i had to take the needle out 6 turns or more and it still killed plugs, we installed a sullivan 6 oz and it will run like hell now, good little motor , pulling a 440/3 blade on his mv 2 running 43 mph.. good fun for a 6 yo.

tk

 

[camaroboy383]

actually missy,, the tiger drive imposes very little to no drag on the engine when its running.... the crank is set up exactly the same as the hpi nitro star units... the crank pin is hollow and has a spring and a hardened steel pin that slides in and out nicely.... the pto shaft has a slight recess in it that ramps down gradually but quickly... when the engine is running the pin just slides around the pto shaft as the machined ramp only goes in one direction... essentially the pto shaft wont spin at all when its running so the drag is very minimal if any.... its a loud design,,, but its a very effective design....

alden

i like the pin and spring, cuz when i pulled trevor's "my 6yo" boat apart and put the endplate on it..that pin wasa perfect for for my savage 25 ss motor that i had lost and could not find a replacement for,, like kiling 2 birds with a brick..lol , i think once we had his out and the junk stock tank was leaking , i had to take the needle out 6 turns or more and it still killed plugs, we installed a sullivan 6 oz and it will run like hell now, good little motor , pulling a 440/3 blade on his mv 2 running 43 mph.. good fun for a 6 yo.

tk

terry,,, that is very interesting info you have there as far as spinning that prop with that engine.....are you sure its a 440 /3??? ... the other beauty of the pin and spring is that it makes putting a standard back plate on the engine a snap....

 

[camaroboy383]

Well...I measured it about three times...and unless I am messing up the math somehow, I am getting a head clearance of .033 with shims installed that are about .017. So...the compression numbers I edited into the post above should be real close.

Now I need to figure out where the crank pin went...heh.

Sean

no,,,thats correct sean,,, your math is right buddy... i bring my aqua's to .007-.008 with a .17 volume,,angled squish...seems to work well for me...great info you have provided,,,just curious what kind of blow down number you came up with also.... my buddy bought one of my st's so im sure its only a matter of time before im called in for a cutting,,,, he is always tryin to go faster than me,,,, but he needs to realize,,, im doing the engine work so it aint happenin :lol: :lol: :lol: :lol: ....

mr. bill,,, hmmmmmmmm how is my pipe down there :lol: :lol: ... you need to get that thing wet man and let me know whats goin on.... marty will get that thing hummin with some prop work for sure.... keep me posted....im gettin geared up and un-winterized over here,,, caint wait to run,,, already got my dock in,,,,, oh man was that watter cold :blink: :blink: :blink: ...... by the way,,, did you see the pic sean posted of the rods????? i want you to look at how the cvr and the st rod is drilled for lubrication... what seems to be missing on the aqua rod??? thats right,,,,the oil galley... this is my new method of drilling the aqua rods,,, so the crank window passes the hole... ... we will see if this proves to help the rod failure of the aqua's....

 

[Sean Bowf]

Blowdown is simple math from the exhaust and transfer timing. With the numbers I got for timing, the blowdown would be 26.

I found the pin, it was in my desk chair. BTW, Tower sells them for about 69 cents if I remember the price correctly.

Again, I am not an engine guru, but it would appear to me that a new head button (not enough meat in the OEM one to make the changes needed), and some work on the very small boost port, and I would think this engine would really pick up some power. I would think with a clearance of .006 and a volume of .24 CC this thing will really hummmmm...

Alden, unless you are changing the exhaust timing a lot....a .17 volume bowl on the AQ engine would really take the CR up. With a timing of 180, you are talking about a CR of over 10 to 1. I would think this would bring loads of torque, but not a lot of RPM...no??

Sean

 

[camaroboy383]

the torque is for sure a noticable difference and they are monster somtimes to turn over... i did not notice absolutely any loss in rpm,,i have absolutely no way to log the rpm,,, but im dang sure the increase in port timing made more rpm,,they sure gained some top end mph so i would assume they are spinning the prop faster...from all the engines ive ever built from sbc,sbf,bbc, snowmobile piston port engines and rotary valve engines,,quad and dirt bike engines,,,rc engines,, the increase in cr has never hindered the rpm unless it was absolutely not right for a good combustion process,,ie detonation,,low octane...to me its absolutely needed to have a engine that will produce torque just as well as rpm,,, that bubble volume you stated at .24 or along those lines sounds excessive... with the lacking torque present already imho,, i think you could possibly have a issue gettin that boat on step.... id be interested to see for sure though....

alden