jombo

ok now for the fun part .my backyard is about 200 ft long and my neibors is 80 ft long ,lets just putit this way you need alot of room for this thing to breath. i was running out of room in a hurry and my dirty danglers didnt survive.

SAVAGEJIM

I too think a tuning vid on STS engines would be great! The only vid that is narated and in which you can hear the engine sounds are a couple of tuning ids from HPI that JC posted some time ago.

I myself am in no hurry; that is, if you decide to take on theendeavor, take your time. Any tuning vid with sounds of the engine are always a great tool (especially when it is a particular engine of question with a given exhaust, in our case, the D30M with STS 0702 in-line pipe).

Anyways, I'm glad the weather is as great as it is now, and Im even happier that I am off today; I'm going to finish breaking in my D30M. Actually, I need to go to my local RC store and get some more fuel; I want to burn about 1.25 to 1.5 gallons to day before I tune for max performance.
Too bad the weather turned south on me this past weekend; I so wanted to finish the break-in of my D30M.

supertib

all the tuning knowledge in the world wont help you you if there is an underlying mechanical issue... If the user isn't astute enough to find the problem, there is no hope of ever tuning the engine... IMHO there are already a ton of tuning information available... IMO most of the peoples problems are from a myriad of other factors influencing the engine....

I would rather try to help people dial in all the other "what if" factors, as then usualy the tuning falls right into place..... I know my own STS 30 would be a breeze for anyone to tune.. Though in the Savage the MGT tank causes some strange lean issues if the fuel starts sloshing around, it will act real lean after a high speed pass.. Alot of people would assume its the LSN is too lean, even though at idle its spitting fuel.. I took the time to try a few different fuel tanks to find our MGT tank was the culprit, not the engine.. I originaly spent several days testing pipes, plugs and needle settings to tune the engine in, only to find the fuel tank pickup was damaged, and the motor was tuned quite fine..... The funny part was even with the faulty fuel tank, i could sometimes almost get a perfect tune, but not quite, so it teased me for 2 whole days, i was ready to launch the STS 30 with a baseball bat...

I have recently started using a break in bench to run in my engines... I find this a excelent way to break in and setup a new engine, and it gives you an opportunity to run the motor on a proven reference setup, no clutch and no vehicle issues to affect the engine, if the engine is faulty you will know imediately..For those who dont know a break in bench is small stand which attaches a specialy designed prop to put load on the engine similating the load of a RC vehicle, so it makes it difficult to over rev the engine.... Since you have the engine freestanding on a bench, with a proven fuel tank (Hellfire tank) and pipe, its very easy to diagnose any possible problems...That way when you place the motor in the vehicle there is no second guessing, you know that mill runs nicely...another nice thing about the stand, is it takes very little time to install a engine, there is no clutch or other BS to mess with, and the engine is out in the open..... Another benefit is it greatly reduces the time and amountof fuel needed to break int he engine, as well it results in a much better break in.... With having the engine on the stand, its very easy to monitor temps while the motor is under load, and its very easy to maintain precise temps...so the motors tend to loosen up and seal in about 1/3 of the time...... This is how profesionals break in in motors, and when you consider the time and fuel you'd save the cost of a $90.00 bench isn't that unreasonable... RD Logics sells a very nice break in stand.... To anyone intending to be in this hobby for a while, and wanting to run tighter pinch race engines, one of these benches is the best investment you can make.

Once you sucessfully use a breakin stand once, you will never again even consider breaking in a engine in a vehicle again... On a stand break in takes 1/3 the time and fuel, motors are very easy to troubleshoot and work on as well the motors make a better longer lasting piston seal....

AllAboutFunHobbies

Do you have a link for the break in stand?

TopSpeedToys

I was looking at that also and found this http://www.rdlogics.com/cgi-bin/cate...000&type=store

not $90 bones tho [&o]

Maybe fleabay?

AllAboutFunHobbies

Does that thing have a liquid clutch to simulate the rc car, like on a fan clutch for your car? What is it using to simulate the car weight?

supertib

the prop itself provides load.... I test modded engines with various sized load props... You would be amazed at how much resistance a prop supplies... and how much air is passed

okay in a CRT one of my modded STS 30's was scoped at 37 000 RPM... i took the same motor and installed a 13x10 prop.... that prop put so much load the engine would barely idle, it wouldn't spool up one bit... anyways I proceeded to cut down the prop inch by inch, and each time I cut the prop I measured the engines top RPM with the prop....well in the end i had the prop cut down to 4.5 " which was a light enough load to let the engine spin to 36 000 RPM.... with a 8" prop the motor peaked at 10 000 rpm LOL.... anyways I use a 4.5" prop to simulate the load from a vehicle... The RD breakin stand has a prop sized plenty big to load an engine....

AllAboutFunHobbies

Oh ok I see so it has a weighted steel disk that the engine has to spin from idle up to full throttle. So depending on what size engine your breaking in you would need different weighted disks?

Sjokoz

Unless i missed some info from that link i see no weighted steel disk mentioned. That would also sound rather stupid as that would only restrict the acceleration and not the top RPM. A propeler on the other hand would give an increasing load as the RPM increases unless my psysics is way off offcourse . From how the stand is designed that also looks like what they made as they made some kinda intake holes forthe prop to draw air from.

AllAboutFunHobbies

Ok, i see how it works now, lol, I found the replacement parts page. That's cool, I want one. LOL, ok ignore the other posts, had a stupid moment, lol.

SAVAGEJIM

Your physics is correct. A propellor provides load by two methods: one is by moment of inertia (rotaing inertia) and by the work the propellor blades must do to move air.

A bigger (larger diameter) propellor (assuming a vacuum) will by its own weight provide more moment of inertia and the engine will have to work more to accelerate it to higher RPMs. An engine with a bigger propellor (one that exhibits more moment of inertia) will accelerate more slowly. Diameter of the propellor is not the only factor. If the propellor has more blades (3 or 4 for example), the diameter of that propellor does not have to increase for it to have more moment of inertia.

Now, factor in air resistance. A propellor with a given diameter, blade area, and pitch will not have to provide as much torque to turn at lower RPMs since the propellor and engines will have a low CFM (air flow rate). But at higher RPMs, that same engine and propellor will be flowing more air and the engine has to work harder since air at a given density has a constant mass and more force (or torque in this case) is required to move it.

I did see the RD logics break-in stand in an edition of XRC magazine, but I am not willing to pay $120 to $160 for it. I will drop $90 for it in a heartbeat! As for the vents of the breakin propellor, the propellor is enclosed in a fan like housing. It is therefore open to the air in front of the prop and also behind it; the porpose of this stand is to provide load to the engine by the moment of inertia of the prop and the work done by the prop and engine to move the air. As for differnt sizes of engines, I guess it would come with a smaller prop for small engines (.12 to about .18 engines) and another larger prop or same size prop with a steeper blade pitch for larger engines (unless RD logics decided on a "one size fits all" approach). I know that RC airplanes now have variable pitch propellors so it is possible to slap one of those on and vary the pitch for the engine being broken it, that is if different engines require different loads to break-in.

blackrain

DOES ANY ONE RUN A MODDED STS 30 if so how is it

supertib

the RD bench works awesome for any motor...it has no issues providing enough load.... the bench sells for $80-90 if you shop around, Hudy also has a bench available..... this is a very good investment...

SAVAGEJIM

Thanks for the tip! I'll google it and also the Hudy one to see where I can find one. I really like the idea of a break-in bench since the conditions are very well controlled like you already mentioned. H3ll, I a long time ago when I was just learning about RCs, I was tempted to buy an airplane break-in stand and propellor (that is, before I found out that the airplane engine bench was too big for our nitro engines).

SAVAGEJIM

I modded my own D30M, but I am still breaking it in; I only have about a half gallon through it right now. Once fully broken in, I'll tune it for performance and put it through some serious bashing.

The mods I did on my engine however did not include any changes on the timing profiles. I decided to stick with the stock timing map bit I cut flow channels into the sleeve, turbo cuts into the crankshaft counterweight, and matched the ports to the engine block passagae ways.

I notice your .18TZ is modded by Ed Bridges, that engine must totally spank the competition! I'm sure that he did all that I did to mine, and probably even modified your timing profile as well!

As for the D30M, Rick Brake modifys them and STS Micro Engines sells them. I've seen Rick' work in other websites and if he employs all the tricks he puts into other engines, the D30M must really spank! I would so pay th additional $100 for all the professional mods he puts into the engine!

blackrain

how many gallons can you get out of this motor im considering the rb mods sts .30

supertib

heres a video i found...this is not mine !

this is a stock STS 30, STS 0403 pipe, stock Savage X, 17/48

http://s144.photobucket.com/albums/r...3-11-07002.flv

pretty impressive IMO...in a stock chassis you can see how it wheelies and pulls.....

rocco212

what is the rpm range for the 30's. I could not find that info on the site. Thanks in advance.

jombo

the sts 30 has a rpm range of 26or 28000 rpm. i think the manual says it.

Harvz

The MAX RPM is it comparable to P3 ?

supertib

yes

jombo

well this is whats left of my wheelie bar,this thing is finally showing whats its made of. unfortunatly the weather forecast here says it will rain for a whileso its time to shelf it till then mayebe for 2 weeks. man i love ne weather,not[:'(].

BicketyBam

This engine is finally coming to life for me. Still running it on the rich side, but it is pulling pretty hard. The Axial carb made a world of difference for me. The only thing that seems weak is it's acceleration when it it's 3rd. It just doesn't spool up as fast as I would like. I am sure that it a tune issue. I want to run another 1/2 gallon before I really tune it for top performance.

SAVAGEJIM

STS does not advertise their max RPM ranges. But according to an engine test I read, the D30M will rev up to 35000RPM. At 30000RPMs, the engine was still producing moderate torque, although the toque curve was beginning to drop. At around 34500, the torque curve dropped from the lack of support of the exhaust system (the tuned pipe's range on tis test was meant for about 20000RPM to marbe 30000RPM bandwidth). The torque curve began to slightly rise after that, but the engine testers cut it off at 35000RPM.

In this test, they ran 30% Byrons fuel and left all the head shims in place. The D30M could have made more I bet, but unfortunately they did not and their results did not show the D30M's best potential.

supertib

the STS 30 makes alot of RPM..I have had them scoped in a 14 lb Savage at 34000 RPM and in a CRT at 37 000 RPM.....this is running on 100% traction with Mulcher tires on grass...On a track they will rev even higher.