beebone

So what about the run time? I remember OS .12 engine never enough 5 minutes run time.

Rich Browne

All of the events we are involved with are 4 minute qualifiers - with the exception of the GLC, which is 5 minutes. We will be testing during the next month to get 5 minutes out of the motor in preparation for that race. I'll post here as we make progress, keep in mind that Scott is an exceptional economical driver.

Rich Browne

We are excited to go have a "test only" session, tomorrow, at Warms Springs Raceway. We will be focusing on the .21 exclusively. We have made great strides with both the .12 and the .21. The .12 is a beast and we are moving our focus to the .21 until it matches the abilities of it's little brother. We have been dealing with fuel tank pressure problems and feel we have that issue resolved. Now, we can focus on finding the right wicked tune. Feel free to jump in and share your experiences.

VS_Rody

Curious to hear how things worked out at the test session.

Rich Browne

Very interesting Empire Racing test session. Driver: Scott Kimbrow, Car: Capricorn 803, Track: Warm Springs Raceway
Goal - Looking for a strong tune.
We have been having issues with fuel pressure, holding a reasonable race temperature and we are down on power. Our baseline engine was our VS 21 Rody motor run at last years GLC. Strong motor. The second VS 21 was the motor we ran last weekend at the KO race. Big difference in the motors. The GLC motor was strong and ran perfectly at 218F. Unfortunately, the KO motor, at the beginning of our test session even with our best tune would just run okay, but, would only make reasonable power at 255F - far too hot. We pulled the KO motor early in this session and boxed it for later review.

Fuel pressure. What we observed - The fuel we are using appears to be building up quickly in the pipe causing a intermittent change in fuel pressure (the pipe only has three hours of run time and it has some serious build up inside). Once we changed to a new pipe the fuel pressure stabilized and the motor held a consistent tune. Our fuel has 11% oil and will change to lower oil option/mix. I guess I have to soak the pipes after every session in the ol’ antifreeze crock pot - stinky process

Continued our test session with only the GLC motor. We removed the CPD (Orion Constant pressure device). The CPD is effective in controlling fuel pressure but they are messy, far too much maintenance and yet another variable we could do without. We started simple - ran a direct pressure line: tank to pipe. Very slight loading up in the midrange - not bad, but we knew it could be better. Added a pressure tank and the midrange brightened up. The pressure tank also stopped the “full tank” fat lap. Fuel pressure issue seems better under control.

Finally we got to have some fun and tested the Hipex 2115 pipe against the OS 2080SC pipe. The Hipex is equal to the OS on bottom and mid, but we feel, pulls better on top. We will do mileage testing next weekend. (Just now I spoke with Rick Davis, who runs in the midwest and was also testing the Hipex against the OS, he thinks the OS has a slight top end advantage, so, he prefers the OS.). There are other pipes and headers we plan to compare as we move forward. Conicals are always good for more power but at the expense of fuel economy. Luckily we have Scott Kimbrow who is an economical racer, smart too and can wring milage with the best

Next session will be mileage testing and clutch setting. We can get even more out of the motors now that we have a clean baseline. The 2115, we believe, is faster - but it will come down to mileage. We will continue to post our progress.

sheeley

Thanks for the info Rich.
What is a pressure tank?

Rich Browne

Hi Justin

pressure chamber/tank/line cooler. mounted in your pressure line from the pipe to the fuel tank. Nova Rossi has a line cooler, others sell a pressure chamber or tank

sheeley

Cool thanks

Rich Browne

Test session #2: 6/24/17. Driver: Scott Kimbrow, Car: Capricorn 803, Track: Warm Springs Raceway
Excellent results. The car and motor combo are now working together like a dream - the power band now matches the chassis and we have a very fast, efficient combination. Great motor Rody!

Here's a recap and a listing of what we tested. We ended up with a very fast car with a bodacious bottom end. Here's what we did:

We started out with the clutch set with a mid-level gap .5mm and we reduced the spring preload to the lightest tension without bogging off a standstill. We were using a Shepard spring; Our previous preload was 1.1mm as measured from the flywheel nut edge to the outer face of the spring tension nut. We backed the preload off to .5mm and then to .0mm. The motor has so much bottom end that the 1.1 setting allowed too much RPM wasting fuel and making the car too "punchy" and difficult for Scott to manage. As we backed off the preload the car smoothed out and Scott felt the car was much more docile and predictable - read fast. It is a much lighter clutch that we typically run, but, it make the car much more efficient with no drawbacks. Sweet. We will continue to refine the clutch testing different springs and will, I would bet, end up with a stock Capricorn spring. Patrizio has this pretty well figured out - not sure why so many people are using such a heavy spring....

We tested two pipe and header combinations - the VS Branded 2115 with matching header and the OS 2098 with matching header. The OS has equal mid range, to the 2115 combo, but, greater top end. Here's the catch - while the OS is faster it uses more fuel - we could get 4 minutes 35 seconds with it. While the 2115 managed 5:20 We will be testing the 2069 next along with different headers. Plus, we will be seeing what a full out fast lap will be as opposed to a "qualifying" lap which is always slightly slower (just for fun).

Next we tested and compared pressure vessel to direct line (no cooler or pressure chamber). As noted in our first session we felt the pressure vessel was necessary to prevent a full tank "fat" initial lap. Now, after we carefully tuning of the carb and motor we managed to notice no change between the two - so, no more pressure chamber - one less item to possibly go wrong.

Here's are two notable changes we made - and I don't suggest you do this unless you have experience - seriously. We adjusted the spray bar to clean up the mid range and secondly we changed the deck height from .25mm to .20mm. We gained more bottom end without sacrificing the top end. We did notice a slight detonation area directly above the exhaust port. it seems we a may be just a touch too lean on the top end or slightly over compressed.


A). .15+.10, VP-11%, 9.96, 2115 combo No pressure vessel- 5 minutes 15 seconds, end temp 225F
B). .10+.10. (all else as A) More responsive in the infield, end temp 220F
C). .10+.10, VP-11, 9.96, 2098. No pressure vessel - pulls better on the straight. end temp 230F
D). .10+.10, Brand X, 9.96, 2115. No pressure vessel- (header change). Mid range flat. end temp 225F - stopped mid sessions as not of benefit
E). 10+.10, VP-11, 9.96, 2098 combo. No pressure vessel - 4:28

More next week....

VS_Rody

Hi Rich,

Thanks for sharing your findings, very interesting.

Totally agree with the clutch, when the clutch is slipping too much you have an easier car and everything is looking sweet but you are wasting a lot of energy and so fuel-mileage which today is important for if you want to finish your qualifiers correctly. It also depends on how the engine itself is reacting how the clutch comes in. As you noticed the VSR02 has a good low-end power so if it is used correctly then you can take the benefit also.

Thanks for the recap on the pipe findings, this confirms what I felt here in Europe also. Only small difference is that the OS2098 is louder so you also have an impression that it is faster.

For the pressure vessel, agree the less you have which can malfunction in the car the better you get. We have tested this also a while ago but dropped it because there is no real advantage and also today's fuel-tanks are working well and so no real need for this anymore.

Concerning playing with the deck height of the motor, yes something to be used with extra care. An overcompression can result in detonation and very often can only do more harm then good.
I have found that compressing more results in better torque but also more fuel-consumption and having a more critical carburetor setting.
In general we decompress(+0.1) to gain some fuel-mileage by not loosing too much power and having an engine easier on the carburetor too.

Anyway great to share this info with you and all the others on this forum too.

Jonathan

iTrader: (2)

Thank you Rich for the great insights. Alway enjoy reading your stuff.

Rich Browne

Thanks Jonathan! I enjoy sharing. Most of the credit should go to the great team I'm part of - Empire Racing. Talented bunch. Rick Davis, the true brilliance of RC, Scott "the finger" Kimbrow, awesomely fast and smart driver and the always trusty "Pit King", Jim Adkins. We'll be sharing much more as we continue our collective return to Nitro Racing. Again, nice to know you are enjoying reading about our passion!

I'm off to port match the headers and pipes....

jimiaxplyr

iTrader: (4)

After watching Scott's engines at the track yesterday, I am excited to take my Rody OS out and run it. The power and runtime of these engines seems to be amazing by everything that I have seen and heard.

Alex Frank

ralphierace13

iTrader: (5)

whats sad is that tracks are still running 5 min quails, this is what helped kill nitro on road and y 90% of the tracks have gone to the 4,6 or 7 min quails. just look what u wrote in 2 days of testing if I was a newbee wanting to get into onroad that would scare the shit out of me... for many reason u would think u have to go test like u did or spend a fortune!! bad enuff nitro is a dying breed here in the usa posts like this font help.. sorry john I don't like posting like this but in my opinion does it make any sense to buy a motor and have to detune it? if I went to chevy and bought a corvette would I like if they put restrictors to slow me down? mostly all other tracks have gotten away from the 5 min quail and we all should !!! now u get into the hobby which is costly enuff and u have to spend all this other money to make run time change this change that have multiple fuels one for quail one for main to make more power, really you guys in the mid west should be changing the quail times also really its not helping nitro onroad plus a 7 min or 6 is a lot more fun guys love having to make a pit stop it creates more action. also the cheating factor there are so many guys cheating to make 5 min its crazy u may not be aware of it but the shit I know and from people u would never believe it!! there are so many other aspects to worry about when racing like setup, tire choice and so on this should not be a worry. most guys also don't have access to a track near them to test stuff so when they come to a race there time is limited they shouldn't have to worry bout this we all love speed!!!! let these bad boys fly we should be testing how to make faster!!!

Rich Browne

Any type of racing takes effort, requires strategy and costs money. I enjoy 1/8th because of the potential of the cars and motors combined with skills required to be consistently fast within whatever rules are set for the event we attend.

I have been out of racing for 10 years. The cost to race has dropped dramatically. Motors are MUCH less expensive, cars cost less and are extremely durable, require less hand massaging to make work and the tires have dropped in cost as well.

As for attendance - in Northern California (where we race) four months ago, when we started racing, there was NO 1/8th racing. Now, there are at least 15 racers who have bought cars and are racing again. I am confident if we continue racing that 1/8th scale will continue to grow. Why? Because we help other racers: we help them tune their motors, show them how to setup cars, share information, promote race events and they get to race against Scott. We help racers and we love racing. We don't complain, we are first at the track to help with setup and most important WE HAVE FUN. Can Northern California, once again, have 50 plus 1/8th racers? I know we can. All it requires is a catalyst. Our catalyst is the love of 1/8th racing and the joy we get from racing and HELPING the race community.

Rody creates a superior product and is a fantastic supporter of racing - this thread is about VS motors. Let's keep the subjects on track.