mrgsr

iTrader: (15)

hi guys

i have been using an os tr r spec and so i thought id dom some light porting on the piston liner.

all i did was make the normal grooves people do to make the fuel more direct. since this porting the engine has been wanting to run richer. i had first left the engine at its normal tune and when i ran the car it blew 3 plugs and was running crazy lean....

im not sure if this sounds weird or if its normal ? the tr used to finish a 5 minute heat with just less than half a tank of fuel, now its using much more fuel than normal.

thanks for your help
John

Team Duratrax

That's quite understandable. You opened the ports for increased fuel/air flow leaving you with a more thirsty engine.

Sean

Speedypeterb

iTrader: (16)

why did you do this? was is to get more horsepower? and be carful you don't just do what everybody else does? i've been told that those little porting grooves just eats up and wastes more fuel. I race with some serious porting groove makers and they constantly are trying to make their five minutes (on road) runs.

mrgsr

iTrader: (15)

i did this because ive always used the os tr engine and this porting really helps the engine rev free-er (if thats such a word)

i was doing 5 min heats with almost half a tank left over

i set the engine back to factory and retuned, now its all sweet

Aphinity

Engines have a simple formula. Air + fuel = Power. The more fuel and air you can combine and burn efficiently, the more power you will make.

Add ports to your sleeve/liner, you'll increase fuel flow. As long as you can burn it, it will make more power, but it will likely use more fuel. So, what you said makes perfect sense to me! It SHOULD use more fuel!

EdwardN

iTrader: (1)

Let me disagree with you little bit.
Are you sure that more ports = more power?
I can get more power from 3 ports sleeve then you can get from 5 port and my ports are much smaller then yours and not modified (tear drops etc).
It is not that simple make more ports, bigger ports and magic works. First of all you need put right ammount of mixture at right velocity at right time to the right place. And if any of this varibles is out of range-no power.
Edward

mrgsr

iTrader: (15)

does tear drop porting on the liner realy make much difference ?

if so what ?

thanks

EdwardN

iTrader: (1)

No it's not.
look please Dyno test results from Brian, that REX RER Palmaris BRB-it seems like it is much more powerfull then everything else there and has no tear drops not any other cuts-just palin "stock" look like sleeve. Angles are different, tapers are different, materials are different, but on extra cuts.
Edward

Team-RTR

i did notice that your BRB engine has more power then all the other engines on that page, how long is the life expectancy on a BRB liner set?

TrickPonYracing

iTrader: (2)

the winter nats are coming ,, lets see it make power on a track that eats power and spits pistons and liner,, i have seen plenty of motor make power on a dyno and fall flat on the track..

Speedypeterb

iTrader: (16)

I have my first generation brb in a x12 rb that has 4 gallons still runs strong but then i needed a little more power so i bought thev12 rb and put the third gen brb p/s set from Palmaris racing in and now have 4 gallons run through and is just keeps getting faster. i'm putting it aside only because i just got the new Palmaris profee 12 with the brb p/s set. so you will probably run 8to 10 gallons maybe more, Peter

EdwardN

iTrader: (1)

Yep, you are right Winternats are comming and that track eats power and motors.
About to see how my sets perform in Fort Myers-just for instance-2004 Winternats, Michael Salven TQd and he was using my BRB set (plain stock). That set was not even broken in properly-just 2 tanks on starter box and 2 tanks was used to tune the engine.
So I am pretty familiar with Fort Myers track and it is not scare me.
Edward

EdwardN

iTrader: (1)

Usualy it is about 5-6 gallons in racing condition, in parking lot bashing 10-12 gallons.
Edward

Artificial-I

iTrader: (17)

MRgsr,

Sounds like you got something right on that porting and polishing. If the motor was in tune before and is now eating glow-plugs , sounds like you have increased air-flow quite a bit through that motor, to where there is now even detonation.

You might have lost some fuel efficiency as well with that , which might make it seem the same. But either way a change has happened and it sounds like it needs to be richened. Now worse mpg's.

You should and always remember to retune a motor after any change, no matter how minor. Engine Modifications , New Fuel , Fuel Percentage Change or even glow-plug changes all needs retuning.

Why, because the motor will work differently and most always will need a carb adjustment to get the proper air / fuel ratio.

Also to tell if it really was beneficial, you really dont need a dyno. If youve got a good handle on motor tuning and how your cars drives , you should easily be able to see if its faster or not on track or wherever you usually run it.

In the mean-time you should probably work on your engine tuning skills before attempting more modifications. If you didnt know to retune after a modification. Sounds like you should stick with the wonders of tuning before attempting to mod.

But if you can notice the changes , go right ahead. Just remember to tune the thing after every cut, no matter how big or small.