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Old 08-11-2009, 09:50 AM   #1
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Default Run time out of Sirio, HELP??

As the title states im a little flustered on how to get some runtime out of my sirio cs7b sti engine.the first two to three gallons i was gitting 8 to 10 min on a tank of fuel and was very happy with its overall proformance. However over the past three weeks im struggeling to get 7 min out of a tank of fuel, my engine however is running better than it ever has. Its making some serious power. both smoke and temp are perfect (temping in the 190-230 range). i have played with carb inserts. im all the way down to a 6.5 mm now. i have seen a small improvement but not as dramatic as i had hoped.

I understand alot of factors are at play here (time on the gas, clutch, tune ,ect.) im just looking for someones advice on these engines.

I also understand that these mills are not known for their fuel milage, but i like the challange

porting and polishing, head shimming, plug, pipe and header anything that has helped in your experance would be greatly appriciated.

i have 3 more of these things new in the package, so im willing to try anything on this engine to get some run time out of it

thanks in advance
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Old 08-11-2009, 09:59 AM   #2
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you might have a bearing that is dragging alittle in the engine. it doesn't take much in these to put a load on them and cause fuel usage.
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Old 08-11-2009, 10:28 AM   #3
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i would also try leaning it out about a hour or two maybe three and check the temp tune by the smoke out of your pipe not by temp. 230 -240 is not to hot. i have a 2 motors that will not run under 260 - 265 and have about 10 gals of fuel though them and still running strong
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Old 08-11-2009, 10:29 AM   #4
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thanks all check on that here in a bit, i think that the issue is in the carberator or head shimming,(if its not in the bearings). the problem is that its putting out perfect smoke and the engine feels VERY good. we tend to tune on smoke aswell, once it gets up to temp it runs like a scolded dog


the engine is tuned very well and there power wise however on start up the engine still sperts unused fuel for about the first three to five min. the weird thing the engine does not load up like its rich. It reves to full rpm, immedieatly comes down to idle and sits and purrs there for ever if it wanted.

its not rich, if anything its a little lean on the bottom, the fuel in the start that i lose seems to be the big issue
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Old 08-11-2009, 10:59 AM   #5
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Curious what pipe you're using? Generally speaking, the Werks, Sirio,Ex Tech..ie Star based engines prefer the 2013 for bottom/mid, respectible top. Or, try the 2057 for a smoother bottom and more top. Also, the 2057 will likely yield better mileage.
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Old 08-11-2009, 11:20 AM   #6
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i have tried a losi re11, jp-3,jp-4, and the o.s 2060,2050 the losi re11 has given me the best results, for power and "fuel milage".

i was thinking of trying the ex-texh pipe next though, then their fatboy pipe, but man is that thing uuuuuugly

ill look into the 2057
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Old 08-11-2009, 11:25 AM   #7
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To be honest ( I might get int trouble for this :P ) I don't care for the (2056) Big Boy. I really, really like the 57. I feel the 56 offers severe hit on the bottom and very strong pull to mid, but to me, it feels like it flattens out from there. Mileage with it is comparable to the 13. Last summer I ran a Race Prep Ex Tech on my home track. I could pull 7:30 easy with a 13. I then tried the 57 on a whim...I was easily topping 9 - 9:15.
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Old 08-11-2009, 11:55 AM   #8
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thats all the milage im looking for, 9 min is my goal is i can pit one less time in a 45 min main.

are there big differances in the ex-tech and cs7b. i know some parts can work between them(at least the rod).

i see ex-tech's go 8-10 min all the time but i never see a sirio do it,

thanks for your help im going to do some simple things tonight and see whay that does.

im going to try to go back up a little on my carb insert so im not on the gas as often, thus(hopefully) saving fuel. im also going to play with head shimming a little cleaner burn and better milage,

more compression+more power= less time on the gas

less time on gas= better milage
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Old 08-11-2009, 12:31 PM   #9
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well according to andrea from sirio it's all in the driving style, I was running a 7mm restrictor on a evo 4 sti polished in and out with a 2013 pipe and pushing 9:45 secs on pit, try to limit the throttle travel if you do not need it according to your track also one more thing that really contributes to your fuel mileage is the throttle servo speed make sure it matches your throttle finger travel, having and out of sync throttle servo really does guzzle up your fuel..
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Old 08-11-2009, 02:17 PM   #10
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how do you polish(sp??) a sleeve and piston.
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Old 08-11-2009, 03:04 PM   #11
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u dont polish the piston, but the sleeve externals body, just use a dremel and polishing cotton bit with polishing compound, then wipe it down with wth a cotton and tooth brush clean for any residue, I use denatured alcohol for the final wipe down and oil out before putting it back in together, polishing helps but not as much as learning how to manage your throttle finger.
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Old 08-11-2009, 04:15 PM   #12
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This is the same problem I'm having with my raced prepped Ex Tech. First few gallons I could
Easily pit at 7:30. Now if I run a 6 min qualifier I'm out of fuel when its over. But the power has
Never been better. Nothing has changed since I got it. It runs great but the run time is getting
On my nerves. I wonder if it could need some bearings?...
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Old 08-11-2009, 06:17 PM   #13
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As for sirio or sirio based motors, run a sirio pipe 2013,2057 maybe even 2066. Anything else never seems to work as well like fuel mileage, power, low end etc.Also limit throttle epa also.Get the temp to the 250 range.
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Old 08-11-2009, 06:47 PM   #14
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On a big track 7 to 8 min is all you will get out of a 7port Sirio when racing. If the motor is running good dont mess with it, with the Big cooling head on the STI if you lean it you will hurt the bearing. That motor should start a tad rich at first and a lap or 2 into warm up should be great. I ran Werks 7ports and this is a good run time 7 or 8 min. If you want more time try a mod Werks 3 port or Orion ABI, Novarossi +4, or V-Spec with a 6mm restrictor
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Old 08-12-2009, 02:54 AM   #15
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Quote:
Originally Posted by Marcus Falconie View Post
On a big track 7 to 8 min is all you will get out of a 7port Sirio when racing. If the motor is running good dont mess with it, with the Big cooling head on the STI if you lean it you will hurt the bearing. That motor should start a tad rich at first and a lap or 2 into warm up should be great. I ran Werks 7ports and this is a good run time 7 or 8 min. If you want more time try a mod Werks 3 port or Orion ABI, Novarossi +4, or V-Spec with a 6mm restrictor
X2

i own a +4 and a vspec, havent really broken the +4 in but my vspec i run 7mm res and i can get 8 min and still have 1/4 tank left, and marcus races with me, out track is huge
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