Sorry to bust in like that, but dude: keep it real. I have had the engine for testing purposes installed in my car for about a gallon, it was smoothly broken in and perfectly tuned. I was very impressed with the engine in terms of how it develops its power and how high it would rev in regard of its cheaper price here in Europe, BUT come on - my O.S. Speed does not enter the "12-13 min club" under racing circumstances and nor does the Arrow which is closer to the blue O.S. than to the Speed.
With the pre-installed 9 mm venturi it richens too fast while idling and cools down pretty quick which leads to the need of a few high speed laps to get it back on temperature and therefore power. Another test-driver just found out that this problem can be solved with a 6 mm venturi (O.S. fits).
The needles are pretty loose in the carb and need some additional o-rings to stay put.

Please don't get me wrong: I really do like the engine and for its price it is more than an alternative to GO or Alpha engines (especially regarding the low maintanence break-in process in comparison). I liked the feel it had to it while driving a lot more than with the Alpha engines and from what I heard it was even better with the 6 mm venturi. But keep in mind: It is no O.S. Speed, it will never be one. There are the differences that manifest in pricing in the end and that's absolutely okay. If I was on a budget and looking for a good solid engine, the Arrow would be my first choice as of now. I dont know how it is priced in the States and the rest of the world, but if it was cheaper, I would even prefer it to the blue O.S., because they dont seem to differ too much, so pricing would decide.

dude lets keep it real :) i have raced it for about three months stock no moding close to 9 gallons no rod change or anything and i get around 10 1/2 to 11min with 6.5 restrictor its better then a stock v spec and maybe not all the way a speed but some where in the middle and it last a lot longer the a speed or stock v spec and carb is good i do agree you have to grease the o rings on carb there little loose this motor is a great motor for the price and you dont have to go out and spend 350 to 400 this motor will keep you in the game

so i belive mark when he say 12 to 13 with a mod

+1 Moded engines do seem to get better run time. This is a 10+ min runtime engine for sure. So with a mod it should be able to do some crazy runtime with proper setup and driver.

Lots of engines are getting great runtime with out the $400 price tag.:sneaky:

I should have been clearer but the engine I was running was my full race ported version. The engine is based off of the vspec and the timing numbers are different stock but end up very similar after modifications and my modified vspecs and speeds were getting 11-14 minutes depending on the class and variables with the 2060 and this engine with the RE10 which is based off the 2060 will run very close to what they did. Obviously there are alot of variables that will affect runtime but my race ported Arrow if tuned and setup well should get 11-12 no problem in most situations. This engine with ambiant temps in the 30's and low 40's was coming in after a 6 minute run with the fuel just below half of a tank so the first weekend with less than favorable conditions was showing signs of close to 10 minute run times so when it breaks in and warms up a little so we can lean it in some, it should easily get 11+ which my vspecs and speeds did on a regular basis.

I did not know that Mark ran a modified version - which mods have been made there? Was the carb modified to hold the needles in place?
I tested the stock Arrow GTR on two pretty much full throttle tracks (one had a good rain the night before and was high traction, the other one was very dusty but one could push very hard due to the layout) and never came over 9 minutes runtime. The initial test-driver who broke the engine in also ran around 8:45 with it and the last test-driver who installed the 6 mm venturi reported runtimes between 9:10 and 10 minutes. So maybe it is the air you guys have or you are really light on the throttle, but I cannot see, under no circumstances, how this engine could be good for 10 minutes stints in a race. I ran it with 2060 and 2041 with short and long manifold, no major changes in runtime, but I found that it is way stronger (not that high rev top end though) with the 2041.

I am sure as hell no one who needs a big price tag on any part of my car but I also stopped praising budget parts over the moon as well. I really think it is a great engine for the money, but still not a Speed. I switched on the second testing day back to my 30 liters old Speed and it is that much more powerful in all situations and still needs less fuel.
That is what I meant with keeping it real: I dont crucify the Arrow, I really dont, but I just read Marks post and thought "Wait, isnt that the engine you tested two weeks ago?" Okay, obviously not - so please take my post as a commentary on a stock Arrow GTR.

No sweat brother! I didn't take the post negatively, I just wanted to make it clear it was my full race ported version and not stock. I also ran it with the RE10 as that is what Mike Cleary from Answer RC is recommending and I wanted to stay on par with his testing so we had fair comparisons stock vs. modified. I will be sending this engine back to Mike for further testing and his opinion on it so that review will follow. As far as the needles moving, I didn't have any trouble with that but it has only run race weekend on it so it is too early to know what it will do in the future but we didn't have to fuss with the needles too much to keep it in the sweet spot, just had to adjust for the temps as they continued to go down as the weekend went on.

If one of you is in Pennsylvainia where it's 40 degrees and your using an exhaust gas cooler and the other one is in Florida where it's 90 degrees and super humid with no gas cooler, there would easily be a 1-2 minute difference in run time.

There are so many things that will determine differences in run times it's never accurate to take one guys word for it either positive or negative

True to a point. This particular engine was run with no coolers in lower ambient temps where as some other engines I was testing with twin coolers in line on the fuel side if the circuit as opposed to the pulse line also in lower ambient temps so those will also vary results between them. I need to wait until the temps are normal for everyday racing before really getting solid numbers but even then, results will vary person to person depending on where, when and how it is run but I can tell you there will be a noticeable increase in performance and runtime between stock and my race ported ones and that is my main concern instead of worrying about the exact runtimes it is getting as results will vary region to region and person to person.

you forgot:

bearings
Pipe choice
Fuel choice
Tire choice
Manifold choice
Plug type
Gaskets
length of fuel line
length of pressure line
Flywheel
Clutch shoes
clutch springs
air filter type
air filter oil type
engine tune ( especially idle )
Epa settings
exponential settings
servo speed settings

the list goes on and on really...thats why when one guy says I got 15 minutes of runtime, or I cant get more than 7 minutes of runtime it means nothing unless every single aspect between their vehicle and your vehicle is identical..you should know this better than anyone Mark

I didn't "forget" anything James so don't try to look like a hero and try to call me out on something. I classify that in the variables department as I have mentioned in many threads over the years. Just because I didn't mention all of that in this particular instance doesn't mean I "forgot" or "didn't know or thought" about it. Most people understand there are alot of variables when it comes to this so I figured I wouldn't beat it like a dead house but since you are the expert on this, you can be my the voice of reason while I finish my tour of Washington DC because I am on vacation and don't feel like making crazy long posts when I should be enjoying myself. Have at it bro!

I was able to run this motor throughout the course of the weekend and the motor is very impressive. I have ran a whole wack of powerhouse modded motors and all of which have been great. This Arrow motor was definitely up there as it ran awesome all weekend. Like Mark said the temps were very cold as it was snowing for part of the weekend ( race was inside a large unheated building) and the carb remained untouched all weekend. The engine was a beast throughout the entire power band and turned many heads. After each qualifier, so around 6 minutes I had about a little under half a tank left. Yes there are many variables that contribute to fuel mileage, but i will say i am not easy on the trigger finger and the motor was running rich yet. So on a decent size track that doesn't require you to have the trigger glue all the time it will get respectable mileage. The only thing uncertain by me is the durability as the motor i ran had less than a gallon of fuel through it.

Actually I was reffering to Mervn's post Mark..was not calling you out at all..was making a point that there are way to many variables for one person to claim such different numbers from another..have fun on your holiday

My bad brother, I am assuming Mervn's name is a Mark as well? I guess the user name would have made it crystal clear.