What can I do to get some fuel mileage out of my plus 4 btt wc engine? I'm running a jq car with 3 shoe all aluminum clutch with 1.0 springs all around. 5.4 restrictor, reedy 2035 pipe. 7 1/2 is about its max runtime. I'd like to make 8 1/2 comfortably. I have an ofna 086 with double bend header I could run, or a reds 2104. I guess I don't know the trick to mileage seems everyone runs better than me. I'm also using byrons 30% nitro/8% oilfuel

mine runs 10min easy with a 2096/41033 with 6mm restrictor sidewinder pro blend 30%on a fairly large open track.
just to be sure your carb gap is about half mm, your total throw for the carb is slightly smaller than said restrictor and you have a proper race tune on the lowend?
a difference in 3 minutes is pretty large are you dragging any bearings? i run the tki4 and its not really known for good milage

9901/41021 for best bottom but flat top with good fuel consumption

2096/41021 for softer bottom with good top and almost same fuel consumption to 9901/41021

9886/41021 best powerband but thirsty

Run 7mm venturi, 5.4mm you race on extreme small track?

I believe the tune is messed up, check if lsn is extremely rich

What do you call extremely rich? It had good power with little smoke. I'm a touch out from flush on the hsn and flush on the lsn

thisis where my needles are at 700m elevation both are in from flush

Try running a larger venturi. 5.4mm really restricts power and narrows your tuning window. Not only that, but a lot of drivers will just drive more agressively with a smaller carb insert which will negate any run time gains. Somtimes running a larger insert like a 7 or 8mm will make you drive smoother, only squeezing the throttle wot sparingly resulting in better run time. Larger inserts are also have a wider tuning window making it easier to dial in.

From your pictures, hsn is very rich, if you put a 7mm venturi, you will notice a lot of smoke. By running 5.4mm you will need to use throttle more often since it lacked power

That's not my engine but mines richer than that on both needles

I just ordered a set of venturis so I can go to 7mm and I put on an Ofna 086 pipe with the double bend manifold hoping it increases power and runtime.

Recently my cousin toasted his mito 7 engine, i find the crank part number is 15027-T, is it possible to replace it with bonito 15068 crankshaft?

No because of the offset carb on the Mito

About how much life should I get out of the Elite5/8 line of engines? Mine has compression, but not a lot of pinch. Debating on getting a new p/s vs just calling it done if this line doesn't get a lot of life.

Nova engine with race tune usually 3 gallons / races, more than that i consider godlike tune, 3 gallons / races mean no mysterious flame out or inconsistent power

Ive got two motors with well over that. The btt posted earlier is Closer to five and half to six and a second set of bearings and still will hold its own weight when you hold the motor by the flywheel.that thing has to be the exception to the rule as my keep off 4 which is pretty close to the same motor has about four on it and there is zero mechanical pinch.
I don't think I ever put the too kill tune on the btt but it runs ten easy at the large open local track.

Only 3 gal avg for a race tuned engine!!!?? Is that just the Top Elite line or all novas?