1) CNC ported to exacting specs with new 2012 port specifications, (Race proven and dyno tested for heat racing and off shore racing applications), and hand finished to perfectly clean detail (like all ESP engines and top end kits). The same top quality, and performance that has won major Championships world wide, right off the DDM shelf.
2) Lowered compression (combustion chamber cut and reshaped) for the higher rpm marine racing application. If you use a 1mm crank in the 36mm bore cylinder with out this mod, your compression ratio will be about 17:1, and would need to run alcohol if it were a larger engine. Compression is reduced to a more “normal” compression ratio, that helps the engines higher RPM power.
3) Piston is relieved at the “crown area” to stop the chance of the piston crown area “scuffing” in the cylinder, do to the expansion of a hot piston crown, in a cold water cooled cylinder.
4) The engine uses the Zenoah 1mm stroked Marine crank. All parts in this engine are Zenoah. DDM is well known for keeping Zenoah and ESP parts on stock, as well or better than anybody in the world, at any point in time.
Power from corner to corner, that can pull outside, and inside lines with authority. DYNAMOMETER numbers--but first--
Dyno note. ESP may own the best dynamometer in the world for the RC Zenoah engines (Land and Sea Water Brake Dynamometer with a ESP engineered drive system), but it still, like every dyno we use, has no “absolute accurate” means of calibration. What is calibration? You calibrate your bathroom scale to “Zero” (A “known value of weight”-- with nothing on the scale) before you step on it. You calibrated your bathroom scale with a “absolute known value“,--of “Zero“,--- but we don’t have a engine that makes a “absolute known” amount of power to calibrate our dynamometers, and “Zero” will not work here, as it means nothing is spinning. The ESP dyno is calibrated with a stock Zenoah air-cooled G260 engine, to 2.95hp at peak, as Zenoah---- “claims“ (Freshly broken in and jetted as well as can be with out an exhaust system or EGT gauge). Any other dyno will get different numbers because of a lack of “absolute accurate” calibration (like this dyno--only using a G260 for calibration),--or no calibration at all. A competitor may claim higher HP with a different dyno, but that does not mean it is true. If no accurate calibration is used, it is very unlikely the dynamometer will be accurate. It is highly probable the same engine and set up will read up to 1.0 hp (or possibly more) different from dyno to dyno. Only when you hit the water, with a optimized set up, will you really know what is faster.
ESP DYNAMOMETER MEASURED POWER AND RANGE
Over 3hp 9,800 rpm to 20,800 rpm---(dyno rpm peak measured - 2.5hp at 21,100 rpm)
Over 4hp 12,300 rpm to 20,300 rpm
Over 5hp 13,200 rpm to 18,100 rpm
Over 6hp 14,600 rpm to 17,100 rpm---(peak power measured - 6.75hp @ 15,900 rpm)
Engine set up that generated those numbers-- “ESP 29.5cc PUM Champ Port” and--
1) “Red line” exhaust manifold for QD pipe. .375” thick. ---(I had to drill water holes out a bit for good water flow)
2) “QD hot pipe” from 2010 25.4cc QDHT engine, 110 deg bend header, external stinger. ---(I brazed on a bigger .470” ID stinger of the same length, for the bigger 29.5cc engine, and shortened the “header to pipe” “coupling length” to 1.550” “visible length“. Dyno was used to tune this “coupling length” for this engine and exhaust manifold. A different pipe set up will change the power out put.)
3) Walbro 12.7mm dia. Venturi, WT family of a 600 series or higher carb. (this was a WT-668 with choke removed and “choke shaft holes“ plugged. A engine running too rich or too lean will significantly reduce power, and possibly cause engine damage. Take the time needed to set the jetting well, and reap the powerful benefits.)
4) “Maxima Castor 927” oil (ESP recommended oil) mixed with 91+ octane pump fuel @ 20:1. Run more oil if you wish, jet accordingly.
For about a decade, ESP and DDM have proven they have the quality, performance, price and service that is hard to beat. Why take a risk on e-bay? Get your 29.5cc ESP PUM racing engine from DDM today!
Thank you for considering my stuff. Doug @ ESP.