Since 2003, ESP has specialized with the Husqvarna/Zenoah family of RC and scooter racing engines, and are used in every application of RC racing using Zenoah engines around the world. The engines and top end kits that are modified range from the first Zenoah G230RC (32mm piston), to the later bigger bores of the RC engine line, like the G320RC (38mm piston). There are also some bigger top end kits, like the GP460 and GSR40 that porting is available for. The work that is done for the most part is what is called “Porting”, where changes in the location and area of the port are done to gain more performance. It is similar to putting a bigger cam in a four stroke engine. Different types of racing require different porting. For example, the porting for National level Boat racing, (where they are wide open most of the time), is cut for lots of power high up in the rpm range. That porting would not work well for a buggy on a tight track with double jumps right after the corners. The tight tracks would like more lower RPM power with a strong midrange. The pipe is a huge factor of how your engine makes power. The pipe should actually be matched to your porting. That tight track with the lower RPM porting will make the best power with a pipe that is also tuned for strong midrange power, (all 3 DDM pipes I used are great here), and the high rpm boat racing will run the best with a pipe that is tuned for those faster piston speeds.
Other work I do a lot of is modifying the head area for stroked cranks. Every 2mm stroked crank set up I build will have the squish band cut, and the compression properly adjusted, (using the stock cylinder base gasket or thinner). Some other engine builders will just put a 1mm spacer under the cylinder to make room for the longer stroke, but that set up loses a lot of power because of very weird port timing that the spacer causes, (spacers are needed, and OK for “long rod” cranks though). One good think I like about the 2mm stroked crank builds is, because I have to modify the combustion chamber, I can set the compression where ever I want. You can’t do that with the stock crank and 1mm crank, (usually), as the head area is not usually modified for those cranks.
You ask, “What kind of porting have you got?”
I offer basically three types of porting for most of the different cylinders I work on, which makes it pretty easy for me to match the cylinder and modifications to your needs.
My first porting was my “Championship Porting”, (HT, High Torque version). The specs have changed a bit over the years, but it is called “Championship Porting”, because we have won major championships all over the world with it.
There is a second branch for the championship porting, that is my, (HR),“High Rev Porting”. Same top quality and race winning performance, but ported for higher RPM, (may need to set the clutch at a higher rpm if sluggish at low speeds).
Third is the ESP “Race Porting”. This is my lower level porting. Still much more powerful than stock, but just a bit less power, (about .25-.50hp) than the championship porting, and revs about 1000 less RPM, (with everything else being equal).
I have also started making “High Rev” pistons, now offered in 34mm, 36mm and 38mm bore engines, (also “light weight pistons“ in the 34mm and 36mm sizes). The piston actually gives more exhaust duration for higher rpm power. When matched with the correct pipe, they can run better in a stock engine than some of the other cylinder porting I have seen from a few pretty popular engine builders. Need a custom piston for your personal build? Give me a call.
I sell my stuff through “Dave’s Discount Motors”, (DDM), and all of the RC top end kits below are also available in complete engines, (unless noted otherwise). DDM chooses what ESP stuff to stock at their facility, so if they do not stock a particular kit/engine you want that I have built before, I can build that one for you directly. Just check with DDM first please.
Here is the list of the engines/kits I work on, from the smallest from years gone bye, to the bigger engines of today. Horse power ratings are based on the engine using a good pipe for the porting.
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Air Cooled Engines:
The 32mm bore 2-bolt cylinder. (fits any 2-bolt Zenoah/CY RC cases and 28mm crank). Race Porting offered, HT,(a EFRA favorite). Championship Porting offered, HT, (a EFRA favorite). HP 5.0 to 5.40
The 32mm bore 2-bolt cylinder. (fits any 2-bolt Zenoah/CY RC cases and 28mm crank). Race Porting offered, HT, (a EFRA favorite). HP 5.0
The 32mm bore 4-bolt cylinder. Race Porting offered, HT, (a EFRA favorite). Championship Porting offered, HT, (a EFRA favorite). HP; 5.0 to 5.40
The 34mm bore 2-bolt cylinder. (fits any 2-bolt Zenoah/CY RC cases). Race Porting offered, HT, (an EFRA favorite). Championship Porting offered, HT, (an EFRA favorite). 2mm stroked kit available with the head modifications, (a 27.2cc). Reed Case porting offered, single boost port. HP; 5.50 to 6.25
The 34mm bore 4-bolt cylinder. Race Porting offered, HT, (a EFRA favorite). Championship Porting offered, HT or HR (a EFRA favorite). 1mm stroked crank fits right in stock engine with no changes. 2mm stroked kit available with the head modifications, (a 27.2cc). Reed Case poring offered, single boost port. HP; 5.50 to 6.35
The CY 35mm bore 2-bolt cylinder. Race Porting offered, HT. HP; 5.50
The CY 36mm bore 2-bolt cylinder. Race Porting offered, HT. Championship Porting offered, HT. 2mm stroked crank with head modifications offered, (30.5cc) Reed case porting offered, single boost port. HP; 6.25 to 6.90
The Zenoah 36mm bore 4-bolt cylinder. Race Porting offered, HT. Championship Porting offered, HT or HR. 1mm stroked crank fits right in stock engine with no changes. 2mm stroked kit available with the head modifications, (a 30.5cc). Reed Case poring offered, one or two boost ports added. HP; 6.25 to 7.2, (about as good as it gets with Zenoah RC cylinders on gas).`
The Zenoah 38mm bore 4-bolt cylinder. Race Porting offered, HT. 2mm crank head modifications offered (34cc) HP; 6.25, (these engines make the best power over any other RC engine from 8,000 to 12,000rpm).
Zenoah 40cc kit, (complete engines not available) Race Ported HP unknown
CY, (complete engines not available) Race Porting offered. Trevor Simpson reed case porting offered. HP unknown, (but reed case has to be over 8hp)
You provide the new twin cases, I build the long block to perfection using Zenoah G290 top end kits. Made directly per order, not sold through DDM Race Porting available, but why? Championship porting available, HT or HR. 2017 reigning East Coast Drag racing track record holder. (Nickolas Washington, custom S&H pipes) HP; 13.0 plus
Water Cooled Engines:
The Zenoah 34mm bore, with the stock stroke crank. Championship Porting available, HR (New porting for 2018). This cylinder is about maxed out, but still structurally strong at the exhaust port. Comes with the High Rev Piston and engraved water jacket. This kit has tight squish, so you will want to check it on your engine before you start it. HP 6.40
The Zenoah 36mm bore. Cranks; stock, 1mm and 2mm. Championship porting available, HR. (includes HR light weight Piston). Reed Case porting available, 2 boost ports added, (new porting and compression for 2018, and running very very well, the best ESP has put out yet) HP 6.50 to 6.75 for piston port engine (depending on crank choice) HP; 7.25 plus for the new reed case top end kit.
You provide the twin cases, I build the long block to perfection using Zenoah G290PUM top end kits. Made directly per order, not sold through DDM Championship porting available, (High Rev). High Rev and light weight Pistons included if wanted. HP; 13.0 plus.
PUM reed cases
Those PUM reed cases are hard to find, so if you have a set, think what will happen when you win with them. Let me build it for you and make it your favorite engine. Trevor Simpson and I build the best reed case top end kits in the world for production. So if you are not using one of ours, you are not getting the best performance out of those reed cases. My reed case top end kits for the PUM are not available through DDM, but I will built it directly, (to tighter specs than I can do for production). Just give me a call.
The ESP High Rev Pistons have expanded and improved for 2018. They are now made for 34mm, 36mm and 38mm diameter pistons, (light weight available for the 34mm and 36mm pistons), and the sacrifice of compression is now very very small, (less than the difference of a .002“ thick cylinder gasket). For sale at DDM, we offer the exhaust duration increased by 5.5 degrees. I have cut the intake skirt for more intake duration for some 36mm pistons, but I think I will leave the intake skirt stock from now on for retail. They are great for stock and modified engines, and will rev higher if the pipe lets the engine rev. But for you guys who build your own engines, and may want maximum duration, call me. I can custom cut your pistons up to 7.5 degrees on the exhaust, and what ever you may want on the intake, saving you cylinder porting time and the cost of different cylinders. If you must have high rpm power, you should not overlook these pistons.