Tech Review: SRP’s New Professional Pistons
When it comes to making solid reliable power in a engine, choosing the right piston is always at the top of mind. Needless to say, we were excited when JE Pistons announced that they were going to be applying their massive knowledge of piston technology to take their existing affordable budget SRP piston and upgrade into the more beefy SRP Professional line. Let’s take a look at the new SRP Professional series – we even put together a video for you that tells you everything you need to know but were afraid to ask:
Both the original SRP and SRP Professional pistons are offered for many popular engines including the Ford Modular, LSX, and of course the old school traditional stuff. Both are “off the shelf” pistons meaning there are part numbers and these pistons are kept in stock by major mail order outfits. So what is the same, and what is different?
While both SRP and SRP Professional pistons are forged from premium aluminum alloy for strength, there is a substantial evolution in design with the SRP Professional. Well over a year was spent by JE’s engineering team building a lighter piston incorporating many of the “tricks” that are often designed into custom JE pistons.
Let’s take a closer look at the SRP Professional.
SRP Professional: Evolution of a Shelf Piston
SRP’s new Professional Series truly does blur the line between catalog pistons and custom race slugs. The Professional forgings are completely “clean sheet” designs, that feature much shorter piston skirts, a reduced-skirt package that reduces friction and weight, and are actually engineered to take more horsepower than the original SRP.
The forging also features the “FSR” process which is Forged Side Reliefs – that aid in the ring seal while decreasing the risks of stress cracks. The accumulator groove is also improved to help promote a better ring seal to keep combustion in their place inside the cylinders – where they belong!
JE also decided to include on their SRP line a brand new skirt coating standard that reduces friction and wear in performance engines.
The JE Pro Seal ring package for the Professional series is redesigned from the standard SRP line to accept a much higher end set of rings – thinner for less drag and more power. The SRP Professional’s sport a 1.2 mm top ring, Napier 2nd ring, and a 3.0 mm standard tension oil ring which is the same width ring package as the LS7 Corvette engine. All rings included with SRP’s Pro’s are standard fit – no file fitting here. This means if you need custom fitment you either need to buy another set of rings or go custom.
A Weighty Matter?
SRP’s Pro Line is lighter, and capable of increased RPM. How much lighter? It can be up to 200 grams or even more in some designs – thanks to the before-mentioned changes to the forging, but also the shorter pin and lock packages. This pistons feature a 2.250” pin which reduces overall weight, while still maintaining plenty of strength to hold the piston to its rod. This is done by using a shorter, but sturdier pin.
So, the big question is — is there horsepower to be gained from these improvements.
JE tested a small block Chevrolet engines with back-to-back dyno runs to compare the same “piston type” – with the only differences being that one was a SRP Professional and the other piston was an SRP Piston.
“We used a 383 cubic inch small block Chevy,” explained Sean Crawford, JE’s Marketing Director. “With a 3.75-inch stroke, 6-inch rod, and 4.030 bore, it’s probably the most commonly built street engine you could find.” “We started with the standard SRP (part number 138093), and then swapped it out with the SRP Professional version (part number 268830).”
JE reports the engine picked up 10 peak horsepower with no other changes, due to the lighter weight of the piston, decreases friction, and better ring package. That’s impressive power for the cost difference of the pistons.
JE is going to continue to make the SRP piston for the true budget enthusiast that simply needs an inexpensive forged piston but doesn’t need to make maximum power. But if you care about your dyno sheet, and don’t need or want to spend the money on a custom piston, you can’t go from with the JE SRP Professional.