Supertech K24A 87mm Pistons for TSX/Accord/CR-V/Element

Supertech 87mm Standard Bore Pistons - Honda K-Series (K24 with K24 or K20 Head)

Building a K24? These Supertech forged pistons are the kind of foundation you build a proper motor on. They're an 87mm standard bore, so they drop right into your stock K24 bore, and they're made for the K24 block running either the factory K24 head or a K20 head, that popular high-revving frankenstein combo. The big thing here: this page carries four different compression ratios (11.5:1, 12.5:1, 13.2:1, and 14.4:1), so you're not stuck with one and hoping it fits your plans. You pick the compression that matches the engine you're actually building. More on how to choose that below, because it matters a lot.

Pick The Right Compression Ratio

This is the decision that trips people up, so let's make it simple. The core rule: boost and compression work against each other. A turbo or supercharger shoves in extra air and effectively piles on compression, so forced-induction builds run a lower static compression ratio to leave headroom and stay away from detonation. Naturally aspirated builds go the other way, they run higher compression to make more power and sharper response without boost, but the higher you go, the better the fuel and tuning you need. Here's how the four break down:

• 11.5:1 - This is your boost pick. If you're building a turbo or supercharged K24, this lower compression gives you the room to run real boost without knocking, and it's the most pump-gas-friendly of the bunch under boost. Start here for any serious forced-induction build.
• 12.5:1 - The versatile middle ground. It's a great choice for a strong naturally aspirated street build that you still want to drive around, or for a milder boost setup. If you're not sure and you want a do-a-bit-of-everything piston, this is the safe, flexible one.
• 13.2:1 - Now you're in high-compression naturally aspirated territory. This is for a serious NA build, think aggressive cams and head work, chasing power and throttle response. Plan on good fuel here (high-octane, race gas, or E85) and a proper tune. Not for boost.
• 14.4:1 - The maximum-effort, race-focused NA piston. This is for an all-out naturally aspirated build spinning to the moon on race fuel or E85, squeezing out every bit of power the combo can make. It's not a pump-gas street piston and it's definitely not for boost, it's a purpose-built race choice.

Bottom line: going boost? Lean toward 11.5:1. Building a hard NA motor? Step up through 12.5, 13.2, and 14.4 as your cams, fuel, and goals get more aggressive. And whichever you pick, get it tuned properly for your fuel, because high compression and boost both punish a bad tune. If you're on the fence, talk it through with your engine builder or tuner before you order.

Built To Take Abuse

This is where Supertech's build shows up. These are forged from an extruded high-silicon enhanced 4032 alloy, with added copper, nickel, and magnesium, and that matters more than it sounds. 4032 has low thermal expansion, which lets you run tighter piston-to-wall clearances for a quieter, more street-friendly motor, while the enhanced alloy brings the strength, wear resistance, and thermal conductivity to survive real abuse. Supertech says this alloy has held up to 42 psi of boost on alcohol without complaint, so there's serious headroom baked in. They're made with a two or three step forging process that lines up the grain structure with the direction of stress, then run through several heat treatments for high tensile strength and evenly distributed hardness, and CNC machined for precise, flat, square ring grooves. You also get contact reduction grooves, honed and reamed pin bores for a precise fit, and cold-extruded chrome-moly wrist pins that run wire clip locks. On top of that, they're finished with a phosphate dry-lubricant coating that protects the rings against micro-welding and helps lubricate the skirt against the cylinder wall. This is a proper forged race piston, not a budget slug.

Built For The K24 (Stock Or K20 Head)

Just to be clear on what these are for: they're made for the K24 block, running either the stock K24 head or a K20 head. That K24-block, K20-head combo is a favorite for a reason, you get the K24's displacement and torque with the K20 head's high-rpm breathing, and these pistons are cut to work with that setup at 87mm standard bore.

One Thing You'll Need: Rings

Heads-up before you order: rings are not included with these pistons. You'll need the matching Supertech 87mm piston rings (part GNH8700) to go with them, so add a set to your order so you've got everything on the bench when it's time to build. Don't get caught halfway through an assembly waiting on rings.

What You Get

• Supertech 87mm standard bore pistons, set of 4
• Choice of compression ratio: 11.5:1, 12.5:1, 13.2:1, or 14.4:1
• Forged from high-silicon enhanced 4032 alloy (with Cu, Ni, Mg)
• Contact reduction grooves and honed/reamed pin bores
• Cold-extruded chrome-moly wrist pins with wire clip locks
• Phosphate dry-lubricant coating
• For the K24 block with a stock K24 or K20 head
• Rings not included (requires Supertech 87mm rings, GNH8700)

Fits These Cars

• 2004-2008 Acura TSX (K24A)
• 2003-2007 Honda Accord (K24A)
• 2002-2006 Honda CR-V (K24A)
• 2003-2011 Honda Element (K24A)

Note: Supertech 87mm standard bore forged pistons for the Honda K-series, sold as a set of 4, for the K24 block running either the stock K24 head or a K20 head. Available in four compression ratios: 11.5:1 (best for forced induction), 12.5:1 (versatile street NA or mild boost), 13.2:1 (high-compression NA), and 14.4:1 (maximum-effort race NA); higher compression makes more naturally aspirated power but requires higher-octane fuel and careful tuning, while lower compression leaves headroom for boost. Forged from extruded high-silicon enhanced 4032 alloy (with added Cu, Ni, and Mg) for low thermal expansion, wear resistance, and strength, and reported to have withstood up to 42 psi of boost on alcohol. Features a multi- step forging process, multiple heat treatments, CNC-machined ring grooves, contact reduction grooves, honed and reamed pin bores, cold-extruded chrome-moly wrist pins with wire clip locks, and a phosphate dry-lubricant coating. Fits the K24A found in the 2004-2008 Acura TSX, 2003-2007 Honda Accord, 2002-2006 Honda CR-V, and 2003-2011 Honda Element. Rings are not included and are required (Supertech 87mm piston rings, part GNH8700). Have your build tuned for your compression and fuel. One set of 4 pistons per order.