Honda-Tech - Honda Forum Discussion - FRM Sleeves Explained

As per the origin of this information:
K Powered EJ1 ripped it (copy/pasted) from some site online who's URL I can't recall at the moment, when he had his hissy fit and left H-T, he wanted to go to his butt buddy's forum he wanted to "take his threads with him" - though in accordance with the H-T license agreement he agreed to when he clicked "I accept the terms" when he signed up for H-T - information he posted is publicized and becomes the property of Honda-Tech.

Onto FRM sleeves (BTW I fixed all his 3rd grade spelling errors and weak sentence structures).

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FRM stands for Fiber Reinforced Metal. This basically means that the sleeve is not full ductile iron like the previous stronger sleeves of the Honda engine world.

This technology was introduced in 1988 with the introduction of the B21A1, which was included in the Prelude Si (JDM/EDM only).

FRM sleeves consist of a carbon fiber matrix, aluminum alloy, and aluminum oxide.

It is rumored that any type of power adder or forged piston in a engine used with the FRM sleeve will need to be re-sleeved, 95 percent of the people who have built an h22 with cracked sleeves will agree, the other 5 percent have never built a motor strong enough to crack the sleeve.

The following engines were created using FRM sleeves:
-B21A1
-H22A1
-H22A4
-H22A
-H23A
-F20C
-C32B(NSX)

FRM sleeves are also referred to as MMA in metalogy, but MMA is simply a blanket term for the MMA sleeves Yamaha used in their engine sold to Toyota.

Toyota motors powering the Lotus Elise, Lotus Exige, Toyota Celica GTS, Toyota Matrix etc. have FRM sleeves, but have a different composition sleeve than Honda's FRM sleeves.