a few questions about FRM sleeves......btw i did a search so don't flame

1.why did honda use FRM sleeves in the h series blocks? and are there any benifits from FRM over iron sleeves?

2.are there any other honda motors that have FRM sleeves in them?

thanks,
David

 

nobody knows the answers to these??

 

The S2k has FRM sleeves. The FRM was used for strength, since the cylinder walls are so thin on a H22. The Iron sleeves were probably not used to due the cost of mass producing the engines.

 

the prelude was the test platform for all of honda's little projects: Rear wheel steering, frm, VTEC, ATTS, styling (all within a few years). and once that was developed then it homologated the technology to other platforms like the civic and then integra and S2000.

the Pirate

 

earlier nsx's have frm sleeves too i have heard

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PirateMcFred &raquo;</TD></TR><TR><TD CLASS="quote">the prelude was the test platform for all of honda's little projects: Rear wheel steering, frm, VTEC, ATTS, styling (all within a few years).

the Pirate</TD></TR></TABLE>

i never really noticed that until now but its true

so just about all honda blocks have frm sleeves? beacuse i think the rsx has iron sleeves. and doesnt the f22 have iron ones too?

thanks,
David

 

b16a, b16b, b18a, b18b, b18c, b20b, b20z, D series (don't know too much about them), f20b, f22, f23 all have iron sleeves to my knowledge. But the H series, f20c and some nsx engines have FRM (maybe all but I don't know).

but seems that all civics and integras have Iron sleeves. Which makes them able to be boosted more readily than the H series.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PirateMcFred &raquo;</TD></TR><TR><TD CLASS="quote">b16a, b16b, b18a, b18b, b18c, b20b, b20z, D series (don't know too much about them), f20b, f22, f23 all have iron sleeves to my knowledge. But the H series, f20c and some nsx engines have FRM (maybe all but I don't know).

but seems that all civics and integras have Iron sleeves. Which makes them able to be boosted more readily than the H series.

</TD></TR></TABLE>

hmm... good to know

Thanks!

David

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98 blacksh &raquo;</TD></TR><TR><TD CLASS="quote">earlier nsx's have frm sleeves too i have heard </TD></TR></TABLE>

LATER NSX engines have frm 3.2L blocks only.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by precord96 &raquo;</TD></TR><TR><TD CLASS="quote">The S2k has FRM sleeves. The FRM was used for strength, since the cylinder walls are so thin on a H22. The Iron sleeves were probably not used to due the cost of mass producing the engines.</TD></TR></TABLE>

I can assure you that iron liners are far cheaper than FRM.
It was used for strength, as the FRM actually stiffens the block, while allowing thin cylinder walls. It also has good lubricity, wear characteristics, and heat transfer properties.
On a FRM block, the block is actually cast AROUND pre-made liners.

 

so why did they make the cylinder walls so damn thin? any good reason for that?

btw....good info is comin in

thanks,
David

 

Thermal efficiency. less material helps a little with weight too.

 

there is some truth to thermal effinciency. but i would disagree with strenth. the walls are not that thin. the pre obd2 blocks were closed deck and the had frm. so the too thin theory is not relavent in this case.

the main reason behind frm is weight.

 

it was strength and weight...

strength as in adding FRM sleeves allowed them to bore out to 87mm keep the same thickness between the cylinders.

That's why all non-FRM F series motors are 85mm

97+ NSX C32B motors had them as well to all boring the C30A out from 90mm to 93mm increasing displacement to 3.2L

It's how they increased displacement with a fixed crankshaft and cylinder spacing

 

yes frm is very strong just not as strong as iron. but yes i correct myself, they do add strenth to the aluminum.

 

FRM was used with our primarily Aluminum-Alloy block to retain high block regidity and low weight while sill fitting a larger displacement I4 with high compression into an Accord-sized engine bay.

If you don't believe me, compare an H23 with an SR20DET and 2997cc 2JZ to a 2259cc H23 (which I got to do when my new motor got dropped in). The h23 seems tiny when compared to the SR20, and rediculously small when compared to a 2JZ (the mechanic and I actually disputed if you could fit 2 H23s sans-tranny into a supra engine bay).

Unfortunatly, that means no forged fists for you unless you take them out.

Honda meant well, but many of us have different plans for our H-Series that the FRM inhibits.