CL-S pistons vs RL pistons...

[changaroo]

i have both next to me, and i cannot tell the difference between them.

the RL is supposed to be forged, but yet it weighs the same as a CL-S piston.

the valve relief domes look exactly the same to me also...

how is the RL supposed to yield higher compression if they are the same?

http://i292.photobucket.com/albums/mm17/changarooFD/pistons.jpg

[hondaboy4life]

hmm. Interesting.

[wolydotmatrix]

i have both next to me, and i cannot tell the difference between them.

the RL is supposed to be forged, but yet it weighs the same as a CL-S piston.

the valve relief domes look exactly the same to me also...

how is the RL supposed to yield higher compression if they are the same?

http://i292.photobucket.com/albums/mm17/changarooFD/pistons.jpg

maybe that arrow at the bottom makes it forged :)

[LKSi]

The RL piston looks like a cast piece as well based on its finish.

[changaroo]

this is the problem main problem about j series builds.

most of them are built by one person up in VA.

everyone else is running around regurgitating information based on old information.

nobody has actually done the build themselves to notice the difference shit pisses me off.

[LKSi]

What year RL are they from?

[changaroo]

05 RL...

the pistons listed in every sticky / j series builds.

[IDon'tKnow]

The comustion chamber on the RL head must be a slightly different shape. Thank you for posting this picture - now I won't bother buying RL pistons; I'll just clean up the ones I have.

[changaroo]

i am about to do a water droplet test. to see how much the valve reliefs hold between the RL and the CL-S pistons.

they look really identical to me. the undersides of the pistons are the only difference i see.

i am going to be pissed if i wasted $500 on a piston / ring set that wasnt even needed.

i am just dissapointed that i had to be the test dummy.

there is no proven info that says the RL pistons give 11:1 whereas the CL-S pistons give 10.5:1

one person did the research back in 02, and who knows if its correct.

[splat]

http://i292.photobucket.com/albums/mm17/changarooFD/pistons.jpg

WTF, i dont see anything to make them different.

I hope the test you run will say something different.

[1diesel2hondas]

I read that the RL piston rumor is B.S. Because when you do real math 3.2 vs. 3.5 cumbustion chamber volum vs. Whatever, the suposedly 10:5 pistons are actualy more comprssion or something. I know this is vague, but I know I read it and whoever posted it knows what I'm talking about. If you know the thread please post a link.

[IDon'tKnow]

That sucks that you spent the extra money on yhe RL pistons and that they are essentially the same as the pistons you already have. I wouldn't rule out trying to return them to Acura if I were you; this is the nature of the beast when you are dealing with a motor that is largely unexplored and undeveloped in the aftermarket.

I argued in several threads that the CL/TL pistons would have to yield more compression than the RL pistons (because they were making 10:5:1 with a ~533cc's per cyl while the RL engine makes 11:1 on ~583cc's per cyl.) under the assumption that head is the same shape between both motors. There are only two possible variables in determining CR in this case and those were Piston Dome and Chamber Shape - with Piston Dome ruled out we now know that the shape of the heads are definitely different.

Compression Ration & EMS Question (http://www.j32a.com/showthread.php?t=741&page=2)
and
J32A2 Specs and Options? (http://www.j32a.com/showthread.php?t=688)


"I don't know how this misconception got out there, or if I'm just missing something, but the RL pistons should actually be lower compression than the TL-S pistons.

J35A3 Compression ratio is: 11:1 so 3500cc/11= 318cc chamber volume at TDC.
J32A2 Compression ratio is: 10.5:1 so 3200cc/10.5= 304.5cc chamber volume at TDC.

So unless the chamber shape the the J35A3 heads is different than on the J32 it stand to reason that the J32 pistons have a higher dome.

304.5cc chamber volume at TDC with a 3500cc engine should yield 11.5:1 compression. "

[changaroo]

apparently the CL-S pistons are forged also?

anyways... its not really worth me returning and paying the 20% restocking fee. i might as well suck it up and use them.

im gonna have so many pistons lying around lol. cl-s pistons, mdx pistons, oddysey pistons and now the RL pistons. hah.

[1diesel2hondas]

Can some one who has inside info please tell us wich pistons are foraged? This would help alot. Thanks!

[changaroo]

Can some one who has inside info please tell us wich pistons are foraged? This would help alot. Thanks!

nobody knows at this point. everyones just throwing around info from what theyve "read" im tired of this he said she said bs. im about to buy one of each piston to bring this myth to a rest lol.

[1diesel2hondas]

There's real info on wich cranks are forged, so there should be info on the pistons someware. It sucks not having all the info, but I love being one of the first. Building a b20vtec after 1,000s of others were done was a little bit of a buzz kill for me. I love being one of the ground breakers.

[IDon'tKnow]

The situation with the forged cranks isn't much better. Wikipedia says the j35a4 used a cast crank while some engineers on the Honda Odysey project have stated that ALL Odysey motors have used forged cranks. Who should we believe? Did someone just mince an interpretation when they read about the J35 being used in the Saturn Vue? Is there an easy way to find the right answer? No.

[hondaboy4life]

Even when going to some of the people higher up information can become distorted. Most people don't know that Ford has one guy that designs their cranks and all that guy does is plug info into a formula/program a guy came up with 20 years ago.

As far as building a J a lot of info i've read out there doesnt seem to have solid evidence of being true, therefore i had planned on starting with scratch. At the cost of $500 for pistons i would rather spend the bit of extra cash and make custom pistons designed to my spec to yield the results i am looking for and calculated towards.

Sell the RL pistons to the guys that are doing the "higher compression" builds based off someones word, and get some of your money back then figure out a better method to reach your goal ;)

A standalone setup on a stock motor should present some solid results (I'm about to finish my setup in the next few weeks). That's where I'm starting until my 3.7 build is done.

[wolydotmatrix]

Great discussion, looks like I will have to call my buddy at Honda again. I never thought to ask about the pistons. Give me a few days and I'll se what he says.