All.

I did some preliminary investigation of the benefits/ill-effects of upgrading to the 3.5 using STOCK parts with limited customization. Attached are curves depicting piston accelration at 8000 RPM for the stock 3.2, stock 3.5 and 3.5 using 3.2 rods.

It appears that stroke is the important factor here. There isn't really a big difference... and I don't think anybody plans on going past 8K RPMS anyways:

http://photos.yahoo.com/bc/gunjan_ra...c=ph%26.view=t

More on this later...

 

allmotor,
Long term longevity you want that rod-stroke ratio nice and tight right? One of the issues that bothered me about using the MDX block.

 

The graph was tiny could you comment what is going on?

 

If you know the rod length, you can also derive acceleration numbers from one of the calculators here:
http://www.slowgt.com/Calc2.htm
I can't comment on its validity, but looks good to me.

 

Hey that's a cool site... saves me some math in the future!

There are two larger effects of rod-ratio and several smaller effects. Larger effects include:

(1) Piston speed/acceleration and motion dynamics (forces on the rod, wrist-pin, crank etc.)
(2) Dwell-time (time the piston spends at TDC)

The real purpose of graph was to ondicate that there ISN'T a very significant difference between the MDX block and the CL-S block at 8K rpms in terms of piston acceleration. Dwell-time changes and hence hence limits very aggressive cam profiles.

Just stuff to think about.

 

So is what you're saying basically that we can continue to use our existing block and just grab the MDX rods and end up with pretty much the same results as if we got the MDX block put in our cars?

Sorry I don't know much about cars, but I am pretty interested in getting the 3.5L upgrade..

 

The rods won't make a difference.. in fact you should use the CL-S rods as they are longer. You have to use the MDX crank, however. The problem is the pistons. If you use the MDX crank and CL-S rods, you have to get custom pistons. I think the CL-S pistons are 346grams each, so you want to definately be lighter than that!

 

So much for using all Acura OEM parts and it being a simple swap-out then if you go for the custom piston route, although I'd imagine that the gains would of course be better with the custom pistons then..

How were people like TypeR doing this in the past? using all MDX parts for the crank, pistons, rods and block?

 

I think they are using MDX crank, MDX rods and an older 3.0 V6 pistons.. same bore I believe.

 

Hey S,

U think u can PM me the link to where u are able to get all ur piston, rod, and crank info.



Tnx







Juker008

 

One of the folks on this board e-mailed me the complete vehicle specifications for ours cars... so if you PM me with your e-mail, I'll just e-mail it to you.

-OR-

MODS: Let me e-mail this to you... and you guys post it in the 'useful info' section! They are .pdf's