AgentLongwood

I noticed that the '13-'18 Acura RDX uses a J35Z2 as it's V6. The J35Z2 is the same engine listed in the '08-'12 Accord V6 . What I can't find is what are the specific differences between the Accord and RDX versions of the J35Z2? The only info I can find is on the wiki, which shows they have the same compression (10.5:1), same redline (6900), and same RPMs for peak power(6200) and peak torque (6200).

Since all that is identical, why do the engines have different octane requirements? And why does the Acura one make 3 ft-lbs LESS torque at the same peak RPM, and 10 hp MORE at the same peak RPM?

What are the differences between the motors? Is it just software? Like VTEC engagement, or cam timing? Does anyone have an actual answer for certain, or is it all just our best guesses?

Alex Medeiros

The Acura is tuned for premium which in turn gets a little bit better output. If you use anything lower than premium however, the car will have to retard its timing and will not run as good as on premium. The Honda is tuned for regular octane gas, so it ultimately looses some performance versus the Acura and gains nothing by using higher octanes. My opinion is that in order to differentiate the Acura apart from the Honda, they wanted to make it a little more powerful and by needing premium gas, it makes the car sound more expensive and luxurious versus the very bland Honda.

AgentLongwood

RIght on, I kinda figured the tuning could be different. That was my guess, anyway. Does anybody know what the actual tuning differences are? Cam timing, ignition timing, fueling, vtec engagement? Do they use different cams, even? Does anybody know what the actual differences are? Or are we just guessing about tuning and don't have a way to get actual answers?

altair47

2013–2015 RDX is the same engine as the 2008–2012 Accord, 2016–2018 RDX is a very different engine, but with the same name.
It is more powerful because the ignition is designed for premium gasoline.

AgentLongwood

If it's "Very Different" then what are the actual differences? Specifically

altair47

As far as I know, on the new J35Z2 at least the short block is molded for 2 knock sensors, VTEC and everything related to valve opening has received a new design

AgentLongwood

This is awesome. Thank you for replying with actual specifics and photos. That's genuinely helpful. Appreciate it.

thericepatch

There are a number of differences between the two motors, including the different knock sensors, different sensors on the vcm, and the RDX has plastic valve covers. The casting is different for the heads,cams, as well as the block. RDX is 5GO castings, the other models are R70 castings. The oil filter housing and gaskets is different as well. They are somewhat interchangeable as an assembly, I've used the RDX engine in an 09 Pilot and 08 Odyssey. The RDX engine is extremely cheap ($500). Took some modifications but runs great. They do have a constant check engine light due to a vps (valve pause system) code that I have never resolved, so it's not a perfect swap at this point. I did put together a youtube video on it when I did the swaps 2 years ago I'd love to have some collaboration to get this combination working without error codes.

altair47

This guy is very funny, instead of changing the engine from 2013-2015 RDX, he did all this job and now his CEL will be on. But he saved $500!

thericepatch

YOLO, a little experimenting is fun and builds knowledge. The motor was only $500 with 50k miles on it, so it saved me over $1000 per motor. Basically I paid the cost of one head and got a full low mileage motor that runs great in a couple of 15 year old vehicles. But hey, if you are more worried about a cel than than saving a couple thousand, to each his own.

altair47

It all depends on how much your labor costs; if you work for food, then this is a profitable occupation, but if an hour of your labor costs at least $50, then it is a fiasco.

thericepatch

Sure, check eBay. https://www.ebay.com/itm/29634032453...mis&media=COPY

This particular listing has unknown miles, but it's on a 5-7 yo motor and includes shipping. Lkq sells them all the time, I drove a couple hours and saved shipping on one of mine, I think I got it for less than $500. Again, my swaps were 2 years ago, but this is still a current price. With shipping. I'm not saying this is the Holy Grail of motor swaps, but getting a low mileage 5-7yo 3.5 to drop in your ride for $500 is a dang sweet deal for some of us budget conscious types.

altair47

What DTC do you have?

thericepatch

P3497 vps deactivated bank 2.

altair47

Only one code? It's not bad at all. Have you transferred all the VСM presure sensors and the resistance of the solenoids is the same as the original Odyssey ones?

thericepatch

We had to change the sensors due to different plugs. I don't think we tested resistance at the solenoids.

altair47

Do you have a VCM muzzler?

thericepatch

We ran the resistor mod, as we have done on hundreds of these motors. I think we ran 120 ohm resistor on those two.

altair47

Due to the fact that you don't have a code for the knock sensor, I liked the idea of installing these engines on cars with electric power steering. That is, of all the changes you will only need to programmatically remove the EGR and VCM, and this is done very easily.