The original MREV/spacer combo, which was marketed in 11.05, only benefits the RevUp engines ('05+'06) equipped with a 6MT. Since the MREV utilizes the non RevUp ('03 +'04) engine's lower collector there is no point in installing the said in an non RevUp engine. The non RevUp engines are better served with a Motordyne plenum spacer, which has been tested to yield healthy results.

The MREV+ is a modified non RevUp engine lower collector. The MREV+ was originally an added option to the original MREV package, if so desired for a few more ponies. Recently, in the later part of March 2006, Tony has tested the MREV+ and determined that it does in fact afford the non RevUp engines good gains.

https://g35driver.com/forums/intake-exhaust/92810-mrev-installed-non-revup-engine.html

Most recently, our good friend at Motordyne, Tony . . . Has developed yet another version of the MREV. This most recent version is a remodified version of the MREV+'s lower collector. For clarity sake let's call this newest version the MREV 2 until Tony formally names it.

This past Saturday, May 6, 2006, Tony and friends held a public dyno testing of the MREV 2/spacer combo at Church's. A non RevUp engine dyno tested with the new MREV 2/spacer combo yielded very good results. Unfortunately, time did not allow for the same dyno testing on a RevUp engine. The MREV 2 was installed and tested without the spacer. This scenario yielded excellent torque gains through the mid range, but dropped in power in the higher ranges. I have to believe that having the spacer installed with the MREV 2 would have made a world of difference in the RevUp engine.

With all of that having been said . . . I personally believe that in time the MREV 2 combo will prove effective and yield very good gains for the RevUp and non RevUp engines alike.

I currenty have the MREV+ with a 5/16" plenum spacer and cannot wait to get the MREV 2 installed and tested.

 

^^^^clarified everything for me in one post

 

From the information I got from Tony (Hydrazine), for <05, this is what he said would probably be the best combination for hp gains:


"Hi Les,

For the best results, I suggest the (plenum) spacer with the MREV+ lower collector.

This will provide the highest level of gains for a plenum mod.

Tony"

From what I understand, the "MREV+ lower collector" is essentially a modified lower collector.

This would be for non revup engines.

Personally, I think on my 03 coupe 5AT, I'm just going to go with the spacer. I don't know if the gains I would see replacing my lower collector, would be worth the time, effort, or money.

I could be wrong!!!

Les

BTW: Posted this before I saw Andy's excellent explanation.