Hey guys,

I've heard many myths on here about MREV2 with a plenum 5/16 spacer being the most bad A$$ combo and others say you can't run that setup because you'll run into problems but not stating what. I've done a search and still have come up with nothing. So if someone could please clear this up for me I'd be most thankful! Thanks in advance!

-Mario-

 

O man! You got that? Nothing but problems! Better sell it to me for cheap! lol.

You might run lean during open loop but it's really up to debate if that really happens. Usually you won't run into this until headers / cats are done.

 

You'll be fine...maybe a little bit leaner, but the ECU will bring it back to check in about 200 miles, unless you do a reset.

Once you go full exhaust, headers, etc...you should tune the AFR - a TS re-flash or AF piggy back and a dyno will do the trick.

You really wont cause any harm, but you will get more out of the mods if you tune it up though...

Rick

 

Mario, do you have the rev-up engine (post 05 6MT, 298hp)? From what I've read, the "lean" condition with mrev2/spacer combo is a potential concern with the rev-up only; non-revup (280hp) motors benefit from one or the other but not necessarily both (again, from what I've read).

Also, +1 to IMSOLUTIONS' post regarding tuning etc.

 

John,

Mine is a non 04 non rev-up. What do you mean that the combo doesn't necessarily benefit as opposed to just one or the other? Please explain. Thanks!

 

so when it runs lean does it hesitate a little? i just put the mrev2 only and have hesitation thought it was something in the tranny dunno, how is this fixable?

 

MREV was originally designed to benefit the rev up motors. ie.. using a stock non-rev up lower plenum and a spacer to give great low/mid hp/torque w/o to much sacrifice on the top end.

The MREV2 is a modified stock non-rev up lower plenum that was found to benefit us non-rev up engine owners. Although you can't really stack the MREV2 and spacer together to get xx + xx hp, they do work together for a good net hp gain.

How did you pay if I may ask?

 

Actually, you have that backwards. The MREV2/spacer combo will cause AFR to run lean on the non revup without a proper tune. The combo works great on the revup.

Taken from everythingg35.com:
The MREV2 is a new product from Motordyne Engineering. It's a new design that works on both the REV-Up and Standard VQ35 engines.

The average power gains on a 260 or 280hp motor (non-rev-up) are better than the 5/16" spacer. This modification increases power across a very wide rpm range. The MREV2 should be used without a spacer on the standard engine, unless fuel/ECU modifications have been performed as it may cause the engine to run lean.

The power gains on a 298hp REV-Up motor are similar to the earlier MREV kits, when used with a 5/16" spacer kit. The 5/16" Spacer is recommended for the REV-Up engines as it will help safely increase power, when used with the MREV2 collector. This setup averages 15+hp and 18+ft.lbs in the upper midrange (approx 4500-5000rpms). Many independent tests have shown even higher gains as well!

 

Man, opinions on non-rev with MREV are like a$$holes, everyone has one!

Would like to hear from Tony Collette at Motordyne himself for the final opinion.

PM "Hydrazine" for the information you seek, and post it on the boardsONCE AND FOR ALL.

 

FWIW I've asked and received answer from Tony on this and Z board more than once about non-revup spacer/mrev combo. He carefully states that every motor/ecu combo is different. Different climates, different gas formulations etc. and so the only way to know is to dyno for accurate AFR readings. In general, it's most logical that you would get better performance from dyno-tuning a configurable ECU...even otherwise stock motors will see gains. My experience in having this combination (1st had spacer for several months) is positive. I feel better pull in the mid-range RPMs where I do most of my driving. Adding the ISO-Thermal components also seemed to cool down the plenum very well.

Worth the extra money?- not unless you're willing to go the dyno-tune route..

Which is better ROI - probably the spacer.

Note that many G's and Z's report good HP and torque gains (dyno-proven) after this combo with a tune.. I've only seen one dyno experiment that measured the difference between stock, spacer alone, MREV alone and combo... combo had more torque area under the curve, a bit less at red-line, which kinda matches my butt-experience.

Hope this helps as I agree this has been questioned to death.

 

Its described very well on EverythingG35. I didn't write it, but I did help them in the product description.

 

Thanks!

 

I am also wondering... what exactly is a REVUP motor? I have an '03 g35 coupe and I am guessing I do not have REVUP. Would I have to get my ECU tuned as well if I got the MREV and the 5/16" spacer?

 

The revup motor is a newer engine with a different ECU and different internals. It also has a higher redline.

Most people can get both of them on their NON-REVUP engine and it will work great, but if your A/F ratio is already on the lean side (above 13.5), I don't recommend doing both untill you can get the A/F back down with a reflash or engine management.

If you have dynod your car and saw the A/F is below 13.5, then you can do both no problem.