Ok so I have researched this quite a bit and by the looks of things the best option to keep mostly stock is to go with the Motordyne Copper ISO thermal 5/16 spacer.

Question is - to all of you who have this mod,

-does it really make a noticable difference in normal spirited 3-5,000 rpm driving
-does it really give you more power? (not like a Z-tube )
-how easy was it to install?
-any trouble stories of problems after install?
-any tips on making the install easier (or saving myself any extra work?

I know that some of you will say "do a search" ive done that, but any extra advice/info would be nice.

 

Read this; I just installed mine.

https://g35driver.com/forum/showthre...346#post949346

 

OK so I want one for my 04 coupe, where is the best place to buy it? direct from Motordyne's website? or is there a better/cheaper place?

 

As far as I've seen, nobody is cheaper than Motordyne. Now several different websites do carry their product, but for some reason they're no cheaper. Hope this helps.

 

Ok, you have done the search and know most of what
it takes to complete the install. Check out the latest
SportZ mag for more information and a comparison
between the diffrent spacers. MotorDynes instructions are very good, take your time and you'll
enjoy the install. Installed my 1/2" ISO spacer last
week....takes close to an hour....I advise you using
a good torq wrench! Hey, the damn thing "really"
works as advertised!!!

 

I installed the 5/16 spacer this Sunday. def. feel a difference from 3k rpm. I would not hesitate to buy this again. Easy install too, took me just under 40 minutes and I was taking my time too. I didnt have a torque wrench though so I had to re-tighten the bolts (6 in the middle of the plenum) a few times after I drove the car for a day. Its been three days now and the bolts seem fine. I am going to check tonight and make sure the bolts are tight. I had to put the cover on today because I took the car in to get my front pads changed. Good luck on your purchase.

 

i dont know about the spacer, but the mRev with 5/16 spacer is hands down the best mod you can do to an 05 or 06 6mt

 

+1 . . . You can say that again.

 

i installed my 5/16 a few weeks back. Ran into problems duruing the install when one of the plastic spacers didnt fit on the plenum. I ended up shaving it and modding it enough to fit.

Install is not hard if you know what you doing. But due to the part that wast fitting right it took me about 4hrs to get it done.

My impressions are not great. Before the plenum spacer i had z-tube, test pipes, exhaust. At 3.5k i would feel that it pulled like no other. now with the spacer... the 3.5k pull is not there. It pulled but didnt feel any major difference. At around 6k it looks to be that it revs faster, but then again it could be just me.

May be with my mods before i cant tell teh difference, but i cant say i noticed anything major.

 

I installed 5/16 thermal spacer about a month ago.
You will feel the performence through the all range..
Easy mod if you already got torque wrench..
Clamp thing is a bit annoying especially the one with underneath throtle body
Other than that.. ah yeah.. Installation gives you a little bit of back hurts.
It's quite simple installation..Try out..

I also tried 1/2" on my coupe and 5/16 gains more power under 4000RPM

Now.. I got Stillen Cat Back on My G and feels slower. way much slower..tho.

Ask Tony.

 

I was told that if you're going to get an exhaust, go with a plenum instead of a plenum spacer. </O

 

Yeah. but I wanted keep the stock engine cover.

 

Are there any dynos available of the MREV w/ 5/16" spacer versus just the 5/16" spacer on the '05+ cars? I've seen dynos of the MREV versus stock, and power is virtually identical near redline, so I'm guessing that if you opt to not install the '03-'04 lower collector in an '05, you'll give up some midrange for some top end. I'm just curious what the trade-off numbers actually are, since I haven't seen such a comparison yet.

 

You seem to know every thing MechEE . You ask a question ????????
And also....a post that is more than one liine....and not negitive ????
WOW !!!!!!!!!!

 

Yes, I have dynod the spacer by itself on a REVUP engine and it did absolutely nothing.

As shown on the Motordyne website dyno section, the spacer produces power almost exponentially, on a 287 HP engine, with increasing RPM (up to redline). They can easily produce 10+ HP at redline.

When a "REVUP" lower colletor (with shorter runners) is put onto a 287 HP engine, it can produce a blip of 10HP but it only produces more power in the last ~500 RPM. The REVUP lower collector loses a lot of power everywhere else on the power curve.

So the question is why would Nissan use shorter runners to gain 10HP when they could have made the top half of the plenum a little taller to gain 10+HP and not lose all the TQ and area under the curve? I don't know....

But by knowing how they traded HP for TQ it wasn't hard to figure out a better way to get both.

By switching in a 287 collector (with longer runners) on a REVUP engine, a lot of TQ and area under the curve is made. But there is a very significant rolloff of HP above 6000 RPM.

Now if a plenum spacer is also used on a 287 collector, it will add power very rapidly above ~5500 RPM. So in short, the combination of the 287 colletor with a plenum spacer produces much more TQ and average power under the curve with only a small loss (~3-5HP) above 6200 RPM. Its a very good trade.

Then there is the MREV+. I found through a lot of dyno testing that while larger spacers add more peak HP, they have diminishing returns and even start to lose area under the curve.

It is best to minimize plenum internal volume to maximize TQ but it is best to increase spacer hiegth to maximize flow area above runners 1&2 fo more HP. It is the added heigth that increases flow area to runners 1&2 for HP, but the added volume also diminishes average TQ to all the cylinders.

But why accept a compromise of one or the other? By machining down the excess material above runners 1&2 and then recontouring the inlets, it gives you the best of both HP and TQ.

Minimized plenum internal volume for more TQ and maximized flow area above runners 1&2.

That is what produces the results of the MREV+.