twitch579

iTrader: (3)

buddy of mine is buying a MREV2 for his revup, wants to give me his old lower collector, will this provide any gains on my non-revup that has a 5/16 spacer already? Less tork is fine, I just want more peak hp.


Thanks a bunch guys.

__jb

iTrader: (3)

From everything I've read, yes it would probably give you more high end power.

I'm not sure how much more power it would give you, but it should help a bit.

ttg35fort

iTrader: (2)

I was thinking about doing exactly the same thing. It seems that the loss of mid-band torque may not be worth the top end HP gains, however. Here is a link to a thread with a dynochart for JETPILOT's car, who used the Rev-up lower plenum:

https://my350z.com/forum/shop-builds/332658-my-car-is-finally-finished-2.html

In JETPILOT's chart, the Rev-up plenum is not hitting maximum torque until around 4200 RPM, and then the torque immediately starts to decline.

On the other hand, I have seen dyno charts where the stock plenum almost reaches peak torque around 3800 RPM, and stays pretty flat until about 4800 RPM. e,g.

http://carv2.com/site/project_detail.cfm?id=526

Of course these are two completely different motor builds and there is a lot more at play than just the plenums. Nonetheless, after scouring the forum looking for information on this subject, it seems to me that the general concensus is to stick with the non Rev-up plenum. Indeed, many Rev-up motor guys are going with the MREV2 plenum from Motordyne, which I beleive is a stock non Rev-up plenum that has been modified.

If anyone has played with these before, it would be great to see a side by side dyno comparison of the two plenums on the same motor.

Hydrazine

iTrader: (53)

Jason @ Performance Nissan did a comparison of the 04 stock lower against the revup lower back in 2005. I'm sure you can find it with an advanced search search.

The revup lower lost power everywhere except at the very end of the spectrum where it gained about 10 HP.

What is interesting though, the spacer makes similar gains at the very end of the RPM spectrum too. ...without compromizing the rest of the power curve.

twitch579

iTrader: (3)

Thanks guys, im going to pass since I already have the 5/16.

__jb

iTrader: (3)

I'm curious what you would recommend for a built RevUp with 4.08 gears that planned to do a bit of drag racing. I currently have a stock RevUp lower plenum and a Crawford upper plenum that I plan to use.

Have you ever applied your performance techniques to a revUp lower plenum?

Hydrazine

iTrader: (53)

If you switched to a MREV2, your power curve would essentially be the same as what is shown in the MREV2 dyno plot section of our website.

The Crawford plenum and 1/2" spacer perform almost identically.

And as far as modifying the REVUP lower plenum, it can't be done. At least not with the same benefits as seen with the MREV2.

The modifications the MREV2 has are used to eliminate a design flaw (excessive pressure drop).
The stock REVUP lower collector was redesigned by Nissan to also eliminate the presure drop... but they also made one more very significant change. A change they shouldn't have done.

They shortened the runners. They shortened them too much.

The shorter runners give a bump in high end HP but the shortening also reduced the average power in the process. (at least when compared to the MREV2/spacer combination)

The longer runers of the MREV2 give the best overall tuning frequency and bandwidth (Q). Once the pressure drop is eliminated by the manifold machining process and by adding the spacer to it, it performs much better.

It's what Nissan should have done the first time around.

__jb

iTrader: (3)

Thanks for taking the time to answer my question in such detail, Tony... I appreciate it.

Have you ever thought of adding some filler aluminum to the RevUp plenum runners and then reshaping them? It seems like it might be the best of both worlds. It would add to the cost... and you'd have to be careful not to warp the plenum (TIG)... but it might produce some worthwhile benefits.

My plan is to leave my current intake system in place and see how much difference the additional compression, head work, and cams make in the new engine. My thinking is that the power range will/might increase enough so that I do genuinely benefit from the RevUp lower plenum.

After I break the engine in and get it tuned, I'll see where I'm at. It would be nice to have the high RPM power and the torque generated by one of your MRev lower plenums.

Hydrazine

iTrader: (53)

For reshaping the plenum, unfortunatly, its not really a viable option.

But certaintly post your results when you get it all put together. Its good to see you have cams as part of the build... I've seen revup engines that were reflashed to 7500+ RPM and surprisingly, the power curve takes a sharp dive after ~7100 RPM. And I think it has to do with the cams.

The sharp dive occured regardless of the plenum used. REVUP or MREV2. And then they both plateu to the same level (-~15HP) before hitting the new redline.

__jb

iTrader: (3)

I'll post my results. Been waiting to post in the "NA Build" forum for a while...

Interesting.

What cams were used in these examples? If they were standard OEM cams it would certainly be expected. You can't just decide to turn the motor harder and see if it will make more power.

Hydrazine

iTrader: (53)

Yep. Stock cams.