What do you think about the installation of the Motordyne spacer on a rev up engine (w/out Mrev)???

Is a good idea?

Thanks in advance

 

nope, doesnt do anything

Tony (from Motordyne) tried it an got no extra power on the dyno. He proved there is an optimal volume of air for N/A Z's in the Z Car Magazine plenum shootout, its not simply the more air the better. The rev up plenum is pretty much spot on for optimal airflow and volume

 

Agreed for the most part with TiPIACE. I wouldn't do just the spacer, it won't yield you anything. I don't quite agree with the reveup plenuum being optimal though, as adding an MRev+ or MRev V2 and spacer will yield some nice gains throughout the power band.

 

the MREV kit replaces the revup plenum with the 03-05 longer intake runner plenum

with the MREV you're basically running the same setup as an 03-05 Z. Thats going backwards imo, no matter how good the midrange is, i prefer to have a smooth free revving top end right to cut out. Afterall thats where the revs spend most their time at WOT. The Z has enough torque for daily driving

im planning on doing the central20 3.9FD just so i can get to that top end powerband quicker

 

Go for it. Let us know the results.

 

Thanks a lot for the reply guys....
I' m thinking to go FI asap....
so is the spacer a good choice for most hp?

 

Smooth revving to top? Other than A/F, and the operator letting off right under 7k, where is the step back here? I guess I don't follow.


edited to add: post numbers are post reflash. Pre is with mods in sig, minus flash.

 

i don't see anything

edit: nevermind it could be because the site's blocked at work

 

Hi TiPIACE,

I recently went to a track event to test just what the effect of the MREV2 & 5/16" spacer would be.

I wasn't able to do pre/post comparisons on lap times but was able to measure time Vs RPM and throttle position. I used this data to try and find an average of where the car averaged on the power curve while tracking.

I aquired data the whole time while on the track but for the purposes of analysis, I put all the data into excel and sorted it based on throttle position. All data at less than 95% throttle was left out of the comparison because anything less than WOT won't really tell us how much of the power potential is being used.

In the baseline condition with a stock REVUP plenum installed on a REVUP motor and driven on the road course, the average time weighted RPM @ 95%-100% WOT, the average RPM is ~5600 RPM.

This means the average HP as applied to the asphalt is just below the REVUP plenum HP platue.

In all honesty, I made every possible effort to keep the RPM's as high as I possibly could during the track event to try to measure average RPM as a worst case comparison against the MREV. Even for my own information, I was curious as to what the true results would be for tracking. And even though I did my best to bias the test in favor of the REVUP collector by keeping RPM's as high as possible, the data shows the REVUP plenum still isn't as good as the MREV for tracking. Its simply not possible to keep the engine at redline all the time. High RPM's yes. Even with most (nearly all) of the shifting occuring at 7100 RPM. But the average RPM at WOT was still ~5600 RPM... Much more than that can't be done on any reasonable basis.

If you try to push the average RPM higher than that, it would severly constrain the flexibility needed to drive smoothly and optimize shift points as needed for cornering. Hook up a chipher while at the track and you will see.
After a while it felt awkward keeping the RPM's artificially high and I felt like it may have even been slowing me down by trying to keep the RPM's near redline. But at least can say to myself I got the worst case scenario data.
And even then the average was ~5600 RPM.

Interestingly enough, 5600 RPM is right in the middle of the MREV peak power band. So if a MREV is installed, it can only increase the average power as put down to the track.

And if you drive with anything less than an average of ~5600 RPM (and you probably will), the advantage of MREV increases greatly.

Then there is also the vastly superior upper midrange of the MREV which will indeed be very helpfull in cornering due to the added TQ which can be used to pitch the back end of the car out when needed. Power on oversteer. The REVUP plenum can't come anywhere near the MREV on this.

I know I'm biased because I'm the manufacturer, but I honestly think it feels a lot better with MREV on the track. And the Cipher data proves the MREV has a power curve better suited to the RPM used on the track.
---
Anyone with a Cipher and a REVUP engine
---
Record your RPM and throttle position Vs time while at the track. Find the average RPM at WOT (or any throttle position for that matter).
I assure you that your average RPM will put you in a much better power band of MREV.

Tony

EDIT: Take a look at the dyno plot posted above to see the power and torque differences at ~5600 RPM.
That is what you will gain on the track!

.

 

I think TiPiace's concern is like a lot of ours (with the rev-ups)...why would we spend $700+ for the Mrev2 + spacer when it might have the same effect as the 287hp engines? For example, how would the rev-ups do with the Mrev2 + 5/16 spacer vs. a stock 287hp ? How would a rev up with Mrev2 + 5/16 spacer do vs. a 287 with Mrev2 + spacer? Assuming that both cars were going in a straight line to...let's say 120mph ? And also assuming that these were the only mods. I think most of us rev up guys would be a lot happier if these answers were provided in a non-bias way.

 

thats all well and good, but why would Nissan spend the money to develop and manufacture a new lower plenum with a completely different intake solution - ie; shorter intake runners vs longer - if the old plenum worked so well

doesnt add up

im going FI with a HKS supercharger so dont really need that extra midrange gain, but i will be needing the shorter intake runners reving a bit beyond 7K

 

The REVUP still makes more top end and a higher average HP because:
1) The biggest difference being the higher rev limit. -> higher average HP.
2) The variable exhaust cam phasing keeps the high end going when it would be dying out on the 287.

Good question. Stock for stock, they will be very similar. No great advantage for either. They each have different curves with respective pros and cons. Its a wash...

But with a full MREV and spacer setup on each, each will see good gains, but the REVUP will always have the advantage because the gains will be much larger with a MREV/spacer. Its average HP will also be quite a bit higher too.

All the TQ of the 287 engine and all the HP of the REVUP engine (plus a little more). Its the best of both worlds.

I agree and understand your reasoning. As a consumer myself I will always be skeptical too. And I will always do my homework on any kind of mod I buy. In fact, this is how I came to start building my own mods...

Also take note mikead_99 posted his dyno plot independantly. I had no idea he did a pre/post dyno or was going to post his results here. I knew of it the same time you did. He even did the pre/post dyno testing on my competitors dyno machine!!! It can't get any more independant than that.

 

Good question! Why would Nissan develop the new lower plenum like they did?
The first answer is "Marketing". It seems the design objective of the new lower plenum was so they could reach the 300 HP mark. This allows them to advertise what appears to be a more powerfull engine... even if the average HP is still the same ...and even if the TQ is significantly compromised. They can now honestly advertise 300 HP in all the mags and that is what people see and that is what makes sales.
I think the new plenum was a marketing decision rather than an engineering decision. It wasn't about making the car faster, it was about being able to advertise higher HP numbers. This higher HP number is important to Nissan with respect to their competition. It affects their sales in a real way. Nissan executives care about sales, not area under the power curve. The average Joe reading a mag only sees the HP rating went up on the Z and that is what motivates him to buy a new Z.

Now for the more sophistocated / hard core Z enthusiasts like the ones that frequent this board, its not the same at all. Regardless of magazine numbers or dyno queen peak numbers, there are some things that will make the car faster. And thats what really matters to the true enthusiast or racer.

Secondly,
The old plenum doesn work so well... It has what can only be called "deficiencies". IE excessive pressure drop at the runner inlets.

The tuning frequency of the runners is actually quite good but its the pressure drop at the mouth of the inlets that pulls it down. And this is why you see all these plenum modifications on the market that make power on the 287 engine.

When Nissan designed the new plenum they changed 2 variables.
1) They eliminated the pressure drop at the runners inlets.
But they didn't stop there... They also reduced the runner length.

2) The runners are now shorter.
And this is where I think they made the mistake.

Yes, shorter runners push up the peak power but it also compromises power everywhere else on the curve. Good for marketing but not good for overall performance.

When I first saw a REVUP plenum installed on a 287 engine, it made about 10 more peak HP. But it also trashed the rest of the power curve. And I asked myself "why did they do that?"... I can put a spacer on the 287 plenum and make at least 10 HP and not compromise the rest of the curve.

And the spacer has rapidly increasing gains above 6K RPM so why didn't they just redesign the "UPPER" plenum to do the same thing?... They could have just made the upper plenum 1/4" taller and the problem would have been solved!
People install spacers all day long for the same effect.

I don't know why they didn't do this. I can give you my speculation, but it would only be speculation.

This may not apply to the REVUP engine with FI but here is a very interesting thing I have noted about 287 engines with FI.

There are plenty of people here who have 287 engines with FI. And several of these people have installed a REVUP lower plenum on their vehicle (while on the dyno) and even after a full retune they lost power EVERYWHERE. Low, mid, high. A loss of power across the entire spectrum.
Just ask Alberto. He did it and said it sucked. A few others said the same thing.

If this is the case, what would MREV2 do on a FI REVUP engine?...

If its anything like the 287 engine, you could expect to see even bigger MREV gains when FI.

In fact, I would really like to see the MREV2/spacer dyno tested on a FI REVUP engine.

I'll make this offer to you or the first person to take the offer.

A Free MREV2 and 5/16" Iso Thermal spacer to the first person to dyno test it on a FI REVUP engine!

Purchase a MREV2/5/16" spacer combo. Install it on the dyno and post your results here on MY350Z. And regardless of the results, I'll give you a total refund of the purchase price.

Tony Colette
Motordyne Engineering

 

Tony,

how about MREV++ and 1/2" spacer for the REUP engine? would you consider that set up or just the 5/16" spacer?

Thanks

 

+1

 

im confused, does this mean that the plenum for the 2006 car is useless?

 

Damn.. all this reading and I still don't know what to do..

 

Tony's posts are the some of the most informative posts on this board, thanks for taking the time to educate the masses sir.

Ordered my 5/16 copper thermo spacer today for my 03 6mt enth.

 

It will make more peak power but it reduces area under the curve.

 

The MREV2 works on ANY G35 or 350Z.

But... The spacer by itself doesn't do anything on the REVUP engine. It must be used with the MREV2.