I am patiently awaiting the arrival of the new MREV mod as well as the install of my 350Evo 3.9 FD... I know the release will come soon but i have extra $$ burning a hole in my pocket, was wondering if i would benefit using the Utec to tune my NA car once the MREV mod came out. would it be beneficial to gain back some of that top end power to have a TXS Utec or just stick with a ts reflash.

Also i know some may not be able to answer this but will this mod be noticable under the hood... that would answer every other question i had as well.

 

The MREV mod is the 287hp lower plenum on the 300hp motor. I have already tested this out with the adition of the Crawford plenum. If you are getting the 3.9 gear then DONT get the MREV mod. The MREV give good torque in the midrange, but kills the topend bigtime. With the gear you will spend more time in the higher rpms, so I would advice against the MREV.

As for the tuning. We are not really sure if tuning will help the top end. The MREV mod helped to lean out the topend to almost a perfect A/F ratio. It seems like maybe advancing the cam timing a bit might help, but then again it might not.

Here is the link to my thread:
https://my350z.com/forum/intake-exhaust/151687-another-secret-mod-had-been-tested.html

 

The MREV work very well for you even with 3.9 gears. The total area under the HP curve will be increased regardless of gears. And area under the curve is all that really matters in a race.

If you are running at the drag strip it turns out that MREV offers its lowest gains in 3rd gear at +3 HP. All the other gears will provide substantially more. See the attached spreadsheet analysis of the dyno plots and how it relates to its effect in the 1/4 mile.

The high RPM loss only becomes significant between 6300 to redline.
For Klumzyees dyno results:

From 6300-redline (a span of 600 RPM) the mean numbers are:
-5.424TQ and -6.844HP This is the mean of the actual data.

Every where else in the power curve 1800-6300 RPM (a span of 4500 RPM) there is a average gain of 9.109TQ and 6.865 HP

So when you multiply the gains and losses by the range in which they occur and take the fraction of the two products you find that even with power dropping above 6300 RPM Klumzyees torque gains are 12.596X greater than the torque losses! And his HP gains are 7.523X greater than the HP losses!

Thats an exceptional trade!

And its putting the new found gains where you can use it the most. Daily driving. And the benefits will apply all throught out a drag with a minimum of +3 HP occuring in 3rd gear.

1st and 2nd gear will an average of 5.5 and 6 HP respectively.

And the finish line is crossed about half way through 4th gear at ~6100 RPM. This means you will cross the finish line while passing through the sweet spot of MREV with 7.6 more TQ and 8.2 more HP than the stock configuration.

Note: The stock configuration hasn't even started into its power band until after you cross the finish line.

So MREV will indeed provide more power in a 1/4 mile race. And it provides way more power for daily driving. And its a difference you can readily feel.

If you prefer to look at the power band as a whole and not broken down into sections, the MREV comes ahead with an average of +7.399 TQ and +5.252 HP. This is way more than any other NA bolt on can provide.

This is all from the raw data of Klumzyees dyno results and his results are typical of all the dynos performed so far.

There were also many exploratory tests I was able to perform on the dyno and made good discoveries with. Further optimizing power under the curve with MREV. These were tests I'm sure Crawford did not (or could not) do due to the cast plenums fixed configuration.

And from what I've seen from the Greddy EU, it can gain about 10 HP on an NA engine with a good tune. You should be able to do at least as good with the UTEC.

Tony

 

You say there is a gain at 1800rmps??? When you are racing you will never be at 1800 rmps or even below 4000rpms for that matter. If you want this just as a daily driver mod and not a pure performance mod, sure go for it. For the track and top end power I will stick with my 300hp lower plenum. Nissan change it a reason and now we know why.

Also with the factory 300hp lower plenum the car is very rich. From 6k to redline I am anywhere from 12.0 to 11.5. Where with the 287hp lower plenum it made the A/F around mid to high 12s. I am almost possitive if I got a tune to get my A/F leaned out uptop there would be even more of a performance gain up top between the 287hp and 300hp lower plenums. For track and racing perposes the 300hp plenum is better. If you just want more midrange and dont race your car then swap the 287hp lower plenum on.

Do you have any dynojet dynoes of before and after? Also, with the spacer and then without?

 

For tracking that may or may not be true, but tracking would have to be road tested to really know definitively.

But for 1/4 mile drag, the analysis of Klumzyees dyno data (as shown in my prior post) shows a net gain in all the gears (and as they are used in a 1/4 mile run). At least thats what the data analysis says. See the attached chart...

I'm sure it will be drag tested soon enough.

EDIT:
"Do you have any dynojet dynoes of before and after? Also, with the spacer and then without"

Yes and yes. Performance Nissan did their own testing on a dynojet. Their results were somewhere between the gains as shown by Klumzyee and Alex.

Many others have been dynod and many others are scheduled to be dynod (tonight and in the comming weeks)... It won't be long before MREV dynos are posted all over the place.

 

When I had the 287hp lower plenum on and floored it in first gear when it reached 6k it made the car feel like it just stopped pulling. It literally just stopped and one time it just sat there before redline and I had to shift early. It is a good mod to get midrange torque, but you need the top end.

 

Past 6300 there is a clear drop. I believe you. Its simple enough to shift at 6500 RPM. And while top end is important, its area under the curve that matters most.

Its hard to say with certainty how it will effect a 1/4 mile run untill its tested by experienced drag racers. But at a minimum it adds significant streetable power along with data analysis that shows it gets a net gain in area under the curve for the 1/4.

Untill it can be drag and track tested, the only thing to go by is comparative dyno data.

 

why shift at 6500 its setup to rev to 7000... that seems like im missing something... is there anything to gain back that lost top end...

 

You could certaintly shift at 7K. Depending on what it looked like on your dyno graph it may be best to shift at any one point between 6.5 and 7.

You could also test different shift points at the strip to see what gives the best results.

EDIT: As far as bringing up the power at the end of the RPM, that is best delt with by the UTEC.

 

Hydrazine,

Have you tested anything with a ported MREV?

 

No. I strongly considered making that part of MREV, or at least an option, but I don't get the feeling the benefit would be worth the added effort and cost.

Its certaintly possible on an individual basis. One afternoon with a cordless drill and a sanding and polishing kit could do it. I havn't A/B dynod the effect of porting so I can't say how much of a gain it would produce. But what ever it does, I'm sure it can only have a positive effect.

 

The reason why he said shift at 6500 is becuase the 287hp lower plenum (MREV mod) kills the top end power. The longer intake runners dont seem to work aswell in the topend, then the shorter runners. A tune might get back some top end, but it is very doubtfull seeing that the 287hp lower plenum made the A/F ratio near perfect up top.

 

I feel area under the curve isn't the only thing that matters. Since you will be spending more time in the higher RPM's (since there is less power and will pull less, meaning you spend more time in the higher RPM's) wouldn't torque matter more then? I'm not too sure what the area under the curve represents. You can't just say area under the curve, it has a value in physics. (i'm guessing net force).

If I am right hydrazine, with the whole netforce thing, then you will also be right. Since accelerating early on means a lot more in straight line acceleration, if you don't concider drag, friction, thermal buildup and such. But if not, what the hell does area actually mean?!?

 

That should be fairly obvious.

Area under the curve menas everything while accelerating. Acceleration is never done at a single RPM. Acceleration is performed passing through a range of RPMs. The average or sum total is the integrated value of HP applied through the RPMs used.

If for example you had a car that produced 300HP only at one point in the curve and produced 100 HP everywhere else. That car would be a total dog on the street, strip or track. But it would be a 300 HP car.

Conversley, if that same car produced 300HP everywhere on its curve and produced 100 HP only at one point in the curve, That car would be a monster on the street, strip or track. And it also would be a 300 HP car.

When racing, the objective isn't to necessarily run the engine at redline, the objective is to run the engine at, or within, its highest range of output. So you don't need to run the engine at 7K simply for the sake of running at redline. If its highest HP occurs at some point below redline, run it where ever the power band occurs regardless of RPM.

MREV increases the average HP all the way through 1st through 4th gear. It evens out in 5th gear. And because the speedlimiter kicks in at 156 MPH in 6th gear at about 6100 RPM, MREV makes 6th gear have a much higher average HP.

The overall average HP is higher with MREV.

...And thats not mentioning the gobs of TQ MREV slams into daily driving.

 

I wouldn't trade upper end horsepower for anything on my '05 sedan 6MT (especially for straight line acceleration. This especially is true with the 3.9 gearing. Every time I shift the rpm falls right into the sweet spot. Here is a recent (dynojet 248E) dyno pull:

Look at the correlation between power and rpm...and then look at what happens when I shift....

time rpm power torque A/F
0.00 2300 72.7 161.8 15.0
0.29 2400 93.4 202.2 14.8
0.55 2500 100.3 211.4 14.9
0.81 2600 108.1 214.1 14.8
1.05 2700 116.4 222.6 14.8
1.29 2800 123.3 224.1 14.7
1.54 2900 125.5 226.0 14.6
1.78 3000 127.9 230.3 14.4
2.03 3100 131.2 229.7 14.4
2.28 3200 136.0 230.2 14.4
2.52 3300 139.6 232.9 14.4
2.77 3400 145.7 233.4 14.4
3.01 3500 152.2 237.7 14.3
3.25 3600 159.5 239.5 14.3
3.49 3700 166.8 239.3 14.2
3.73 3800 170.0 242.4 14.3
3.96 3900 176.7 242.1 14.3
4.20 4000 181.4 248.8 14.3
4.44 4100 185.2 248.7 14.4
4.68 4200 189.6 247.3 14.5
4.92 4300 191.4 249.9 14.5
5.16 4400 196.8 254.2 14.5
5.41 4500 200.8 256.1 14.5
5.66 4600 211.5 259.6 14.4
5.91 4700 218.6 261.4 14.4
6.16 4800 229.9 264.9 14.3
6.41 4900 243.5 266.9 14.3
6.65 5000 254.4 264.5 14.2
6.89 5100 263.3 262.4 14.2
7.13 5200 267.8 260.5 14.2
7.37 5300 266.3 258.2 14.1
7.61 5400 269.9 255.5 14.0
7.85 5500 272.2 252.9 13.9
8.10 5600 277.7 252.0 13.9
8.34 5700 279.1 251.7 13.8
8.59 5800 279.9 250.6 13.8
8.84 5900 282.7 249.9 13.7
9.09 6000 283.2 248.5 13.6
9.34 6100 284.5 246.3 13.6
9.59 6200 285.0 246.0 13.5
9.84 6300 285.4 244.7 13.4
0.09 6400 285.9 242.0 13.3
0.34 6500 281.4 237.1 13.1
0.60 6600 272.7 233.8 13.1
0.86 6700 266.4 229.6 13.0
1.13 6800 263.1 228.1 13.0
1.40 6900 255.4 226.8 12.9
1.67 7000 247.1 224.3 12.9
1.96 7100 232.7 211.0 12.8

For instance shifting at 7000 rpm, when I shift from 1st to 2nd it drops me in the 5200-5300 range (267hp & 260pft), the 2nd to 3rd gear shift puts me at 5500 rpm (272hp & 252pft) 3rd to 4th gear change puts right into the 5700 rpm range (279hp & 251pft) and 4th to 5th gear change sets me right at 5900 rpm (282hp & 249pft). Any usable power "under" those rpm ranges are insignificant unless you are just punching it from LOW rpm areas in any given gear/road speed.

My '05 6MT sedan has the following mods: Crawford plenum, Crawford headers, Crawford hi-flow cats, messaged lower plenum, port and polished upper, cleaned up throttlebody, UR underdrive crank pulley, Fujitsubo Legalis-R exhaust system, Z-tube, JWT pop-charger, fan shroud mod (to let more cool outside air into filter). On this run I also ran 5 gallons of 100 octane unleaded race fuel, which BTW gave me a solid gain of 11hp and 12 pft peak. The non modified ECM retards alot of timing on the dyno which really hurts the numbers. The race fuel lets the ECM go to full advance without pulling timing, hence the substantial power gain.

I'm quite certain a reflash will gain me some power, especially in the mid range as my A/F is quite lean.

 

Hydrazine im not slamming you, i agree with you that this mod would be worthwhile for drag racing and street racing IMO. But i was asking what the area under the curve actually represents. Which is totally different from what acceleration represents. For example..if you were to graph force vs distance graph, the area would represent total work done (simple physics). I've always wondered what TRQ vs RPM represents.

For comparison, HP vs RPM does represent work done per unit RPM, or power. The HP curve is more important for comparison of a initial vs final, but not how it got to the final. There could be HUGE dips in between the curve, yet the average (final - initial)/(delta RPM) would conclude power.

1HP= 33,000ft/lb/sec i think..

With proper conversions you could convert to ft/lbs/rpm or torque.

However, if you will be spending most of your time out of the optimum powerband with MREV, you would be better off with stock since (initial - final)/(delta rpm) would be a great deal lower than if you started in the optimum power band.

I hope you understand what I'm tryna say cuz its hella confusing to me too lol.

EDIT: after some more thinking..

Lets apply some calculus to this?
The slope of the trq curve would represent ka.. where k is a constant determined by the mass of your car and a which is accerleration.

Trq is linearly (directly) related to how fast you can accelerate.

The slope of the HP curve is the rate at which trq is given per unit RPM (as a function of RPM). I think..lol. This would represent the feel of the trq curve..is it spikey like a turbo supra? Or is it very smooth and linear like on a NA car.

 

I guess I'm not entirely clear on what you are saying here. But the intent of moving the curve to the left is to put the power band into a more usable area. Where it will end up giving more average power with the way the gear ratios are set.

BTW please take note of ZXiMANs post above. His intent is not as an objective critic but as just another unethical Crawford cheerleader. Take a real good look at the numbers he posted.

You may not be able to see it but I imported the numbers into excel for data analysis. And the truth (or lack of it) was revealed.

Its just another example of the slag, bash and deception that always seems to be associated with Crawford Cheerleaders.

 

Ohhh James.... Do you want to retract the above post? Or would you rather I call you out on it...You just got
I know exactly what you did.

If you don't respond I'll take it as a retraction.

If you or any other Crawford thug responds with any more of the same unethical garbage... people are just gonna have to know what you just posted. And Thawk don't tempt me.

Is tearing down others is your way of building up Doug Stewart or CrawfordZ? Why do you even feel a need to do that? Just give it a brake. Its getting old.

I've asked the moderators to watch this thread. So don't bother trying to edit your post.

 

Back to the topic of discussion about 3.9FD. There will be less topend power to help you pull through that gearing up top. The 3.9FD is a good mod on our cars simply because of our top end power and ability to take advantage of that gearing.

I'm not knocking you or anything Tony but if you increase low and midrange torque you take away some of the cars ability to hook from a stop as well which basically changes the car into more of a Mustang and less of a Z.

Also, about shifting at 6500...it is better to be in a higher gear multiplier with slightly less power being produced than being in the lower gear with slightly more. Therefore shifting at redline in every gear will generally net you better acceleration and times.

 

Im not too fond of the FD drive. Someone whould just come out with different 1st 2nd and 5th gears for our cars -.-. Make the gear ratios better rather than changing the final gear. It would cost 1000 dollars more + install for tranny but the payoff would be HUGE especially for turbo/sc/high perf NA engines.
The FD just changes the multiplicative factor of the transmission gears. It alters all of the gears. The weak gears (1st, 2nd, 5th) will be improved, but at the cost of making 3rd/4th gears less useful. So what gear do you spend most of your time?? Also, if you have to shift more often, u will lose a lot of time where you couldve been accelerating!

Hydrazine:
I noted the excel graph and i didn't even bother to read it. It made no sense to begin with. I myself don't really feel so partial to the crawford plenum (although their headers and cat pipes are sexy). There is always more than opening up the intake..

Well I'm trying to prove what y our saying with math. Just b/c you say by moving the optimum range to the left (lower spread of RPM spectrum) will improve average (since you would spend more time and RPM's in the lower range) doesn't mean its definatley true. Also, I want to find out myself what area under trq represents, otherwise, whats the point of even getting a dyno graph?? For show?



"Back to the topic of discussion about 3.9FD. There will be less topend power to help you pull through that gearing up top. The 3.9FD is a good mod on our cars simply because of our top end power and ability to take advantage of that gearing."
3.9FD will not change your 'power'. Power will always be the same in the same gear/rpm. It will not change your trq either. It will lessen the amount of time your car spends at a certain trq range at teh expense of velocity.