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Plenum spacers.....


Jared350z

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Okay here goes, we shall start with a standard DE.

 

Plenum spacer fitted will exceed the spacer performance gains over that of a GT4 and Revup - because the DE tunes better. Just the way it is.

 

GT4/Revup

 

A spacer alone will provide some gains but in order to gain over and above a plenum spacer on a DE you'll need a Motordyne MREV 2 lower plenum. A GT4/Revup will then gain more than a DE with just a spacer.

 

Two ways to resolve the GT4/Revup.

 

1. Get a used or new MREV 2

 

2. Get hold of a DE lower plenum. Shave the front two ports flat which is all a MREV 2 is.

 

I have a modified DE lower plenum with shaved ports and it performs exactly the same as the MREV 2

 

Considering what Motordyne charge, modifying a DE lower collector if done correctly will provide the necessary gains.

 

Abbey will I'm sure suggest you buy a MREV 2 from them to see nice gains.

 

To be honest the DE tunes better NA with added mods. GT4/Revup gain better power with FI, and furthermore with HR.

 

Although the upper hand with GT4/Revup is the higher rev limit. So what is lost in lesser gains is resolved by a longer power band. Horses for courses really.

 

 

Thanks Wasso, was a bit lost..

So basically even though they re-designed the plenum on the uprev, the best gains can still be achieved from an MVREV2 plenum (with a spacer) which is basically along the lines of a DE plenum with the ports modified.. So more dollars to do this mod on an uprev engine in comparison.. booo

 

DE plenum

standard_intake.jpg

 

GT4/UPrev plenum

35th_intake.jpg

 

Motordyne MREV2 plenum for GT4/UPrev

Motordyne-uprev_plenum.jpg

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You'll get roughly 25 miles of added benefit before the ECU has learnt and mapped the increased airflow.

 

Engine noise/growl is there all the time which is a bonus.

 

Sorry does that mean you need an uprev to see any power gains? Mine is already uprevved, so would I need to remap the car again?

 

Are these best done in conjunction with airbox upgrades? Are they worth the hassle expense (always struck me as a bit pointless but there you go)

 

How much power would this add to a DE? +5bhp / +5lbft ?

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Motordyne claim 11-13hp which is I've not heard of being achieved.

 

5-9hp is more realistic with TQ following just behind those numbers.

 

ANY air in, air out mods need a remap to reward the gains. The standard airbox is supposed to give slight gains over aftermarket.

 

Best to build a small list of mods and get the remap done all at once.

 

To be fair though there's no harm in having an Uprev done, say with a spacer or exhaust. Then going back further down the line with decats and maybe a mrev2. The second tune is only charged at Dyno and Mapping time. The licence cost is during the initial Uprev tune and installed on the ECU.

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Had a chat with Mark at Abbey about this and he basically said the same thing as Wasso.

The MREV2 is simply a modified DE lower plenum and the high cost is because they start with a brand new DE lower plenum. Combined with a spacer you'll see some nice gains.

 

If it helps, my car is a 2005 GT4 (RevUp DE) and has been regularly serviced. Its also got the following intake/exhaust mods.

  • Motordyne 5/16 plenum spacer
  • Berk HFC's
  • Milltek Y pipe, centre pipe and back box.
  • HKS Super Hybrid panel filter.

The RevUp engines airbox is also slightly modified from the DE airbox in that it has a velocity stack installed which helps funnel the air more cleanly into the intake pipe (after filter)

 

After the RevUp she is producing 261 Hp at the hubs which equates to roughly 296 Hp at the flywheel.

My car was supposed to have 296 Hp at the flywheel from the factory however time/wear will cause Hp to drop so its not bad for a nearly 10 year old car.

Based on dyno sheets I've seen for stock RevUp 350's I've gained roughly 20Hp after ALL the above mods so I wouldn't expect the plenum spacer to give you a massive boost on its own (and I doubt you'll get any gain without a remap)

 

In all honestly the only way you are going to see any noticeable Hp gains is by going forced induction (supercharger or turbo). That said, to keep the engine running sweet I'd suggest getting the UpRev tune done once you've finished making your changes. There's not huge difference in power but extra midrange torque and better throttle response are a plus for me.

Edited by longsh07
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Also the published book figures for ALL 350's is wrong. Take it from manufacture to a dyno and you'll never see the book figures.

 

I think mine was 245 at the hubs when just two years old.

 

This makes me feel a lot better about my 261 :teeth:

 

If you look at the "dyno results thread" everyone is super unhappy with their stock or tuned results because Nissan told big fat lies.

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Also the published book figures for ALL 350's is wrong. Take it from manufacture to a dyno and you'll never see the book figures.

 

I think mine was 245 at the hubs when just two years old.

 

This makes me feel a lot better about my 261 :teeth:

 

If you look at the "dyno results thread" everyone is super unhappy with their stock or tuned results because Nissan told big fat lies.

 

Yeah I had seen that. Already set myself up for numbers lower than expected (if Nissan were to be believed).

Still, its not about numbers at the end of the day. Love my car to bits and the modifications were totally worth it in my book (even if just for the noise :thumbs: )

Edited by longsh07
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  • 7 months later...

Would something like a K&N version 2 induction kit help on the uprev or would i be better sticking to the modified air box and upgrading the filter inside?

 

Would I be better leaving the engine alone, putting Cobra HFC on and having a Remap once fitted?

 

 

Only mods i have so far are Cobra rear, centre and Y :) Black 350Z GT4

Edited by MarkZZZ
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