Installed the 5/16" Copper Isothermal plenum spacer on Friday. Just testing the waters to see if what I'm feeling makes sense.

Before the spacer, let's say up to 2k rpm, I would get decent acceleration. Solid up to 2k. I know you guys are rolling your eyes but in city driving with stop lights nobody is hitting 5k without hitting children. At stock, pressing down on the gas let's say an inch, I'm at 40 mph already and the rpms didn't need to go over 2-2.5k.

Now with the spacer installed...

I press the gas, the car hits 2k rpms instantly, but not much acceleration. It feels like I'm pressing the pedal the same amount, or slightly less. Gets to 2k immediately, then anything after really gets the acceleration going. But between idle and 2k, not much power.

Does this make sense? I guess I was thinking I would get an "increase" in power all the way through the power band, went with 5/16 specifically because it was touted to give power even in the low rpms.

So... do I need to reset my ECU to get some more oomph at 2k and below? Or is this what the spacer does... It makes it so that an equivalent amount of pedal press/gas gets you to 2k faster, and then feeds the power moreso into 2k+ rpms for actual acceleration. I thought I wasn't going to lose power below 2k. Or maybe I DID get power below 2k, in that it GETS to 2k immediately when you press the gas and then the power boost happens.

Any of this make any sense to anyone else? Is what I'm feeling and seeing correct, or is this just because it's new and the ECU is confused because there's more air now? I was going to give it another couple of tanks of gas and then submit an update to what I was feeling after the ECU learned what was happening.

 

After such a significant mod, absolutely reset ECU.

 

So the full super duper everything reset, or just the normal reset? LOL.

Battery off, or pedal dancing?

http://www.6mt.net/forum/performance...rocedures.html

-- Basic

-- or Basic + Accelerator Pedal Released Position Learning + Throttle Valve Closed Position Learning + Idle Air Volume Learning?

Or just unhook the battery and call it a day?

 

Subscribed!

 

Indeed lol

 

Same, as I'll be doing this mod myself when I do a tune-up.

 

How in the world would you be getting to 2krpms faster, but with less power? That makes zero sense unless your clutch decided to go at the same time. But, yes, absolutely reset, and it takes 200 miles for a relearn cycle. The real results will come after a tune tho.

 

Just telling you how it feels empirically. I gas, 2k instantly, but the pull for acceleration really kicks in after 2k. It used to be a stronger pull from idle to 2k. Hence the post, to see if anyone else felt or noticed this. Everything I've read about the spacer says it is an even hp boost across the rpm spectrum - except on the dynos it seems they start the measurements at what, 2-2.5k?

http://g35project.com/motordyne-516-plenum-spacer/
http://www.motoiq.com/MagazineArticl...gineering.aspx

Which doesn't speak to anything under 2.5, where us city boys often live. So here I am trying to find out if anyone else notices differences post-spacer that align with mine from idle to 2k. The charts/measurements don't bother going that low.

I'm considering doing an ECU reset today, though if it takes 200 miles for the ECU to adjust regardless, then it might be pointless. The ECU seems very mysterious.

And to make sense of it, my theory is... more air at the lower rpms, ECU hasn't adjusted so doesn't put as much gas into the lower rpms. Hence lower acceleration/wheel torque, but rpms go up faster than before. Gas is applied at a more correct ratio post 2k.

 

It's not pointless tho, because without resetting its fighting all the previous values. That is to say it would adjust but not fully be beneficial for quite some time.

 

Do I need a tune, or will the ECU figure out what the appropriate new fuel/air ratio should be post-reset?

Wasn't accounting for an extra 500 bucks to blow on a tune for a simple plenum spacer mod.

 

Need? No.

But the benefits won't be fully had without one. That goes for any breather mod. Usually people get all their intakes, exhausts, plenum spacers, art pipes/HFC, headers, any porting/polishing/gasket matching, then they get a tune.

The stock ECU is smart, very smart, but the parameters in which it thinks are not made or written to accommodate the extra breathing fully, so they must be adjusted via a tune.

 

Reset my ECU this evening after work using battery negative disconnect method.

It worked. Power sub 2k is back. Cruise @ 40 mph is 1.6k rpm instead of 2.2. Cruise @ 60 mph is 2.2 instead of 2.6. Cruise @ 70 mph is... 2.8 instead of 2.95 since the spacer was installed.

Idle to 2k rpm feels like the majority of the power is back, and 2.5k+ I can feel the spacer boost. Subtle, but noticeable.

So yeah, reset your ECU's. Not sure from here whether it's learning the new A/F mixture, but at least it isn't worse than stock.

 

It will adjust A/F within its allowed parameters. It can't rewrite its parameters tho, that's why a tune will make it better. Glad it feels more normal tho.

 

Damn, why does it cost $500 for a tune? That's insane.

 

Well, it doesn't. That's with a cable you can keep. Member here seymour4 can etune you with a borrowed cord for $350. I promise you tho, no mod you ever do will be more satisfying than a tune. It takes the feeling of your car from a Nissan to a corvette. Obviously not in HP, but in drive quality.

Before the tune the motor feels 'held back' and clunky and chunky..non high rev friendly. Afterward it loves to rev..feels like it wants to go..throttle response becomes insanely crisp. There is no mod for the money that is better; it just feels like a higher end vehicle. You DO wanna get all your breather mods done before you tune tho, or you'll have to redo it every time you improve breathing

Also, uprev is not like any piggy back tunes. Other tunes try to 'write over' the ECU parameters, whereas uprev actually reverse engineered the Nissan ECU over many years and erases your current ECU, and reinstalls true new learning parameters. This means that the original ECU will never 'learn' to override the piggyback. Uprev actually made it a true program. It's great stuff that other platforms simply don't have.