Plenum Spacer?

[Rspected]

I was just thinking about my old car (G35) and one of the most bang for your buck mods was adding a plenum spacer to allow for more air volume to hit each cylinder. My Gen is a 2012 R-Spec, and I was looking at the plenum and noticed its awfully deep in the engine bay which leaves room for a spacer without causing trouble closing the hood properly.

Question is, how hard would you guys think it would be to get one of these custom made? or is it even possible with this car? I think with a mean engine like this 5.0 TAU, we could probably see some great top end gains from a half inch spacer....

Thoughts?

 

[Boger13R]

Without a good tune, you wont really see gains. Being a former LS (GM) owner, there's tons to be had with adding more air/fuel to make power gains as long as you have a good tune to make it all come together.

 

[12Rspec50]

It would be mildly beneficial adding a spacer. Without supporting mods, more air doesn't mean much.

However unlikely, you could also run the risk of detonation from too lean of an afr.

 

[Rspected]

Did I forget to mention that I have a BTR ECU/TCU tune?

 

[edizzle89]

It would be mildly beneficial adding a spacer. Without supporting mods, more air doesn't mean much.

However unlikely, you could also run the risk of detonation from too lean of an afr.

that not exactly how that works, no matter how much air is in the intake manifold the engine will only draw in as much air as they cylinder allows, a larger plenum volume wont force more air into a cylinder, it just provides a lightly larger amount of air available, but it's still a small enough amount that the factory ECM should be more then capable to compensate fueling with no problem.

also as far as i can tell the v8 intake manifolds are a 1 piece design so there's not really a way to use a spacer to increase plenum volume like on the Z/G, so your only other options would be a throttle body spacer or a spacer between the intake manifold and the heads

the Z/G intake manifolds are also pretty pancake'd for packaging reasons so they probably do see a decent gain from the spacer, the Tau engines seem to have a pretty decent intake volume but it's one of those things that we wont really know any gains until someone trys it

 

[12Rspec50]

Which is why i said "however unlikely" I've seen stranger things happen, and it's not outside the realm of possibility to get a bit of detonation.
I know its entirely implausible that the 5.0 would get a lean detonation from more intake air volume, especially due to the direct injection.

Its also miniscule at best that giving longer intake runners on the 5.0 will give much gains due to the ECU not being tunable.

Seems to me that Hyundai made their ecu tuning on the safe side and just left it "fat and happy"

If there's ever someone who can manage to adapt an AEM or Haltech in place of the factory ecu, maybe these engines will have their potential shown. Until then it'll mostly be a bunch of 'what ifs' and bench racing.

 

[OUsig]

yes a tune is what would be needed for these engines. there is plenty of air flow to the engine as is. the stock intake is a great design
now how to turn all of that into usable power. I mean MORE usable power is the key
cant see much happening as it hasnt as of yet
I did enjoy a nice run with a 2017 5.0 Genesis the other day. I was able to pull on him pretty easy as our model is lighter

 

[Rspected]

Which is why i said "however unlikely" I've seen stranger things happen, and it's not outside the realm of possibility to get a bit of detonation.
I know its entirely implausible that the 5.0 would get a lean detonation from more intake air volume, especially due to the direct injection.

Its also miniscule at best that giving longer intake runners on the 5.0 will give much gains due to the ECU not being tunable.

Seems to me that Hyundai made their ecu tuning on the safe side and just left it "fat and happy"

If there's ever someone who can manage to adapt an AEM or Haltech in place of the factory ecu, maybe these engines will have their potential shown. Until then it'll mostly be a bunch of 'what ifs' and bench racing.

yes a tune is what would be needed for these engines. there is plenty of air flow to the engine as is. the stock intake is a great design
now how to turn all of that into usable power. I mean MORE usable power is the key
cant see much happening as it hasnt as of yet
I did enjoy a nice run with a 2017 5.0 Genesis the other day. I was able to pull on him pretty easy as our model is lighter

Guys, the genesis IS tunable and BTR made the tunes for it. I have one myself and mentioned that a few posts above. They can account for the extra air and up the fuel ratio to make power with it. So, let's get back on topic... if I had a custom plenum spacer made do you think it would see some power gains once tuned?

 

[12Rspec50]

Guys, the genesis IS tunable and BTR made the tunes for it. I have one myself and mentioned that a few posts above. They can account for the extra air and up the fuel ratio to make power with it. So, let's get back on topic... if I had a custom plenum spacer made do you think it would see some power gains once tuned?

What we are referring to is an ECU that can be actively plugged into a laptop and have the car put on a dyno to adjust Air Fuel ratios. As far as i understand, the BTR ECU is shipped with a "Tune" flashed onto it that accounts for exhaust and intake changes.

With the BTR ecu, i still dont believe the gains you'd see with plenum spacers would be of much value.

 

[12Rspec50]

For the cost, you'd almost be better off having an intake manifold made with longer runners.

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[Rspected]

What we are referring to is an ECU that can be actively plugged into a laptop and have the car put on a dyno to adjust Air Fuel ratios. As far as i understand, the BTR ECU is shipped with a "Tune" flashed onto it that accounts for exhaust and intake changes.

With the BTR ecu, i still dont believe the gains you'd see with plenum spacers would be of much value.

Yeah that is how they tune it. I believe they estimate the extra air volume from the mods and adjust the fuel output higher to make it run more on the rich side than lean. They could do this with a plenum spacer as well. It got great gains of like 20whp on my infiniti but the original design of that plenum had an angled cover which restricted air to the first few cylinders so installing the spacer allowed the proper air to reach those cylinders, which wouldn't be the case with the Genesis, but I had thought it we could force in a little more air with that and add the proper ratio of fuel that we might see like 10-15whp gains and a custom spacer w gasket would probably only run about $500 from a custom fab shop

 

[OUsig]

you just answered your own question and basically what I said before - the stock Genesis intake is designed very well as is and a spacer is not needed here
at least it sounds like the Infinity design was easier to benefit from a simple change like the spacer
What we need is a real tune to open up the engine some more but it seems everyone is focusing on the turbo motors now. Leaving us NA V8 guys out on our own

 

[Rspected]

you just answered your own question and basically what I said before - the stock Genesis intake is designed very well as is and a spacer is not needed here
at least it sounds like the Infinity design was easier to benefit from a simple change like the spacer
What we need is a real tune to open up the engine some more but it seems everyone is focusing on the turbo motors now. Leaving us NA V8 guys out on our own

I'm really just looking for small ways to add some power in conjunction w my BTR tune. I realize they dont sell anything so it will have to be custom and I have a custom shop willing to do just about anything for the right price. Plenum spacer, crank pulley, headers, tb spacer or larger bore TB are a few things that come to mind...