Went to go dyno the car after installing 5/16 Plenum Spacer (Finally)

Result: Gain of nearly 4hp and pretty much the same torque.

My best run was actually 249.24whp and 232.34tq
However, that run's graph got messed up, so I just posted 2nd best pull.
Torque gain is none/irrelevent because I have gotten more than 232tq even
before the Spacer install.

The Plenum Spacer leaned out my car more. My A/F at idle is 17+

The car feels like it's 'chocking' and 3rd gear doesn't pull as good as it used to.
5th gear pull has improved, and feels more torquey

Would getting HF Cats richen out my A/F?

I want to avoid ECU reflash if possible.

 

hf cats will lean you out more

there's something not right if you didn't feel more grunt - before spacer install it always felt like my car would die around 4500RPM (like i wasn't getting enough air)....now it just pulls like crazy at 4500+.

 

Install was done at Performance Nissan.
There's no vaccum leak, but when I gas it in 3rd (especially in low RPMs)
the engine feels pretty weird.

 

So this dyno is just 2 pulls with the exact same setup?

Did you reset ECU?

 

You should have driven the car for at least 80-100km's before you did a dyno run. I personally only felt the real gains of the spacer 80k's after installing it.

+1 on the ecu reset not to mention the TB reset is essential if you disconnected the TB plug like me.

 

3 runs with exact same setup.
I did reset the ECU.
I also drove a while to get to the dyno place.

 

no way your a/f was 17. something's wrong w/ the dyno.

 

Interesting. What other mods do you have? You have pretty much the same numbers as me and I have... Well read sig.

 

Thanks for the dyno. I can see fuel problems at about 4,200 and 5,000 – 5,500 rpm. Its the 5,000 – 5,500 rpm range that concerns me. Will increasing exhaust efficiency decrease air:fuel ratio? I doubt it.

 

My other mods are JWT Pop Charger and Nismo Exhaust

 

I'm so concerned about my A/F..I'm actually thinking about taking
out the spacer..

 

This seems pretty dissappointing. Doesn't the spacer promise something more like 8-10 hp?

 

that does seem really lean...

 

talk to hydrazine.

 

I sitll think it's a problem w/ the install possibly

and i would never trust performance nissan after their stunt with spacer (ooooh, we'll just remove the gasket from all our boxes because i'm certain MD just put it in their for fun )

 

i would check it out it sounds like there could still be a vacum leak.

 

It looks lean in the before spacer dyno. Running 14~15 to 1 at WOT is no way to make power.

How exactly is it making more power in 5th than 3rd?

"talk to hydrazine"
+1

Chris

 

Are you serious?

I was going to buy the spacer from Performance Nissan and have Street Image install it.

I guess i should not even buy it from Performance Nissan then huh.

 

Since you spent money on the mods, leave them alone. Its time for a ECU tune to get the air:fuel ratio right.

 

I see your join date is 2005. You don't have a 2005 or 2006 350Z do ya?