I just got my car back yesterday from Z Car Garage after a Osiris Retune.
Big thanks to Rob for taking care of my car, honest and awesome guy.

The first dyno was almost a year and half ago with about 65k miles with the following mods:

5/16 MD spacer
MRev 2
Stillen Intake
Nismo S tune
HR Y pipe
Grounding Wires

The car made 235whp / 230TQ before the tune. With the Osiris tune, the car made 251whp / 235TQ.



1 year and half later...

The Retune dyno included the following changes:

1. New spark plugs 5k miles ago
2. HR Headers
3. R2C Intake
4. XYZ Pipe with Resonator
5. Amuse Exhaust
6. Throttle Body Spacer


The results...

267whp/250TQ!
That is 17whp / 15TQ more to the previous tune pretty much throughout the entire RPMs.

I obviously understand that HP / TQ do not add up, but I do want to share my observation:

1. New vs. Old Spark Plugs - I swapped the spark plugs at 80k miles and my mechanic said it was a waste of $... The spark plug looked good (see picture below). I wouldn't be surprise if the new plugs gave it a few hp.

2. OEM vs. HR Headers - I definitely had some loss in low end power after the HR headers were install but it did open the mid and high end. With the tune, this mod DEFINITELY picked up power for me.

3. R2C Intake - I swapped this so I can clean this filter without the K&N oil. I did not feel any loss in power, but also didn't feel any gains. Due to the filter size, I am sure there has to be some small gains with the tune but nothing big. I wouldn't be surprise if this contributed a few hp.

4. HR Y pipe vs. XYZ Pipe with Resonator - The XYZ pipe definitely made some high end power but no changes at the low to mid rpms. It did bring up the TQ. I would say this mod added TQ and mid to upper end power.

5. Nismo S Tune vs. Amuse Exhaust - The Amuse Exhaust definitely had a good 5 whp more than the Nismo... There is no question and it's across all rpms.

6. Throttle Body Spacers - I bought this mod hoping the car would sound better. However, Rob at Z Car mentioned that my throttle response felt weird compare to other G.Z and I probably should take this off on my next tune. I tend to agree with him and will take this mod away. It does NOT give you power or tq... However... I somehow got slightly better mpg with the throttle spacer prior to the retune...

7. The Osiris Retune - The retune was definitely to put all the magic back together... It revived the throttle response. Prior to the retune, I could hear rasp from 1.5k to 3k from the HR headers. Now it's all gone. The exhaust also sounds better as if it's more well-mannered and screams louder at higher end. But the most impressive thing about the Osiris tune is the low end power that you can use. The car use to pull on the freeway at about 3k, now it will start pulling at 2.4k making freeway driving much more enjoyable.

To add, I am no dyno expert but the weather was much hotter yesterday than 1 1/2 year ago when I had the car dynoed in April... There are definitely variables in the dyno but I would imagine the effects to make the retune worse since it was hotter and the car is now older...

In the old days, cruising at 70, 6th gear meant you have to wait a few seconds for the car to pull up. Now, it will start pulling. The feeling is as if you get more power giving it less throttle.
I would have to say that MD spacers / Mrev 2 and Osiris tune are definitely the must have options to the car...

All in all... Each of the small pieces made some hp/tq and I am very happy with the results.

A lot of people ask me to put on ART pipe / XYZ straight pipe..etc... Well, I totally would if the Amuse exhaust is more quiet... I have to use the resonator to quiet it down for daily commute to work on the freeway.

With 267whp / 250TQ in a well manner sports coupe, I can't be any happier

 

Spark Plugs & Amuse Exhaust

 

You pretty much showed the part of the spark plug that isn't necessary to see. The gap are is what you should've pictured. Glad your happy, but it seems like a lot of money went into so so results.

 

You are right... I see people making the same power with less modifications. Not sure if this is due to my engine being 85k miles, but the car does "feel" better while the paper results are not too great... But I can't complain as a DD

 

Yes that's good that your happy. What I meant is for the gains, not the power its hard to compare dynos. I have 93k miles and I gained 17whp w just a plenum spacer and exhaust for 265rwhp/237rwtq

 

Baller exhaust

 

Great numbers man!

 

I also got my car dyno tuned by Rob at Z car garage. I have a very similar setup to yours, except I am using the stock exhaust. Do you think there are any more gains to be had if i switched to a true dual exhaust? Is giving up the stock exhaust tone worth it for those gains?

BTW, my numbers are here: https://g35driver.com/forums/tuner-d...6mt-coupe.html

 

yes, i saw your dyno bud. i am not sure how my car didnt make more power than yours.... could be due to many variables.


imo, and this is after owning many exhaust... oem exhaust sounds best...
i even miss it with the amuse... if i were you, i would go art pipes xyz pipe and hfc module. this wilk give you a goos 20 hp tq while maintaining the aweaome G roarrrr.
honestly, if i were to do it again, thats what i would do... not too loud, goos hp tq and pass smog.

there are defibitely gains opening up rhe exhaust, eapecially with thw hr headers.