!!! Since last review, have updated z-tube notes, added hi flow cats and stillen exhuast !!!

Ok, so I won't bore anyone with details like facts, or dyno data.
My goal is better performance without more noise, or looking nonstock.
I am old, and I don't want to deal with shifting, so I have an AT.
Clearly that has some disadvantage moving the power to the wheels
I have been very happy with the car (owed about 16 weeks now)
I thought I'd offer some opinions and observations on mods I have done.

1) Z-Tube (www.everythingG35.com) !!! UPDATED !!!
I thought this was a wasted effort, didn't feel anything, just louder.
Several people showed me dynos proving an average of about 3HP.
Given the other breathing mods I have done, it may be paying off more now.
PRO:........... Minor improvement in power.
CON:........... Makes the car louder.
COST:.......... About $75
INSTALL TIME:.. 10 - 20 minutes



2) Stillen High Flow Air Box. (www.everythingG35.com)
Frankly the best solution I have seen IF you are going to replace the intake/filter.
At least it isn't sucking anywhere near as much hot engine air as most of the supposed
'Cold Air Intakes'. I modified the housing to seal in the compartment so it only draws
air through the normal intake vents as well as a few other holes to the grill area.
PRO:........... Seems to offer some performance at WOT and/or High end of RPM range.
CON:........... Loud, damn is that thing loud when you floor the gas.
COST:.......... About $180... I am not sure it is woth it.
INSTALL TIME:.. 60 - 90 minutes including the mods I did to it


3) Motordyne Plenum Spacer 3/8" (www.motordyneengineering.com)
This Mod ROCKS !!!, absolutely showed noticable improvment as soon as install
was done. Without a doubt improved pulling and acceleration through the entire
RPM range. It also appears to have improved my gas mileage.
PRO:........... Great performance improvement, absolutely great.
CON:........... NOT A SINGLE DOWNSIDE !!!
COST:.......... Depends on size and if you get in on a group buy ($150 - $240)
INSTALL TIME:.. 40 minutes

4) Grounding Gear 5AT Performance System (pm GordGee on this bulletinboard)
This Mod ROCKS !!!, absolutely showed noticable improvment as soon as install
was done. Without a doubt a win all the way around. I got the full blown 10 wire
(7, +1, ECU, TCU) system. The car is smoother, it shifts like a madman.
Now being that for 25 years I have done microcontroller work with a lot of
sensor inputs, I knew it would improve things like smoothness, shifting etc.
I had no idea how much I would feel the improvement - Jaw Dropping...
PRO:........... Great performance improvement, absolutely great.
CON:........... NOT A SINGLE DOWNSIDE !!!
COST:.......... Depends on kit you buy, if you have an AT, get the full blown
10 wire. Send a message to Gordon for details.
INSTALL TIME:.. 120 minutes (also doing the connect to the tranny is a bitch
but well worth it)

5) Stillen Cat Back Dual Exhuast
Added a good bit of sound level, and some performance.
PRO:........... Great power/performance improvement - particularly at 3k+.
CON:........... Noise, as expected it is louder than stock, more bass. This may cause me to sell it.
COST:.......... $1216 direct from Stillen - I picked it up to save shipping and time.
INSTALL TIME:.. 120 minutes


6) Kinetix High Flow Cats
With the Stillen exhuast, the increased noise is too much I think.
I may put the stock exhuast back, and leave the cats.
PRO:........... Definite increase in power, no doubt.
CON:........... More noise than I would like (with exhaust) I also don't like that
cats stock mount is not used. I would like to have the exhuast system supported there.
COST:.......... $400 with shipping.
INSTALL TIME:.. 150 minutes (I have a floor jack, and air tools) otherwise add an hour.


In short....(updated)

Z-Tube, offers some gain in HP (shown to me on dynos) more agressive sound.

Likely not worth bothering with a CAI, but if you insist The stillen is likely the
best solution.

Run, don't walk to get your Plenum Spacer from Motordyne... You will be thrilled.

Run, don't walk to get your Grounding Gear system. Don't bother with the others out
there like Stillen, or Nismo, etc. Absolutely don't cheap out. Get the best kit
available (10 wire for an AT, and 8 Wire for the MT).

If you can deal with a little more exhuast noise, I recommend the Stillen. All
the dyno I saw online/ mags gave it the clear win, and it certainly performs.
A little pricey compared to many, but outperforms them based on the data I could
find.

High flow cats gave some great punch, but increased noise even further with the
stillen exhuast. I may remove the ehuast and return to stock, leaving the cats.

 

Hello Kevin

So do you think you are going to loose much if you pull the stillin exhausts off? Like you I want quiet. Do you think the CATS" are worth the money or do you feel that the cats by them self could be the best bang for the bucks? I still worry about back pressure and drivability. What are you thinking here? I will be down in Cali soon and maybe we can hook up. My younger brother just picked up a new 2005 G35c At. He lives in Upland and he wants me to help him on all of his installs. This will be a mod a thon. Grounds. Intake, both spoilers, And exhausts, and to be determined the plate or the crawford plenum. All in one day. This could be fun.
I will buy the beer. Dam IM thinking I bet you have some good tools. He will probably be buying some Volks also. This would make a great transformation in one day with some pictures. The before and after would be breath taking. What do you think? Dennis

 

Hey ya,

It is hard to say on the cats... what i mean is...
The Stillen exhuast really made a difference, but man is it loud.
The cats added a bunch more power, no doubt, and I feel a pull like I can't believe.
What I can't say at this point is how the cats would be without the exhuast....
I may be finding out soon... I mean i really like the power, but damn... when I drop that pedal in the floor to WOT.. I have exactly the kind of noise I didn't want.

I may be making someone a good deal on a stillen exhaust with a few hundred miles on it... I just don't know. I think some of the noise is the actual body of the resonators and muffler vibrating... I am thinking about trying to dampen them some how.

I'd love to hook up, and se a new G , and a new G owner... But i doubt I will have a full day to do any mods and the like. I tend to be lucky to get maybe 3 hrs late at night. My schedule and job are outright unforgiving. We can talk, you never know.

My tools are adequate, nothing that special.... I just started building up some auto tools again, so they are OK quality. In a way it bums me out I sold all my stuff 20 somthing years ago when I left auto work for electronics. Back then it was all snap-on or Mac, I sure don't need that for personal wrenching these days...

 

Sickone

Thanks for the reply. Like you I never know what or if I will have time for anything. I believe you are one of the guys here that just love your car like I do. I think there is a club out there in so cali and the way IM thinking maybe we all can hook up and bang this mod of thon Out"
Tools I just cannot put them on a plane. G35 guys in So Calif. I will buy the beer and food. This could be fun. In the planning right now. Brother you rock. Dennis

 

I'm watching this thread with interest, as well. You've gone the exhaust mod route I am thinking of going. I too am concerned with the noise level of the stillen exhaust with the Kenetix cats. My set up will include DC sport headers, kenitix cats and a "to be determined" exhaust.

One idea that I'm considering for the stillen exhaust is to fabricate and have installed some resonator chambers. Just like some cat removal pipes (test pipes) have done to dampen vibration/harmonics/raspiness sounds. Not sure if I'm on to something or if I'm WAY off base. What do you think? I know the stock exhaust has one and some of the quieter test pipes have them ..... so why not? Before you remove and sell the stillen exhaust, this might be a more affordable alternative. While your at the exhaust shop, remove the support brackets from the old cats and have them installed on the kenitix cats.

 

thanks for sharing your thoughts on the mods Sickone, I think it it useful to a number of people trying to decide the value of different modifications to their system. I plan on adding the 10 wire system from Gord (if I ever get out to get an International MO ) and that will probably be the last of my mods. I can't see removing the stock exhaust for the power gains vs the cost.

 

hey ya,

Maxpower - the MO is easy, just go to a post office, tell them you need the international one, and you can mail while you are standing there...

On the exhuast noise/level. I will say this.
1) I went to a dyno day today in Socal, and I was ****** impressed with the numbers I pulled. Given that I have an AT, so a good deal more drive train loss than a 6MT... I pulled a 252 RWHP, in fact when I left as far as I know (I am sure the results will be posted soon) when it came to NA cars myself and a Z owner (name is escaping me) who had done intake work, port polishing, plenum and spacer were neck and neck.

I saw one, '04 6MT pull a 259 RWHP and he also had the Technosquare reflash.
(these are all the SAE corrected outputs, the actuals were about +10HP)

any way _ i was feeling pretty good about the whole thing. Glad I went, and met some of the other G and Z lovers.

Anyway after running the exhuast for about a week now, I am fairly certain a good deal of the 'noise' is actual resonance and vibration of the pipes, resonators, etc. And not so much the actual level out of the tail pipes.

I am going to try damping the the stuff both with sound damping and deadening material, as well as high temp rubber contacts (pressure against the various exhuast points).

I will keep you posted.

It is also worth noting I have shaved a few 10th of my 0 - 60 times with all this, and the punch is definately there.

 

hey SO,

after I posted about your mods update I ran out to pick up a few things from the store and as I headed to the checkout I realized that Wells Fargo had an in-store branch so I stopped in,got the MO, and PM'ed Gord with my shipping info. Monday it will be on it's way to the Great White North. Everything I have read about the 10 wire set and the 5AT has been very positive and I am looking forward to the install. the only connection that will be a problem is the direct to the transmission since I don't have a good jack or stands. I'll have to check with my neighbor tomorrow what color did you get? I am going with the smoke.

 

Maxpower... you are obviously man of style and taste...
I also picked the smoke color

The tranny one is a pain, you can for a few bucks (under 30 or 40) get one of the small floor jacks and a basic jack stands. What ever you do, don't crawl under with only a lift jack supporting the car.... it is rare, but it happens, and peole get hurt or killed.

If you are feeling adventurous, do as the instructions suggest and do the first 6 or 7 wires, drive it, then do the last few (tranny, TCU and ECU) then take it out, get in manumatic mode, and wind first up all the way and bang it to 2nd... I bet you feel the difference

 

Sickone,

Congrats, great numbers on your dyno. I have a small exhaust leak with my Kinetix HF Cats. I purchased new exhaust gaskets, and will install them soon. The Cats with my Injen SES Cat Back system is very loud. I was thinking of putting on bigger resonator pipes, but the cats are making alot of noise from the front of the car. Some guys have had a muffler shop weld a piece to secure the HF Cats to the frame for less vibration.

I agree the Grounding Gear 10 Wire Kit really works, although I have not installed the last two wires yet, probably tomorrow.

Maxpower - glad to see you installed the Motordyne XL Spacer.

 

I agree the Grounding Gear 10 Wire Kit really works, although I have not installed the last two wires yet, probably tomorrow.

Maxpower - glad to see you installed the Motordyne XL Spacer.

Thanks, for me the 3/8" MD spacer and stock look was the way to go. As Sickone had suggested, I did the install and then out for some 'butt dyno' testing and then the ECU reset and another test drive. I am very happy with the results.

 

KeithN: One of the things i wanted to do with the Cats anyway was add the mounting support which the stock one had. They connect to a damped bar offering vibration reduction as well as support for the exhuast system.

I will likely add a few more well placed dampers, and some good sound/vibration deadening stuff to the floor boards.

 

you say its loud...does it still sound deep or like a riced out Honda...?
Pingo