Phoenix Gold Phorum

The subject: Pontiac G8 GT with magnussen TVR2300 supercharger and Meth injection







This car is insanely fast. It is said to have 650 hp. I believe it. It goes from 15 to 100 in no time, doing it so fast that I dont really have time to enjoy getting there.

Install: It was done at a "reputable" shop in the area who has done many magazine installs. They broke every panel when removing them, installed the tweeters by sticking them to the bottom of the dash piece with fake dynamat (there wasnt even a brand on the material), went from 16 gauge to 18 gauge back to 16 when running wires to the mids in the doors (including using the factory speaker wire through the door opening) all with butt connectors, build the wrong box for the IDMax 12, and did many other stupid things.

So for the tweeters I build some pods in the factory tweeter locations. I cut the factory grill out and used MDF rings and grill cloth to make the pods. The pods can be rotated 180*.

So my other corrections to the front stage are I rewired both front tweeters and mids in the doors. I found that the drivers side mid was wired out of phase. I also found that the crossovers were set to -3dB for the tweeters, which would explain the lack of high end. Surprisingly enough both doors were dynamatted properly and the adaptors were made right.

The head unit is some fancy shamcy Alpine 8" touch screen that is not available in the US. I guess its made for the G8 and Holden Commodore (i think thats the aussie version).





With a high tech head unit and its built in DSP you get lots of adjustability. Great if you know what you are doing, horrible if you dont. Well the parametric EQ was set up all kinds of funky. He boosted the bad frequencies and lowered the frequencies that the customer likes (the customer listens to trance and dance music).

So I set the EQ properly.

Because of the issues with the front speakers the customer had to move the balance to the right because the system was left biased somehow. Now I am able to center it up.

Now on to the subwoofer. Its a 12" IDMax. Its a version 2 but has been reconed and according to Image Dynamics it uses the version 4 specs. According to the website it needs a 1 cuft, well the box that was built by this shop was just short of 2 cuft. Did I miss something? does the sub have 1 cuft of displacement? no it has .14 cuft of displacement. Also, the box was a basic 3/4" MDF box. Great, if they hadnt shaved off parts to make it under the amp rack.



So I made a new box. It turned out that I overshot the size so I made an adjustment.











and thats where Im at now. Without the sub I can say that I have the rest tuned in. Tonally and stage wise its as good as its going to get. I am very happy with how it sounds. I have used all of my test music and this system could compete with other systems with much higher end equipment. The addition of the sub will bring it to a whole new level.

Love the car! Very nice rebuild. Is it your car? Hope your keeping the vwdude name

How you always get away with thous tinted front side windows? Is it legal in your state?

Nope not my car. It actually belongs to an LAPD lieutenant.

No tint is not legal, but as long as you are not doing anything else wrong they won't pull you over. This guy won't get stopped, he has the police union license plate frame (which he said I can have).

Picture update...

So as promised here are the eq tunes...
Previous:


Mine:


And box:










Overall the sound is incredible, but I don't think the sub output is enough for the owner. I suspect that he will want me to build a vented box for the sub. My suggestion would be to get a more powerful amp. I like the accuracy of the sub in this box. It's extremely tight hitting and accurate but since the owner listens to trance he wants insane amounts of bass.

Looks good! What is he running for an amp? Glanced at the post again and didnt see one listed. Going to get him a Phoenix gold to run that sub?

Thanks
Justin

Right now he's running an Incriminatory amp. I'm not a fan but he likes it. He has an orion "the beast", I forget the model number. I'm not letting any of my PG amps out of my collection. We were contemplating using one of my PPI pc21400 amps, and we still might.

As,for his components he's running an MB quart 4 channel, and Focal polyglass components up front and rear.

The equipment is not my choice (I do like the sub and head unit) but since it's not my car I don't get a lot of say. He has a collection of old school amps, including a US amps 4 channel that he wants to try but the MB amp doesn't sound bad. He's also having me repair an A/D/S amp.

I caught a glimpse of a bass cube in his collection. Maybe I'll try to work out a deal with a partial trade for the work that I did.

So I'm onto stage 2 of the repairs. There was an engine whine that is more obvious now that I got the noise floor down. Also, the owner wanted to try a different amp for the components.

So I checked the grounds behind the deck and here's what I found...

A mess

In case the unfocused picture is hard to see, or if you think you are seeing things, no that's a ground with the insulation slide back, another ground inserted and secured with a zip tie.


Here are the grounds, both factory and added ones. Notice two grounding spots, one on the left is factory where is goes to a bolt and bare metal, bu the hole is elongated and the contact is minimal. The second is what the shop added, and it's grounded to paint.


And my fix, all grounds together going directly to a metal post support. It ties in to the chassis.

So when removing the old amp, they had extended the speaker wires run with 2 feet of 22awg speaker wire. They did an awesome job with connecting the wiring to the amp...








I don't see a need to show pictures of my repairs, we've all seen properly wired amps. I removed that 22 awg extension and properly extended the wires with 16 gauge speaker wire, properly seated into the amp terminals.

uuuuum wow....thats some nice work the shop did there....

Yup. Is is why I taught myself to do installs so many years ago. I never trusted shops.

The sound is 100x better after all of my corrections, but the owner still wants improvements. I'm getting to a point where I'll recommend better speakers (these were recommended by the shop). I have done my best with these but were reaching the limits of these speakers (focal poly glass with the crappy crossovers).