Is there any aftermarket for the 4.6 northstar?

[cam99]

Other than the 4.4 v motor, is there anything available for the 4.6?

 

[2004XLR]

Not much you can do the cold air kit and exhaust but if you want a big gain you have to do the heads and cams http://www.chrfab.com/

 

[GizmoQ]

First off the official answer is no. Cadillac left little out of the 4.6 NorthStar in its development. Other than the modifications they made between the vin Y and vin 9. There is little aftermarket (CAI, headers, exhaust) to no OEM add-ons for the motor. "No pulleys. No cams. No heads. No chips. No worthwhile air filters. No nitrous. No chrome goodies. What you have is what you got."

That being said, there are several people doing crazy stuff with this motor. As mentioned above chrfab is the wildest of all, but you'll never get one of their motors to work in an OEM installation without extensive and costly workarounds (they use a completely separate engine control system). One company developed an ad-on chip to enhance the PCM code, but after developing the prototype, no others were ever made.

The primary problem encountered by all is the lack of data on the PCM computer. GM continues to refuse to release info on the code. There are folks trying to reverse engineer it with only limited success. I have a modified PCM in my 96 Eldorado and with a ram air intake and Corsa exhaust it gained me 16HP, but at least it changed my RPM limiter to redline and removed the speed limiter.

Other modders that I know of include one grinding new cams for the vin 9 (limited testing, development on hold); one is working to change the PCM to support a supercharger (there are three of us with different configurations all waiting for the programmer - ETA unknown); another is perfecting a stud kit to strengthen the heads (hundreds have been installed after head gasket failures, long term testing still ongoing); and there were some 80mm throttle bodies with spacers developed (good for maybe 5-8hp), but that was 10 years ago.

As for one off mods there's the TwinStar (two northstars in one car); there's the twin turbo Seville (~$12,000 hand-made mod); several people have modded NOS from 50-shot to 400-shot (the 400-shot blew up); and many have built custom 3" exhaust systems.

Good Luck with you mods.
Giz

 

[2004XLR]

Wish I knew the was no aftermarket support for the 4.6 I would have gotten a V

 

[mtrocket]

I, granted, may be opn of few, am quite content with the 4.6 stock... just as it came out of Bowling Green.

 

[carterchapman]

I, granted, may be opn of few, am quite content with the 4.6 stock... just as it came out of Bowling Green.

I'm with you Mtrocket. There's always a ZR1 Corvette or a CTS-V coupe if you need more "omph"...

I was out your way in Missoula the other day and it almost hit 50° - heat wave!

 

[cam99]

Thanks for the replies. It's a little discouraging for me to have a car that is basically untouchable, mod wise. I like improving what the factory gave me, its in my blood. My last few cars were a 2008 Shelby GT500, 05 GTO, 03 Lightning, 03 Kenne bell Cobra etc. All were modified from minor to major and that was part of the fun. Now the xlr is a whole different animal and I don't expect it to be in the 600+ RWHP range as the cobra's were, but I'd like it a bit faster. A V would have been more mod-friendly, but to be honest, until I bought my xlr I never knew an XLR-V existed!

 

[rwd]

A base car with an LS-anything motor in it (one of them ought to work) hooked up to a manual transmission would make an interesting car. Haven't heard of anyone doing it, but that's hardly surprising.

 

[james04xlr]

I just sold my C5 Z06 when I picked up this car a couple weeks ago. I just put the top down, crank the Bose and enjoy! It's not as fast as the Vette but it's fast enough for what it is

 

[mtrocket]

I just sold my C5 Z06 when I picked up this car a couple weeks ago. I just put the top down, crank the Bose and enjoy! It's not as fast as the Vette but it's fast enough for what it is

Plus, in my estimation... a MUCH better ride. And alot more unique!!!

 

[ChicagoDave]

You will love the Corsa - it has a GREAT sound! You definitely notice a bit more "punch", nothing huge, but a little bit more. The fuel economy is a plus as well. Maybe work it from a "sounding better" and "better gas mileage" angle.

Good luck - you won't be disappointed.

I am considering the Corsa and Volant upgrades and they are suggesting maybe 20 hp gain Is this a realistic number? I also read in another post where K&N were installed on a V and the gain was 10hp. So what is the best combination and bang for the buck on the 4.6? In other words how do I sell a $1800 dollar exhaust system to Thirsty4?

 

[mtrocket]

I am considering the Corsa and Volant upgrades and they are suggesting maybe 20 hp gain Is this a realistic number? I also read in another post where K&N were installed on a V and the gain was 10hp. So what is the best combination and bang for the buck on the 4.6? In other words how do I sell a $1800 dollar exhaust system to Thirsty4?

Good luck on that... I haven't been able to sell one to Mrs MT as of yet. Think I'll give up... it'll never happen!!

 

[graytoad]

You will love the Corsa - it has a GREAT sound! You definitely notice a bit more "punch", nothing huge, but a little bit more. The fuel economy is a plus as well. Maybe work it from a "sounding better" and "better gas mileage" angle.

Good luck - you won't be disappointed.

Totally have to agree with you ChicagoDave on the Corsa: it has the sweetest sound. When you get into it it really sings and everyone turns their head in the direction of its music! (sweet exhaust systems are really music to my ears!)

I am not too sure about the better gas mileage angle......since it sounds so good I have a hard time keeping my foot from mashing down just a-bit-extra to remind myself that I am a proud owner of an XLR: aka the luckiest girl in the world!

BTW: What's it with all the non-car-loving wives out there. If there is one thing my husband & I agree upon is sound and performance. Nothing stays stock in our house for any longer than it takes to decide what to add on and waiting for delivery of the parts