In Association with

Cadillac Northstar 
Modifications (Mods)

(Updated Sunday, August 11, 2002 )

Cadillac Northstar Supercharger Project

Performance Reports   AP22

Northstar Mod Summary

Cadillac Northstar Exhaust Options

Northstar Peak HP Test

Northstar Intake Test - Airbox vs Cone

Northstar Cone Installation Example

Northstar 4.0L Intake - K&N, Airbox Mods with Dyno Test Results

Northstar Dyno Results

Back of the Seat Coat Hanger

What about under-drive pulleys?

Transmission Performance  Mark  1:46 pm monday march 25, 2002
From a reliable source at Powertrain Engineering, it will not hurt the transmission to lock in 2nd and redline shift 1-2. It just raises the line pressure in the trans which gives you the
firmer shift. It does not override the  "torque management" used to protect the trans during the shift.
This will certainly improve 0-60 and qtr mile times.

Mark 99STS

RSM Performance Parts

Info from Wheel to Wheel -- Mar 8, 2001: 

Thank you for your interest in our Cadillac related products.  We are currently working on performance products to offer for the Cadillac DTSi and the STSi.  These product will resemble the Tim Allen Designs DTSi that many enthusiast's saw.  We are hoping to have complete kits available in the next 4 - 6 months. 
Please bear with us during this time period.  We will not offer any
products to the public until they have passed or stringent engineering and quality requirements.
Mike Gauss
Wheel to Wheel Inc.
Aftermarket Product Development

Tim Allen Design Car & Driver Article

Info from Pro-Tech Transmissions:

    We can build any Model & Year transmission High Performance and/or Heavy Duty. We also cover Allante 89-93, Deville 87-95, Eldorado 87-95, Fleetwood 87-94, Seville 87-95 with our Pro-Tech Chip. On the Cadillacs we rage from 17-35hp gains & 30-45ft/lbs of torque gains. If you would like to get more information you would have to send or call with a specific year, model, & engine size so we can give you an exact figure. You can reach us toll free @ 1-866-PRO-TEC1.
Pro-Tech Transmissions

Cadillac Hotrod Fabricators -- Mar 6 2001 Update: CHR specializes in use of the NS in Street Rods, not in the Cadillacs they came in.  "We use only aftermarket computers that can be programmed via a laptop computer.  The heads alone are worth 100 hp.  The head and cam package is up to 425-430 hp.  We have a 5.0L engine planned that will put out 650 hp with no boost.  It is very expensive about 17K.  The crank is being made now.  Stay tuned."  Alan  -- in San Clemente, California (south of LA) Voice: (949)498-7000.  They are also in the process of moving to a larger factory.

XMS - Extreme Motorsports in San Diego, California  Custom exhaust, computer programming, MAF for the 98 and after Northstars.

Performance springs -- Intrax [Suspension, Intrax]

Performance Chips -- (93-95 engines only).

K&N Air Filter

With outstanding performance and superior quality, the Hydra-Matic 4T80-E continues to live up to the expectations of those who drive high-tech, luxury performance vehicles. Its electronic controls, viscous torque converter clutch and ability to handle higher combinations of torque and speed than any other front-wheel drive passenger car transmission in the world, make it the ideal luxury vehicle transmission.
Assembled in Ypsilanti, Mich., at the Willow Run assembly site, the 4T80-E is available on the Cadillac Seville, Eldorado and DeVille, as well as the Oldsmobile Aurora. Its adaptive shift quality is designed to provide the same high level of performance for many years.
Shift timing is carefully monitored and line pressure is adapted to maintain optimum shift feel. This adjustment compensates for changes in the operating condition of the vehicle system, which occur naturally over time. The adaptive shift quality also adjusts for minor variations in each new unit, so that every 4T80-E will meet its customer's
high demands for many years.
The 4T80-E is mated to GM's 4.0-liter and Northstar 4.6
liter engines.

Shine Street Aerodynamic Package "Tycoon" for the Seville

Accel Wires

Time: Tue, 28-Sep-1999 14:34:03 GMT     IP:
Mark Gogots writes:

For all '98-'99 STS owners, I have found an easy "free" mod you can do to really help your Northstar breath better. It takes about 30 minutes with common hand tools. If you installed a K&N filter, this mod will help even more.
If you take your air filter out, you will notice a hole at the bottom of the air box. Believe it or not, this hole goes down to a "black box" that is COMPLETELY sealed. Go figure!? Not much fresh air coming through there. Go under the car, just in front of the driver's side front tire. Pull back the plastic liner that covers the bottom. Be careful when pulling out the plastic plug clips - there are two at the bottom front of the front tire's wheel well. Those should be the only ones you will need to snap off. Carefully pull back the liner. Once that liner is pulled back, you will see the "black box". Cut the bottom of the box out. I drilled a few holes first,
then used a hack saw blade and easily cut through the plastic. Sand the edges down smoothly. Once the bottom is removed, you will see the hole which leads up to the air filter. Finally, cut an approx. 8" x 6" hole out of the plastic liner directly under the box. GM was nice enough to give you an indentation to use as a template. Make the hole just large enough to allow the air to get up into the black box. Again, sand
the edges down smoothly. Carefully pull the liner back into position. Clip the two plastic clips back into place and you're ready to go! Optionally, I also removed the metal screen located in the throttle body to help further increase air flow
into the runners. But it's up to you if you want to do that.

Net result is that the throttle response is MUCH better and the Northstar really sucks some cool fresh air now. Also there is a great sound when you
punch the gas - but not overly loud or annoying. Good luck. 

Carol Heim writes:

I just recently changed my plugs and wires in my 98 SLS and I upgraded to 8mm MSD instead of stock 7 mm, Might of been just the plugs but It chopped a sec. off my 0-60. I was just looking under the hood of my SLS one day. And There was a big oval shaped plastic cylinder connected to my rubber intake guide so I took it off and put a bottom of a cup in there to close the hole. I found that it was drasticly reducing the airflow to my engine. I ran my car with it first and got a 6.6 0-60 after I ran a 6.45. So it shaved some time off and it also gives it some added gurr on the the way up and on the way down it gives almost a pocket rocket sound.

 Open Andorra's Box: 420 hp Northstar  Bruce Nunnally  1:56 am thursday february 15, 2001

I found an engine builder named G IWASA in Andorra (between France and Spain)
selling a supercharger for the Northstar.  See h ttp://

Stock (304 hp): [isn't the Euro version rated at 320 hp?]

With compressor, 420 hp:

That ought to add a little pep to the car.  Sorry the graphs are not bigger or
clearer, but this is what they sent.

>> We prepare the engine completely , pistons , valves , injectors , cooling
>> ecu reprogramming , intercooler, reinforced clutch system , different exhausts
>> The problem is to fit everything inside , there is no place for the
>> intercooler & the supercharger
>> and there are few different body models for that car (depends of the year)
>> price of the modification here in our workshop is $20,000
>> If you can make the mounting in US we can study a price just for parts .
>> Regards

I think it is good to see more Cadillac based development.

Mods for Car & Driver's One Lap of America Car, 1998:

The Caddy wasn't quite stock. Thanks to Scott Badenoch and his merry men at Delphi Automotive, the suspension electronics had been reprogrammed to provide a little more roll stiffness and a considerably higher threshold for the onset of the StabiliTrak spin-control system.

We also used 18-inch P255/45ZR Michelin Pilots (versus 16-inch P235/60ZR Goodyears, the STS's optional tire) mounted on a handsome set of BBS wheels, plus harder brake pads and a Borla exhaust system. The first two tweaks yielded more grip and shorter stopping distances in a quickie predeparture test -- 0.84g versus 0.82g on the skidpad, and 169 feet from 70 mph versus 188 feet in our December 1997 test of an STS wearing H-rated Goodyears. The Borla pipes didn't do much other than lend a wonderfully menacing rumble to the exhaust note.

Mods for the STSi "Cunningham" edition:

While Cunningham and Cadillac are still evaluating additional modifications to the vehicle the initial features include:

The STSi boasts 320 horsepower - 20 more than the already impressive 300-hp rating carried by the standard STS. The extra performance is achieved through a combination of reduced inlet restriction, lower exhaust back-pressure and blue printing of the ports.

Future Northstar?  Here is the write-up for the Evoq Supercharged Northstar:

The 4.2-liter, 32-valve V8 features a supercharger with an intercooler, and variable valve timing (VVT) with a new low-friction valvetrain that combine to provide considerable power output, producing 405 bhp (302 kW) at 6400 rpm and 385 lb.-ft. (522 Nm) of torque at 4000 rpm. This impressive performance is accomplished in a relatively small displacement and in an environmentally conscious package. The supercharger assembly is a compact, totally integrated unit with the intake manifold, intercooler and rotor housing," said Roxann Bittner, GM Powertrain senior designer and member of the Evoq engine project team. "This configuration provides the increased airflow that produces 'power-on-demand' while allowing the engine to deliver impressive fuel economy during normal driving."

At the heart of the air-induction system is a tri-lobe supercharger with a displacement of 112 cubic inches (1.8 liters) per revolution. The supercharger rotors turn approximately twice engine speed, which results in more airflow into the engine than it would naturally breathe. The extra airflow causes pressure to build up in the intake manifold creating supercharging of the engine. This is also called forced induction because the air is forced into the engine instead of being merely drawn in by the action of the pistons and valves. While supercharging has been around since the start of this century, the integration of the supercharger into the Northstar V8 is an all-new GM design which is patent pending.

"The integrated Evoq supercharger assembly improves airflow and eliminates a lot of bracketing and plumbing," Bittner said. "It allows for machining the rotor bore without clamping the rotor housing, a major cause of housing distortion. Another advantage is the easy serviceability of the intercooler, which is what cools the compressed air for greater density. This provides increased horsepower and a more efficient burn."

The four-camshaft, continuously variable valve timing enables the intake and exhaust valves to open and close at the optimal time depending on engine operating conditions, delivering a broad torque band and improved idle quality. Because of this optimized control of valve timing and the new low-friction valvetrain, exhaust emissions and fuel economy also are improved.

"Engine design, concerning cam timing, traditionally has been a matter of compromise," said Greg Prior, GM Powertrain engineer leading the Evoq engine project. "If you have low overlap between inlet and exhaust valve timing, then you have good idle and low-end torque. If you have high overlap, it breathes well at high speed but you tend to have poor idle quality and some erosion of low-end torque. With variable valve timing, we free ourselves from this classic compromise."

The engine also received several upgrades to handle the increased power output, including a steel crankshaft, an iron inserted lower crank case, heavy-duty connecting rods and pistons, plus upgraded valves and head gaskets.

Hey Bruce, What about my Catera?

Steinmetz supercharger and body work

Discount Tire has Intrax lowering springs



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