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W-Body Performance - Pushrod / DOHC

"Let's add some horsepower, shall we?"

Before we go any further, I want to express that I DO NOT hold responsibility for the faults of careless acts, damage or destruction to anyone's vehicle. This page is to help out fellow W-Bodies owners in providing helpful information about performance parts / ideas. Basically, you people are smart enough; do your homework and research before you do anything... think it out and don't be an idiot...


Do YOU belong to the 150mph club?


About the most easiest way to grab a couple extra horsepower from your engine is letting your DOHC suck in more air, faster and non-restrictive. The most basic upgrade is a K&N filter drop in that will use the existing stock air box. For the 1990 - 1993 motors, the stock number for the drop in is #33-2038; for the 1994 - 1996+ motors the stock number is #33-2063-1. The filter runs around $45, and expect to see about a 3-4 horsepower gain from that product.

For all of us gear heads, we know that engines crave colder, dense air for running their best. The best way for that is to have the intake air pulled from outside the engine compartment. K&N is also know for these types of systems, but unfortunately, K&N does not provide a Fuel Injection Performance Kits (FIPK) for the 1992 - 1996 W-Bodies. Many, including myself have e-mailed to create such a model, but very little responses have been returned about the idea. Cross your fingers, but don't expect anything anytime soon.

Although, many creative people have created there own cold-air intake system by using quality parts through many different home improvement stores and such, I have not been able to research the design well enough to make one for myself.  But there are many other sites of people who have a concocted such a device, check them out and and questions about it. Best of luck with that, and if anyone has any ideas please feel free to share the good news!!!


Okay, you got you car as fast as possible, but it's time to stop the beast... On a stock W-Body, the brake pads are made from an organic materials which have good wearing properties, but the stopping distance is very poor. New pads, rotors and even bigger calipers are not hard to find at all. Many companies have available on-line catalogs that will search for the system provided by that certain company.

Overall, the more surface the pad touches the rotor, the more stopping power you have. But with the power comes a price gap: it starts anywhere from a couple hundred dollars for basic performance rotors / pads for all four wheels to as much as $2000 for the bigger caliper conversion plus all the hardware.  Also, think about stainless steel braided brake hoses for easy maintenance and performance.  Since our cars are getting older buy the day, it might be wise to replace those before they bulge and burst.  Personally, grab some performance pads / rotors and brake lines and slap them on. $2000 can get you better things... at least I think so. 
An easier solution to help stopping power is updating the brake booster hose from the master cylinder to the intake plenum, it's a growing issue over the years as W-Bodies age.  Heat from the LQ1 expands and dries out the rubber hose and poor braking / pedal to the floor can exist; even with the installation of new brake components.  Check often and replace when brake pedals feels mushy or non - responsive.


The computer chip is the heart of your electronically controlled vehicle. The chip is installed into you ECM, which is either located under the passenger side of the hood or under the glove box, depending what year of W-Body you own. The Memcal chip hold's the timing, fuel, spark and all other computer related functions. There are over 800 functions that this computer chip holds. And only 8 of them are changed for increased performance.

There are a handful of companies who sell the upgraded chip. Do your homework before buying and installing one. Many of the companies will answer questions via e-mail, if your unsure or tense about making a selection. Always remember though that price, warranty and tech support are three key things to keep in mind just in case anything happens. Depending on which company you choose, many claim to boost you horsepower from 10-20 and your torque around 12-18 ft/lbs with some other minor modifications. But money is a big thing too, and the sticker price isn't the best sometimes; so anything around $200 or less is fairly a good buy, depending on what the company claims.


Now, since your DOHC can suck in more air, how about the exhaust system? GM has made a decent effort to keep the sound quality of the exhaust note, but has failed to realize that there are serious problem with back-pressure and flow restrictions. To find a Cat-back system or even headers, is very hard to locate. Again only a handful of companies offer such products; but the ones who do, have quality behind their name. These system can be quite expensive, around $700-800 for the Cat-back exhaust, but the return is pretty good: anywhere from 10-18 more horsepower is expected along with a good, solid exhaust note.


After installing a cold-air intake, computer chip, or other heavy-duty  modifications your car has some real zip... but are you forgetting to give all it needs to run top notch? A fuel pressure riser can do that; a necessary modification after doing many, many other upgrades (beyond head work and sport camshafts) and such on your vehicle. As more air is entering your engine, the ECM does recognize this but does increase the fuel supply to the fuel injectors. The air/fuel mixture can be lean and may hit extremely low levels to where the car is starving for gasoline. A fuel pressure riser bumps that level back to a normal running state. Very few companies offer such a product and it runs for about $150 - $200. It's very easy to install and it holds the consistant horsepower you already have.  But, the bottom line, if you're mods consist of small list, this particular product is not needed for you.

Some people have told me that a recalibraited Mass Air Flow sensor can also increase power. I don't have any confirmed reports about such a thing, but I am trying to conduct research about the topic. As for now, I can't agree or disagree: but only tell you the facts.


Spark plugs and wires are very important to have you car run well all the time. But the fact of the matter is that many motorists over look this simple idea to keep power and fuel mileage at it's best. Foul plugs lower performance after so many miles, usually around 25K-30K miles the plugs should be replaced. As being a GM man, I have stuck with AC Delco Rapid Fire spark plugs; I've had very good luck with them, and plug spacing comes preset. A set of six should run around $24 or so. You won't see a power gain, but you fuel economy will surely improve after installing any new plugs since more fuel is burned more completely.

Who of you on-lookers are electricians? Anyone? Does any here wire stereos? What's the best rule of thumb for wire width: thicker is better. Standard spark plug wires can hold the electrical current from the ignition coil, but it can be improved greatly. Companies out there do have precut 8mm, 8.5mm, and I've even heard that 9mm and 10mm wires are available for the DOHC, but only used for highly modified engines. Prices go anywhere from $50 - $200, and just like new plugs, fuel mileage is expected to rise since resistance of electricity is decreased.


A pair of 1995 Oldsmobile Cutlass Supreme SL convertables in Dark Green Metallic


For some instant power increase for drag racing, nitrous oxide systems can produce anywhere from 10hp - 120+hp shots to get your car past the finish line first. The benefits of the this is that the system is pretty user friendly after installation. Mostly all NOS products use a push button firing system or a full throttle switch (which when the gas pedal is on the floor-board the nitrous is shot).

The major downsides of this are that usually older motors can't handle this volatile compound since the added heat and compression can severely damage the pistons, piston rings, seals, connecting rods and so on and so forth. Rebuilding components in the engine are highly recommend for using big shots of nitrous oxide, because spending $350 - $1200 on NOS is nothing compared to a damaged $2500 engine.


Handling on a vehicle can be increase by many different ways. Many choose to use bolt on products, such as strut tower bars, and sway bars. Strut braces decreases the 'body roll' of a car. Basically it makes the car use it's suspension parts as how they were designed to work, not having the frame and body bend as you take a corner. Companies sell them for about $100-$110 a piece (front/rear), but people have created there own for much less than retail prices.

Sway bars, or also know as Anti-Sway Bars, help with stability of the car. When taking a corner they help keep you wheel stick to the ground creating more contact and less margin of skidding out of control. Sway bars can run from $60-$120 and usually comes will all new bushings and hardware.

Lowering springs are another common way to enhance handling and to lower the center of gravity of your W-Body. Kits usually contain all four springs and retainers, but reuse your existing struts and shocks. Spring kits run anywhere from $250-$350, and can lower you car anywhere from 1" to 2.5". To get rid of your old leaf springs (if applicable) some companies offer the rear coilover conversion for around $450-600. Again, you can reuse you existing shock and struts, but for the most part, the market will tell into buying performance hardware... this one is your call. If you got the money I say go for it.


1993 Oldsmobile Cutlass Supreme SX convertable in Electric Blue


Today, almost any customized Import you see today will have stickers all over it blasting out that it's powered from some super / turbocharger. The myth around these complicated products is that these "things" came out within the last few years or so. Not true, and in fact GM has been researching this phenomenon since the early 70's. The real scoop behind it is that, a super / turbocharger makes for more maintenance and somewhat less durability. Now granted, that the boost behind these things can be neck-breaking, but it's the fact the tuning and development is a big step into creating a powerful and responsive engine.

Superchargers use a turbine to push air into the engine and having more air to combust with the fuel.  It must have the serpertine belt or and accessory belt to drive the turbines; at low RPM's it doesn't create a big positive boost and almost "robs" power from the engine since its a belt drvien accessory. However, at higher engine speeds, the horsepower and torque are greatly increased from high positive boost of air in the intake manifold and the combustion camber.  Three major designs currently used in the automotive industry are roots, centrifical, screws, vanes and axial flow

Turbochargers do just the same but use opposite methods, with a turbine it uses the exhaust gases to such and compress ambient air through the intake manifold and into the combustion camber. This extra influx of air helps create a more powerful "bang" which in turn drives the turbo at a faster pace, pulling more air in to the engine producing power.  Yet, the power boost won't be noticed untill medium to high RPM's are met becuase it will take longer to spool up the turbo to begin pulling in air.  There is a signifficant power loss due to a turbo since more exhaust back-pressure is created, however you'll overcome the losses with the positive boost the turbocharger makes.  Also, there's a good possibility that you'll feel the effects of "turbo lag".  That is time when there's little engine response between open throttle to positive boost, and again when down shifting when engine speeds are faster than the turbo producing lag; basically is produces a vacuum blockage not leting exhaust gases pass by.

The fine line between using either or is still up in the air.  Some swear that turbos are only meant for smaller engines, and yet other say they're pulling faster times with a supercharger in the same vehicle.  The main thing comes down to this, it's based on application.  A supercharger give the car an instant boost the time you hit the gas, where turbochargers take time to spool up in the 3000 - 4000 RPM range untill shifting.  But from what I've seen and heard, is that turbos are great for little four-bangers and very small V6's.  This is where the line is now drawn here when turbos wouldn't seem to fit or work.  But the Dodge Stealth R/T, the Nissan 300ZX and the Mitsubishi 3000GT VR-4 and others are a good example of twin turbo engineering with a 3.0 liter V6.  This was done since "turbo lag" was extremely horrible with one large turbocharger.  Therefore, thise companies went to two smaller units instead of one big one where less inertia is required to spool up the turbos.  But from there on, the bigger V6's and V8 would be good with a superchargers, but I have seen a working Twin Turbo Corvette that kicked butt up and down the track.  So, again the bottom line when it comes down to what to use, it's based on application.  Nonetheless, the numbers are sometimes scary to see with superchargers adding an extra 20 - 150+ hp and turbrochargers adding around 10 - 130+ hp.  These are relative ranges, some systems can create more or less depending on setup and atmosphere.

So, ...yes, it is possible to add a supercharger or turbocharger to our cars.  There are parts and what not to get you started on the project, the major bad side to this is that a lot of what is created is custom made either by yourself or someone in the industry. Also, just like NOS, some parts of the engine, especially when turbocharging, need to be changed for increase pressure and heat. I'm personally not discouraging people to give it a shot, but for me it's probably too big of a step for me to handle. If looking to supercharge your vehicle expect to pay around $500 - $2000 plus a ton of hours under the hood re-wiring the electronics and setting up vacuum hoses. Turbocharging is little more, anywhere from $2000 - $4500 for all components along with an intercooler and electronics. My final word, uh... I really can't say much beyond use common sense people.


1994 Oldsmobile Cutlass Supreme SL convertable in Emergency Red


The cooling system for the DOHC has it's bad and good days, depending on driving conditions and weather... so to keep you engine cooler install a low temp thermostat. Automobiles from the factory have anywhere from 190 - 195 degree thermostats and that great if you want you car toasty all the time in the winter, but what about the summer time? A 160 or 180 degree thermostat will open the flow-gate to have the coolant circulate more often to keep the water temperature, and therefore the engine temperature cooler.

A thermostat costs around $12-$15 plus a couple dollars more to refill the coolant after installation. Expect to see a better throttle response and minor pick-up out of your vehicle.  Unfortunately, the only downside to a 160 / 180 thermostat is that the heater will not blow as hot through your heater core... but, at the same time no one want to crack a block or overheat while on the street or on the racetrack.  Plus many, if not all engine builders will agree to get the most "umf" out of you car is to have a 'at-running tempreture' engine with cold coolant circulating.  If unsure about installing in your vehicle, check with the FAQ's to get the full story on lower tempreture thermostats.


OK, if the world was perfect, some of us gearheads would be in heaven and find our W-Bodies with a manual transmission; unfortunately, reality sets in. Many of the W-Bodies are equipped with the HydraMatic 4T60-E 4-speed automatic transmission, and dreamed of having the Getrag 5-speed manual instead. But since the conversion price from auto to manual is ridiculously high, very few have done the transfer.

But there is hope: to keep your auto transmission living longer and to get a little more push out of it, there are a few things to look over. First thing is that GM made these auto trannys to be smooth shifting for the common driver. We want that changed... there are electronic adapters, when installed, to produce firm, accurate, predicable shifts when desired. The adapter costs around $75-90 and feels great once put in. But the only downside is that a qualified professional technician should only installed this type of product at your local transmission shop.

Another thing to think about is the fluid in the transmission. During running conditions, the temperature inside the transmission can be scorching, weakening the molecular bonds of the transmission fluid. Along with using synthetic lubricants, a transmission cooler helps prolong fluid life, the torque converter and to reduces 'slipping'. Many W-Bodies came with a transmission cooler, but some did not come that option. GM dealership parts departments is the best resource since they designed them to fit. Check there first to purchase a correct factory fitting transmission cooler before heading off to other companies. The price for these run from $30-$45; beats a transmission re-haul for a couple thousand dollars.


Okay, this is about the only thing that performance goes along with appearance. Again if you refer back to the suspension part of this page, lowering the center of gravity is important for handling conditions. To take this a step further, bigger wheels with a combination of smaller tires increases precision cornering and gives you car a nice look. Many different styles and brand fit the W-Body bolt pattern of 5 x 115mm, and wheel diameter can be increase as far up to 18" without having to deal with changing speedometer ratios.

Tires alone can make a big difference with handling. Soft vs. hard tire compounds have both there good and bad points, but depending on specific use, it's basically a toss up on what to use. Soft tires have very good dry traction and provide very good response on the road. Unfortunately they wear very quickly and only last 20K-30K miles with constant rotation. Hard tires last for a very long time and have good traction in the rain or snow to keep you from sliding all over the place. But, they don't hold well under hard cornering at all, squealing around the entire corner. Two sets of different tires may be an option especially if you live where climates change on a seasonable basis.

With having bigger tires, the tire side wall must be smaller to keep the entire tire/wheel circumference the same. If that size is skewed, the speedometer and odometer will read and count incorrectly due to more/less wheel rotations. Companies where you buy wheel/tire sets will help you find out tire fit your increased wheel diameter and shorten the sidewall of the tire. This trend is known as "low-profiling", and with less of a sidewall, the less it can bend while a car takes a hard corner. The tires completely grips the road, and like said before above, the suspension does the rest of the work. But unlike many performance options, the price range is very open depending on tire size, tire brand, and wheel style/coating. The list begins at $50-$700 a wheel, and tires from $30-$400 a piece. Again, do your research and do what you got or want to do.

These are the major components of increase power and performance from your car, but don't forget the little things as well. Check the Tech Tips for helpful information about scheduled maintenance and part changing techniques.