Bolt-Ons 101: The Newbie Guide

Last Update:

Stay tuned for a significant revamp to this page. We'll go more in depth into the art of turning a stocker into a meaner machine with logical progression in mind. Not just descriptions of each part, but also a guide, giving more information on how to progress with your own project car. All this and without having to shell out huge bucks or having your car on the blocks for more than a day at a Time, hopefully.

Welcome to my first attempt at creating a comprehensive guide for the would-be car modifier. The main focus of this particular page is to arm the owner of a stock PGT with some good information that will hopefully help to start him or her on their way to turning an already sweet car into a sweeter car. (duh) This page does not really contain the SPECIFICS behind installing particular parts (this isn't a how-to guide) but gives a good general overview of logical progression to go from mild to wild.

Comments and criticisms are highly welcomed, insults and wild claims will be completely ignored. I'll make it easy, even. Click here to send me mail.

FYI, the information contained in this page mainly refers to what I have and what I know best, the 2nd generation Probe GT (93-97) with a 5 speed transmission. Most of what is here applies to the Automatic as well and also the Mazda MX-6 V6. 1st generation Probes are not covered (although I have owned a '90 PGT before I wrecked it) and neither are the base/SE models of the 2nd gen car. This is not intended as any sort of insult, it's just that I have no experience with these vehicles. Some of what I list here is relevant to the other cars, but not much and I have no way to verify any of it.

For the sake of sharing the wealth, any specific information on how to perform certain tasks will be linked to some web pages that have this information already. Besides, saves me the trouble of typing it all in or cutting and pasting then altering so it doesn't look like a blatant rip off.

E ssential Web Pages
There are a couple of Probe GT specific pages which I consider almost essentials when it comes to learning more and becoming almost intimate (no, not in that way) with the workings of the car. They are
Julian Bradbury's Maintenance Page. The authority when it comes Time to fix or perform maintenance on your car. Bookmark it, worship it.
Eric Van-Der-May's Probe FAQ. Lots of great info and useful links to many other pages.
Ross Lapkoff's performance page. Lots of very useful info about installing aftermarket parts and drag racing.

Mailing Lists
For those of you who don't know, there exists two great mailing lists specific to the 1st and 2nd generation Ford Probe and Mazda MX-6, all models, all years. One is a maintenance list where you can pose whatever repair or troubleshooting questions you want and the performance list is specific for those nuts who seek more power and handling. For information on how to join either of these two lists, visit
Bay Area Probe Owners Club (BAPOC) page, mailing list section

Ok, for starters, let's say you're the proud owner of a brand spankin' new Probe GT. Or let's just say after saving up your hard earned money you put down the dough on a nice used ride that caught your eye. Most owners will probably be of the latter type since Probes are no longer manufactured. Your car will probably be putting out about 133 HP at the wheels. Now you want to boost performance. So what are the most important questions? How about the following...

1. What does it do?
2. What performance parts to get?
3. Where to get them?
4. What should I avoid?
5. What should I expect to gain?

Let's begin by addressing the logical steps in making your car even faster via bolt-on parts, Power Mods and Handling Mods. I will put more information about power because most people are interested in beating the car next to them in a straight line.

Power mods(fluids, intake, headers, exhaust, UDP, forced induction):

Fluids - What does it do?:
This is probably the easiest of the "what does it do" questions.  The fluids are an essential part of the whole machine.  Lubricants are what reduce friction and heat between moving parts in the car.  The easier that two pieces of metal slide past each other, the less friction they generate from them rubbing together, thereby reducing heat and increasing efficiency.  Part wear is also reduced the slipperier it is.  The effect in terms of power gain is fairly minimal, due to a simple idea.  If the parts slide together well, then you get what you should expect.  If they don't slide together well, then you're probably going to experience problems.  There is only a slight difference in pieces that slide well past each other and slide REALLY well past each other.  That's the difference between normal and synthetic oil.

In the case of coolant, the water-glycol (usually) based liquid circulates around the engine block collecting excess heat which is then passed through a heat exchanger (radiator) and cooled by circulating air.  By making this heat transfer and heat dissipation more effective, you cool the engine faster, and cooler equals more power.

The combined performance effect of the above is fairly minimal, but then again, the cost is also equally low and you'll still gain the benefit of longer life and better operation.

Fluids - What should I get?:
Proper use of fluids is the first step to getting faster and is also the cheapest steps. Normal engine and transmission oil is garbage. For the manual transmission, do yourself a favor and track down some Redline MT90 or MTL tranny fluid. This pure synthetic fluid is not expensive (about 25 bucks for 3 quarts, what your car needs) and it's pretty cheap getting someone else to do it if you don't care for this type of work. The auto tranny has a similar product by Redline. Look for it.

Also, if you don't mind eating the extra expense during servicing, consider using Mobil 1 synthetic motor oil. This oil has very few particles of carbon in it, unlike some other synthetics like Castrol Syntec. Mobil 1 is about 4 bucks a quart, depending on where you go for service and if you do it yourself.

To a lesser degree, look into getting a bottle of Redline SuperCool (with the Watter Wetter additive). This pink bottle helps your radiator dissipate heat much faster and more efficiently than with just normal radiator fluid. The bottle is cheap, too, at only 7-8 bucks at some auto parts stores. Some say the benefits in our particular car are dubious, but for 7 bucks a bottle once a year, I'm willing to buy into it. It can't hurt.

Fluids - Where can I get it?:
Redline SuperCool is available at Pep Boys auto parts centers. They're the only major chain I've seen that carries it. Everyone seems to carry Mobil 1 engine oil. If you have trouble tracking down SuperCool or the transmission fluid from Redline, visit Redline Oil and contact them about finding you the nearest retailer in your area.

Fluids - What should I avoid?:
No major oil additive has been proven to be worth a damn. Some have proven to be slightly harmful. Avoid any and all products that claim miracle gains in horsepower or engine longevity such as Slick 50, Prolong, Duralube, Motor Up, etc... Slick 50 has been around the longest and it's just amazing that people still buy it up. Not to mention the stuff is usually expensive. I won't waste my Time pointing out the specifics (not to mention I'm no expert) but "9 out of 10 Probers agree," stay away from the snake oils!

Fluids - What will I gain?:
Ahh yes, young grasshopper, the most important question of all. After all of the trouble of swapping fluids, you will be lucky to see about 3-4 extra horses, provided that you started with stock fluids from the start. Your are now up from 133 to about 136 HP at the wheels. That ain't s#!t, you say? Hey, what do you want, MIRACLES? Go watch a televangelist. There are no miracles here or anywhere. Sort of. We'll talk about that later.

If you were already running a synthetic motor oil (Syntec, etc.) then don't expect any big gains by switching to Mobil 1. The tranny fluid, though, makes a good deal of difference since it is not only better lubricating, but will also help to lower overall temperature. Lower temperature, more power.

Intake - What does it do?:
Air is sucked into the engine, mixed with fuel, and detonated in the cylinders.  At full throttle, a stock PGT tends to run rich (verified by the use of a voltmeter during WOT).  So technically speaking, if we can somehow get more air into the engine, then we can achieve a more complete burn of fuel, generating more power.

The first important step to making the big power is to improve the airflow of the car. The more air that passes quickly and cleanly, the more power your car will make. The best thing to do is to get rid of the stock airbox setup. From the plastic "s" pipe that serves as the intake to the square box that holds the panel air filter, it all has to go. Sure, you could get away with just buying a K&N drop-in replacement panel filter, but what's the point. You're not going to see any extra power out of the thing since it's the intake setup itself that is causing the greatest restriction to airflow.

Intake - What should I get?:
The piece of hardware that comes most recommended the Hotshot Cold Air tube. With a cone filter of some type attached to the end of it, the Hotshot replaces the entire stock airbox, up to the VAF (the thingy that controls air intake). This wonderful piece of metal tubing will perk up the performance of your car immediately. You'll love it for a couple of days and then you won't feel it anymore. Why? Because you get used to the extra power!

A lot of people complain that the Hotshot intake tube sits too low and that water may get sucked in and next thing you know, you're staring at a horrific repair bill. While I won't say that this is impossible, let me put most doubts to rest by saying that "9 out of 10 Probers agree," you're not likely to have any problems driving through rain. Just don't drive through deep puddles. If you expect rain, take the Time to put the stock air system back in or something. Extra power comes at a price of extra diligence.

For those who are still worried about the Hotshot filter placement, there's the PRM intake system. Granted, I know very little about this setup, but the idea is similar to the hotshot. The difference is, the filter itself sits up by the VAF (the air thingy) and a tube extends down in a fashion similar to the Hotshot. The filter takes less damage, but the benefits are similar. Colder air.

For those on a budget, you can fabricate a ram airbox similar to the PRM setup by making it yourself with a few simple tools and some patience. Just takes some PVC tubing, PVC pipes, and a dryer duct. Can be Time consuming and is heavily dependent on your handywork skills.

Intake - Where can I get it?:
The Hotshot tube can be had for relatively cheap from CB Performance's Eddie Wu. A complete kit with all you need can be had for about 150 bucks. That's the tube, air filter, an inline filter for a vacuum hose, a nifty Hotshot sticker and a Hotshot license plate frame. WoOHoO!

I have no idea how to secure a PRM intake. You can try contacting Jaewon Ahn and asking him. He has one in his Nitroused PGT. But don't bug him, ask only if you're serious cuz I didn't ask him for permission to include his email address. Sorry, Jaewon, fellow Korean bro.

If you want to try and fabricate your own airbox with a ram air, then I'd highly recommend checking out Brian Young's excellent URL. His custom ram air intake and airbox are really top notch quality.

Intake - What should I avoid?:
Avoid attaching a K&N cone filter directly in front of the VAF with nothing else! This is very bad! Not that it's going to hurt anything, but keep in mind that if you do this, the only air available to the filter is going to be HOT engine compartment air! This is very detrimental to performance and has been shown to drastically cut into your usable power, as shown on Dan Dunhem's dyno chart page. About 2-6 HP across the power band. Ouch. At the very least, run some ducting from below the car so that at speed some cold air is blown directly onto the filter. I would still consider this a poor alternative, but it's better than nothing. Expect to break even in the HP department by doing this, and maybe slightly more as your speed increases.

Another bolt-on to avoid is the Tornado Air Management System. Due to a prior agreement with the general manager of Tornado Air, I won't say much more about it except that while the product may work for other applications, test results have shown that it has no significant benefits for the Probe V6.  The tests are still ongoing, so stay tuned for more later.

Intake - What will I gain?:
Doing the intake properly will yield a good 5 HP over the stock setup. This gain is added to the power given by the proper fluids, so doing both you will have shot up from 133 stock to about 141 HP. That's right, still no miracles here.

Exhaust - What does it do?:
The exhaust system of a car is the piping which allows gasses to leave the engine, get unburned fuel catalyzed by the catalytic conver, and sent out the tailpipes.  The portion of this system most referred to as exhaust is the system of pipes following the catalytic converter.  This is why complete exhaust systems are often referred to as "cat-back" systems.  The muffler portion of the exhaust system is also what keeps your car from being too loud as you drive around.

Exhaust - What should I get?:
The most common answer to this question is one of two choices, the Greddy or the Borla. The most obvious difference is the tip. The Greddy is a single "grapefruit" shooter tip while the Borla has "intercooled" twin tips. Without getting into too much detail, the Greddy is supposed to make more horsepower than the Borla. Frankly, I am very doubtful that the Greddy will provide a substantially higher level. We'll discuss that a little farther down.

There are other alternatives, such as HKS, Bosal/Brospeed and Remus among others. Then there are the generic mufflers like Dynomax, Flowmaster, and others. In all cases, they are trying to be less restrictive, but there is a pitfall if you don't get a cat-back setup like the Greddy, Borla, or HKS. Again, a little farther down.

Exhaust - Where can I get it?:
The Greddy can be had from CB Performance's Eddie Wu. As a side note, CB Performance has been a great help to the Probe community, providing parts for as cheap as they can get them. Give them a try and see for yourself. No, I don't get paid for plugging them.

The Borla is a bit tougher to find, but R&E Racing has it for about as cheap as the Borla gets. The Borla is about 150 cheaper than the Greddy, scoring points in its favor. You can also contact Borla directly for a distributor near you, but trust me, R&E is probably the cheapest.

An HKS is a similarly priced as the Greddy (about 500+) and is harder to locate. Remus is easier to find than the HKS but it's only the muffler and tips. The generic brands such as Dynomax can be found at almost any cheap muffler shop.

Exhaust - What should I avoid?:
I would suggest staying away from exhausts that are not an entire Cat-Back system like the Greddy or the Borla. Why? Because the pipes on the Cat-Backs are mandrel bent, which means that the pipes have been bent in such a way as to maintain their inside diameter constant. Most muffler shops cannot do this. They rely on crush bent tubing, which means that anywhere the pipe bends it is crushed, effectively reducing the space through which exhaust can flow. Consequently, there is a slight power loss. If you can find a shop that can mandrel bend, awesome. But you're not likely to find any. But if price is a big consideration, then you get what you pay for.

Exhaust - What will I gain?:
The gains from an exhaust aren't big. In fact, you may be disappointed to hear that adding just an exhaust as a mod will yield virtually no HP. Try 2, from a stock of 133 to 135 HP. Disappointing you say? Don't forget to add your fluid gains (after all, you DID do that first, right?). Still the yield is only 138 HP. What gives? The truth is, the stock exhaust already works pretty well. In its basic form, a better exhaust isn't going to improve things much. But throw in an intake and the gains improve considerably. Try from 136 fluid base to 144 HP. Ahh, see, the combined effect of having an intake AND an exhaust yields more than the individual components themselves. See how wonderfully that works?

Headers - What does it do?:
The stock PGT has two exhaust manifolds, one covering each bank of three cylinders.  The manifold is essentially a single cast piece of metal.  The inner hollow chamber is roughly L-shaped, with three holes along one edge of the L-shape, and an exit hole at the other end of it.  Exhaust gasses enter through the 3 holes and are piped into the catalytic converter and passed out of the tailpipes.

Stock exhaust manifolds are motivated by a really simple factor.  Cost.  They are fairly cheap compared to steel tubes which have to be individually bent, welded, and fitted properly (i.e. headers).  They are cheaper, but they also ram the exhaust leaving the three cylinders into a single pipe, which isn't very good for smooth exhaust gas flow.

A proper set of headers, on the other hand, start out by giving each of the three cylinders its own individual exhaust pipe, called a primary.  Then, the pipes are merged together into a point called the collector, where they join up at a Y-pipe (for the other bank of cylindersa) and then go out the catalytic converter.  This gives a much smoother exhaust gas flow than the standard manifold.  For a more detailed explanation of this phenomenon (and with pictures!)   Check out the link to Ross Lapkoff's headers subpage.

Headers - What should I get?:
There has been a debate of sorts among various PGT owners as to which headers are the best.  How one defines "the best" is really open to interpretation.  Are you looking for cost?  Ease of installation?  Overall performance?  Quality?  Availability?

There are several brands of headers to choose from, namely Bosal, Hotshot, and Pacesetter.  I believe the Pacesetter has been around the longest, but is considered to be of less than good quality.  The upside to them is that they feature long tubes, said to produce more high end power than "shorty" headers, which is what the Hotshot headers are.  Despite this, the Hotshot headers still benefit from being the most popular headers for the PGT.  They are fairly well constructed and still provide a good sized kick in the pants.  The Bosal headers are fairly new and I haven't seen any pictures of them yet.

Headers - Where can I get it?:
The cheapest source for the Hotshot Gen III headers is Hector Gil at $330.  Eddie Wu of CB Performance is of course very cheap as well at $350.  Eddie can also score the Pacesetter headers.  Keep in mind that the price for headers may have gone up since the Hotshot headers are now Jet-Hot coated, making them more temperature resistant but correspondingly more expensive, like $20 more.  The Pacesetter units start cheaper, but end up more expensive than the Hoshot units once you get the coated ones for durability reasons.  I have no information regarding the Bosal units, but I've heard reports between $370 and $670.

Headers - What should I avoid?:
No real set to avoid here.  In principal they should all provide definite gains in power.  For durability/quality reasons I'd stay away from the Pacesetters, but my recommendation is based purely on word of mouth from other people.  Most Probers have the Hotshot headers but the highest HP Probe on a dyno has been a unit with the Pacesetter headers.  Nobody else has dynoed Pacesetters to confirm or dispute this.

Headers - What will I gain?:
This is purely a guess, but if headers is the ONLY mod on your car, you probably won't see more than 5 extra HP.  This estimate is based on the idea that if you take a drinking straw and pinch both ends, it doesn't matter how fat the straw is in the middle, it's still very restricted.  But working in concert with an intake AND an exhaust, expect the gain from the headers to be closer to 7.  Headers really should be your last modification due to its complexity and installation cost (if you don't do it yourself).  So on top of the other mods that have been bolted on, your total would go up from about 144 HP to a good 151 HP.  This would put your vehicle on par with some of the most powerful normally aspirated Probe GTs around.
UDPulley - What does it do?:
When your engine is running, it's not just providing power to make the car scoot.  It's also spinning a couple of accessories that are necessary for the vehicle to run properly.  In the case of the PGT, the accessories are the water pump (for the radiator), the power steering pump (power steering), A/C Compressor (cold air), and alternator (to charge the battery and electrical goodies).  The underdrive pulley is a smaller pulley than stock.  Due to its smaller diameter(about 30%) the pulley provides less power to the accessories, in theory freeing up more power for the car to us.  It's sort of like the difference between 1st and 2nd gear only to a lesser degree.  At any given rpm, while you will be going faster in 2nd gear than 1st, 1st gear always has more leverage and gives you more power.  Also since you don't spin the accessories as quickly, they tend to last longer than normal because you're not subjecting them to higher rpms and the problems associated with that.  So what are the drawbacks?  Uderpowered accessories.  The AC will be less cold at idle, steering effort will be a little heavier when you're just idling around (like in a parking lot), and lights will dim noticeably when you're at a stop light.  But once your engine starts running up into the 2000+ rpm range, these problems will go away.  I've had an underdrive pulley in my car for two months now and I have no problems with it.

UDPulley - What should I get?:
Possibly the easiest "what should I get" question of all.  Only one company makes a pulley for our car, Unorthodox Racing.

UDPulley - Where can I get it?:
CB Performance now stocks the underdrive pulley.  Based on their history of relations with the Probe community, I'd guess that they would provide very competitive (if not the cheapest) prices for this item.

UDPulley - What should I avoid?:
With only a single product available for our cars, there isn't much room for screwing up, other than really messing up the installation.  And it goes without saying, avoid the expensive prices.

UDPulley - What will I gain?:
This is the trickiest question of all to answer.  Why?  Because my dyno experience has shown that the UDP provides no additional gain at the wheels.  "Now WAIT," you might ask, "surely the theoretical mechanical advantage of an underdrive pulley would mean that SOME horsepower is freed up for the wheels!"  Yes, very true,  but consider this for a moment.  When I installed the pulley, one of the things I did was to spin each of the accessories by hand.  what I found was that they were all very free wheeling, meaning each was already very efficient and spun easily with just a finger.  Granted, when the car is actually running, there's probably a bit more effort used to spin two pumps and an alternator, but how many horses could it possibly be?  Imagine 3 HP to properly spin the accessories.  Even if you free up 30% of that energy, that's only an extra horse.  Not a whole lot to get excited over.  Granted, the pulley has enjoyed a lot of success in a lot of other applications.  Technicians at Superior Automotive (where I have all of my work done) were telling me about a Mustang that had an underdrive pulley plus a bunch of oversized accessory pulleys getting an extra 15 horses on the dyno.  That's a lot of extra power.  So the bottom line is, the underdrive pulley doesn't seem to give much benefit to our cars, but there are other compelling reasons to have it installed.

Forced Induction - What does it do?:
Coming Soon!

Forced Induction - What should I get?:
Coming Soon!

Forced Induction - Where can I get it?:
Coming Soon!

Forced Induction - What should I avoid?:
Coming Soon!

Forced Induction - What will I gain?:
Coming Soon!

Handling mods(struts, strut bars, sway bars):