Blog Wrenches Trailblazer SS Modification Guide

Trailblazer SS Modification Guide

I have a stock TBSS and I want more power. Where do I get started?


The best thing to do first is to determine your goals for the truck. Do you want a tame daily driver, a heavy hitting sleeper, or the unmistakable chop of a cam loping at idle? There will be pros and cons to all set ups – here are a few suggestions.

Getting Started


The best things you can do to improve driveability, gas mileage and horsepower are an intake, tune and electric fan kit. These modifications work great together and will net around 35-50hp depending on which intake you select. The intake helps the truck breathe better. The electric fans remove the heavy mechanical fan, freeing up horsepower. And lastly, the tune helps all around driveability. We are able to get rid of the sloppy factory shifting and lag from take off, as well as improve horsepower and torque!



A good intake will definitely perform much better than stock and be one of the essential building blocks to a great performing truck in the future. There are many options out there but in our experience, the best performing intakes are ones that have large sweeping bends, use 4" tubing, and if at all possible exit the engine bay. The stock airbox sits over the washer tank which holds a little more than a gallon of washer fluid. What's the big deal? Well that washer fluid gets extremely warm from engine bay temps ~ 145F in the summer and that heat pre-heats your incoming air. The next time you drive your truck pop your hood and try touching your washer tank. The stock air box configuration is also very restrictive. My last tip- pass on any intake that fits underneath the stock engine cover without some sort of trimming. To make the bend sharp enough to do so you have to kill airflow. We have built several 4" intakes to address these shortcomings and have them listed on our site for sale. We do not believe there is any rocket science in putting together a intake out of silicone bends and metal elbows and for this reason we have posted a "build list" on for just about every one of them. Trust me, these intakes work leaps and bounds better other alternatives. Picking up 10-15rwhp over another aftermarket intake and 2 tenths at the track is not uncommon. Use a intake that reuses the stock MAF sensor for builds making less than 380rwhp, use a 4" MAF for builds greater.


"I picked up .2 after I installed the 4"/ls7 maf........It was done on different days, but it did gain! I am a firm believer in this intake!!! This is by far, the best intake out there................(Thank you Alvin!)" - Anthony from


Intake comparsion thread can be found here!


Electric Fan kits


These are a great mod for any Trailblazer SS. The most popular efans to use are LS1efans. These are found on any 1998-2002 Camaro/Firebird V6 and V8. They are also found on 1998-2004 Corvettes. Similar fans can be found on 1993-1997 Camaro/Firebird but we recommend sticking to the 1998-2002. These fans are found cheap used often between $50-$125. Good sources to find used fans are,, Ebay, etc. If you prefer to use brand new fans we recommend not to get them from GM. GM has recently changed the plastic used for the shrouds and they are very brittle and easy to break. Dorman makes a really nice set of aftermarket fans that work fantastic. You can find Dorman fans from Summit racing and your local auto parts store. Dorman PN 620634. The LS1 Efans cool better than C6 Efans. Our plug and play LS1efan kit includes all the hardware, bracketry, and a plug and play harness to install LS1 Efans on any V8 Trailblazer, Envoy, Saab,etc. They install with no cutting or modification to the truck and operate just like if your vehicle came with electric fans from the factory, completely automatic and controlled by the engine computer. A computer patch is required to run efans but we offer that as a free same day service to anyone who purchases a kit from us. You may also install the computer patch yourself if you own HPtuners or EFIlive.


We also offer a C6 Efan kit which uses a fan off a 2005+ Corvette Coupe, Z06, ZR1. We do not recommend them as they do not cool as well as the LS1 Efans, are more costly, and have voltage sensitivity issues. The C6's fans require 12 volts at all times and will crash if voltages dips below 12 volts even if its only for a split second. LS1efans do not have these issues! We have customers in Arizona, Kuwait, Saudi, and all over the US with LS1 efan kits and doing very good!


Some other things to keep in mind are a 3 wire battery cable kit, and a transmission cooler kit. You may notice your lights dimming when an accessory kicks on. Our 3 wire battery cable kit helps to minimize this issue and provide the vehicle with better power and ground cables.


The stock transmission in the TBSS is fragile. Sometimes you don’t even have to modify the truck and it will still let loose. Heat is a transmission’s second worst enemy (with flat out abuse being the first). Our transmission cooler kits knock down transmission temps by about 30-50F degrees, helping it run cooler and last longer. Our transmission cooler kits are extremely easy to install and are definitely cheap insurance against transmission failure. For those who tow a cooler is a must. Even if you do not purchase a kit from us please get a cooler kit ASAP as it will make a big difference in trans life!


Mail Order Tune, Dyno Tune, or HP Tuners?


Here at PCMforless, all of our mail order tunes are based directly off of what we do on our dyno and track. Remember that Alvin and Bryan have a combined 20+ years of experience! For that reason, they are very close. We are also happy to do a dyno tune for you (2WD only), this allows the customer to see exactly what hp/tq the truck is making, and allows us to squeeze out every last hp.


HPtuners is the tuning software that we use. While it is a little overwhelming at first, it is very user-friendly and there is a lot of support on the forums. For people interested in doing their own tuning, or having the ability to provide feedback to us via datalogs, HPtuners is the way to go. With HPtuners we can trade tune files through email, review datalogs, and streamline the tuning process since you will not need to send in any modules.


HPtuners makes two cables, Standard ($499) and Pro ($649). Both cables come with software/everything you need to install it on your laptop and use it in your truck. They also come with 8 credits each, which is enough to license 3-4 vehicles. The difference between the two is that with a Pro cable, you can datalog external sensors in your log (i.e. plug a wideband into it) which is helpful when it comes to touching up tunes.


Moving On


It’s easy to advise someone on the first set of modifications, but once those are done, it’s time for the customer to do some serious planning and decide which direction they’d like to take the truck. If you enjoy racing your vehicle at the track, a torque converter is a great modification. It improves off the line acceleration. We recommend Yank and Precision Industry "Vigiliante" converters – excellent performance with great driveability. Allow a Yank representative to make the call on which converter to get – but generally something that stalls around 3000-3200 will be a good compromise for most people. "Hands down, the proper torque converter will drop et's between .3-.5 seconds. For the money you cannot beat the performance gain of a good reputable torque converter" - Alvin

Headers or Stock Manifolds?

While adding a set of long tube headers is a great modification for most cars, it is not necessarily the best bang for the buck for a Trailblazer SS. The power gains are good, around 10-15hp, however the cost of the headers themselves throws off the horsepower per dollar ratio. Prices generally start around $1200 and go upwards from there. Most shops will charge around 3-4 hours labor to install them.


Whether or not you should add headers depends on your future plans for the truck. If you’re happy with the way it is with your starter modifications but you still want more power, a stealth camshaft is a better choice. Our stealth cams pick up around 30-35rwhp and can be used with stock manifolds and a stock torque converter.


However, if you plan on going with a larger cam like our Rob Style or Attitude, or you see a supercharger in your future, you definitely need to let that puppy breathe with some long tubes. A big cam or supercharger with stock manifolds will be missing out on a lot of horsepower.


Whether or not you use catalytic converters depends on your personal preference. A hi-flow cat will not hurt horsepower that much, and will help the vehicle smell a lot cleaner. Even with a great tune, a truck without cats can still have an exhaust stink to it that your wife probably doesn’t appreciate. “To cat or not to cat” is always a heated debate no matter what crowd you are in! Modern hi-flow cats do not hinder performance especially on builds around 600rwhp or less. We did a back to back test using Kook's cats on a 2001 Z06 that made right around 500rwhp. The gains from removing the cats where around 2 1/2 rwhp! That's hardly worth the aggravation of driving a car that will not pass inspection or emissions testing! Our recommendation, save your self the grief and keep cats on your street vehicle!


Catbacks and the TBSS

From the factory, the TBSS has an exhaust that flows rather well. Adding a catback exhaust won’t do too much for horsepower, but does change the tone of the sound. We suggest listening to as many TBSS’s in person as you can before making your decision on which catback suits you best. Some customers cut out the resonator and replace it with a straight pipe to help with flow and make the truck louder. A good bang for the buck mod with the catback is also to use a cutout. Bolt-on trucks typically gain 5-10rwhp from a cutout.

Camshaft Selection


We at PCMforless are proud of the camshafts we have to offer for the TBSS. After extensive research and development with our own 07 TBSS, we have come up with several grinds that work awesome, helping these heavy trucks feel a lot lighter on their feet. Due to the weight of the TBSS, a regular car camshaft generally will not perform as well. We’ve taken out the guess work for you!


Please note most of our cams will pick up around 30-50hp. How much you gain will depend on what supporting modifications you have.


1. Stealth Cams – our stealth cams are for the enthusiast who wants more power, but does not want to sacrifice too much gas mileage, or be able to hear the cam. We offer a low lift and high lift version. The high lift cam will pick up more power, but is slightly noisier (not in chop, but being higher lift the valvetrain will be more noticeable). Both of these cams can be installed with stock exhaust manifolds and torque converters, which is another bonus.


2. Rob Style Cam – developed for our friend Rob who travels from Canada to see us – the rob style cam is a great performer with a noticeable chop at idle. With tuning it retains great driveability with a very noticeable gain in horsepower. It will take away 1 MPG in city driving (highway mileage is unaffected), but our customers tell us it’s worth it!


3. Attitude Cam – larger than our Rob Style cam, the attitude will pick up a little more horsepower. We recommend this cam for those who like going to the track, as it is not MPG friendly! Neal H. of SC used our Attitude camshaft to set a cam-only record with a Trailblazer SS. The Attitude cam was meant to be a max-effort camshaft for cathedral port heads, stock displacement. It works very well! Driveablity is also very good with the Attitude. The only disadvantage is its not friendly on gas mileage. Most people report a 1-2MPG drop in the city, no change to highway mileage.


4. L92 Cam – We have designed a few L92 cams to go along with the hot new trend in the TBSS community – L92/LS3 heads. This is a great budget set up for someone looking for a serious gain in horsepower. We offer head/cam packages for all price points – using either stock L92 heads, CNC’d L92 heads, or the heads from the renowned West Coast Cylinder Heads. Our L92 Head and Cam package will produce ~445 RWHP and 440 RWTQ with supporting bolt-ons (Headers, 4" Intake, etc). Trucks with this combination have been deep in the 11's with little weight reduction. Driveablity is fantastic!


5. Custom Cam- If you feel like one of the above options does not fit your goals than by all means please shoot us a email at This e-mail address is being protected from spambots. You need JavaScript enabled to view it . We will be more than happy to work with you on a setup to meets your goals. Alvin has many years of experience designing camshafts for street/strip vehicles. We hold a couple "cam-only" records including one for Trailblazer SS and the MPH cam-only record for LS1 F-bodies. We pride ourselves in examining the whole package to produce a camshaft that is well rounded but potent both on the street and at the track.

Transmission Upgrades

When you begin modifying your truck for more than just bolt ons, you should highly consider a built transmission for your TBSS. Transmission failure in these trucks is not a matter of if, but when. There are several companies who offer great built transmissions that will last a long time and take a ton of abuse. We recommend RPM Transmissions and Finish Line Transmissions for your TBSS needs.

Cylinder Heads

For some, bolt ons and camshafts are just not enough. The next logical step in modifying a naturally aspirated engine is to consider cylinder heads. When selecting heads, the camshaft needs to be considered and matched accordingly. Our L92 packages are consistent performers, but there are other great companies out there as well. Trick flow and AFR heads are some of the others we recommend.



Always a cheap favorite with the racing crowd, nitrous is the king of horsepower to dollar ratio. With a dry or wet kit, you can pick up 50-200hp. Be sure to check our special products section on our website. We offer a solenoid mounting bracket that really cleans up the install of a good nitrous kit. The good thing about nitrous is that it is only on when you want it to be – so it will not hurt driveability or gas mileage. The downsides are that you must be extremely SAFE when using it as to not cause engine damage. Constantly refilling the bottle, monitoring pressure, making sure the tune is safe, etc is a hassle for some people. For those we recommend…


Forced Induction

There are several ways to go about forced induction in a TBSS, whether you choose to turbocharge or supercharge. We are big Magnacharger fans here (ask us about our blower stealth cam that adds another easy 64hp!) but will be glad to install or tune just about anything in person. A magnacharged TBSS is a heavy hitter off the line, administering a big kick to the butt at low RPM’s. A turbocharged TBSS is a treat also, not as much power off the line but once the turbo spools up – hang on! Our own personal truck has had a STS turbo system. By far our favorite kits for the Trailblazer SS's are Magnachargers. The install is very clean, the power is smooth and linear, and they are great performers. The price tag is steep but I'll promise you won't find anyone disappointed with their magnacharger purchase.


Engine Assemblies


Maybe the stock cubes aren’t cutting it for you any longer, or maybe you’re getting a bit nervous running 10lbs of boost on a stock bottom end. Either way, there are several options for getting more horsepower, safely. A 402ci or 408ci will allow for a bigger cam/better heads, and pick up more power. A forged bottom end is always a safe bet for those looking to add boost or a lot of nitrous. If you consider upgrading before your stock engine fails – you can even recoup some of the cost by selling your stock engine.

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