turbo engine tuning secrets -
featuring original research

By Josh Straub, 2009


Key Ingredients to a Fast Truck

Syclone Modification Stages

Stage 1:
How to Get a Stock Truck Deep in the 13's

Tuner's Guide to DataMaster

Real World Tuning Example:
Vortec/PT67GTQ Syclone on C16

Performance Roadmap: Syclone 4.3L Turbo V6

3 Bar Chip Tunes for Download

My 1991 Syclone

11.45 @ 117 Budget Build Spreadsheet

Vortec Heads Budget Spreadsheet

Racing Videos

Turbo Grand Prix

My 1990 TGP


Unfreezing Frozen Windows Applications

Stage 1

How to Get Your Stock Truck Deep in the 13's
...without buying hardly anything



List of Requirements for Optimum Power

Part 1: Tune Up

Part 2: Scan Tool

    How to Connect Your Truck to a Computer

    What Should a Good File Look Like?

Part 3: Common Causes & Solutions for Knock

Part 4: Free Mods

Part 5: Find out what it runs!

    Tips For At the Track

    Expected Quarter Mile Results

Getting a Stock Syclone in Top Shape

So you've got your first Syclone/Typhoon but now what? It's fast, but chances are good that it's not as fast as it ought to be. If you've already raced your friend's LS1 or taken your truck to the drag strip to compare timeslips, you may have already come home disappointed, with timeslips as much as 5 tenths to a full second slower than you thought it would run.

When I first got my truck, I was as green an amateur as anyone. I had read all the magazines and assumed my truck would automatically run near 13.4 in the quarter mile. After all, I had no reason to believe it wouldn't, right? After the first trip to the track, the best I could manage was 14.2 @ 94.8 MPH with a worst of 14.4 @ 93.7 MPH. Sound disappointing?

With this guide, anyone of average skill willing to invest some personal time and effort, should be able to achieve quarter mile timeslips with their Syclone in the:

13.0 - 13.4 @ 97-102 MPH range.

Results will depend directly upon reader's persistence, level of patience, and attention to detail. Of course, the condition of your vehicle's drivetrain is also a large factor, but keep in mind these results are absolutely possible even with a 100,000+ mile truck.

After spending a year working on my truck and learning the ins & outs, I was able to get it to run 13.01 @ 101.5 MPH with the stock chip on pump gas at the stock boost levels in street trim without any "gimmicks". This type of change in performance is completely noticeable, and worth the effort it takes to achieve!


Why doesn't it run like it did in 1991 off the showroom floor?

To make optimum power, your truck will need to:

  • 1. Run cleanly & smoothly at WOT (Wide Open Throttle, i.e. flooring it 100%). This means it can't be misfiring or stuttering, or slowing down/bogging at any RPM. When you stand on the gas pedal, if something doesn't feel "right" with the engine, there's almost certainly a problem that needs to be solved. These trucks do produce very smooth power at WOT when properly tuned.

    Common problems include: a hesitation when floored, bucking, fuel cut off (it feels really fast for a second when you first hit it, and then seems to die off sharply), or a truck that feels faster at part throttle than it does at full throttle (WOT). Your truck ideally should not experience any of these issues.

  • 2. Operate at WOT with no more than 4 degrees of Knock Retard, monitored via laptop datalogging software.

    Without question, the #1 performance killer of Syclones and Typhoons, is Knock Retard.

    This means the engine's computer is detecting potentially engine-damaging detonation and as a safety precaution, it is reducing the total timing advance (just like turning the distributor) by the number of degrees under "Knock Retard". These trucks only operate about 14* total spark advance at WOT in stock form, so if your knock sensor is pulling 8-10* timing from Knock Retard, your truck could be running with a total of only 4 degrees of timing! This will absolutely kill performance.

    Yes, tuning these trucks requires the use of a laptop computer. Yes, even a stock truck! Even though it's a 1991, it's still a relatively high tech fuel injected vehicle that simply won't "tell you" what is wrong with it by "seat of the pants" alone. The truck's factory stock "computer" (or E.C.M.) constantly analyzes every main aspect of the engine's operation and will gladly transmit it to a laptop computer while running, and you can review this information at home with software that tells you 10 times more than simply "listening for knock" or "cutting plugs" ever will.

    12.8 second 1/4 mi. DataMaster run

    With a chart like this, you can immediately tell how the drivetrain (engine and transmission) are operating, and pinpoint performance bottlenecks. A good way to sum up the majority of performance tuning is simply: by eliminating performance bottlenecks one by one! Solving a crippling problem like a case of severe Knock Retard is like unleashing tons of free horsepower...

  • 3. Run as much Turbo Boost as possible (14-15 PSI in the case of a stock truck). The more boost you run, the more power it can make. If Boost were nitrous, increasing the boost pressure would be very similar to increasing the jets on the nitrous kit. Often, a stock truck will produce substantially less than the desired 14-15 PSI range, for various reasons. Mine only made 9-11 PSI when I first got it. However, turning up the boost should be one of the last things you do to your engine, after you've covered every other aspect mentioned here and ensured the motor and transmission are running 100% FIRST. You won't hurt your engine if you run too little boost, but you definitely run the risk when you run too much boost. Remember the patience I mentioned. This means NOT falling for the urge to just pound on the throttle or crank up the boost, even when you know your truck is malfunctioning. Don't kid yourself when you know there's something wrong!

  • 4. Not be suffering from any major drivetrain malfunctions!
    This means your transmission can't be slipping, or have a generic replacement 700R4 with the wrong torque converter, or a blown transfer case, a weak fuel pump, a clogged stock fuel filter, etc. Every single truck that runs worse than 13.8's needs something. A full list will be covered further below.

  • 5. Finally, your stock truck needs to really be... Stock!
    I can't tell you how many trucks I have seen that would have gone faster with less modifications, and more stock parts! I know the average hot rodder assumes that if it's stock, it's junk, but that's just not the case. The factory Syclone may not be a fire-breathing monster, but it is honestly a very well-thought out COMBINATION of parts that are all designed to compliment each other.

    Common violations of this rule include: aftermarket upgraded fuel injectors (terrible idea!), trucks with ported heads, aftermarket camshafts, boost controllers, removing/gutting the factory catalytic converter or using open (dump) exhausts (very dangerous, experts-only), ... and losing your mind and buying every performance part you can get your hands on!! (you guys know who you are...)

These trucks are hard to make fast.
Don't make your job harder than it already is.

Unless you're a glutton for punishment, your best bet is to keep things as simple as possible by reducing variables. Eliminate things that can go wrong! Whenever you run an aftermarket part, you run the risk that it will have some unintended consequence. When you run factory parts, you can at least have the reasonable expectation that they should work as intended for this unusual turbo truck. My best advice is to GET IT RUNNING FAST IN STOCK FORM, FIRST! and only THEN consider moving to the next step like boost controllers, chips, 12 second timeslips, the much-ballyhooed "big turbo" upgrade all your friends will be begging you to do, larger injectors, etc.)

If you bought your truck already modified, it might even be a good idea to return some parts to stock until you get things sorted out!

Part 1: Tune Up

Perhaps the most critical thing these trucks need is a well maintained ignition system. The cylinder pressures of a high specific output motor (HP/L) like a turbo motor are much higher than on a typical naturally aspirated motor, and therefore require stronger spark to fire the mixture. (Imagine trying to light a cigarette lighter while your buddy is blasting it with an air compressor at 15 PSI.)

You'll Need...
Item Type Notes
Spark Plugs NGK brand, UR5 gapped at .030-.035"

Price: $2.00ea. (6 needed)

item on Summitracing.com
This is one of the most important basic components! The turbo motor can lose hundreds of horsepower if your spark plugs are incorrect (too hot a plug, too big a gap). GET THE RIGHT PLUGS. The NGKs tend to idle better, but the factory AC Delco CR42TS may be substituted. Platinum plugs will definitely cause problems!

When you pull out your current plugs, stop and give them a good look. Are they sooty black? Are any damaged or badly worn/rounded off? Plugs give you a window inside your engine, pay attention to any clues they are trying to tell you!

This is so important, at one point during some heavy tuning I was changing spark plugs about once every 3-4 weeks. For you, I'd recommend to check them often during tuning (maybe check once every few weeks and during major mods) and at least once a year or any time you have a suspicious knock retard problem and the spark plugs are older than 5000 miles.

A few tanks of race gas will leave a ton of deposits and will accelerate this need even sooner.
Distributor Cap & Rotor (any)

Price: approx. $15
Get a good $15-$20 brass terminal cap and rotor kit somewhere. Michael Hood on www.syty.net sells these at a reasonable price with good service, in fact he stocks all of this stuff specifically for Syclone and Typhoon owners as a service to the community.

I change mine every 6-12 months. If you have a knock retard problem and yours looks like this:

...try changing the cap and rotor.
Spark Plug Wires Taylor Spiro-Pro 8mm

Kits for Syclone/Typhoon:
TAY-74232: Red
TAY-74632: Blue
(Michael Hood also has 'em in black.)

Price: $38

item on Summitracing.com
These can be the source of some pretty subtle engine performance issues. They can get burned, especially on the passenger side exhaust manifold #4 and #6 and nearby turbo downpipe. Burned wires are always a suspect in a knock retard situation, if they haven't been changed in a while (or ever).

The Taylor's are a good bang for the buck, I like to use the TAY-43392 tool ($12) to pull them, a real lifesaver considering how often you're going to be pulling the wires on these trucks. If you just yank on them, you will split the boot from the wire on the straight #1 and #6. This tool almost eliminates that.

MSD also makes a set, hell I've even seen AutoZone cheapies perform well if you're in a pinch. Try to stick to quality, especially if you're already scratching your head at some problem. (Remember: eliminate variables; things that could possibly be the source of a problem)

I've got mine zip-tied out of the way and have ran the same set for nearly two years now.
Solid Visual Inspection Price: Free You are going to be getting intimately familiar with your engine if you want to seriously tune it, and the first step should be a good visual inspection for anything that doesn't look right. Cracked or broken/disconnected vacuum hoses are among the prime suspects here. The GM service manuals say that "the importance of this step cannot be overstated". Listen to what they're saying.

Even if you are new to engines, if something looks wrong or missing, ask someone for their advice. You just might find the key to one of your engine problems.
Check Engine Timing Price: Free You can't really know your engine unless you know the base timing. On our trucks the ECM handles spark advance electronically, so 0* base timing is the correct adjustment. After buying/testing 5 different Chevy distributor wrenches, AutoZone's cheap 3-piece distributor wrench works best for me. You'll also need a timing light. Instructions on how to perform this check can be found anywhere, Google.com, www.syty.net, etc.

If your timing is advanced, the truck's knock sensor will retard (pull out) an overzealous amount of timing in retaliation, causing you to be slow. This is especially important to check after you buy your truck, or install a new engine or distributor. Don't take anyone's word for it! YOU need to be SURE the timing is actually at 0.
Check/Replace Vacuum Hoses Price: $10 There are several critical vacuum hoses on these trucks. The one from the rear of the upper intake manifold goes down to the Fuel Pressure Regulator (keeps you from going lean) and also to the MAP sensor (this is what determines how much fuel to inject!). There are also critical lines going from the turbocharger to the wastegate. A crack in that line can cause quick engine failure. In fact, leaks in any of these hoses will cause SERIOUS problems. If your truck doesn't idle properly or have good driveability and you've tried everything else, you may want to just replace all vacuum lines as a matter of course. By now many of these hoses are dried out & cracked.
Install an Aftermarket Boost Gauge Price: $50

AutoMeter is a favorite brand.

Absolutely necessary if you're serious about getting your truck to perform like it should! This is simply the single most important gauge in your quest for maximum horsepower! The stock "Boost gauge" near the tach is a joke, very inaccurate and rendered totally inaccurate on trucks running the common "3 Bar MAP Sensor" with an upgraded chip.

You need to (accurately) know exactly how much boost your turbo is making at all times.

There are plenty of SyTy ignition tuneup guides on the net so I'll point you to those for anything not covered above.


Part 2: Scan Tool

Now that your truck's "tuneup" is pretty much done, you need to get a laptop computer running a scan tool software program like TTS DataMaster. This allows you to tap into the truck's stock fuel injection "computer" (ECM) and record all the engine operating parameters. Then you can look over them afterwards to identify whether the engine is performing properly or not.

This is the most important advice I can give you to make your truck fast and reliable.

Learn to use a scan tool, then get in the habit of running it frequently to monitor your engine so you know what's "normal" and what isn't.

I guarantee all of the fastest owners/tuners keep the scan tool data in the back of their head at all times. Information like: peak boost, shift RPM, average and maximum Knock Retard, etc. You can't master the tune on your truck if you don't know anything about it!

Let's take a look at an example DataMaster file from a problematic truck. Back in 2002, I met a Syclone owner who wanted me to take a look at how his truck was running with my laptop scan tool. The truck had a large handful of parts from the ATR and Kenne Bell catalogs. Ported heads, unknown aftermarket camshaft, upgraded turbo, oddball 40# injectors, 2800 stall torque converter, 2 Bar ATR Pitbull chip. Sound like a solid 11 second truck? Nope, it ran somewhere in the mid 12s.

As soon as he started laying into it, I could tell it was detonating. You could easily hear the engine start to ping like crazy on top end. It sounds like a sharp ticking sound coming from under the hood when you're at full boost. Here's what his DataMaster file looked like:

Download the DataMaster file: dm_2002matt_14d_kr_test6qtr2.uni

The white chart at the bottom is the most important. It represents a quarter mile run. The legend is on the right. Look at the black line (TPS), this is how much throttle the driver is giving. The driver holds it around 50% throttle to build boost, and then quickly hits it to the floor (100%). If you look at the RPM, you can see his Knock Retard is perfectly okay in 1st gear. When the RPM drops into 2nd gear, you notice the Boost starts to climb constantly ("Too Much Boost!"), and the Knock Retard starts to explode (arrows). The higher the Knock Retard, the louder the actual "pinging under the hood" sounded. Generally, you won't hear anything below 10 degrees of knock. But it is still very harsh on your motor and costing performance. This is why the Scan Tool is so valuable. You can "see" the knock, long before it gets bad enough to actually hear. That is precisely how you use a Scan Tool to make your engine Fast & Reliable - By watching it for Knock! If your truck is knocking, STOP FLOORING IT until you can make some repairs/adjustments and then try again. By keeping it out of knock, you keep it out of danger!

The bottom line is, this guy's truck was knocking/detonating heavily, and he should have got off the throttle much sooner and diagnosed his issues, instead of continuing to stay in it and beat the truck. He ended up blowing at least two forged, professionally built $$$$ motors afterwards, because he didn't have enough respect for Knock Retard and he didn't take the steps to keep his truck out of it.

Don't Let This Happen to You!!

If he had been monitoring the truck with a scan tool, he would have seen all the knock retard that resulted from his boost exceeding the 15 PSI limit of the 2 Bar ATR Pitbull chip he was running. He could have lowered the boost until the knock retard got to a manageable level (0-5*). Anything would have been better than continuing to floor it when it's knocking 14 degrees!

How to Connect Your Truck to a Computer

You'll Need 3 Things...

  • 1. Laptop computer. The smaller the better. Minimum 200 MHz, 32 MB RAM, Windows 98 or better. Cigarette lighter power supplys worth their weight in solid gold.. Nothing worse than the laptop battery dying just as you get to the end of the staging lanes.
  • 2. ALDL to Serial/USB Cable. This is what plugs into your truck's ALDL service port under the dash (right above your knee). $80 at Moates.net for a nice USB one, http://www.akmcables.com/ also sells both Serial and USB style cables.
  • 3. Scan Tool software. I recommend TTS DataMaster, which costs about $110, but the first 20 recordings are free to try. You can get a complete package deal with a USB-ALDL cable and DataMaster CD-ROM for $195 from syty.net vendor DetroitTurbo.com. There are alternatives with less functionality than DataMaster. TunerPro is free tuning program with some datalogging features, and an optional $30 donation fee to remove a 'nag screen' at startup.
Connecting DataMaster (or any scan tool) to your truck the first time can be very frustrating and difficult. Unless you have your settings just right, your truck's ECM won't "talk" to your laptop. The worst case scenario is attempting to use an adapter between Serial and USB. If your laptop has USB ports, get an ALDL cable in USB style. If your old laptop has no USB and only serial ports, use a Serial ALDL cable. Try to keep it simple with as few adapters as possible. I can't tell you how many hours I have wasted just trying to get a truck and a laptop to connect due to issues like this.

One critical tip for connecting DataMaster: the "ALDL Link Timing" needs to be adjusted after DataMaster is installed, from the default value of 0, to a final value of between 190-210. My truck "likes" 196. Some trucks won't connect below 200-203. You have to experiment and find a setting that works best for each truck.

This can be found by clicking the File menu, Record ALDL Data..., then click Options, Advanced..., Serial Communication Timing...

What Should a Good File Look Like?

Here's an example of a file from my truck in 2002 running 13.0's when I had a very stock setup (stock chip, stock turbo etc.), after I was able to get most of the kinks out of it. The Knock Retard is low enough to be safe. It is best to have a flat line of 0.0 Knock, but that is not very common. Many trucks will have a small amount of knock like the file below.

"The Art of Reading DataMaster Files" is a subject for another article on this website, but I can point out some basic values on the file above:
  • The Knock stays less than 4 degrees maximum.
  • The Boost averages 14-15 PSI.
  • The RPM rises nice and smooth between gears.
  • Maximum shift RPM stays below 4500 RPM (perfect shift point for a stock SyTy)
Two problems I can see in the file are the wavy Boost control (something almost unavoidable with the stock turbo), and the DTC Err warning in the upper right corner. DTC means a "Check Engine" code has been set. In my case it was probably a Code 42 from the last time I set my distributor timing.

Want more information on reading DataMaster values? See the Tuner's Guide to DataMaster Scan Tool.

Part 3: Common Causes & Solutions for Knock

By this point you've connected a scan tool and have a general idea of how your truck is operating. What can you do if your truck has a knock problem?

  • Tune-up. Sound familiar? You should have already done this since I made it "Part 1" of this guide. But many times, once is not enough! You could have a plug wire touching the downpipe or exhaust manifold. Once a wire is burned, it's junk. You could have a tiny crack in the plugs (maybe they were damaged in shipping or dropped on concrete). Your distributor hold-down bolt could be loose allowing incorrect timing. All of these things have happened to other SyTy owners in the past.

    This is the second most important piece of advice on here.

    Every SyTy struggles with ignition problems, you absolutely need to keep your ignition in top shape (spark plugs, wires, cap & rotor, timing)!

  • Too Much Boost. The limit of the stock "2 Bar MAP Sensor" is 15 PSI, so if your truck is accidentally running 16 or 20 PSI, the ECM still thinks it's at 15 PSI (big danger of running lean!). SyTys run 14.5 PSI from the factory - that doesn't leave much margin for error! If your wastegate rod has been tightened or if the catalytic converter has been gutted/removed, the extra exhaust flow can cause dangerous boost spikes.

    Remember the vacuum hose inspection in Part 1? Here's a good look at those wastegate vacuum hoses that directly control and limit the boost (keeping it safe):

    Have you checked/replaced your wastegate vacuum hoses, and it still knocks and makes too much boost? Try unplugging the black/blue WeatherPack connector in the photo above (red arrow). This SHOULD make your turbo spool up very slowly and reduce your boost to 9-11 PSI. Great way to temporarily remove about 100 HP, so you can test and see if it STILL knocks even at low power W.O.T.

  • Boost Leaking From Intake! If you've never owned a turbo car before, this problem might not be immediately obvious. The stock turbo is small and has to work hard to pump your 4.3L engine twice as full with air (Boost). If there is a hole in your intake, Boost pressure escapes like a hole in a balloon! But the turbo will increase it's speed (and heat) in a useless attempt to pressurize your "leaky" engine. Turbos normally spin near ~150,000 RPM. With a big enough leak you could send it skyrocketing over 200,000 RPM! If your engine has a leak and you floor it long enough, you can overspeed and damage your turbo very quickly. Fixing a boost leak almost always results in a big performance increase! (You're getting back the power you should have had in the first place...)

    How to identify a boost leak? Does the truck get slower at Wide Open Throttle than it is at 50-75%? Does the turbo's pitch continue to change higher and higher even after boost peaks? An experienced ear can hear a boost leak immediately because the turbo shrieks higher than normal at peak boost.

    How can you fix a boost leak? SyTyArchives.com has a great idea about using a bicycle tube stretched over the intercooler to test for leaks with air pressure. SiliconeIntakes.com sells silicone intake leak testing tools, with instructions at the bottom of this page.

  • Bad Gasoline. "Premium" 93 octane and "Race gas" confuse a lot of people. It's actually really simple. The higher the octane, the more boost you can run safely. It really is that simple! The stock 14.5 PSI boost is fairly high, so these trucks require a healthy diet of high octane fuel. If you live in an area with only crappy 91 octane (California) Premium, this might be your problem. Try running a tank of higher octane fuel (100 octane unleaded race gas, 5 gallons of 110 race gas, or even 93/94 Octane (if you were running 91/92). If your knock drops dramatically and the truck runs like a different animal, you're definitely on the right track.

  • Something Banging Inside Your Truck! My own truck was plagued by a hellish knock problem for years because of this! No matter what I did, the truck would knock 3-7* even with very high octane fuel. Ultimately it turned out to be a steel fuel pipe banging on the tranny bellhousing right near the knock sensor. I insulated the pipe with a rubber bike tube zip-tied so that there could never be any further metal-to-metal contact. That same day was the first time my truck ever experienced Flat-line Zero Knock!! Other common "false knock" causes include: turbo downpipe banging against the frame (pipe can be repositioned), bad motor mounts, or even a knock sensor that's been overtorqued (factory spec is 14 LB-FT).

Part 4: Free Mods

Now you've got the basics out of the way, and hopefully your truck's knock is down to a manageable number (0-4* ideal, but engines can usually tolerate even 7-8* K.R. for a little while). There are still a handful of extra horsepower you can unleash by optimizing a few weak links in the stock configuration, without spending hardly any money.

Free Mods...
Item Type Notes
160*F Thermostat "Robert Shaw" 160*F P/N 330-160 is the best, but any brand will work

Price: $5-20

When I opened the hood on my bone stock truck, so much heat would release that it would actually blow the hair on my head. The stock thermostat maintains engine coolant temperature around 195*F. 160*F is about as low as you want to go, for compatibility with the ECM (most chips won't lock the torque converter clutch until 150*F), among other reasons. Changing thermostats is a 15 minute job and an easy way to reduce Knock, underhood heat, improve performance via a cooler engine, and also prolong the life of rubber components.

I have had fantastic luck for the past 7 years using a heavy duty brass Robert Shaw brand 160*F thermostat, model #330-160. I paid about 8 bucks at AutoZone back in 2001.

Whatever you do, don't run without any thermostat.

Air Filter Ideas:
  • Stock replacement panel filter
  • Cone filter on stock crossover tube
  • Cone filter directly off turbo with battery relocated
Price: $30-$45 (K & N)

Nothing big here, most people do this as the first mod on any car. Really not worth much (maybe 1 tenth) but does make the turbo a lot louder :)
One of the best ideas is to eliminate the stock airbox/crossover pipe and aim the stock orange silicone turbo intake hose towards the passenger's fender, and put a 3" cone filter directly in there (you can use a $3 AutoZone 3"-3" exhaust coupler to join the two). However, this requires the battery to be relocated which is a much more involved job than simply replacing the air filter. (Here's a suggestion: Link 1, Link 2.)

Check the usual sites for plenty of air filter/intake suggestions.
Intercooler Hose Upgrade (see Notes)

Price: approx. $10

GM's default configuration of the intercooler leaves something to be desired; but it's easy to tweak for better performance by removing the stock metal coolant pipes and replacing them with common 3/4" black rubber heater hose. This prevents the hot engine from directly transferring heat into the intercooler coolant. www.syty.net has threads with more detail on how to perform this mod. You can see my rubber hoses in this photo of my engine.

The stock Garrett "air to water" intercooler is actually a great performing unit, so good in fact that when a local Syclone friend of mine upgraded to a $2000 custom full-size "air to air" intercooler, he didn't experience any performance gains whatsoever... (Imagine that!)
Intercooler Pump Switch (Engages factory intercooler pump; see Notes)

Price: Free

The stock intercooler has 2 parts, an aluminum box on top of the engine that turbo "Boost" passes through on it's way into the engine, and a small radiator underneath the front bumper. A small electric water pump circulates fluid between the two, allowing the heat removed from the hot compressed boost, to be moved down into the radiator and released into the air, and the cool fluid returned up to the intercooler reservoir.

By default, your truck won't activate the intercooler pump until the intake manifold reaches over 200*F! For a lot of trucks, this point would never get reached, and it's almost as if you don't even have an intercooler. Fortunately, you can engage the pump any time you want with the use of a simple wire and switch tapped into the intercooler pump relay on the firewall under the hood. I've ran my original pump full time for 50,000 miles now, and I've got 75,000 miles on my truck, so you shouldn't worry about "wearing out" the pump by operating it far more often than GM originally intended.

Again, SyTyArchives.com has a how-to guide for this mod, and www.syty.net has threads with more ideas as well.

Fuel Pump Walbro 255 LTR/HR "High Pressure" Pump

Price: approx. $110

Buy at Auto Performance Engineering from Ron Gregory, SyTy community member and major supplier of high performance Walbro EFI fuel pumps
It takes fuel to make power. The stock SyTy fuel pump is marginal, and you will definitely need to upgrade it in the future if you plan on modifying your truck. The Walbro 255 LTR/HR. "High Pressure" pump is the best one to get and rated to 600HP (some sources claim 700+HP is possible) flow potential with gasoline. Sometimes even a bone stock truck can regain lost horsepower with a fuel pump upgrade, so get this done early and get it out of the way. Good guides are available in the usual net sources.
Engine Tie Down Strap Price: $5-20

With the 450+ LB-FT of torque these turbo V6 motors put out, the engine really wants to "twist". The only thing keeping the motor from leaping out of the truck is the motor mounts. Weak or broken motor mounts can let the motor jump so high that the alternator fan cuts into the radiator hose! An engine tie down strap keeps the motor in place, and is proven to work very well. It also can prolong the life of your motor mounts.

Most importantly, a tiedown can help put more power to the tires instead of wasting it twisting the motor. Here is a picture of my engine tie down.

Once again, if you need help with any of these mods, how-to guides with photos are available at www.sytyarchives.com, and more info can be found Searching at www.syty.net

Part 5: Find out what it runs!

At this point, if your knock is down to 0-4* and everything else feels good, it's time to find out what it runs in the quarter mile. This is the standard test to determine how fast your truck runs compared to everybody else's. This is also where a lot of dreams meet harsh reality.

You can visit a dragstrip and get a timeslip (which is the best and most legitimate method), but if you don't live close to a track or don't want to spend the money, you can also use a G-Tech or the DataMaster "Quarter Mile Calculator" feature. They aren't as accurate as the track but they can be repeatable if you operate them consistently.

Regardless of how you measure your truck, make sure you take the time to run it and record the performance numbers. You will need this "benchmark" to compare against if you modify your truck further in the future. Comparing performance gains is the best way to determine how effective mods are at making your truck faster.

Tips For At the Track

#1. Record the Run With DataMaster

If you race at the track, make sure you bring your laptop (and charger/batteries) and record the runs!! These will be the most important records you can make. Trucks often act differently at the track than they do cruising on the street. Mine always did. Having the DataMaster files from your drag strip runs lets you look over them afterwards and jog your memory so you can play the run back in your head. Did the tires squeal a lot on launch? Did it hit the rev limiter on the 1-2? Did you notice any strange noises? Did it get slower in 3rd gear? Did you remember to shift into 4th when 3rd runs out at 4400-4600 RPM?

#2. Make Notes On Your Timeslips

Every time I race, the first thing I do after getting my timeslip from the shack, is to park the truck somewhere and write down some quick notes on the major things that happened during the run, while it's still all fresh in my memory. (Trust me after making a few runs, you'll never remember which run was the one your truck acted up on.) I write things like "Stock Chip. 3 PSI Launch. Tires spun a lot. Felt slow at top of 2nd? Shifted into 4th late."

Making notes like these are what will seperate you from the slower trucks! Remember as the owner, it's your responsibility to become the master of your truck's tune. Making "test and tune" runs at the track is your greatest opportunity to analyze just what your truck is doing!

#3. Race the Truck Properly!

There's no point going to the track and pussy-footing around. If your truck is running well enough to be at the track in the first place(!), then it should also be able to handle a proper boost launch. This technique involves FIRMLY holding the brake pedal, and simultaneously applying 40-70% throttle to load the motor against the transmission's Torque Converter so the turbo gets a maximum amount of exhaust to spool it up. Keep your eyes on the boost gauge and use the boost as a launching aid. I typically launch between 0-7 PSI at the line. 4 PSI is a good place to start. You want to try and time it out so the lights go green right after you reach your target boost. You DON'T want to be loading up the torque converter too long (more than 5-7 seconds) or you can overheat your transmission. As soon as the light is green (or the last yellow if you're going for reactions), release the brake and stomp the gas pedal to the floor at the same time!

This technique can be tricky if you have never drag raced a fast car with an automatic transmission before. Sportmachines.com has a boost launch guide. The 11.79 run on my videos page is a great demonstration because I had the stock torque converter with an open exhaust dump, so you can easily listen as I load the engine, how the boost builds and the engine RPM slowly climbs. (Followed by the sound of tires squealing!) You can also watch this video of my tach during a boost launch to get a feel for what it's like. (Not a stock truck but the technique is the same.)

#4. Shift the Engine Below 4600 RPM!

In my experience, the stock SyTy engine makes peak power around 4200 RPM! This is due to its unusually small (179* duration) camshaft and poor flowing cylinder heads. Take a look at these two photos inside the stock heads off my truck!

If your truck is shifting at 4800, 5000 or higher, you've got BIG PROBLEMS. It's most likely either a slipping transmission, torque converter too loose, or the incorrect transmission (not a factory original SyTy 700-R4). There is a small chance you just need a different governor, if your transmission has ever been rebuilt. A worn out or out-of-adjustment TV cable could cause this too.

Take a look at these dyno charts (Horsepower, Torque) of a stock Typhoon #488. You'll never want to shift over 4600 again (until maybe some day when you do heads & cam).

Finally, upshift to 4th gear when 3rd reaches 4500. A lot of guys miss this. The SyTy 700-R4 transmission is one of very few GM calibrated from the factory to do a WOT 3-4 upshift. In my truck (when it was all stock), 96-98 MPH was about how fast I was going when my tach reached 4500. It should be nearly identical for your stock truck. Depending how fast you are, you might get through the traps before you need to upshift. Once you get fast enough (100 MPH+), you'll need to do this shift every trip down the track. If your transmission doesn't do this shift, you've got problems and you basically won't be able to get a real 1/4 mi. run out of the truck until you get it fixed. Many rebuilt transmissions have a poor chance of doing the 3-4 WOT upshift, unless the builder really knew what he was doing, or took special care to keep all the valve body components matched from your original transmission.

Expected Quarter Mile Results

If you follow all of the advice in this guide, and your truck doesn't have any outstanding mechanical problems in the engine/transmission, you should be able to get these results:

Syclones: 13.0 - 13.4 @ 97-102 MPH
Typhoons: 13.4 - 13.8 @ 95-100 MPH

My best timeslip with the stock turbo and stock chip was:

60': 1.687
1/8: 8.195 @ 81.94
1/4: 13.013 @ 101.52 -- (Best MPH was 102.85 on a different run)

Someone could be the first to make a 12 second run on the stock chip - maybe you?

My next article will focus on taking things beyond stock, with modified chips and high octane fuel to support raising the boost! Subscribe to PowerTuneNews to get an email when new articles are added.

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2008 Josh Straub Home | Syclone | Turbo Grand Prix | Computing | Contact
  Last Modified: Wednesday, 25-Nov-2009 01:24:14 UTC