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
The Key Ingredients to a Fast Truck



#1. Low Knock Retard!!!

#2. Good Combination of Parts

    List of Parts That Must Match

#3. Strong Tune

#4. High Boost

#5. Realistic Goals!

I saw a post on www.syty.net today by a new Typhoon owner who also owned a low 12 second Camaro, and he felt the Typhoon seemed unimpressively slow compared to what he thought it "should" run like. The truth is, he's almost certainly right!

The Syclone and Typhoon are known to be extremely picky and require a lot of "TLC" and upkeep to maintain their full performance. This guy's truck was a good example. But why are they like this?

The 4.3L "LB4" V6 in the Syclone and Typhoon only makes about 140 HP without the turbo. The factory chip controls the turbo boost to approximately 15 PSI, which is a significant amount of boost (exactly twice as much air flow as if it were naturally aspirated). Therefore, it's no surprise the trucks make "280 HP" considering the turbo is doubling the engine airflow. (N/A 140 HP x double = 280 HP @ 15 PSI)

However, when the turbo system malfunctions on one of these trucks, they stand to lose a HUGE amount of power because your HP MULTIPLIER goes down! All the way down to that 140 HP level if the intercooler hose blows off completely, for instance. Here's another example. When I first got my Syclone in 2001, there was a wiring problem with the stock boost control that caused the turbo to spool up slowly and then only produce 10 PSI boost compared to the 14 PSI it should have been. I took it to the track and it only ran a best of 14.2 @ 94 MPH. The magazines all tested the Syclone in the low 13s! Boy was I disappointed.

How do you get your truck to run like it should? Here are the key ingredients that make up the foundation of any fast truck (Some are borrowed from How to Get Your Stock Syclone Deep in the 13's since they apply to all trucks):

#1. Low Knock Retard!!!

This is the most important advice on this site. Just fixing the Knock Retard to be safe and low at WOT would probably add 50-100+ HP to half the trucks out there right now!! Knock (detonation) is the most common problem keeping any SyTy from being as fast as it should. It should go without saying that you simply MUST solve any knock problems (both false or real knock) before your truck has a chance at performing to its maximum potential. A great place to start is with this article: How to Get Your Stock Syclone Deep in the 13's (even if your truck is modified, the techniques are the same.)

#2. Good Combination of Parts

The mods must compliment each other for a strong combination! For instance, if you have a stock torque converter and want to run Mid 12s, you should run a turbo that is good to mid or low 12s. (The stock turbo fits the bill.) If you went against this rule, and ran a low 11 second turbo, the result would be a truck that likely runs worse than mid 12s!! Your turbo would have all this extra capacity that your engine can't even use, and you'd suffer the penalty of slow spoolup. Terrible trade-off! It's like shooting yourself in the foot.

There are many trucks out there plagued by bad combinations like this. If yours is already modified (chances are good since there aren't many 100% stock 17 year old trucks left), you have to decide which mods have to stay and which have to go. Which direction do you want to take the project? For example, if your truck came with a race cam (422 or bigger) and the previous owner sold it because he never could get it to run right, and you have never tuned a fuel injected turbo car before, you might consider running a stock cam. If you weren't planning to custom tune the truck or upgrade the heads, the swap back would make even more sense.

What some people do is try to ignore the mismatched part or work around it, and it prevents their truck from ever running as fast as it could. Trust me, once you get a solid combo and get it dialed in, the first time you stand on the throttle with your newfound horsepower, you'll be the happiest guy on earth. I know I was!

Click to watch HQ video, high 11 second run.

I have seen even more basic mismatches. How about a $15,000 race engine........running a STOCK CHIP!? Unbelievable, but it happens.

List of Parts That Must Match

  • Chip must match fuel injectors

    50# injectors won't run well with a stock chip, and 60# injectors won't run well with a 40# chip. That doesn't keep some guys from trying anyways. Many headaches could have been avoided by simply running the correct chip for the injectors.

  • Turbo must match engine

    A stock engine can max out a stock turbo in the mid-low 12s around 20 PSI boost. Put that same stock turbo on a built heads & cam engine, and the turbo is still maxed out! It's not going to go much faster than it did with the stock engine at 20 PSI. Most of the extra horsepower from the heads & cam will remain "locked away" until a properly matching turbo is installed.

  • Torque converter must match turbo

    Small turbos need tight converters. Big turbos need looser converters. However, loose converters (like everything), are a tradeoff. You trade off some top end power and shift firmness, in exchange for quicker spoolup at low RPM. A loose converter with a stock turbo is a bad match. Why would you trade off your top end (which is weak to begin with on a stock turbo) for quicker spoolup when a stock turbo already spools up fast enough even with a stock converter?

    For best streetability (and performance!) I recommend running the tightest converter that will still spool up your turbo. For my 57mm PT51 turbo, I went with a tight 2700 RPM custom Yank power-adder converter. Watch this video of my tach during a boost launch to get a feel for what it's like.

    If you want to know more about high stall converters, check out: Real World Tuning Example: Vortec Heads/412 Cam PT67GTQ Syclone on VP C-16 at High Boost

  • Fuel Octane must match boost pressure

    The higher the octane, the more boost you can run safely. This is truly the key to going fast with ANY turbo engine! With just 93 octane pump gas, you are limited to about 15-16 PSI on a stock engine, and 17-20 PSI on a thoroughly modified engine. With alcohol injection or race fuel, you can run 20-25 PSI or more (depending on your combo).

    Remember what I said in the intro about the stock Syclone 4.3 making 140 HP N/A, and double the HP at 15 PSI? Guess what happens to that horsepower at 30 PSI! The most hardcore turbo drag racers pay up to $12-$20+ PER GALLON for the highest octane race fuel (VP "C-16" and "VP Import"). It's worth it to them because they know it's the only way to run the highest boost for the highest power possible.

    Nothing causes faster engine failure than running more boost than your octane can support!!

    Remember this image? That truck ended up blowing at least 2 forged motors. No engine, no matter how well it is built, can tolerate being run at a boost pressure higher than what the octane supports. Plenty of guys have found this out the hard way. You don't have to become one of them. Some guys rationalize to themselves "It will be alright, I'm not 'RACING' it" - but it doesn't matter to your truck. Whether you put your foot to the floor at a stop light or at the christmas tree, it's all the same to your engine. Never turn up the boost beyond your fuel's safe limit.....Not even for a day.

  • Camshaft must match cylinder heads

    The purpose of high flowing head upgrades is to allow more airflow at higher RPM. But it's the "Duration" of the camshaft that directly determines how high the RPM where your engine makes peak power! It's similar to the Turbo-Engine Match. The stock cam works well with the stock heads because they both flow well at LOW RPM (3000-4000). Putting a high RPM cam in with stock heads isn't going to do much because the cam would be trying to make power at high RPM, but the stock heads would still be choked for flow!

    The opposite is also true of course. If you put on high flowing ported race heads, but still run a stock cam (or a very small aftermarket cam like the "Comp 412"), you're not going to be using the extra flow of those heads anywhere near full potential! The heads will be begging for a cam that allows higher RPM, and they won't produce all possible horsepower until they get it.

For more information on choosing correctly matching parts for a solid combination, check out this page: Syclone Modification Stages.

#3. Strong Tune

A modified motor (whether the parts match or not) without a good tune, is just a pile of parts! You will notice this theme all over this site. Nothing is more common than a truck with a bunch of "upgrades" or "go fast goodies" but lacking a tune! Why? Because it's a lot easier ordering parts, than it is to make them work correctly to produce extra horsepower! The "bad news" is that it takes time to get your truck in tune. But the "good news" is that it's a LOT cheaper than buying more parts, and a LOT more effective. Believe it!

What do I mean exactly by a "strong tune"? Of course the ignition parts need to be in top shape, and any mods must match as mentioned in #2. But your truck also needs the correct amount of spark advance (timing), as well as the correct amount of fuel ("Air/Fuel Ratio")! There are plenty of trucks out there running WOT AFRs of 10.5:1 or even richer. This seems totally absurd to me! Running an engine excessively rich (too much fuel) doesn't make it "extra safe". It just makes it slow and inefficient.

Remember, the #1 enemy is Knock Retard (detonation), usually caused by running more boost than your fuel octane can support.

Running the engine extra rich has ALMOST NOTHING TO DO WITH ALLOWING HIGH BOOST! This seems to be a common misconception. Think about it! If this were true, nobody would need costly high octane fuel, they could just run the engine richer when they raised the boost. It's all about the octane.

During some tuning for alcohol at high boost, I actually ran into some situations where I ran safer with less detonation, at leaner AFRs!

Tuning your AFR is a topic for another article, but to summarize: I consider 11.0:1 - 12.0:1 to be completely "SAFE". For advanced tuners (or those willing to take more risk in the pursuit of every last possible horsepower) with a solid tune, I have been able to run lean with low knock all the way up to 13.0:1 at high boost! Every truck is different, and every Wideband O2 AFR gauge is a little different, too. (Keep that in mind.)

Start with something safe (11.0 - 11.5) until you learn what you are doing and get some experience. Then you can start to slowly experiment and find what really makes your truck scream!

Chuck ran me down with an 11.7!
I was running a stock chip and managed to beat him off the tree, and that's about it.
Low Quality Race Video

#4. High Boost

This fits in with "Strong Tune" but it's worth repeating. With a stock motor that only makes 140 "Base Horsepower" (on average Vortec head/cam motors, still only 200-250 HP), our trucks need all the boost they can get. You start to realize why an alcohol injection kit is such a killer piece of hardware on a real street machine. Once you try running high boost, you never want to "go back to normal" when the race gas (or your wallet) runs out. I hope to have a comprehensive alcohol injection article for you in the future.

Remember, any truck that is "fast at low boost" is also a truck that would be a hell of a lot faster at high boost! (So long as the octane, fuel delivery, etc. are sufficient and the turbocharger isn't already at it's limit). Once you assume responsibility for your truck's tune and get used to monitoring the Knock, the Wideband AFR, etc., you realize that your engine's safety has a LOT more to do with the condition of the tune than it does the boost pressure being run. An engine at 14 PSI with a bad tune is 10 times more at risk of failure than one at 23 PSI on high octane fuel with a cautious & responsible owner double checking that the engine always gets what it needs.

#5. Realistic Goals!

A truck will never be fast if it never finishes getting built! It's amazing to me how many people with little to no experience with a high tech, high strung turbo motor, will dive head first (and thousands of dollars) into a fully custom monster race build. It's just not that easy! The higher the power, the less room for error you have. Learn how to tune and calibrate your truck at a reasonable power level first. Then you can upgrade it and use your knowledge gained from the first experience to make the jump to a faster truck.

My truck is fast because I planned realistic goals with a strong chance of being able to reach them. (I love racing my truck, so I wanted to plan something that would get it back on the road within a few months!!) The funny thing is, every time I made a goal, the truck ultimately ended up running better than I expected! If you have a plan that seems reasonable but there are one or two parts that will require you to learn a new skill or you're unsure of, I say "Go For It!" On the other hand, if pretty much every part of the project involves something you've never done before, my advice is to scale the project wayyyyy back!

Alternatively, if you just don't have the time or money, you hate computers, you have no patience and punch the wall if something doesn't work the first time you try it, etc., then you need to be honest with yourself and plan something you can live (and deal) with.

On the bright side, even just a stock truck with a tuned alky kit is awesome! You barely have to open your wallet and once you get it dialed in, it will pretty much run the same all the time but it'll still wax those pesky Evo's and WRX's... (see recipe "Low 12s For a Grand" in my truck's budget spreadsheet.) Hell, even a BONE STOCK but well-kept mid-13 second truck is WAY more fun and satisfying than a truck that's forever "Gonna be done next year.." Just ask anyone who's been building their truck for more than 2-3 years!

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2007-2008 Josh Straub Home | Syclone | Turbo Grand Prix | Computing | Contact
  Last Modified: Wednesday, 25-Nov-2009 01:23:34 UTC