GMC SyTy Recipes for mods.

Before you race your truck, you need to make sure it is running upto par, please make sure you do the reliability mods first. You should expect a stock Syclone with a properly boosted launch to run 13.3-13.7 and a stock Typhoon to run 13.8-14.2 1/4 mile time. Higher air temperatures and altitude may affect your results. If your way off, you most likely have some issue that need to be resolved.

The Basic SyTy Engine Upgrades

• Scan Tool
• I would highly recommend a Scan Tool software, such as Datamaster or Tuner Pro. You will also need a Laptop and ALDL cable to run the software. Detonation is the number one killer of SyTy engine and the timing (spark/knock retard) the ECM pulls greatly reduces your engines performance. This post is a good source for reading a scan tool. Don't be discourage if your new Syclone or Typhoon doesn't run clean on a scan tool, a large majority of them do not. You want your truck to have clean scan tool run before you do any more mods.
• Relibility Mods
  • This Includes Walbro Fuel Pump, Adjustable Fuel Pressure Regulator, Intercooler Pump and Quality Cap, Rotor, Wires, & Plugs.
• 3 Bar MAP & Chips
• The stock boost target is set for 13.8psi and usually peaks out around 15psi. The stock 2 Bar map sensor only read until 14.5 psi. This is a problem if you want to control boost above 14.5 psi and add more fuel. Almosty all of the older 2 bar MAP chip available for SyTy are based on the stock Chips with a few tweaks. Some of the tweaks are detrimental as in the case of the Kenne Belle & Hypertech Chips. The 3 bar Map sensor allow the ECM to read boost upto 29 psi, you will need a chip that is recalibrated for 3 bar map. The ultimate is a very popular chip, but I think its discontinued. Many of the availble 3 bar chip are quality programs. You can search for them on www.syty.net. For more advanced tuning, their is a code $59 programing that will allow you have complete control of your ECM's tune and including many features of aftermarket engine management systems.
• Boost Gauge
• The factory boost guage is inaccurrate. When you add a 3 bar MAP sensor, it rescales the factory boost guage to make it even more worthless.
• Torque Converter Switch
• To lock up the torque converter, you need to ground pin of F of the ALDL connector. The connector is by the driver side under the dash, but you should alreeady know this because its where your scan tool connects. Pin A of the ALDL is ground, I put a switch between them and lock it up just after I get into 2nd gear. I have noticed a 1.5mph difference in my quarter mile trap speeds.
• K&N Air Filter
• You can use a stock replacement K&N Air Filter or a connical air filter on the end of the crossover tube. You may want to think eliminating the crosover tube particularly on higher mileage trucks. The crossover tube get brittle and can break apart and ruin the turbo. Eliminating the Crossover tube usually mean using a Thin battery or relocating it.
• Rubber Intercooler Hoses
• Their is a good tutorial on SyTyArchives for replacing the metal hoses with rubber lines. I ran my hose to the driver side of the engine bay, but its basically the same idea. This is also makes working on the engine easier, because you don't need to drain the upper IC everytime you need to move it out. After doing this, you do have to make sure the IC is pumping properly with no kinks or air pockets in the hose.
• Catback Exhaust
• The stock exhaust used Dynomax super turbo mufflers, it was decent for a factory exhaust system, but by now a lot of them have been replace or need replacing. Borla and ATR made catback exhausts that have been discontinued. As of right now, RPM is the only current producer of a bolt on catback exhaust. Other options include eliminating the muffler(s) or having a custom exhaust bent up. If you making your own exhaust, I would try to use a 3" mandrel piping and a straight through muffler.
• External Wastegate (optional)
• The stock internal wastegate is undersized and on most trucks the boost fluctuates quite a bit under WOT. Often with a stock turbo truck, I see a +/- 1.5 psi fluctuation and sometimes even more. So on a stock truck the boost target is 13.8 psi but I often see it hit a peak of 15-15.2 psi but with usually fall back almost to 12 psi. So basically you need a tune good enough for 15 psi but you engine will spend a bund of time in the 12-13psi as well. The time spent at lower boost levels is HP lost. The boost control can be helped with porting of the wastegate and a custom calibration of the chip in the wastegate table, but this is an advancing tuning for most. The quickiest and easiest solution for steady boost control is an external wastegate with a boost controller.
• Alky Injections/Race Gas
• Race Gas - Higher octane in general allow you to run more boost and/or timing. You still will need look at the scan tool to make sure tune of the engine in still good. Another option to race gas is mixing Xylene in your tank. I think that Race Gas has more specific energy than Xylene has but both are effective in raising the octance of your fuel. FYI Don't bother with the octance boosters you can buy at the parts store.
• Alky Injection - It raises the octane and offer additional intercooler of your intake charge. The addition cooling can often bring the intake tempereatures to ambient and sometime slightly below. Two things nbeed to be done to run alky injections. One thing that needs to be done is the spark plug gaps need to be reuce to 0.26-0.28. The other thing is the alky adds additional fuel so it often runs rich, one solution is to lower the Fuel pressure and other better solution is to take out fuel is in a custom chip

Beyond the basic bolts ons

• I am not going to go into much detail about these because their are so many different choices and directions people take. Very often at this power level you will need an u[graded transmission, unless you pick a very mild turbo, I would count on need an transmission upgrade. Maybe even do it before you grenade a perfectly goo tranmission. Some of these mods will be required depend what turbo upgrade choosen. For instance PTE-52 will pretty much require higher stall torque converter, 3" downpipe and larger injectors. I would keep the 70mm and larger turbo if your using the stock heads/cam/long block. With a decent sized turbo, Syclone can run deep into the 11's and Typhoons can run 11's with these mods. Just a quick note the further you push the stock shortblock an d internals, the margin of error you have for an out of tune motor.
  • Larger Turbo
  • 3" Down Pipe
  • Torque Converter
  • Bigger Injectors

Beyond bolts ons

• You could add more mods, but with a stock long block you have pretty much reach the near end of a its capabilites with the above mods, so going any further really pushing it. At this level you really should think abpout doing a built motor. This is just a quick idea of upgrades. Some of the higher end upgrade do get quite pricey, but would be require if you looking for 9 sec or faster truck.
  • Forged Piston and Rods
  • 4 bolt splayed Stock Block or Bowtie Block
  • Cyro treated/Nitrided stock crank or Custon Billet Crank
  • Aftermarket Cams and Valvetrains
  • Upgraded Head such as Vortecs, Bowtie, & Pontiac
  • Bigger Turbo's
  • Headers
  • Bigger Injectors
  • 4L80E Transmission
  • Custom Intakes