This area will feature the FASTEST FIVE SATURN CARS in their respective categories. Think your car is fast enough to be featured in the Fastest V? Send your information and mods to poc301 to have your car listed here.

Street Class
1) UnderdogSDA 13.3 (Nitrous)
2) S.Bretz 13.35 (Turbo)
3) Poc301 13.50 (Nitrous)
4) BoostedSL2 13.56 (Turbo)
5) Yardbird 13.59 (Nitrous)

Unlimited Class
1) Nefarious 12.26 (Nitrous)
2) LowSC2 12.4 (Nitrous)
3) 92saturnSS 13.33 (Nitrous)

DOHC
1) UnderdogSDA 14.21
2) Green Monstah 14.5
3) DonBaker 14.71
4) Applebit 14.8
5)SaturnMotorsportsOfCary14.84

SOHC
1) ProjectPhase1 16.61
2) Sh1FT 16.90
3) Wraith 16.98
4) jhsl1 17.2
5) SL_Sled 17.96

Ion
1) JGreen 15.48
2) schzzo97sc2 15.60
3) Chris 15.79
4) rascon11 16.06
5) IonJon 16.27

Updated 1/05

For the most recent list of the fastest five cars click here.

 

 

Fuel Injectors

by:Titan

There are 6 basic types of metering devices used in fuel injectors today but I will only cover the 3 that I feel will have the most impact. The first is the pintle type made by Bosh/Nippon Denso. This single pintle discharge injector tends to increase atomization and pattern width at higher pressures. Next, is the disk type fuel injector manufactured exclusively by Lucas. This injector possesses stainless steal internals and a unique metering disk that is years ahead of the 40 year old pintle type injector. The Lucas injector is the best at maintaining its spray pattern cycle to cycle, under varying pulse widths and fuel pressures. Lastly, there is the diffuser/pintle type injector found on Toyota and various other makes and models. Diffuser/pintle type injectors do not change atomization quality at higher fuel pressures like the Bosh/Nippon Denso type injectors. Diffuser/pintle injectors are not high atomizers, they are used to target fuel toward the valve stem reducing intake wall wetting or "puddling" of the fuel. This targeted approach is accomplished by the impact of the fuel on the diffuser surface, which concentrates the fuel at the center of the cone producing a tighter pattern. The distance from the injector to the valve and the cross sectional area of the intake must be considered when incorporating this injector.


Injector types

Peak and Hold injectors, also called low impedance, are initially fired at 4-6 Amps, through a ballast resister, and then fall back to 1-2 Amps for the rest of the injection event. This injector is often used on high fuel pressure systems (75-100psi+) where the increased initial amperage overcomes the high hydrostatic pressures of the fuel pressure. Peak and Hold injectors These injectors tend to respond faster than Saturated injectors

Capabilities
The minimum pulse width cycle time for most pintle type fuel injectors (Bosh/Nippon-Denso) is 2.0Ms for the Peak and Hold and 2.5Ms for the Saturated injectors. Alternatively, disc type injectors (Lucas) will cycle as low as 1.0Ms for Peak and Hold and 2.0Ms for Saturated. The difference in pulse widths between the pintle and disk type injectors can be attributed to weight differences. The Lucas disk only weights .4g while the pintles used by Bosh/Nippon-Denso weight 4g ten times heavier! The disk's lighter weight offers reduced inertial loading allowing it to overcome hydro-static load faster and return to its seat quicker. This decreases response times of the pulse widths and also provides a more constant cycle to cycle flow.

Most pintel injectors tend to fail at around 86% duty cycle while the disk type injectors can usually go to 90% duty cycle. This means that the injectors will increase their flow rates until they reach their highest duty cycle (listed above) and then go semi-static or half-open just before going full static. At semi-static the injectors are only delivering a 50% duty cycle flow rate and at static they lock closed. This usually occurs when you are running WOT, high RPM, and or max boost when you need 100% fuel delivery and your only getting 50%. This situation creates a lean condition that will have you shopping for a new engine fast. If you plan on running higher fuel pressures be warned that at higher fuel pressures this situation seems to be amplified a bit more. When choosing an injector a larger than necessary injector running at a 70% duty cycle will provide more controllable performance than one being pushed to 90%+. Remember, when choosing an injector a larger than necessary injector running at a 70% duty cycle will provide more controllable performance than a smaller one being pushed to beyond 90%.

Atomization
When you consider that at 6000 RPM the intake valves are opening 50 times a second leaving only about .010 seconds to provide all the necessary fuel. With such a brief intake valve open time you may feel that having a fuel injector that delivers a wide highly atomized pattern into the intake would be ideal to ensure a homogenous mixture but this is not necessarily the case. At low RPMs highly atomized fuel has enough time to pass by the intake valve and create a homogenous mixture but as the RPMs increase problems start to develop. In an engine running at high RPMs there is limited time for the fuel to reach the combustion chamber. This is compounded by the fact that often there is residual exhaust pressure present when the intake valve is opened. The residual exhaust pressure tends to blow the lighter drops of atomized fuel back into the intake, which tends to adhere and condense to the intake walls. This presents a few problems. Fuel "puddling" in the intake increases drag thereby reducing airflow, large quantities of highly atomized fuel can displace air in the port, and if the "puddled" fuel does reach the combustion chamber it will cause air/fuel ratio variances between cylinders.

Remember that by choosing the proper size of the injector based on flow rate and duty cycle you will be able to avoid any injector pit falls. This will leave you with plenty of time to worry about other things such as, "how to increase the amount of fuel being delivered to the injectors?"


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August 2005 TSN will be holding its first ever meet in Chardon, Ohio. Some of the fastest Saturns in the country will be attending. Activities will include drag racing, dyno, tech session, and BBQ. Look for the latest information in the forums.

 

Different Racing

Jeff and his team Different Racing have big plans on breaking into some really low quarter mile times this year. Last year he posted a 12.40 on a pretty healthy nitrous shot. This year he has a new turbo setup and some serious determination. Visit his website for the latest news and information. I expect we'll be seeing some low 12's from him by the end of the year.