I have a 03 Cobra with upper only 2.8 pulley Stage V+ Eaton with now a ported stock Throttle Body. Is there any advantage to adding a 2 or 3 lb lower or a 2.49" Pulley to it? Has anyone went from a upper only ported to adding a lower? If so how much of difference did it make at the Drag Strip?
Ported Lower Pulley Question
- Thread starter PKFIRE
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From what I have read I don't think the lower pulley will help your peak numbers much at all. However, it will bring up the torque in the mid range and hold it longer. I think on street cars the popular combo is a 2.93 upper with a 4lb lower. I do see your blower has been ported so im not sure how that will change everything. Im sure one of the more knowledgeable guys will chime in and clarify everything for you.
Yes, you will gain torque and horsepower going to a 2.90/4# combo. I am at 16.5# of boost, with a Dragon throttlebody/plenum. That is a great street combo. 2.90/6# adds mostly torque and a little more horsepower but the heatsoak goes up more as you push the Eaton into the more inefficient range. 17# - 18# on a ported Eaton is about maxed.
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How necessary really is this even cooling mod when adding a lower? I think even if I don't make too much more power on top I'll have a greater overall horsepower gain which should help out. I'm not sure how much though. Going from non ported to ported 2.8 M112 I dropped about 1/2 seconds and added almost 3 mph on my Trap speed.
The driver side head heats up the most and is the typical hot spot on the engine. Back in the early days someone shot it with infrared before and after the head cooling mod and yes it made a significant difference. Invest in a good set of gauges to monitor temps. The killer chiller or a trunk mounted ice box are the typical drag mods for cooling off between runs. If you are that into drag, go 6# lower and 2.9x upper. Proven over and over as the best combo in the 1/4. Also, when adding a lower - that point the Dragon TB/plenum will remove the airflow bottleneck.
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also tq is most important for our heavy cars, so look into an e85 conversion that combined with what cobracide said 2.9 / 6 lower and slicks expect low low 11s and high 10s with weight reduction
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