Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB - View Single Post - Jackson Racing Rotrex Supercharger System Info and Discussion

Jackson Racing · 10-30-2013, 04:26 PM

@digital_assassin -

I think we are getting lost in the maybes. I simply stated the supercharger bracket cannot accept a C38 and that in a C38 upgrade on the FA20, that would be the least of your worries.

Now the only reason a C38 should be considered on the FA20 engine is if you want to run 15psi or more. If you are looking for boost up to 14psi, then the Jackson Racing system as it ships has the capability to produce the power levels you are looking for with a simple pulley change. Our standard system ships at 9psi and we will have pulley upgrades up to the supercharger limit.

We know there is a part of the market looking for big numbers. We have worked with many race teams to develop high horsepower Rotrex cars on a proper budget. But that leads us back to the cost of modifications. The list of requirements for a reliable high HP package gets longer and the price tag gets larger with each horsepower level. The C38 units alone are not cheap. We already know from many engine builders and even threads on this forum that there are weaknesses in this engine (i.e. connecting rods, etc).

When we set out to design the Jackson Racing system, we talked with new and future FT86 owners around the country/world. Overwhelmingly, the requests were for:
• Reliable
• Street Legal
• Quiet
• Track Capable
• Broad Power

With this information, we set out to design a system that fits these market requirements and we think we have hit every bullet point (except one that we are working on right now.

)

Regarding Intercooler Design-

It is not as simple as “bigger is better” with intercoolers, especially with Rotrex units. Intercooler efficiency is dependent on many factors. Internal core design, core thickness, core length, exposure to air, etc. all play important roles in intercooler efficiency.

Building a bigger intercooler with some of the core blocked off by the bumper is a waste:

• The larger core will have more pressure drop, thus requiring you to run your compressor (turbocharger or supercharger) harder to reach the same boost levels. Now that you are running the unit harder, temperatures will go up. As you can see, this is a slippery slope. Also, restrictive core designs can hurt intercooler efficiency resulting in more pressure drop.

• Leading intercooler designers state that even doubling the size of an intercooler will only add maybe 5% efficiency, but will definitely add more cost, weight, and pressure drop.

• It is important that ambient air actually goes across the core. If the intercooler is too tall and not receiving air across the core, then it is not doing anything.

Ultimately, the air flow and temperature drop on the exit of the intercooler are the important data points here. We still have headroom for more boost and have low intake air temperatures, proving our intercooler has been properly designed for the package.

10-30-2013, 04:26 PM	#38
Jackson Racing Join Date: Jun 2013 Drives: JR FR-S, Location: Chino, CA Posts: 152 Thanks: 160 Thanked 401 Times in 110 Posts Mentioned: 53 Post(s) Tagged: 1 Thread(s)	@digital_assassin - I think we are getting lost in the maybes. I simply stated the supercharger bracket cannot accept a C38 and that in a C38 upgrade on the FA20, that would be the least of your worries. Now the only reason a C38 should be considered on the FA20 engine is if you want to run 15psi or more. If you are looking for boost up to 14psi, then the Jackson Racing system as it ships has the capability to produce the power levels you are looking for with a simple pulley change. Our standard system ships at 9psi and we will have pulley upgrades up to the supercharger limit. We know there is a part of the market looking for big numbers. We have worked with many race teams to develop high horsepower Rotrex cars on a proper budget. But that leads us back to the cost of modifications. The list of requirements for a reliable high HP package gets longer and the price tag gets larger with each horsepower level. The C38 units alone are not cheap. We already know from many engine builders and even threads on this forum that there are weaknesses in this engine (i.e. connecting rods, etc). When we set out to design the Jackson Racing system, we talked with new and future FT86 owners around the country/world. Overwhelmingly, the requests were for: • Reliable • Street Legal • Quiet • Track Capable • Broad Power With this information, we set out to design a system that fits these market requirements and we think we have hit every bullet point (except one that we are working on right now. ) Regarding Intercooler Design- It is not as simple as “bigger is better” with intercoolers, especially with Rotrex units. Intercooler efficiency is dependent on many factors. Internal core design, core thickness, core length, exposure to air, etc. all play important roles in intercooler efficiency. Building a bigger intercooler with some of the core blocked off by the bumper is a waste: • The larger core will have more pressure drop, thus requiring you to run your compressor (turbocharger or supercharger) harder to reach the same boost levels. Now that you are running the unit harder, temperatures will go up. As you can see, this is a slippery slope. Also, restrictive core designs can hurt intercooler efficiency resulting in more pressure drop. • Leading intercooler designers state that even doubling the size of an intercooler will only add maybe 5% efficiency, but will definitely add more cost, weight, and pressure drop. • It is important that ambient air actually goes across the core. If the intercooler is too tall and not receiving air across the core, then it is not doing anything. Ultimately, the air flow and temperature drop on the exit of the intercooler are the important data points here. We still have headroom for more boost and have low intake air temperatures, proving our intercooler has been properly designed for the package.