Intercooler & charge pipes
The centerpiece of the Soho kit is the large air to air intercooler measuring 28 x 8 x 3.5 inches. Both the inlet and outlet are 3” to maximize the cooling of the boosted intake charge. This same intercooler is used on supercharged applications like this pushed above the 600 whp mark so it should provide enough charge cooling for the foreseeable future and well past the traction limits of our rear tires.
There are two charge pipes in this supercharger kit. The first elbow that comes off the supercharger has a 3” inlet and outlet. Soho then welds on a v-band fitting provisioned for a Tial BOV. From there the elbow then routes into the aforementioned intercooler. The 2nd charge pipe is 3” exiting the intercooler and splits into two 2.75” outlets as a Y pipe into the Stillen intake manifold. Soho spent a lot of time determining the MAF locations on the Y pipe for minimal turbulence on the MAF’s for tuning.
Our Stillen intake manifold didn’t come with the water inlet and outlet provision for coolant but whether you bought a full kit like our’s or your upgrading your current Stillen supercharger kit you’ll need this block off plate. A breather filter keeps the factory PCV and crankcase ventilation in working order. This requires your own hoses and T fittings and will be covered in the installation process of our series.
14 comments
Wait, 60-70whp from a filter? Do you mean 6-7?
Yes 60-70whp in forced induction doesn’t seem out of the realm of reality. We haven’t confirmed this with our own car this was confirmed by both Soho and our tuner at Specialty Z.
Here are a couple of dyno charts for your reference if you scroll down a bit on these pages. While they don’t show the results with the filter on and off they are really big numbers for a supercharged v6. Based on the numbers we’ve seen on our car and others I’d think these runs were with the turbo guard.
https://sohomotorsports.com/products/soho-motorsports-a2a-supercharger-kit
https://sohomotorsports.com/products/soho-motorsports-air-to-air-upgrade-for-the-stillen-vq37vhr-supercharger-kit
In this particular case with a supercharger, 60-70whp seems reasonable. Once you see the install, you’ll see how little space is available for the filter and why the small K&N from the H-D was used. Relatively speaking, this filter is highly restrictive. On a turbo car, you can adjust the wastegate to spin the turbo faster. On a supercharger, it only spins as fast as the fixed pulley sizing will allow, so it can’t compensate for loss of mass air flow due to the restrictive air filter. So, 60-70whp loss is the result.
Because of space constraints, this is a silly small filter. In the future, we might cut a hole in the core support and fabricated something less restrictive to test.
why the move to air to air? whats wrong with air to water?
If you have the space, air to air is generally better, air to water systems have smaller bricks and greater pressure drop and the water side has smaller heat exchangers and can thermally saturate more easily.
is it possible to make an air to water system that won’t saturate? that would fit in a car that is, not some enormous system in a lab with no space constraints… or will all air to water systems saturate? specifically in a lapping day scenario with 20-30 min sessions…
It can be done. Just have to size a really big radiator for the IC system. Ferrari ran an air-to-water setup on their F1 car. so yeah, it can be done.
I think You would be better off using some sort of cobra-head silicone hose and re-routing the filter somewhere more sensible.
https://www.do88.se/en/artiklar/silicone-hose-_-hoses/silicone-hose-black/cobra-head/index.html
I’ve never seen a silicone hose like that before. I took a look at the flow charts and it seems like the testing is there to prove the airflow improvements over a 90 degree hose. At some point we’ve got to punch through the core support and get past the radiator to the fresh air in front. I’d think we’d also want a shield to prevent turbulence in airflow; similarly to what was on our V3 cold air intakes from Stillen when the car was N/A.
This is definitely top of mind before we start looking at e85 or adding more boost.
Do you have a part number for that KN Filter?
I’ll get in touch with the vendor and get the part number.
The part number is a K&N # RX-4130-1
What would you think the hp gains would be like with running soho’s air upgrade that they use on their new a2a kits? it routes it to the front around the bov with a full filter like you described. I will also be running a 9lb pulley with long tube headers hoping to make 600whp on 93