Testing the CSF BMW S58 G8X Intake Manifold

The pressure drop across the core test was interesting. The OEM core showed very little pressure drop but something is going on with the overall restriction.  Look at the area under the boost curve.

Now compare the boost drop across the core with the CSF radiator.  Although the boost drop looks to be higher, look at the area under the curve, much more air is getting through the core!  We saw the same sort of thing when we tested the A90-A91 CSF intake manifold we tested a few months ago.

Now look at another interesting phenomenon.  The pre-intercooler core temperature on the CSF manifold is way lower than OEM.  We saw this same thing happen with the CSF Supra manifold.  The CSF core is so much less restrictive that the compressor of the turbo doesn’t have to work as hard and is operating in a more efficient part of its map. Thus the pre-intercooler temperature is lower!  Since the compressor isn’t working as hard to make the same boost, the turbine doesn’t have to recover as much energy so the engine sees less exhaust backpressure as well.  Less work being done to make the same boost by the turbo means more free power in a synergistic way.

The CSF manifold made a power difference of 20.6 whp and a peak torque improvement of 20.4 at the engine’s peak but this doesn’t tell the whole story.  In the thick part of the engine’s powerband, at around 5500 rpm, the CSF manifold makes a whopping 100 more whp and about 90 lb/ft more torque!  The gains are big, fat, and across the board.  These are some of the biggest numbers we have ever seen just for a change of intercooler and intake.

If we had tested the CSF manifold plus intercooler heat exchanger vs stock manifold and stock heat exchanger the gains for the CSF combo would have been more impressive but we decided just to test only the effects of the manifold. If we had attempted to do some tuning changes to take further advantage of the manifold’s flow capacity and gains in turbo efficiency, we would have seen much larger gains too.

We are also very impressed with the B58 engine. It absolutely killed the previous bolt-on power record holder,  the Nissan VR38 by a huge margin.  Direct injection and the beefy bottom end shared with BMW’s diesel is a killer combination.  Beware of the sleeper G8X xDrive BMW’s you had better be packing a big stick to take one of these bad boys down.

Just for fun we really sent it to see what an FBO G8X could do and look, 1021 whp!  Amazing, you would have to spend a ton of money on a R35 GTR to do this.  The capability of the G8X is a pretty well-kept secret.


CSF Racing

GTP Motorsports


  1. That’s an impressive piece and holy hell that can be done with modern cars as far as power outputs. One thing I do wonder though is… every time I see CFD of manifolds published it’s always as if the manifold is sitting loose – throttle body flowing to every port at once. I’m not sure it’d make a difference, and it’d be more setup work, but intuitively it seems like seeing if flow is equal with only one cylinder at a time fully open would be more realistic. Has experience showed that it doesn’t matter, and or is this just kind of a “beauty shot” as a subset of a lot of different test cases? Because obviously it works, I’m just curious as to the thought process.

    1. Good question. The way I figure, it’s all an approximation one way or another. When I did the exhaust manifold for my S2000, I did do one cylinder at a time. Either way, I don’t think basic CFD captures pulsation effects. It’s been 8-10 years since I used GT-Power, but they had added functionality at the time where you could import the 3d CAD and it’d create system model in GT-Power for you. The stuff you can analyze in GT-Power is amazing.

      1. I wonder too if just, every port open at once might be a worse case scenario anyway for distribution, maybe show some choke points that in practice don’t matter as much as they do in reality.

        Wish there was a realistic way for me to mess with GT-Power or one of the other 1d sims even at a more basic level. Too many areas of car stuff for one person to mess with in one lifetime.

          1. I should shoot them and email and at least see how many zeroes of dollars a seat would be; the GEMS GDA software was well within my means, for example, and I’ve had a few other instances of being surprised. As long as I’m over-ambitious and in over my head, why not shoot for the moon, right?

  2. The B58 and the S58 are not the same engine. Toyota has never received any version of a S58 engine ever for the A90 or A91 Supra. Hope this helps.

      1. You need to amend your sentence where you say the s58 is the bmw variant of the b58. Lol. They were both designed by bmw, the b58 released in 2015 long before there was a mk5 supra. Toyota is a customer of bmw for supra parts/chassis. They did lots of testing beforehand but the b58 is not their engine, never has been.

        1. They are pretty close to being the same engine. They are the same engine family. Just stuff like stronger pistons, higher pressure injectors, and twin turbos but most of the engine is the same and I bet parts interchange.

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