Dyno result for the risky business Porsche

[ptuomov]

Here's the manifold pressure, rear axle torque, and rear axle hp for the black car with its current settings. This is with a reasonable safety margin to detonation and not the highest dyno graph we've pushed it by any means. However, these settings are those that I'd be comfortable leaving the car with and never think about it again.

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It's really nice for a street car, but we want more in the name of science, so it's going to be torn down now.

[ptuomov]

John Kuhn cast some exhaust manifolds for this 928 S4 turbo conversion project.

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Below are the old, hand fabricated manifolds next to the raw castings to be machined:

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Some pics of the CAD model, the 3D-printed molds, the pouring process, and the raw casting here, the last thirty or so photos of the album:
https://picasaweb.google.com/1059510082 ... directlink

Also see:
http://rennlist.com/forums/928-forum/56 ... ts-62.html

[dieselgeek]

this project is awesome!!

[ptuomov]

this project is awesome!!

Thanks!

[novadude]

John Kuhn is a friend of mine. I went to school with him and we graduated together (Mechanical Engineering). He has been sending me information on this exhaust manifold project as it progresses. Really cool stuff!

[ptuomov]

John Kuhn is a friend of mine. I went to school with him and we graduated together (Mechanical Engineering). He has been sending me information on this exhaust manifold project as it progresses. Really cool stuff!

Yes, I think these exhaust manifolds were really well thought out. Everything was considered.

[ptuomov]

The jig is up!

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[SWR]

nice. anyone know how to make my 2.5 86 944 a little quicker

47mm inlet valve, cam with the most lift you can make - 0.5" - on stock durations or just a tad more... And some epoxy in the ports helps wonders.

[ptuomov]

John took some photos of the new hot side and turbos:

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[turboivo]

Reading the first page dyno numbers, I have hard times to figure out how exactly one could triple the engine power with only 17psi of boost? The DJ power is at the wheels. The DP power is also ATW but the man says "at the wheel". Everything is "Stock" and the max power rpms are the same- 6000.
What I'm missing here? Possible ...200 hp loss in the tyres or in the wheel inertia?
The car and the craftmanship are second to none though!

[ptuomov]

Reading the first page dyno numbers, I have hard times to figure out how exactly one could triple the engine power with only 17psi of boost? The DJ power is at the wheels. The DP power is also ATW but the man says "at the wheel". Everything is "Stock" and the max power rpms are the same- 6000.
What I'm missing here? Possible ...200 hp loss in the tyres or in the wheel inertia?
The car and the craftmanship are second to none though!

The first page run had a more aggressive boost ramp up program and it went significantly higher than 17 psi at peak power, must have been low twenties.

The later dyno graph in the thread is more accurate for that about 17 psi peak power rpm boost, although there the program is also ramping up the boost linearly at higher rpms. The power ratio: (670/271) = 2.47 or about 2.5x. The boost ratio is (17+14.7)/14.7 = 2.15. Some of this is the motor scaling better than linearly in terms of frictions, some of it is taking off the stock exhaust, some of it is hub versus tire roller dyno, some of it is just good old fashioned measurement errors.

[ptuomov]

A quick update. The whole system is updated, and everything is now slighly less restrictive. Here's a low-boost test run with about 10 psi (0.6 bar) boost:

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These are from the rear axle. Pressures are cycle averages with slow sensors, reported in absolute pressures in bar.

Once the basic instrumentation is set up, John will dyno it with higher pressures. Probably next weekend.

[In-Tech]

Nice dyno sheet and applause for the beautiful fab work on the exhaust.

[ptuomov]

Nice dyno sheet and applause for the beautiful fab work on the exhaust.

Full credit to John Kuhn on all the fabrication work.

One more sensor in the mail, once that comes it's time to dyno this with higher than 0.6 bar boost.

[ptuomov]

Short update on this: https://youtu.be/LnavQHFTmk8