2G Intake manifolds: JMF billet or Magnus

[jakelandry]

We have very little data floating around about these two manifolds. Does anyone have any recent dyno graphs or general input they would like to contribute about either of these manifolds? I’ve seen all the initial flow bench data on the JMF so no need to link it, but I’ve heard very little about personal opinions on it. Basically I am buying one of the two and figured I would hear out some people’s input before pulling the trigger.

 

[b00stedtalon2]

I went with the Magnus for two reasons 1) The quickest and fastest DSMs use them and 2) It feels twice as light being cast.

 

[NOSLO2PT0]

What’s wrong with an evo 3 manifold? Are you building an 800+ whp car?

 

[jakelandry]

What’s wrong with an evo 3 manifold? Are you building an 800+ whp car?

I am indeed but I’m not worried about peak numbers. I’d like to hear some real world results and opinions if possible.

I went with the Magnus for two reasons 1) The quickest and fastest DSMs use them and 2) It feels twice as light being cast.

The Magnus being lighter is actually not something I expected to hear. I installed a jmf in a friends car and tuned it at idle and cruise but he had issues that prevented wot tuning. It was surprisingly heavy.

As far as performance claims, I’ve only heard from a single statement that Magnus is flow balanced between cylinders to 1% and jmf seems to be around 3%. As dumb as this sounds, that leans me more toward the jmf because their claim is stated as being true under the circumstances they tested whereas Magnus Website just says it flows within 1% period which I am skeptical of.

 

[motomattx]

Buschur Racing used to sell their own intake manifolds, they did a test of the Magnus V3, during that time they were known to not get along, still Buschur found that the Magnus V3 could not be beat performance wise, even by their own manifold, that was enough for me.

 

[DSSA]

Buschur Racing used to sell their own intake manifolds, they did a test of the Magnus V3, during that time they were known to not get along, still Buschur found that the Magnus V3 could not be beat performance wise, even by their own manifold, that was enough for me.

There was more to it than that. But yes, I remember reading that.

The Buschur stuff was almost bottom of the heap for a long time. I had one back in the day.

 

[bastarddsm]

I have the 6 bolt billet JMF race, and it made about 15hp more at 8200 than an unported EvoIII made stuck on a 6 bolt head. At 5000, the evo3 was up almost 100hp just due to turbo spooled up earlier with it. The $700 JMF prettymuch new sits in a box, and the $125 Evo3 piece is on the car.

All the intakes are a comprimise between looks, manufacturablility, and performance. From what I've seen they are more geared toward manufacturablility and looks than performance. I personally don't think one of them stands out amongst the others for better performance. I strongly doubt if you back to back tested the two manifolds you are asking about that you would see any significant difference in power that can be 100% attributed to the intake.

As for the runner to runner flow, that's such bullshit it's ridiculous. Magnus's claims is based on some steady state cfd on ancient software, and jmf is on a flowbench. Both cases ignore the effects of the cylinder head ports, and the pulsing nature of the real flow. Neither have any real science behind them besides "cut and try" I am working with the type of software that does this, I'm on an academic version, and I likely have more than the average dsm's value invested in a small cluster to run the software, and it still takes a week for each test, an industrial seat would be over $100k/yr, and you'd have to pay someone like me over 100k to run the software, plus probably 50k in a real cluster. Point is, unless it's a major major manufacturer, any "cfd color pictures" is a crock of shit. I have even seen that a giant like edelbrock, farms out this type of work on some of the newer high volume shit they do. Magnus ain't doing it for $50k worth of intakes.

 

[jakelandry]

I have the 6 bolt billet JMF race, and it made about 15hp more at 8200 than an unported EvoIII made stuck on a 6 bolt head. At 5000, the evo3 was up almost 100hp just due to turbo spooled up earlier with it. The $700 JMF prettymuch new sits in a box, and the $125 Evo3 piece is on the car.

All the intakes are a comprimise between looks, manufacturablility, and performance. From what I've seen they are more geared toward manufacturablility and looks than performance. I personally don't think one of them stands out amongst the others for better performance. I strongly doubt if you back to back tested the two manifolds you are asking about that you would see any significant difference in power that can be 100% attributed to the intake.

As for the runner to runner flow, that's such bullshit it's ridiculous. Magnus's claims is based on some steady state cfd on ancient software, and jmf is on a flowbench. Both cases ignore the effects of the cylinder head ports, and the pulsing nature of the real flow. Neither have any real science behind them besides "cut and try" I am working with the type of software that does this, I'm on an academic version, and I likely have more than the average dsm's value invested in a small cluster to run the software, and it still takes a week for each test, an industrial seat would be over $100k/yr, and you'd have to pay someone like me over 100k to run the software, plus probably 50k in a real cluster. Point is, unless it's a major major manufacturer, any "cfd color pictures" is a crock of shit. I have even seen that a giant like edelbrock, farms out this type of work on some of the newer high volume shit they do. Magnus ain't doing it for $50k worth of intakes.

I believe you are an engineer are you not? I have an engineering degree myself, and I actually wrote a GENERAL technical paper on intake manifold designs back in college. They’re definitely the type of subject where people know just enough to ignorantly assume they know more than they do. This is why I am so skeptical and prefer educated opinions like this. Thank you for sharing your experience.

 

[bastarddsm]

Yes and no, I'm just about finished with a phd in mechanical engineering - in this exact area. but mostly I'm a farmer and machinest now.