Why do people hate other shops for no reason??
It's not like MRC doesn't know their stuff.
Some people are so one-sided with things where it just becomes ridiculous.
Most people just can't be open minded I guess...

 

Some people are so one sided and ignorant they cant let it go, even when their side shows them that they are wrong..I just dont get it.. 22% is about the average high side drive train loss, as Sharif confirmed..Phil just hates us for no reason and loves to attempt to bait me into BS..
Back on topic, Cosworth plenum...Looks very nice, cant wait to se real world testing.

 

Thank you MRC.

 

Question about Plenum volume size. The Cosworth looks like it has more volume but how does the increased volume help. I just "heard" that optimally you would want one that is double the size of your motor, so in our case about 7 liters.

 

I dont have that number, but it is larger than stock volume.

 

Once you get a plenum volume larger than 100% of NA engine displacement the throttle response becomes soft.
As interior space increases (vs. cylinder volume) the buffer or anti-reversion effect increases, but this isn't linear and probably decays to a minimum value with some multiple of cylinder size.
[not sure that matters with drive by wire]
For supercharged make sure the extra air volume is calculated in a desired plenum size. 40% boost = 140% of displacement
Really depends on runner length [torque peak tuning] short runners are more sensitive to plenum volume above [100% of displacement] than longer lower tuned runners...

Unfortunately simple Helmholtz equations get muddy and inaccurate above 5,000 rpm and you need to convert to 1D Wave Equations methods.
http://ceta.mit.edu/pier/pier20/04.980219.Gaffour.pdf

Or jusr cast one in plastic and measure a few volume variations until the point of diminishing returns occurs.

 

Huh?

 

I'm glad I'm not the only one. LOL!

F1 engines idle at 8,000 rpm and this year they are capped at 19,000 rpm. My head hurts just thinking what your respose would be for that. LOL!

 

Two years ago i probably would have a clear idea of what you were talking about and be able to have an intelligent answer. Damn engineering school! I forgot more everyday!

 

A few people per year get their Phd from plenum design and spend their entire lives tinkering.

https://dspace.lib.cranfield.ac.uk/b...+revision2.doc

This one is more to the point in latter half:
http://upetd.up.ac.za/thesis/availab...ssertation.pdf

 

LOL those wave equations are almost identical to transmission line equations... or to the schrodinger wave equation.... At least it's 1D and not 3D. Most antenea design involves 3D wave equations of this type, which is why you usually get a general idea and then take it to the lab and play around with it tell it works like you want... The equations are a huge pain the **** to solve, and even then you end up in a conundrum because of the boundary conditions such that you cant solve the equations backwards from results. You have to use a finite element analysis or some other step algorithm. Seems like electromagnetics and sound (in this case air flow through the plenum) again have something in common.. lol

I like how classic DSP things are mentioned as well like doing an FFT with a hanning window, and other classic tools for electrical engineers like Lorentz and Laplace transforms, partial diffy q FTW!

I just had a thought though... how come no one has done any wavelet analysis on something like this, it would be perfect for it.

 

Woah! This is getting complicated. You guys keep going, I'm going to crack open a Miller High Life!...

 

OK, headers or Cosworth plenum?

 

One thing not discussed is the design air temperature is very important especially if supercharging is used as the tuning frequency still varies as the speed of sound varies thru the medium.

50F vs 250F changes tuning by 22% [1107 vs 1306 feet per second]

 

Depends on a few things... Do you plan on going Turbo anytime? If you go with the Cosworth, it won't matter either way. If you go with the headers, it's going to cost just as much, if not more in the long run with probably less usable gains.

 

how much is this? and HP gains?

 

These are unknown questions if u look back a few pages.......

 

When are you going to get one Sharif?

 

I am the first person on the list....LOL. It was mentioned several pages back, but pricing in mid April (soon), and product in May. I will post updates as they are available.

 

Thanks. So we should see some test results towards the end of may.