TMIC/FMIC piping volumetric efficiency debate?

[94 Leone]

I remember a while ago someone had some really good information and maths backing up the FMIC debate regarding cfm vs pipe volume essentially making the point that the miniscule amount of lag from fmic is negligible compared to the advantages. cant seem to find the info; anyone remember where it was?

Cheers

[Rosssub]

Pretty sure it was a comment by Boon in the dumb question thread...

Edit: Post #4786 page 479

http://clubsub.org.nz/forum/showthread.php?20532-Dumb-Question-Thread!/page479

Originally Posted by boon

On the TMIC/FMIC spooly business thing - I have given this much consideration and done some maths on it.

Let's say you use 2.5" intercooler piping and a Perrin FMIC. For argument's sake we'll say you have 3 metres total of intercooler piping.

The piping has a volume of roughly 9.5L or 0.33 cubic feet.

The intercooler core has a volume of 0.52 cubic feet - that's total, in reality it's probably about half this in terms of actual air passage size but whatever.

So you have ~0.85 cf of volume.

A VF22, flat out, flows about 420cfm, or 7 cubic feet per second.

This means it takes about 1/8th of a second for a VF22 to pump enough air to fill your intercooler piping.

Ok so on a TMIC setup that's probably going to be more like 1/16th of a second but who cares.

And with regards to distance, well, the intake port velocity of a turbocharged vehicle at high RPM is usually around MACH 0.5 - maybe 150m/s - again, with 3 metres of intercooler piping the air is covering this distance in 1/30th of a second.

Conclusion: other than the pain of having to cut the front and make the piping fit, the spool/boost threshold/response/blah argument around TMIC vs FMIC is purely a mathematical one, because in the real world you are unlikely to notice, and this is reflected in what a lot of people see when they install one.

Extra conclusion: I'm installing a FMIC.

Edited May 15, 2015 by Rosssub

[Guest]

If its technical and helpful its rosssub.

If its technical, helpful with any possible scientific element or its simply 10,000 characters its boon.

[94 Leone]

Knew id seen it somewhere. Cheers guys.

that dumb q thread is full of handy as **** info. Just difficult to find

[Guest]

Yep that and the general section...and thats why feedback is good then we know its not just the com going "oh suits us lets do it". Appreciate any input to help improve things.