Thank you!

That equation is too simplistic. Coming up with those variables is where the fun begins..


-M

 

HEHEHEHEHEHAHAHAHAHAHA


You said ORIFICE!!!!!


Seriously if you guys are worried about mounting brackets, don't They are mainly there because of the WEAK stock clamps that barely hold and strip quite easilly when tightened. I use T-Boltclamps, Set them almost a year ago, they are holding fine. I live my kit, larger diameter then stock.


BEFORE my I added My IC pipes, I measured 322WHP, I then added them along with a UR Crank pully. I went to 350 and held boost MUCH MUCH Better, I can hold 21PSI to damn near 8000 RPM's. Now I KNOW that teh Crank pully added some whp, but not it all.

 

I didn't see this topic but was asked to come here from a customer who wanted me to respond to it.

You guys know I don't sell parts that don't "work". I spent a couple of months this winter trying our own parts and others and posted the actual results from the testing....good or bad. I made some enemies from it and re-did our WHP results on our own site from the testing.

With that said. The stock intercooler is O.K. on the car. IT IS NOT GREAT. Our FMIC kit for the EVO will gain an additional 15 whp from the stock intercooler on the stock turbo. So to say the stock intercooler is fine for the stock turbo is not correct.

As for the intercooler tubing itself. Our upper kit did pick up some whp, but the gains were small, if I remember right (someone can go check me on this if you like) I think around 7 whp or so. Drag Sport did a test and gained the same thing.

The lower i/c pipe we did some testing on too and is also worthwhile to swap. I wrote the gains off as a fluke because I just couldn't believe them. I still have not got around to making a stock replacement lower i/c pipe. Our solution was our deluxe FMIC kit that comes with the short lower pipe.

That's my input.

David Buschur
www.buschurracing.com

 

"I wrote the gains off as a fluke because I just couldn't believe them."

and I mean

 

Thanks Dave... I guess everyone is right in their own opinons then...

 

Thanks Dave, but other trusted Vendors have replaced FMIC's with other names, including yours, and NO gains were shown. Now I know you will be less inclined to heat soak but as far as adding just a FMIC, no piping, could add any measurable power was not seen at all.

I personally have seen on Evo's on the NY/NJ/PA area that get no power what so ever, but damn it looks kewl.

 

Were they running more boost with the upgraded intercoolers and did they still see no power gains?

 

Same pretty much as in no noticable power gains. It is also unfair to DYNO test a FMIC, as it doe snot see the 70++++Winds it is supposed to see on a 4th gear pull so it would heat up pretty quick unless you had a crazy wind tunnel that BMW has.


I know the STOCK FMIC has been flow tested and it is SAID to be able to flow 600CFM's efficiently, of course it would flow more if asked, but you would get some pressure drop and heat soak and that's no good. The Stock Turbo on the EVO is a BIG 16G and will flow 550CFM's so these parts are well matched unlike the DSM's. Daves FMIC is great and I am locked in a battle to get either his or the AMS unit.

I still stand by and recognise that the Greatest improvement one could recieve is by replaceing that stock lower Intercooler pipe. I have, and got GREAT gains.


Don't get me wrong, I would LOVE a larger FMIC as it would be one less mod to do, looks great, and you can't really go wrong with it. But the cost Vs. Gain really doesn't show to me

 

Buschurs flows 1100+ and when you install any aftermarket I/C you will see a drop in boost.. usually less than 1psi.. one advantage the stocker has is its so much lighter.. maybe 1/2 that of other aftermarket kits...

 

my equation is not to simplistic, that is the equation for Volumetric efficiency


ok then. to describe Q which is the only uncontrolled variable in the equation...

Q is a volume/time and for an idea pump the equation looks like this:

Q=D*N - Cs*D*deltaP/(2*pi*mu) -Qr
D->displacement which is constant
N -> speed which is constant
Cs ->slip coeffcient
deltaP is pressure differential accross the pump
Qr is cavitation losses

now this equation only somewhat holds true for our application because an IC engine acts both as a pump (on the intake side) and a motor (due to generating torque). if we look strickly at it from a pump standpoint, the equation tells us that if we assume we have no caviation, and that the displacement of the engine is relatively constant, that the biggest difference will be the deltaP. for an idea pump you have max flow when there is no pressure difference across the pump.

however sense we are not that concerned with the efficiency of the rings sealing, and the valve overlap right now, we are going to look solely at the supply pressure for the pump (i.e. our engine). That equation is for an idea pump and does not take into account the fact that your engine may not have a constant supply. that will affect the displacement value because we are no longer ideal (however in the Ve equation, you do need to use the ideal displacement). Knowing that for an IC engine that we want the maximum pressure going into the engine, we can start by looking at the flow across the orifice.

using an incompressible flow approximation (which is extremely close to actual) the down stream pressure from the restriction is described with this equation:

P(down) = P(up)/2 * [1 + sqrt(1 - (2*mdot/(Cd*A*sqrt(2/R*T)*P(up))^2)]
mdot is the mass flow which can be related to volume flow Q
A is area of opening (at the tightest point)
R is the gas constant
T is the temp in absolute
Cd is the discharge coefficient which is determined by the shape of the restiction exit. if it is a sudden change in diameter, Cd is close to .5 whereas a nice gradual change makes Cd 1.
this holds true as long as P(crit) < P(up/P(down) where P(crit) = .528 aprox.

and the equation is hard to explain over the internet, but we can do an example to make a point.

assume we have a GT35R with the stock lower IC pipe that has a 1.5" restriction with a reasonably sudden diameter change so Cd = .6. A will then be pi*(1.5/2)^2 = lets say we are running 30psi of boost right out the turbo (not the pressure at the manifold, which we know will be less, but thats what we are going to find out. also at 30psi of boost or 44.7psi absolute pressure for a P/R of 44.7/14.7 = 3.04 for a good estimate we are looking at a massflow rate of 50lbm/min for a reasonable efficiency from the turbo which is 72% (just choosing numbers here...). outlet temps will be 353 degF so absolute is 460+353 = 813 degR.

now the equation again:
P(down) = 30(lb/in^2)/2 * [1 + sqrt(1 - (2*50(lbm/min)/(.6*1.767(in^2)*sqrt(2/R*813(degR))*30(lb/in^2))^2)]

i am having trouble finding R in the right units for this equation to work out, so i will post up results later when i get out of work.


oh and thus far i think i have come to the conclusion having the restrictor before the intercooler is much much worse then after the intercooler because the temps are about 350ish deg before and only 150ish using this example.

 

Serves you right for using degrees Rankine! Try http://www.katmarsoftware.com/gconvals.htm

Dave

 

You still haven't computed deltaP which would most certainly require taking the derivative. The problem is, you are using basic physics which is linear or at most quadratic in the equation you've shown. I want to know temperature drops (again requiring the derivative). I want to know how much temperature is changing when flowing air through those crappy stock rubber hoses after the intercooler. At least the stock lower I/C pipe is all aluminum. Without taking measurements of these actually flow-carrying objects, we are just taking stabs in the dark.


Face it, this problem requires way more work than the simple formulas you are using. Why? Because those formulas are assuming way too many things. You are simplifying the problem by having so many constant variables.

-M

 

well first of all fluids is by far the most guess work of any course you will ever take relating to science. everything related to turbulant flow is far to complicated to model perfectly, but the equation i gave will model a system to a pretty high degree of accuracy. i have most of the equation modeled in simulink and will modlify it to fit this case, and run some tests to give the numbers. but your right, it requires ode solvers to solve it because it is not linear (mdot, and delta P both).

thanks for that R webpage thingy... that will help!

 

unimiami,

I had an independent shop call us over a year ago and ask to send our FMIC for them to test against their own and some others they had.

THEY did the testing and didn't want it to be made public, just wanted to compare.

I send the intercooler and we came out on top. Our gained 13 whp on their AWD dyno, which was more than anyone else's.

I feel that the best way to test an intercooler is with NO air being pushed across it. Unless you have a way to control the amount of airflow across it I feel you are better off running with no fans. The intercooler is as much a heat soak as it is anything when you get right down to it. Testing on the dyno is actually a very good way to check the efficiency of an intercooler. If it works on the dyno it is going to really work on the street.

Also, with as many boost leaks as guys end up from improper installation of our FMIC kits any dyno comparison from the average installation is not going to be a good reflection of the gains. We now have instructions in the kits so they can be put on correctly.


David Buschur
www.buschurracing.com

 

Name the shop. I mean I am not trying to flame anyone's product and your FMIC would be MORE then welcome to my Evo. BUT every addition of a FMIC to a STOCK TURBO Evo had yielded no gains from my personal experience. HOWEVER your FMIC kit that COMES with the Lower IC pipe already attached had yeilded WHP every time. But this is probably because you replace the terrible LICP with what appears to be the shortest Pipe offered.

I have seen many Evo's dyno'd with and without a FMIC upgrade and it offered no gain, none. I have seen multiple gains from a simple LICP including myself. Maybe that independent test was a couple of runs with an already hot stock FMIC and then you swap on your FMIC, allowing the car to sit for at least 10-15MINS as you install it and to cool off all vital liquids, oil, coolant and so on. Then run again immediately with a VERY cool FMIC and cooled off car, there is no wonder a gain was realized.

Again I love your products and run them on my car, I just don't see how you can properly dyno test a FMIC without the proper air supply hitting it at Highway speeds.


Maybe a proper test would be a road test and an acceleration test from a certain MPH to a certain MPH. I know you like no airflow but seriously when will that EVER happen? Also is it wise to run a FMIC that is more then DOUBLE the size of the turbo’s efficiency? Doesn’t that add Pressure drop and lag? If a FMIC Is very free flowing then how can it cool effectively?

Again I am no expert on the subject and you are and all I have is questions and opinions and dyno numbers (from the same exact Dyno and tuner) and I have seen no increase or decrease in performance. You are also a vendor, not that it is bad, I just always get conflicting information from each vendor and tuner and both swear by it yet both cannot be right. From my personal experience of about 20-25 Evo’s on the Dyno with and without FMIC’s I see no difference between theirs and mine, heck sometimes I make MORE power with people who run larger FMIC’s as the only difference in mods, sometimes by a margin of 20WHP or more.

Don’t get me wrong I would LOVE your FMIC, tell you what. I’ll post my Dyno Sheet, I make 347 On a Dyno jet just 2 weeks ago. Send me an FMIC, new or used, doesn’t matter, I’ll pay shipping and then I’ll pay to have it installed and Dyno’d and retuned to optimize the new air flow. That would run me about $220 all together which is fine. For every WHP I gain I’ll pay you for the unit, so I guess I would see an even 360 whp? Deal? That would be a great way to get a FMIC, believe me I want one for the looks of it alone not to mention I could just bolt on your 21G afterwards with no issues. I just can’t justify the cost without a larger turbo is my main concern. It is also the same reason I don’t have an AEM EMS, it is a great unit and I love every part of it, but I can’t justify $2,000++++ for a minimal increase of performance not to mention half of the respected tuners preaching that you are downgrading when converting to a MAP which makes sense until they try to sell me their unit, so I’ll just leave it that there is a LOT of CRAP being spurted on the Internet, and I have no idea what to believe anymore.


Thanks again for your Info

-umiami80
www.ihavenowebsitecuzithesuck.com