[s-cars] FMIC Alternatives - 1 or 2

[Lewis, Gary M]

I'm with Trevor.  Everyone's goal (yes, this means you) should be to lower air-temps AND lower pressure drops.  Lower temp drops don't mean much if the turbo has to work 4 psi harder to get the same flow.  

At 22 psi, sea-level, 70 degrees ambient, at 22 psi the air temp leaving a turbo working at 70% efficiency is 293.8F.  At 26 psi (4 psi flow loss thru IC), now the turbo efficiency drops to say .65 efficiency, you get to 342.4F.  Also, you get more lag time while the turbo has to toss another 4 psi to get to the requested boost profile.  This is just innefficient.  A bigger turbo helps with efficiency and temps, but you suffer needlessly on the bottom-end.  

If you can put in a more efficient IC for more or less the same cost and effort as putting another IC in front of the existing one, why bother??

Hap, MLP, and Trevor in my opinion are smack on when they went looking for pressure losses.  Run the numbers.

BTW, I have created an Excel spreadsheet to help in this regard.  Copy requests will be granted.

After you get you your pressure system in order, I'd then suggest going to WI, which in my opinon is awesome, but pick low hanging fruit first.

All this is in regard to my URs4/6 experience at the RS2 equipped and 26 psi experience.  YMMV, esp. if you are not going this route.  WI for example might work great with the MTM 3 bar s/w, which seems to ping BAD in SoCal on 91 octane.  Spec out your system or you requirements, then ask the list.  An FMIC on an otherwise stock car nets little cost vs. performance.  On a car like mine, I expect in the 30hp range, and 400 rpm lower boost threshold. 

Gary Lewis

1995.5 S6 Avant, Green/Ecru, RS2 MAF, RS2 Exhaust Manifold, RS2 Injectors, Custom Turbo (K26 Turbine, Factory K26 Cold side (Audi Works '999' P/N) with 50mm intake and custom Innovative Turbo compressor wheel), TurboXS Type 25 Bypass Valve, Bilsteins, Eibachs, Big Reds, Spec II Clutch.



> -----Original Message-----
> From: Trevor Frank [mailto:tfrank at symyx.com] 
> Sent: Thursday, February 26, 2004 10:14 AM
> To: Charlie Smith; Eric_R_Kissell at whirlpool.com
> Cc: Audi S Car List
> Subject: RE: [s-cars] FMIC Alternatives - 1 or 2
> 
> 
> 
> I have to totally disagree, the time that the air will spend 
> in the IC in a series setup or a parallel set up is the same. 
>  The velocity will be cut in half on a parallel set up.  This 
> means that you will have at best nearly the same temp output 
> with much less pressure drop on the parallel version.
> 
> That being said you need to find out how long it needs to be, 
> I suspect the 9in or so of the stock is plenty.
> 
> -----Original Message-----
> From: Charlie Smith [mailto:charlie at elektro.cmhnet.org]
> 
> Sent: Thursday, February 26, 2004 8:10 AM
> To: Eric_R_Kissell at whirlpool.com
> Cc: Charlie Smith; Audi S Car List
> Subject: Re: [s-cars] FMIC Alternatives - 1 or 2
> 
> Earlier, Eric_R_Kissell at whirlpool.com wrote:
> >
> 
> >
> 
> > Let me throw another idea into the mix here.
> >
> 
> > The discussion turned to running two intercoolers in series.
> >
> 
> > What would the advantages and disadvantages be for running two
> intercoolers
> > in parallel?
> 
> Two in series will lower the temperature more (which is what 
> you want).
> 
> Two in parallel will present less restriction to the air, ie: less of
>   a pressure drop across the IC's.  The temperature at the IC-out side
> 
>   will (roughly) be the same as the temperature in between the series
>   IC's (IC-out side of the first IC).
> 
> If they are large enough to present minimal restriction to air, with a
>   minimal pressure drop, two IS's in series will be better because of
> 
>   the lower final output air temperature.
>  
> 
> > I barely have time to keep up with reading emails right now.
> 
>    [   comments withheld  ]
> 
>     - Charlie
> 
> _______________________________________________
> S-CAR-List mailing list
> S-CAR-List at audifans.com 
> http://www.audifans.com/mailman/listinfo/s-> car-list
> 
> =======
> 
> Notice: This e-mail message, together with 
> any attachments, contains
> 
> information of Symyx Technologies, Inc. that may be confidential,
> 
> proprietary, copyrighted, privileged and/or protected work product,
> 
> and is meant solely for the intended recipient. If you are not the
> 
> intended recipient, and have received this message in error, please
> 
> contact the sender immediately, permanently delete the original and
> 
> any copies of this email and any attachments thereto. 
> _______________________________________________
> S-CAR-List mailing list
> S-CAR-List at audifans.com 
> http://www.audifans.com/mailman/listinfo/s-> car-list
>