[alfa] More MegaSquirt and intakes

[webb.p@xxxxxxxxxxx]

For those following the progress on the MegaSquirt and custom intake...

I got some pretty exciting numbers on Milano 3.0 with stock intake with the AFM removed.  Much better than I expected.   With the help of Mike Besic of Besic Motorsports, Glen Ellyn IL - (shameless plug for a great Alfa guy) and Ken Baurly of Baurly Auto Sport, Addison IL (full race prep and fabrication shop) I got the new intake built and installed.   Still working on the tuning.  It started first time.  Once I fixed my own mistakes with the air leaks, idled smooth even with the Shankle cams.

I had a terrible rich stumble right out of the gate.  Turned down the req_fuel number and it was much better.   The VE table was too lean at idle so bumped that up to restore good idle.  Idle is controlled by cracking the throttles a little.  There's no idle air or aux. air device installed.   Most of the MS installations forgo it.  I suppose I could reinstall the AAV some day to restore a better cold idle.   However, I do have an ok cold idle just using the warmup enrichments in the MS.   Still working on that.  After setting the warmups and idle pulsewidths I have a nice smooth idle.

Next I had to start tuning the VE table.  The initial table ran and drove but was aweful off-idle with some bucking.   Got that tuned so it transistions smooth from a stop.

Acceleration enrichments can be handled one of 2 ways in the MS, depending the code revision installed.   Generally, acceleration enrichments are determined by the voltage differential of the TPS increasing, using a pot type TPS.  Commonly referred to as TPSdot.  Since I didn't have one of these on the old throttle, I used a custom code mod to determine the differential of the MAP sensor instead.  Under heavy plenum vacuum transition it would detect when you stomped on it.   Commonly known as MAPdot.

The new setup uses a pot type TPS from a 155 (also used on the 164QV) so I reverted back to TPSdot accel enrichment and had to change all the settings TPS for voltage differential.  This was difficult to get right but I think I have it close.

Cruise VE is still a little lean.  Not to the point of melting anything.   The TPSdot enrichment gives me extra squirts even under hard passing acceleration.   Not sure if I'm going to leave the cruise lean yet.  With gas prices the way they are, I'm not in any hurry to decrease my general highway mileage.  The programmablity allows me to increase the fueling at higher RPM and load, and three levels of acceleration so I may be able to leave the economy in the cruise and not sacrafice power.

I'm still working on the high RPM/load VE entries.  This is where I'll make all the power.  I'm still a little lean once the acceleration enrichment squirt is used up.   Not going to bother trying to take any meaningfull power readings until I get this right.  The GTech will help me determine where the best power is during this tuning cycle and the result of each change.

So the car is running and driving well on a base set of tuning.  It's in semi-daily use in it's current state as I drive around with my laptop trying to the finer points dialed in.

I've posted pictures of the custom plenum fabrication and installation at:

<http://home.comcast.net/~webb.p>

Details on the intake and fueling:

164L plenum (powder coated)
164L 39mm runners (powder coated)
1 155 70mm(ID) throttle w/ Milano bellcrank
2 164 70mm(ID) throttles with Weber bellcranks and rods
TPS on the first throttle from a 155TS
3 3.125"(ID) tubes welded to the plenum.
1/4" plate for throttle mounting
Stock Milano throttle cable
1.75" silicone turbo tubes plenum-to-runner joints
3 3.5x6" K&N filters (and ugly PVC tubes to clear fender)
164 Right side cam cover for plenum mounting
Custom plenum mount to lower cam cover bolt for support
6 24lb 350SBC high-z injectors 
(soon to be 29lb LS1 (Delphi) or 30lb Ford SVO injectors)

*** no modifications needed to the wiring harness!! ***

I welcome any comments or questions on the installation.  The plan is still for the installation session at the convention in New Hampshire.  GTV6.org have kindly lent me some forum space to communicate on the event.   It's empty right now so please go over to www.gtv6.org under the forum section for information on the event.  I'd ask you to post your real name and email on the forum if you'd like to participate.  Please include what you want to convert, any details of the car and your level of expertise with tuning and building performance engines.

Thats it for now.  Article in the Owner eventually.  Just need some time to sit down and write.

-Peter
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