Piggyback Tuning

Since I put the new motor in with larger injectors to deliver more fuel, I have really put off getting the car tuned properly.  The problem was, with the bigger injectors, it was running so rich, it was actually causing the plugs to foul on wide open throttle (WOT).  Needless to say, the fuel economy was horrible as well, lol.  So I finally got around to installing a Vitesse Racing SMT6 piggyback tuner.  Since I am already running his MAF and chipboard, the piggyback was a perfect match.

The piggyback unit installs into the vehicles engine wiring harness at the DME.  It involves splicing in about 8 different wires to the existing harness to allow the piggyback to control the tune.

First thing to do is to pull out your DME and locate the wiring harness.  Then wire in the piggyback controller to the harness.

Wired in and ready to test…..

Once the piggyback is wired in, you can load the tuning software on your laptop and connect the piggyback via the serial cable.   Then comes the tuning portion.  Using the AFR gauge, you can fine tune each RPM level by fuel and ignition and throttle input.  Ideally, a couple hours on a dyno is the safest way to tune the car.  Or, you can use the poor man’s way, and go out and tune on the road.  Your local law enforcement will probably not like you a whole lot, but what the heck.

I chose option B:  I went out and tuned by myself.  If you are tuning on the street, it is best to have the passenger tuning while the driver drives.  Doing it by yourself involves driving the car, watching the AFR’s, and trying to enter data in the laptop on a spreadsheet like program…..I got the rough tune done with, and will use a 2nd person to help me do the fine tuning, as it is just too hard to watch everything at once.

Here is an example of the basic tune.   The the values started at 0, and you can enter a postive number to add more fuel to the car, or enter a negative number to lean the mixture out.

There are multiple options out there for wideband gauges.  You can tune via a permanently installed gauge, or a portable gauge.  Either way you go, check out innovate’s products.  The new LM2 portable AFR gauge works great!

There are a lot of capabilities of the SMT6 that go beyond just tuning the car to run correctly.  This is just the tip of the iceberg for now.

If you are looking for upgrades for a 951, contact John at Vitesse Racing out of the Atlanta area.  Not only are is products top notch, his customer service is the best out there.  Having installed many different performance products on 951’s, I can tell you that his stuff is the best out there.  He has everything from basic chips for a 951, to big turbo kits that really put down a lot of power!!  His website is www.vitesseracing.com

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September 23, 2009 at 12:32 AM

Does it have a built in dyno estimate too? Wondering if the car pulls much better after the install as running rich can actually lower hp.


    September 23, 2009 at 2:35 AM

    No dyno specs built in. It picked up a little hp, but mostly smoothed things out.

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