View Full Version : Suggestions on retune for a Supercharged Mallett 435 C5


ibjamin
08-29-2006, 10:45 PM
My friend needs a re-tune on his supercharged 1999 Mallett 435 C5. Looking for possible suggestions on what to do. The tune that is on the car originally from Mallett is locked so I can't read it with my EFI Live. He could take it to Mallett in Ohio but we're in Milwaukee, so not convienent and likely pretty expensive, (like the car was).

Since I doubt Mallett will give him the key to unlock the PCM, he could get a new PCM and have it reflashed at the dealer and start from scratch with my EFI Live. Or take it to Speed Inc or FLP or someplace.

Not too sure of how the hardware is set up on the supercharger and it has an upgraded fuel system but it also appears to have a FMU.

Does he need to go with an upgraded Operating System, 1 bar SD tune, or what? What do you guys think?

George

Billiumss
08-30-2006, 05:15 AM
Contact them and see if you can just mail your PCM to them to get it unlocked or have them make the adjusts.

SSpdDmon
08-30-2006, 10:20 AM
If he's running less than 8lbs of boost, he most likely won't need to run SD. In other words, as long as he's not maxing out his MAF he should be using it. If you feel confident enough tuning it yourself or know someone in your area that could tune it, you could take it to the local GM dealership and have them wipe the PCM clean with a full flash back to the stock tune. Only thing you have to worry about is getting the car to the tuner from the dealership or getting the tuner to the dealership.

ibjamin
08-30-2006, 01:39 PM
Thanks.

But the system really shouldn't use a FMU should it? I would think that you want a steady fuel pressure and then just adjust the maps to get the fueling right. Isn't that correct? I thought an FMU was just a crutch to allow you to put a SC on a car and be able to use the stock computer program. Shouldn't a custom tune remove the need for an FMU?

George

Viper
08-30-2006, 01:42 PM
Might want to ask in the FI section.

SSpdDmon
08-30-2006, 02:05 PM
Thanks.

But the system really shouldn't use a FMU should it? I would think that you want a steady fuel pressure and then just adjust the maps to get the fueling right. Isn't that correct? I thought an FMU was just a crutch to allow you to put a SC on a car and be able to use the stock computer program. Shouldn't a custom tune remove the need for an FMU?

George
Once you start getting into a SD tune, then yes you just adjust the maps to add more fuel. The problem is, the stock operating system isn't setup for boost. The VE table only measures up to 105kPa. A FI car will require a 2-bar MAP sensor and custom operating system to tune that way - not to mention a great deal of time (and possibly a speeding ticket or two) to tune it trying to hit most of the cells.

As for the FMU, I know guys in the FI section are running systems that add extra fuel for every extra pound of boost. This is one way to help dial in WOT. Don't close your mind to tuning it the old way by manipulating the IFR and PE tables. This works fairly well even though it's kinda frowned upon here. A local guy here just tuned a Mustang w/ twin turbos that way in a day or two. The car made 620+ rwhp & 650+ rwtq and made the drive back to Colorado getting 25mpg with 72lb injectors. This is also how my current car (not in sig) is tuned (was done by a shop in PA). It puts down nearly 430rwhp and gets 27mpg on the highway when I keep my foot out of it.