SICAMG

Is a re tune with a smaller pulley really needed. These E55 engines are speed density so I dont see what adding 2lbs of boost more will do to the engine as far as throwing off the air ratio to much. I know on all of the Western Motorsport and FAST DFI system that are speed density on Ford musangs we have tuned adapt perfectly with no problem and only because they are speed density. Just useing them as an example and not trying to compare to a Ford.
More boost...more fuel ....as long as it does not swing off the factory fuel scale it should be all good I would think, no? There are guys I heard of just throwing on a pulley and have had no problems.What do you guys think.

HeissRod

Do you already have an aftermarket tune? If not, there are huge gains to be had.

SICAMG

No I don't but I have heard of to many bad story's about reflashed computers not running correctly so alittle leary of that since I can not do this myself.

3BNick

I would tune. Also keep in mind that depending on your cars mileage, if your fuel pump/senders are aged over 60,000 miles chances are your filter is getting nasty and you may see fuel pressure drops under load. I'd deal with a tune that may have a slight hiccup (I'm not sure that is really as big an issue on these cars as you are making it out to be) than lean out hard and smoke an expensive power plant.

Fueling and cooling are huge deals on these cars. I would seriously consider looking into both if you are going to keep throwing mods at it.

dchl21

get it tuned. don't mod it if you are not going to do it proper.

Sir-Boost-a-Lot

iTrader: (1)

Why don't you be the guinea pig and find out? If it blows up, it's probably cheap to fix just like a mustang, right?

SICAMG

Thanks sufa that will help alot

kompressede

I don't know what stories you heard about tunes?

Go with a reputable tuner and you shouldn't have any issues, or go with Sir- Boosts suggestion and let us know how you make out?

loungn14

Tune the car or go with a pulley and tune package. (we can help with that)

The costs these days of tuning is dramatically lower that it has been and it is cheap insurance.

We have done thousands of cars...we know these engines very very well.

sthoms

Think you are confused on Speed/Density versus Mass/Flow. Speed/Density calculates the mass of air entering the engine (using RPM and known efficiencies of the engine). So changing efficiencies (boost, exhaust, head porting,...) will throw off the calculation and hence fuel mixture. On a "Ford", like a Mustang, they are Mass/Flow, where a sensor on the intake side (MAF) determines the mass (using velocity and density). Changing efficiencies on this system will not have the same issues as long as all the air is drawn through the MAF. (the MAF will have limits though)

HeissRod

Fox Mustangs were speed density pre-'89, I believe