Question on 94-95 Mods

[dads95gt]

My son Steve-O is up at Wyotech taking the Chassis Fab & Hi Performance Engine elective. He would like to do a H-C-I swap such as Trick Flow or similar on the 95GT. After all I have read in MM&FF or 5.0 Mustang about the computer issues on the 94-95's I am not convinced. What issues will we have if I agree to do this? What else is necessary besides the H-C-I package? The GT currently has a CAI, BBK H pipe w/cats and Flowmaster American Thunder cat back. Steve has run a 14.07 with drag radials(stock gears). Any input would be appreciated.

[Killercanary]

I'm running out the door now but I'll type a book for you later LOL! It is true that the 94-95 EEC is a little finicky, but its nothing to shy away from. I'll be home after 5pm and will tell you more then.

[yeahloh95]

do it just get a cam with a 114 centerline and you should be ok then plan on a tune to dial it in

[Killercanary]

My son Steve-O is up at Wyotech taking the Chassis Fab & Hi Performance Engine elective. He would like to do a H-C-I swap such as Trick Flow or similar on the 95GT. After all I have read in MM&FF or 5.0 Mustang about the computer issues on the 94-95's I am not convinced. What issues will we have if I agree to do this? What else is necessary besides the H-C-I package? The GT currently has a CAI, BBK H pipe w/cats and Flowmaster American Thunder cat back. Steve has run a 14.07 with drag radials(stock gears). Any input would be appreciated.

The most common issue that comes from a buildup such as this is that the EEC doesn't like a cam swap. The 94-95 EEC differed from the fox body's A9L in that it is a load based setup. The A9L was more of an RPM based one. The 94-95 EEC uses mostly the mass air voltage signal (an a few other things like TPS, vehicle speed sensor, etc) to determine how much load the car is seeing. Think of load as the amount of starin the engine is seeing. Example- driving on a flat road at a steady speed have very little load compared to driving up a mountain. The engine has to work harder to accelerate and even maintain speed. During the steady cruise on a flat road the EEC will see that the throttle is barely open (TPS voltage will be low), there isn't a lot of air flow coming in through the MAF as shown by the voltage, and the vehicle speed is constant. The EEC will then use the lower values of load in the spark and fuel tables to determine how much of each it needs. Now when climbing a steep hill the throttle may be wide open, but the EEC will see that the air coming into the engine isn't increasing as fast as it should if it had no load, it will also see that the vehicle speed isn't increasing very fast given a wide open throttle. This is HIGH load. The computer will takes the readings from these sensors and determine how much load this is and then look at that cell in its fuel and spark tables to determine how much of each it should use.

Now that you have an understanding of this, let me explain why these EEC's are touchy. There are two things here to concider. First is that when you do a HCI setup you will also be changing injectors. The way that this is usually done is by buying a "calibrated" MAF. All a calibrated mass air sensor is one that alters the voltage from what the stock sensor would send for the same airflow. It does this to "trick" the EEC into thinking that less air is entering the egine than there really is. The EEC then shortens up the pulsewidth (or time that the injector is open) so that less fuel is delivered. Since you will be running larger than stock injectors at this point, they will still flow more fuel than the stockers did. Its all a balancing act in terms of getting this right, but IMO Professional Mass Air systems have the best track record. C&L does this by using sampling tubes that either speed up or slow the amount of air that passes over the MAF wires. I do NOT like this method as there are a number of other things that can effect this like MAF clocking, bends in the tubing before the MAF can lead to high and low velocity areas inside of the MAF, etc. Anyway... The reason this can have a negative effect on the 94-95's is because the EEC is using that voltage to determine load, if you trick it and send a different voltage to shorten the pulse width, you also decrease the load that the EEC thinks its actually seeing. Now don't worry too much about this as there are thousands of guys running like this (I am) without troubles. You would think that the larger injector you have the more problems you would see with this, but lots of guys are running 42's without a problem.

The second problem is with the cam. There is a LOT of speculation on this. Most will tell you to stick with a cam that has an LSA at or higher than stock, but I don't like this way of thinking. These types of cams are good for power adders, but they are not the best at producing NA horsepower. I run a 110* LSA in my car. It gave me fits when I first installed it. Typically the car will develop the "surge and die syndrome" where it hunts for an idle and eventually stalls because it can't find one. The more overlap you have the worse the problem seems to be. This may be due to decreased vacuum, reverb (exhaust gases backing up into the intake at low RPM), etc. The way i fixed mine was to bump the idle speed to 850-900rpms and cut some puslewidth back at idle. My method of thinking is this, don't sell your combo short by picking a "safe" cam. Make up you mind to get the cam that will make the most power for the given combo and just plan on needing to tune around it.

For tuning options you can get a custom burnt chip, or get soemthing like a PMS, twEECer, EEC Tuner, etc and tune it yourself. You will find that a lot of 94-95 owners choose this route because a lot of tuners are not familiar with the 94-95 EEC's. What ever you do, do not get talked into getting the PIH that alows you to convert to a A9L. The A9l was good in its day, but its slower and not as sofisticated as the 94-95's EEC. Plus, the PIH will run you at least $600 and in the end all you'll have is a stock A9L in your car.

[Killercanary]

As for what else is necessary with a HCI... here's some of what you'll need or should change.

-roller rockers
-timing chain
-fuel pump
-MAF
-injectors
-possibly a fuel pressure regulator
-some sort of tuning devise
-head gaskets
-intake gasket
-timing cover gasket
-thermostat and gasket
-headers and gaskets (I'd also do locking header bolts)
-head bolts or studs
-new rear gear ratio to match the combo

As for which HCI combo is right for you, it will all depend on how much power you want, how the car is driven (daily or weekend street/strip terror), what RPM range you want and how high you want to shift it, will this be going on the stock bottom end, etc.

I REALLY like AFR165's for stock short block applications. they work great out of the box, they provide great flow AND velocity which is great in a street car, and they allow for some decent cam choices without too much piston to valve clearance issues.

[yeahloh95]

yeah what he said

[dads95gt]

Thanks for all the info. I was thinking of a kit like the Trick Flow Street Heat. From what I have seen or read Holley, Edelbrock and Ford all have kits also. The Trick Flow seems to be the most complete though. They are all about the same price. It seems that in addition to the kit I would need lifters, MAF, injectors, fuel pump, headers and a tuner at a minimum. I don't know enough to mix and match components. A kit seems the safest way to go unless we start out with heads and slowly build it up. Something to think about. Thanks

[Steve-0]

Ok so I took a look at the kit and the things from your list that it doesnt come with are as follows: Fuel pump, MAF, injectors,fuel pressure regulator(maybe), tuning device of some sort,t-stat and gasket,headers, and maybe gears. What do you recommend as far as fuel pump and injectors go? Also what about a bigger tb? My dad, if he goes for it, is leaning towards the trick flow street engine package. Comes with most of the things needed and is relatively cheap. Thanks for all the help so far.

Also, you got a link to a MAF that I can look at that would work?

[Killercanary]

AFR165's would be my choice, especially in that heavy car.

[Pure Stock]

AFR165's would be my choice, especially in that heavy car.

More cubes would be my choice, via a 9.5" deck.

[Steve-0]

Over a year later....the AFR 165's came today! Guess I need to start taking it all back apart again!

[Killercanary]

Over a year later....the AFR 165's came today! Guess I need to start taking it all back apart again!

Nice! What cam are you going to run?

[scott5]

wow, i cant believe i missed this thread for over 3 yrs.. But im also kinda curious what kinda of gains you get with those 165s.. I am thinking of throwing those on until i get my other motor done.. Steve did you check into the anderson ford cams?

[scott5]

p/n B-21

Same as B-31 except utilizing 1.7 R.R. N2O or S/C 8-15 lb 302 c.i.d. Best performer for 1.7 R.R., stock pistons and 6200 rpm. Great with TFS or Edelbrock heads. Minimum 30lb injectors and 80mm mass air. Recommend 3.55 or 3.73 gears. Good drivability down to 1900 rpm, mild idle, rpm range 2400-6200, works best with 89-93 EEC, needs 2600-3000 converter. Great N.A. cam for 94-95 Mustang with great drivability. With bolt-down R.R., needs 0.040" longer push rods.