SD questions

[74grabber]

Been doing alot of searching around and seem to come up with 8 different answers to sunday.

Im told with SD i can do heads and intake, that SD reacts to cams sometimes good and sometimes bad. I have seen afew run cams ok... have heard its the duration the sd has issues with yet see a guy here running a Ecam on a SD car. So whats the word from those running SD and cams?


Current set up i have is a SD 1987 5.0 5speed. It has 1.7 rockers on a stock cam, E7 heads, stock intake, Hpipe with dumps and 3:73 gears. not sure what it runs - a Gtech said 13.8, but no official 1/4 mile times yet.

Personally i would like to put some gt40 heads on it, a decent intake, get a cam to go with it and see low to mid 13's on the engine. Maybe throw some nos into the mix and visit the 12's. keeping the stock interior in it.

Do i REALLY need to do the mass air swap to do this?



Thanks

[grey88gt]

I to have te same basic ?. What all mods can be done to sd car? I have an 88gt with SD. When I was looking for Stang I saw several on e-bay at the time that were SD with super chragers and other mods. I even contacted the pepole saleing the cars to confirm that they were still SD. The biggest problem they had was surging idle. Just what I have seen. My car is all stock no mods of any kind YET.

[74grabber]

Been doing some research and found some answers to my questions - interent is wonderful lol....

Found one proven combo:

1988 Lx Hatch 5 spd SPEED DENSITY. Bassani full lengths/ x-pipe, flowmasters, 1250 intake matched E7's, bowls blended, exh-bumps removed, GT40 intake w/65mm TB, STOCK CAM w/1.7's, pullies, K&N, 190 lb pump, pro5.0 shifter, spec 1 clutch, Eibach DL kit, 90/10's 50/50's, 4.10's, 26X10 Et Drags, front sway bar removed, full weight- A/C and smog still there! lol Best ET (n/a): 12.68 @ 106 w/ 1.64 60' Best ET (75 shot) 11.86 @ 111.8 1.54 60'

With a ton of others running low to mid 12's as well. Looking at his combo and what he is running id say im not far away with some home porting and afew bucks in springs, shocks, TB and intake.

I am assuming in a GT that i would guess is a tad heavier then his LX and on street tires its still a honest low 13 and maybe a high 12.

Also found that the following cams will work with SD - you will need an adjustable fuel reg -

comp cams nx264hr
crower 15510 or 15511
comp cams xe270hr


Info was found at 50tech.com

So its off to ebay to see about getting some parts and seeing if i can make this thing any faster heehhe.


FYI right now i run a stock cam with the 1.7 rockers and i get a surge at idle till the car is warmed up - its NEVER died on me, but gets annoying when the police are sitting next to you at a light lol.... After the car is warm it idles smooth at 900rpm and sounds very strong.

I liked the sound of the 15511 crower cam - had a slight lope to it and wanna see if that will work with the stock 87 block with the 1.7 rockers.


anyways found some answers


David
87 GT hatch
short shifter on 5 speed standard
3:73 gears, 1.7 rockers on stock cam, cold air induction

[aar0s]

i put a cobra intake with no problem and have read that a mild cam and heads can be done but the fuel psi has to altered for some reason.

[tmoss]

One way you need to tune SD is with an adjustable fuel regulator. Definately get one with mods. I'm still speed density and recently dynoed at 277RWHP and 330RWTQ.

[Dark_5.0]

If I put my 19# injectors back in my car runs great with the old speed ensity set-up I still have.

I have

Canfield Aluminum heads with 2.02 1.60 valves
Ported cobra intake and 65mm TB
E-303 cam

An adjusable FPR is a must with a speed density car

[Unit 5302]

The reason the FPR is absolutely necessary with SD is because the computer cannot measure fuel or air entering the engine by volume. It has a finite table of adjustments that it can make, and once your car is running outside that 20% or so, it can no longer compensate for the modifications, and you develop problems.

All the mods you're making increase the amount of air flowing through the engine, but the computer doesn't know anything about that. All the computer knows is air density, rpm, throttle position, and engine temp. Based on that, it says "okay, I think I should be injecting fuel for about this much time" When you add all the mods, it injects what it thinks is the appropriate amount of fuel, but it's reading knock sensors and oxygen sensors that are screaming lean condition at it. By increasing the fuel pressure, you trick the computer into injecting more fuel than what it thinks it's injecting, and things work out.

[grey88gt]

Very nice Unit. Well said. I was wondering how the fpr was going to fix the problem. Thanks. Ive put off doing an thing to my car just for what ive read about the to systems. Didnt want to spend lots moneys and the thing not run right. This is not an issue, but what does it do to the gas milage?

[tmoss]

The EEC does know how much fuel should be being injected as it monitors the O2 sensors in closed loop operation. It will adjust injector pulse widths if needed to richen or lean depending on whether there is too much or too little fuel. In open loop (wide open throttle - WOT) the EEC ignores the O2 sensors and goes straight to the table look ups for fuel and spark. So, you can tune your fuel needs at WOT with the fuel pressure regulator and the EEC will tune A/F ratios back into spec when running part throttle normal driving conditions. This keeps fuel consumption at or close to stock.

[88workcar]

I have had a B, an E, and a wolverine 1087 in mine. E7s, ported E7s, big valve E7s, shaved E7s, Edelbrock performers, ported perfs, and now I am tring heavly ported perfs on a 342, ported cobra, cut and extended, and a X-cam reground by cam motion. I have had NOS on this car for 10 years. 70 - 100hp shot dry. And even a supercharger. All with 19lb injectors, (sep the super crger, 30s) It all worked. My car has seen many 11 sec slips, and whipped manny-a-ass. I an now tring to run 10s on the motor and a little more 10 on the spray. Do what you want and don't worry about the SD blues, its a myth, the people selling mass air are tring to get rich

I even made a box that fit on top of the stock lower intake and had 2 stock TBs on top of it linked together, that worked too.

[grey88gt]

Wow Let the tuneing begin. This is great to hear. So what your doing I guess is bolting on the mods , makeing a pass on the enigne at wot and reading the pugs and adjusting fpr to get the right burn?

[Unit 5302]

Originally Posted by tmoss

The EEC does know how much fuel should be being injected as it monitors the O2 sensors in closed loop operation. It will adjust injector pulse widths if needed to richen or lean depending on whether there is too much or too little fuel. In open loop (wide open throttle - WOT) the EEC ignores the O2 sensors and goes straight to the table look ups for fuel and spark. So, you can tune your fuel needs at WOT with the fuel pressure regulator and the EEC will tune A/F ratios back into spec when running part throttle normal driving conditions. This keeps fuel consumption at or close to stock.

Well you have the theory right, but your deduction isn't really accurate.. It has absolutely no idea how much fuel it's injecting. It knows how much fuel it thinks it's injecting. Most of the time it also has an idea about how much more/less fuel it needs to inject. In addition, it knows how much air it thinks it's taking in which is where the problem arises. It's really clueless on both so if you modify only one variable it quickly throws a temper tantrum because nothing adds up.

The 02 sensors tell it how lean/rich the engine is running in closed loop, but since closed loop goes out the window about 3 seconds (unless you're an unlucky person with a Cobra) after you put the pedal down 75% or more, it doesn't even care what the O2 sensors are reading. Also, the O2 sensors don't know how much fuel or air is being mixed in the engine so it can only read lean/rich fuel conditions, not actual air or fuel volumes.

The SD EEC has a finite table (which is much more flexible than MAF car tables) of injection data to use. If you go outside that table, the EEC assumes a sensor is malfunctioning so it either discards data or goes into limp mode, and this is when the drivability issues surface.

The idea is to keep the ratio of air and fuel coming into the engine close enough to stock so the EEC can compensate.

An analogy is the EEC is balancing its checkbook, but it only cares to get within $200. It thinks it knows how much money there is, but its balance doesn't match the balance on the bank statement (oxygen sensor). It looks at it's tables and counts deposits for $1000 (air intake) and it counts its withdrawls for $1000 (fuel injected). The problem is mom (the E303 camshaft) made a birthday present of $500 (air) into the account that it didn't know about.

[tmoss]

Originally Posted by Unit 5302

Well you have the theory right, but your deduction isn't really accurate.. It has absolutely no idea how much fuel it's injecting. It knows how much fuel it thinks it's injecting. Most of the time it also has an idea about how much more/less fuel it needs to inject. In addition, it knows how much air it thinks it's taking in which is where the problem arises. It's really clueless on both so if you modify only one variable it quickly throws a temper tantrum because nothing adds up.

You right about not knowing how much fuel it injects when it fires the injector, but it quickly knows in closed loop if it was too much or too little

Originally Posted by Unit 5302

The 02 sensors tell it how lean/rich the engine is running in closed loop, but since closed loop goes out the window about 3 seconds (unless you're an unlucky person with a Cobra) after you put the pedal down 75% or more, it doesn't even care what the O2 sensors are reading.

It goes into open loop immediately, there is no 3 second time delay. It monitors the TPS voltage and goes open loop at about 75% throttle.

Originally Posted by Unit 5302

The SD EEC has a finite table (which is much more flexible than MAF car tables) of injection data to use. If you go outside that table, the EEC assumes a sensor is malfunctioning so it either discards data or goes into limp mode, and this is when the drivability issues surface.

Are you aware of the Adpative Control feature of the EEC IV and how it uses KAM and under what circumstances it writes corrections to cam? When the EEC monitors out of specification air fuel ratios and it sees a "persistant" rich or lean condition it writes permament correction factors to Keep Alive Memory (KAM) for the table load cells that are out of spec which that are then used to change the permanent table "target" in that cell. This is how any EEC, even SD, can adapt to changes in air flow and fuel requirements. It's not an MAF function but it does adapt and does not throw a "fit" until you get about 20% on either side of the stock target ratio as it can't correct any further. The difference in the 87-93 and the 94-95 adaptive control features are the 87-93 does not use KAM in wide open throttle whereas the 94-95 EEC uses the last KAM written for WOT operation.

Originally Posted by Unit 5302

The idea is to keep the ratio of air and fuel coming into the engine close enough to stock so the EEC can compensate.

I have written articles on the EEC function that have been critiqued by more than a few people. They are posted at www.veryuseful.com/mustang/tech/engine and if I have an incorrect working knowledge of the EEC IV I'd be glad to listen to your critique. You'll also find articles by other authors on that site too, like Tom Cloud and Mike Wesley.

[grey88gt]

I must say very nice. Thanks For the link to that web site very well appreciated.

[tmoss]

Your welcome, lots of info on that site actually, not just limited to the EEC stuff. Lots of diagrams and tech stuff also.

[Unit 5302]

Perhaps its just a myth about the 93 Cobra computers having a 7 second delay before entering open loop then.

[tmoss]

To the best of my knowledge it is. 7 seconds is forever in EEC clock speed - why would they delay it that long?

[Unit 5302]

I believe the word was they were worried about the warranty claims they expected from Cobra owners. It's the reason they detuned the heck out of the Cobra computers with the worst fuel/air and timing curves.

Open loop delay is one of the things an EEC tuner or similar device can adjust.

http://www.allfordmustangs.com/techa...CTuner_FAQ.pdf

The top of page 13 lists this command, though it's indicating high load is 1/3+ throttle.

Of course, the fact it can adjust it doesn't necessarily mean that it's preset at 3 or 7 seconds, etc.

[hardheadfamily]

I know this is not a mustang question but there seem to be a lot of people that are very knowledgeable. Here is what I have in my 89 Ranger 2wd. 86 non H.O. Speed Density with an AOD from an 86 Grand Marquis (the car was cheap complete) no A/C no smog pump, all else is stock.
I have been reading a lot of info about using an Explorer or Cobra intake and gt40 heads and a cam with the duration of no more than 114 because of vacuum issues.
Would this work with my non H.O. engine and would I see any significant increase in power, would I need to upgrade to 19# injectors I believe mine has 17#, and would I need an adjustable fuel regulator, more gph fuel pump, headers, dist, coil, and wires?

I am looking for some specific info. on what combos might work since money is tight and do not want to just through money and parts at it that wiont work.

[tmoss]

If the EEC you are using was meant for 17# injectorsyou beter stick with them. You might want to get an adjustable fuel pressure regulator for some added pessure if yu need it. The EEC will not tune out the added fuel if the engine needs it.