EEC-4 tuning

[711]

Put an Edelbrock Power Package in my 1991 about 3yrs ago,and have been VERY pleased with the street sound and feel.(heads,cam.intake,70mm TB,BBK cold air package,stock 19lb injectors,Ford Racing shorty headers,no cats,Edelbrock mufflers W/dumps,timing 13 BTC,3:73 rear gear W/rear discs,PA auto trans. Thought I had a runner until I went to the drags....15.70 @93MPH.(good traction) Car starts and runs perfect all year around,but am disappointed with the drag strip times. (Driveability is ranked #1 in importance) Any "experts" recommendation on tuning W/O hurting reliability?....thanks....walt...tulsa,ok

[Augie88GT]

Hi 711,

Your track numbers don't make sense. In 100% original factory stock condition, these cars put up better numbers than that. You made all of those modifications, and your car got slower? That doesn't add up. Something is wrong.

You can't have your cake and eat it too. You can have a nice, smooth-running, pleasant, reliable driver, or you can have a really fast track car. You can't have both. Unless you put some kind of "switch" in the car to alternate between street mode and strip mode. But even that won't be 100% effective. For example, you can't change your cam every time you want to switch back and forth between street mode and strip mode.

You could have kept the catalytic converters on the car and solved the problem by putting Y-pipes (splitter pipes) right after the headers. I learned that trick from my father. He started using home-made/custom-made Y-pipes with plumber's caps on his car in the early 1960s. Being an environmentalist, when I see the phrase "no cats", it makes me uneasy. There is really no need to run a street car without catalytic converters. In fact, in many cases, removing the catalytic converters can screw everything up, and it can actually make the car run slower - because the car's computer isn't getting the right information. There are sensors located on your cats, and it is a "feedback control mechanism" (as an engineer would say).

Your other option would be to buy 2 Mustangs - one for the street, and one for the track.

At least you have your priorities straight enough to realize that the #1 most important thing is to have a reliable and pleasant driver year round. Some people get too carried away in the other direction (they are too concerned about track times), and the car ceases to be a reliable and pleasant driver.

[711]

Augie,
Thanks for the reply! I do actually have two Fox bodied Mustangs here,but their both street. The Edelbrock Power Package has shown to be a great street package(sounds GREAT) and very reliable.(hot/cold/idle,etc.) but I agree with you....somethings not right. My 1993(manual trans) seems to run just as quick with no mods! The 1991 has me puzzled....big time! I suspect that the computer is holding it back but other Mustang owners who I've talked to are highly modified and still running the stock computer.....not really sure where to go next?.....walt....tulsa,ok

[Augie88GT]

Originally Posted by 711

Augie,
Thanks for the reply! I do actually have two Fox bodied Mustangs here,but their both street. The Edelbrock Power Package has shown to be a great street package(sounds GREAT) and very reliable.(hot/cold/idle,etc.) but I agree with you....somethings not right. My 1993(manual trans) seems to run just as quick with no mods! The 1991 has me puzzled....big time! I suspect that the computer is holding it back but other Mustang owners who I've talked to are highly modified and still running the stock computer.....not really sure where to go next?.....walt....tulsa,ok

Hi 711,

You mentioned that your 1993 (manual trans) seems to run just as quick with no mods. That is consistent with my thinking. My 1988 Mustang GT (manual trans) is in 100% original/stock condition, and it puts up those kinds of numbers or better. I've never taken my car to a track, and I've never been overly concerned about how fast my car is. I just love driving third-generation high-performance Mustangs for the fun of it. But I do remember reading the automotive magazines (Motor Trend, Car & Driver, Road & Track, etc.) back in the 1980s. And these cars do put up better numbers than that in stock condition.

You also mentioned that you suspect that your car's computer is holding it back. That was my suspicion too. I was sort of implying it in my previous post. But I didn't want to come right out and say it because I didn't want to lead you on a wild goose chase just in case that wasn't the problem. But, in a way, that doesn't make sense either. If your car is a 1991 model, it should have the "mass air" system. My 1988 Mustang GT still has the "speed density" system, which is very inflexible. I couldn't add a supercharger or even a ram air kit to my car without first converting it to mass air. But Ford switched to mass air on their Mustangs in 1989 or 1990. So, your car should be mass air, which is much more flexible. You should be able to add an air compression device to your car or make other adjustments with no problem. The computer in the mass air Mustangs is designed to handle those types of mods.

Unless the computer is getting the wrong information from somewhere? Are all of the sensors that relay info to the computer working properly?

[711]

Augie,
The car shows no "codes" and runs perfectly!(I have a hand held scanner and the computer show clean) I can't help but wonder if the camshaft is installed incorrectly.(retarded/advanced?) It's been a few years(at least) since I installed the Edelbrock Package but I'm no virgin to engine building and assembly. I was awful careful and followed their instructions exactly...I guess I'll have to Dyno it. Would like a "pro" to evaluate it and offer suggestions.....walt,,tulsa,ok

[Chris-90LX]

Originally Posted by 711

Put an Edelbrock Power Package in my 1991 about 3yrs ago,and have been VERY pleased with the street sound and feel.(heads,cam.intake,70mm TB,BBK cold air package,stock 19lb injectors,Ford Racing shorty headers,no cats,Edelbrock mufflers W/dumps,timing 13 BTC,3:73 rear gear W/rear discs,PA auto trans. Thought I had a runner until I went to the drags....15.70 @93MPH.........

15.70 and only 93 is not acceptable for a stock automatic 5-Liter never mind with the mods you have done. If you have a time slip handy, from the 60 foot mark on what are your times and speeds going down the track?

About 10 years ago, I was drag racing the LX often. We might be able to help see where things are going wonky here. Even with the stock injectors you should be running into the 13's and going over 100mph.

[711]

Chris,
Thanks for responding.....2.43(60ft) 6.74(330) 10.28@69.59mph(1/8mi) 13.29(1000ft) 15.76@92.91(1/4mi).....walt

[Chris-90LX]

Originally Posted by 711

Chris,
Thanks for responding.....2.43(60ft) 6.74(330) 10.28@69.59mph(1/8mi) 13.29(1000ft) 15.76@92.91(1/4mi).....walt

Your 60ft time could be a lot better. On my stock 15" street tires, I was pulling slow 2.20's. How are you leaving the line? I never seriously raced an automatic. With the stick cars, we had to hop off the line at a high idle (like 1500 RPM) and then dump into second gear as fast as possible. I would not get any tire spin and just a load tire bark would come from out back. My trap speeds were in the 97MPH range. One night while out with Jerry, I ran in the 14.30's.

When are you shifting between gears? Is the transmission shifting itself? I had to do some test runs before I learned that shifting after like 5300 was not getting me anymore speed or quicker times. My motor is stock with only exhaust work, pulleys and a K&N panel filter.

How is the transmission setup? Are you using a good shift kit from like Trans Go? What kind of a converter are you using? I assume this is an AOD.

Work on your driving first, but that 93MPH is telling us that you just aren't making the power. I'd be curious what that motor would pull on a chassis dyno. If the AOD is all good the 19lb injectors could be the only weak spot. Other than that, this car should be a real animal.

[711]

Chris,
The Mustang has a Performance Automatic with their converter which I believe near stock stall speed.(they asked me what converter I wanted and I told them "street")(Ford AOD trans) At the track I left it in drive so it shifted three times after leaving starting line above idle.
You would't believe the car is such a dog....it runs great on the street and even gets 24MPG highway with 3:73 gears. Runs and drives great in all types of weather,no hint of anything suspicious!
I'm tied up working another project at the moment but will directing my attention to it soon.The first thing I'll check,I guess,is spark advance to ensure I'm getting advance.(motor seems to run cool so I believe it's advancing) I did throw a MSD complete distributor at it and it was in at the track.....walt....tulsa,ok

[mike g]

still have the stock MAF? even though you should still be going faster than that even with a stock MAF.

Pulled your plugs lately to see what they look like?

did you install the cam straight up/retarded/advanced?

Have you done a compression test?

mike

[skunk]

What heads you running and cam? I'm keying in on the19lb injectors, they might be maxed for the combo and starving the car. 19's are fine for just a cam swap but 24's and fuel pump are the basic for heads / cam. 24's/pump and a tune for the injector change and to dial it in and I bet she will be good to go. I would also check for codes and you can checkthe fuel trim at the top end.

[FISHTAIL]

I agree with the others..something is definitely not right. However, you CAN make the car faster and keep good driveability. I have a H/C/I 331 car and it drives like stock. It idles rough, and it's loud, but it drives perfectly fine around town.

In order to do that though, you'll really need to tune the car. And I mean the correct way..with a tuner, like a TwEECer or a Quaterhorse.


That said, even as is your times are off from where they should be. With a stock cam, stock E7 heads, 1.7rr's, Trickflow intake, 70mm TB/Spacer, exhaust and 3.73's my 200k mile GT was trapping 103mph and running 14.00's on street tires with a 2.4 60'. If I'd bothered risking a clutch slip (which I couldn't do at the time out of fear of burning it up) I'd have been in the 13's easily..and my car didn't have anywhere near your modification level.

A good H/C/I car should be in the 12's. Even with an Auto, I'd still think low 13's would be attainable without much trouble.

Can you post more details about your setup here? What brand h/c/i are you running? What MAF? Intake setup? Timing? Fuel pressure (if you've adjusted it..which you hopefully haven't)?

[Blown88GT]

Originally Posted by 711

Chris,
The Mustang has a Performance Automatic with their converter which I believe near stock stall speed.(they asked me what converter I wanted and I told them "street")(Ford AOD trans) At the track I left it in drive so it shifted three times after leaving starting line above idle.
You would't believe the car is such a dog....it runs great on the street and even gets 24MPG highway with 3:73 gears. Runs and drives great in all types of weather,no hint of anything suspicious!
I'm tied up working another project at the moment but will directing my attention to it soon.The first thing I'll check,I guess,is spark advance to ensure I'm getting advance.(motor seems to run cool so I believe it's advancing) I did throw a MSD complete distributor at it and it was in at the track.....walt....tulsa,ok

I'm pretty sure it's the auto transmission converter. Something is wrong with it or it's not the right one.