95 Mustang Gt Upgrade Question

[Vekxun]

So I recently purchased a 95 GT a few months ago with some basic mods done to it; and after some thought decided to pull the motor and upgrade it the best that I could afford with my brother.

I'm very inexperienced with this sort of thing, but my brother has done it several times now; three times with fox body mustangs and once with a 69 Chevelle; so he's much more capable than I am in this field.

I pretty much told him that I want to do it once, and that I didn't want to end up pulling the motor back apart next year because I wasn't satisfied with the performance. I'm more of a one and done type of person, I don't like wasting money upgrading the same component repeatedly chasing horse power.

So he put together a pretty reasonable package we feel, and we're getting close to getting the motor back into the car and buttoned up so we can run it for the first time. I'm a little concerned that the stock computer / tune could prove to be a problem though; so I thought I should ask someone with more experience with the 95 mustangs while there's still some time before it goes in.

I've read elsewhere that the 95 computers are very difficult to deal with compared to the older fox style computers, most especially for what sort of mods I'm doing.

I'm swapping from stock heads to GT40-X aluminum heads, stock length hardened push rods, a new comp cam with matching lifters, 1.6 roller rockers, a typhoon intake, K&N cold air intake, upgraded throttle body, 24 lbs injectors, upgraded mass air flow sensor, upgraded stock converter and a upgraded fuel pump and fuel pressure regulator.

I believe that's the total list of current mods we're installing; and I apologize for not having specific model numbers for each part. I'm just trying to keep up with him, and this is all a little overwhelming.

So with what little information I'm able to provide, is there any danger of running my motor with the stock 95 tune? I've been reading like crazy just trying to familiarize myself with this; because I'm really nervous that something will go wrong and all that money and work will go down the tubes and I'll have no car to boot.

I totally understand paying to have it dyno tuned will improve its performance, but will it run 'decent' with a stock tune until I can afford to pay to get it dyno tuned? Will there be any danger of running it with a stock tune, or will it just be performing below its potential? Any information you guys can offer is greatly appreciated; thank you very much.

Vekxun

 

[revhead347]

The SN cars are a little more particular about modifications than the older foxbody computers. Something to do with the load based logic that makes them a little quirkier. Basically if the manifold pressure drops too low because of a cam the computer doesn't know what to do. You are definitely in the range of needing a tune. We just did a similar engine here. It is actually getting harder to find people who even do OBD1 tunes. Where we live, a dyno tune isn't even available. We just got a chip from these guys and the car idles like stock. Still troubleshooting some idle issues when the car is warm, but it is basically lack of time to deal with things that is keeping us from getting it done.

JMS Automotive Products

I would sell your typhoon intake and buy a quality one if you can. That is your biggest detriment to performance. Not sure what MAF you are running either, and the tuner is particular about that. Most want to tune with a PMAS, PRO-M, or SCT meter.

Kurt

 

[Vekxun]

Something to do with the load based logic that makes them a little quirkier. Basically if the manifold pressure drops too low because of a cam the computer doesn't know what to do.

Oh, any idea what the expected behavior would be? Should I expect stalling or sluggishness or just sub optimal performance? I'm going to find the part #s and post them.

 

[jozsefsz]

If your MAF is matched to your 24lb. injectors, you should be "safe." You can probably expect idle issues (hunting / surging) and perhaps some cruise / low-load bucking. Those types of problems are easily tuned out, you might be able to "fudge" them out to get running ok with idle air bleed and fuel pressure adjustments.

I agree with Kurt, PRO-M is a good MAF. I'm no expert but if you want one-and-done, you might be happier with a nice Trick Flow top end. You might consider skipping the converter (your tune could firm up your shifts and change your shift-points electronically), and consider instead investing in some nice gears on the rear which make a huge difference with an auto trans. I also love my Crane 1.7 pedestal-mount rollers, they gave me some nice top-end power and fit under the stock valve covers.

If you're up for a little learning, tuning yourself with a Moates Quarterhorse is within the reach of a tech-savvy mechanic. The Bama / AM folks do tunes, a couple of guys on this board do remote tuning, and in my area the tuners will install an SCT chip and don't really care much whether it's OBD-I or II.

 

[poboys 94]

I did bolt on mods on my first SN95 with info and help from these forums and the guys in this section.
I got the Typhoon but sold the upper and replaced it with the Eddy Performer for better low end punchiness. Your head choice is solid, 64cc for reg pump gas but almost anything is better then the e-7s.I was fortunate to be able to trade some custom exhaust work and got AFR 165s for half price back then.
Putting off the tuning can be accomplished with a cam like the Steeda#19 as it has an sn-95 friendly LSA of 115. I got stuck with 1:7 RRs and the cams .480 lift with those was .512 and very safe with stock pistons.. I would probably stay with the 1:6s as there are more cam choices that use those. Like the intake, don't get carried away with the big TB, I had a 65mm BBK but when I converted to a Fox TB setup I went with a 70mm accompanied by the Pro-M 75mm but it was calibrated for 19lb. squirters. Your 24lb set up is the way I'm going to go on my 95 this time.
I can say that I had minimal idle issues with these mods and was very happy for the most part. I was ready to pull the trigger on a Tweecer and learn how to tune but then I got sick and had to postpone my project and eventually had to sell it..With an automatic, I would go with 4:10s like jozsefsz said but if you can't do a tune still, perhaps a shift kit may be a viable alternative till then..
It needed a new clutch (and possibly a better driver) and had a stock suspension but I managed 13:23@105 at Gateway in STL.

 

[revhead347]

I'm going to go against the grain on all the combo changing advice and say stick with what you have. The GT-40x heads may not out perform a Trick Flow combo, but they have advantages of their own. It's just about the easiest head to install, and you can run it with pedastal rockers that fit under the stock valve covers. There isn't much performance difference. Comp Cams does excellent grinds. You don't happen to know the grind number to you?

The others have pretty good info on what issues you can have without a tune on it. Keep in mind that most of us are running manual transmissions which are less effected by a poor tune. Those driveability issues are going to be magnified on an auto car.

I don't even recommend dyno tuning anymore. In my 20 years of doing this, I've seen more cars screwed up on the dyno than fixed. Unless you have someone that really knows what they are doing, it's a crap shoot. For us here in Georgia, it means putting the car on a trailer and making a 1200 mile roundtrip. I haven't had too many cars that I was dying to get an extra 5hp out of that it was worth 2 days on the road. There is a dyno about 8 miles from my house here, but the operator doesn't have a clue how to tune OBD1 stuff. I'll use it when I need to tune nitrous because I like to have a wideband on the car, but I don't have the computer messed with. I don't have any experience with the self tune stuff. That really depends on how much effort you want to put into it. You can get a tune mailed to you for the same price, so, eh, I don't see the advantage of it it unless you are doing constant modifications.

Kurt

 

[Vekxun]

Sorry it took me so long to reply, been a little tied up. I did manage to dig up some part numbers and specs to your inquiries though.

The MAF I purchased is a #BBK-8009 and the cam is a xe264hr 114 comp camp. (212/218 at 512 lift).

Current set up is as follows:

Comp cam xe264hr 114
Gt40x heads
1.6 svo full roller rockers
Hardened pushrods
Qualifier intake 1500~6500 range same as edelbrock
Bbk 70mm throttle body
Bbk maf for 24lb injectors
For racing blue 24lb injectors
Adjustable fuel pressure reg
Bbk cold air intake system
Under drive pulleys
Arp bolts throughout
2800 stall
Aode with shift kit
373 rear gears

 

[revhead347]

That's actually a very small camshaft, with a lot of lobe separation. I would guess you would have at least 16" of vacuum at idle. You actually might be able to get away without a tune at all. Give it a try and see what happens.

Kurt

 

[Vekxun]

Well we gave it a try, and so far we're having some issues getting it to idle right. We spent several hours tinkering with it thus far; with dubious results at best.

At first we were able to get it to idle somewhat decently without the spout on; then when we put the spout back on it instantly stalled and wouldn't restart. He figured it was because we didn't let the car get up to temperature before he tried setting the timing; so he finagled with it for a bit longer.

The RPM gauge is jumping around a lot, at best we manage to get it to stay between 750 and 900 rpm; and that's where it will stay running at idle; but when we try to put it into gear it tends to stall out frequently. From my thinking it seems to just naturally want to idle a little higher than it used to; but the BBK throttle body that I purchased specifically states not to adjust the screw on it to change the idle as it is "pre-calibrated" and shouldn't require any adjustment what so ever.

So we don't want to alter that and end up messing up the throttle body. Thus far at a bit of a loss. Considering buying a bama tune, just don't know what else to do right now.

 

[jozsefsz]

Does your throttle body have an idle air bleed? I can see not adjusting the idle stop to change idle speed (the computer controls that), but to get our cars to idle properly, they need to stay running with the IAC disconnected... which is where the idle air bleed comes into play. Pre-calibration doesn't make much sense on a modified engine either.

If you do feel a higher idle is in order, then yes getting a tune of some kind is the way to do it. Personally I DIY with a Quarterhorse... while the Bama type mail order tunes are nice for mild mods, if they don't get it right the first time, or you change something later, on our cars it's typically "remove chip and mail it back in" and not "download the new tune." If it were me, I'd pick up a Moates Jaybird, and an F3 adapter, and use TunerPro RT to modify it (heck I could send you a binary with the idle tweaked), and the Moates Flash & Burn software to write to the chip. You're out $135 total.

 

[Vekxun]

Took your advice Joz and used the idle air bleed; with that we managed to get it to idle decent. It still surges some but it's much better than it was. I have ordered a bama chip today which should arrive by next week; so I will post how that affects the hunting/surging problem. I hope that it solves it completely, as right now I can drive the car I just have to maintain around 1,000 rpm at stops manually by slightly riding the gas. It's an inconvenience but oh well.

That aside, the car seems very solid. I do have a question, has anyone encountered any issues with their stock radiator/cooling set up after modifications such as mine? I'm noticing that the car is running hotter than it did previously; and I'm sort of at a loss as to why. I did purchase a new temperature sensor so I know that it should be working well; my only thought is that maybe the stock radiator is too small or the fan isn't providing sufficient cooling for the motor anymore.

I'm paranoid because the stock instrument cluster is 'wonky' to say the least. Having no numbers makes interpreting the gauges a challenge; it just says "Normal" with an arrow, so when it's around the L I feel very much like it's close to overheating but I don't know "how close" it is. I'm heavily considering buying an after-market gauge with numbers so that I can better monitor the temperatures before I jump right into an after-market radiator/fan set up.

Any insights would be appreciated, thank you very much for your on-going support everyone.

-Vekxun

 

[jozsefsz]

The Bama thing always sounded pretty cool to me, if I didn't DIY I probably would have given them a try (they wouldn't do one for turbo when I went that direction). I'm glad the idle air bleed adjustment helped. You may need to re-adjust after you install your chip... if they made adjustments to the throttle body airflow parameters (they probably did). You'll know if it idles too high, or if your idle 'hangs' when coming to a stop.

If they adjusted for your MAF transfer sheet, you should see some nice gains there too (above what a matched-MAF does for you which is a bit of a kludge as far as tuning goes).

My mods are not at all like yours (I'm sure others have done so). My turbo put a lot of heat into the engine bay, but I was able to see the temps and adjust when the fan comes on with the Quarterhorse -- Bama should be able to adjust that for you, for me it made a bigger difference than the old-school low-temp thermostat -- the big intercooler opening in my ugly bumper helped too). You can guess how hot you're actually running based on when the fans come on (the stock tune turns them on at 208, and to high speed at 224) assuming your temp sender (the one that feeds the ecu) is good.

There are actually 2 temp senders, one tells the computer how hot the coolant is, the other runs the gauge, so they don't always match up. You can "test" using a laser thermometer on a coolant hose, or as you mentioned install an aftermarket gauge, and see how hot you are when the fan kicks on -- you should be around 208 degrees. If not, the sensor being used by the ecu might be off. You can also then check where the gauge sits, and whatever letter is your baseline for 208.

The high-speed fan goes off at 220, and the low-speed goes off at 204, if that helps in your troubleshooting at all.

 

[toyman]

I believe that should read "low-speed fan goes ON at 220* and OFF at 204*". High speed ON at 230* and OFF at 220* or ON with the a/c on at any speed less than 48 mph.

 

[Vekxun]

I believe that should read "low-speed fan goes ON at 220* and OFF at 204*". High speed ON at 230* and OFF at 220* or ON with the a/c on at any speed less than 48 mph.

The A/C was taken out of my car, would that prevent the fan from triggering while the A/C switch was still turned on?

 

[jozsefsz]

I believe that should read "low-speed fan goes ON at 220* and OFF at 204*". High speed ON at 230* and OFF at 220* or ON with the a/c on at any speed less than 48 mph.

I took the numbers directly from the stock tune - here are a few small corrections. Up to 208, no fan at all. As it cools, it turns off at 204. If you manage to get to 228, the high speed kicks on until it cools it to 220. At 220, the low-speed will still be on, unless and until it cools it off to 204. If it goes above 228 again, high speed kicks on. There are other adjustments for speed, load, and RPM...

If you're below 45mph, then the high-speed fan can come on at 224 (the lower value).
The load has to be above 150% for the lower high-speed fan on value to be used (224).
RPM's have to be above 1808 for the lower high-speed fan on value to be used (224).
I don't see any parameter related to whether or not the A/C is on.

I've read that the service manual reports the numbers that you've produced, but they don't match what's in the stock tune, so I'd have to say the service manual is incorrect (they probably weren't trying to be dead accurate). It's not a big difference, but big enough (at least on the low-speed).

 

[Vekxun]

Well, some progress at least I suppose; not necessarily the kind I wanted though. It turns out something about my temperature gauge was on the fritz; and it was reporting that the car was overheating when it was actually well within normal operating temperatures. I bought an after-market temp gauge which now reads accurate, numbers and all; so that seems to solve that.

No clue what went wrong with the old one, but the running theory is some sort of bad ground.

On the flip side, a less positive and much more depressing step backwards; my bama chip arrived finally and I installed it. The first chip arrived with an incorrect tune sheet, and I had to send it back to get the correct chip before I could install it. After waiting 2 weeks for my chip, I finally got around to installing it tonight. The entire reason I bought the chip was to alleviate the surging and stalling I was experiencing at idle; only the chip doesn't seem to have solved either issue.

I've been driving the car for over a month now with the awful stalling issues, and I've had to ride the gas at all times to keep the car from stalling while idling at stops. I've noticed the more I've driven it the worse it seems to have gotten, as when I first got the motor back into the car it would idle on its own until it got up to temperature; where as now it won't even stay running once I start it without assistance. I don't know much about the computer; or how it learns, but I can only assume that the computer is somehow getting used to always being on the throttle and trying to compensate and falling on its face or something. I don't know if it can learn such a behavior, if I'm the cause of the worsening idle conditions, or what I can really do at this point.

After setting the timing back to 10 degrees as instructed; we started the car with the chip installed. It started faster than ever; and was immediately at 1,000 rpm which I've never seen. I was very pleased as it idled perfectly without any issues in the street while we stood around for a few minutes listening and waiting to see what it did. Thinking the problem was solved I took it up the street to get gas, only to realize I was wrong. It behaved much the same, and started to stall after only one stop sign. First it surged a little bit, but caught itself; but quickly I realized that it wasn't able to consistently stop itself from stalling on its own. It seems like when the car down shifts it just drops the RPM too damn low; and the engine dies. It goes from 1000-1100 rpm to 500 rpm when slowing to a stop; which I can't explain.

I'm getting worn out with this project, after all the money I've spent it just seems like it's never going to run right; and it makes driving it so much less enjoyable knowing that it's half-ass done. I don't know if I should try adjusting the idle screw, try unplugging the battery overnight to reset the computer and try to see what that does, sending the chip back to be retuned, or just giving up on that and taking it to a dyno tuner and risking them overwriting the stock tune and ruining the car even further...Or just taking the cam out and putting the stock one back in.

Not sure which is the least bad option at this point. Any thoughts?

 

[jozsefsz]

Ok here's what I'd do. I believe what's happening is that your closed loop idle settings are off base, probably running too lean for what your engine wants. It runs good and idles good until it goes into closed loop, and it learns the idle mixture over time and makes it over-lean. Personally I'd disable adaptive learning at idle, and force idle into open loop. (I learned this trick from something @Decipha linked on these boards, a genius with tuning imho). Incidentally this is how I run my own tune for a turbo, and just passed emissions testing with flying colors so...

I actually sympathize with Bama here, since figuring out what's happening remotely without a datalog is next to impossible. But truth be told that's the product they sell. If you want to have it re-tuned, I'd still avoid the dyno. I'd hook up with one of the remote tuners who post here and let them get you straightened out. They'll get datalogs, work with you interactively, and get you running perfect. A dyno tune will probably leave you disappointed. Those guys are good at getting you to max power, but don't focus as much on day to day driveability (if you're really unlucky the symptoms won't even show up when you're on the dyno). Some of them may be able to work with your SCT chip as well.

But try this first. Disconnect your battery for about 30 minutes, learning will be cleared. Disconnect your O2's. This will throw up a check engine light, but don't worry about it. This will keep your idle (and rest of your tune) from ever going into closed loop, and will disable adaptive learning. Drive around a while (don't overdo it) and see how things work.

If this works well, give the folks at Bama a call and ask them if they can disable closed loop at idle, and adaptive learning throughout the idle range. (I know this is absolutely possible in a tune as I do it on my quarterhorse, just don't know if they'll do it for you). If they will, ship it back, wait for the return, and hopefully you'll be solid.

If not, as I mention, consider a remote professional tuner (not mail-order like Bama). Or get a refund from Bama, and get yourself a darned quarterhorse and we can get you running pretty ok with a little advice in a couple of hours. And that way you can keep adjusting it well into the future for any other changes you want without the 2 week delay (as I mentioned in a previous post, that's why Bama doesn't work well for us since you have to mail the stupid thing in for changes).

Don't give up, you've done a lot of work and you're almost there. What you're experiencing is absolutely fixable. Give this a try and report back.

 

[Vekxun]

I'm just woefully unimpressed with Bama at this point. My interactions with them at every point have left me feeling like I should've just bought a tuner and hooked up with someone that knows what they're doing and did it myself. If they couldn't manage to mail the proper tune out the first time, and the second tune they sent didn't do what they advertised it would, there seems to be little reason to believe another try will yield different results.

That said maybe I'm being overly critical. I admit that you have a point, it must be like taking a stab in the dark trying to tune one of these cars without even seeing it. It seems like a recipe for failure and dissatisfied customers, which makes me question why they do it outside of just milking people for easy money.

So after reading your post Joz I googled around just to see if I could dig deeper into what you were saying. If I'm understanding you correctly, disconnecting the battery will clear the computer's memory of everything that the adaptive learning has taught it thus far (which shouldn't be very much since I unhooked it for over an hour last night before I plugged the chip in; in order to disconnect the computer safely). Once the memory is reset, if I unplug the O2 sensor plugs from the harness and hook the battery back up and fire the car up; the car won't be able to enter a closed-loop cycle at any point without the missing O2 sensors sending information to the computer.

From what I understand, the O2 sensors send air to fuel ratios to the computer and the computer interprets this data to determine how the car is running, too lean, too rich etc; and when the car is in a closed-loop the computer updates this table to adjust the air to fuel ratio by adding or removing gas. However from what I have read the computer cannot make adjustments to the stored tables of previous data while it's in an open-loop, and it must first enter the closed loop for the "adaptive learning" to take place. So if the memory is reset, and the O2s are unhooked, the car should have no stored memory of anything it has learned previously, and it should never be able to enter the closed loop to begin learning anything either. It will just run with the base values stored on the tables before the computer has had a chance to trim them based on driving habits. Is this correct?

My only concern is running the engine too lean without the computer's help; and causing any damage. If the car maintains a solid idle all the way to temperature without the car's adaptive learning in place that would presume you are correct and the problem is the closed loop idle settings.

If I'm able to get bama to 'tune out' the adaptive learning from say 500 to 1100 RPM, that would essentially mean that the car wouldn't try to alter the air / fuel mixture at all until I was actually driving, right?

What did you mean by over-do it, just as in don't drive it too hard without the O2s?

 

[jozsefsz]

You are correct on all counts sir. Yes, I suggested take it easy because without the adaptive learning, there may be spots outside of idle where you're a little rich or lean and I wouldn't want you to have engine problems. But since you're naturally aspirated I think the worst you'd see is some bucking or perhaps pinging. If you get that, then just back off of the throttle a bit. I wouldn't immediately go do a bunch of wide-open-throttle runs, just to be safe.

And yes, you could ask them to tune out adaptive learning in the idle range, and there's also a force-open-loop idle parameter they can set to make sure the computer is always trying to use the "requested" air fuel ratio (around 13.8:1) and not try for the leaner, emissions-friendly but generally too lean for the 5.0L, 14.7:1 (stoich) which it does in closed loop at idle. You'll find this makes the computer much more forgiving to mild mods in the future too, and may help remove some cruising bucking too (which comes with the lean afr).

These tune changes won't impact learning or function outside of idle, and your emissions should still be perfectly solid (while disconnecting the O2 sensors disables it everywhere). Ford just got a little too aggressive thinking closed loop would work well at idle, because the 14.7:1 air fuel ratio is too lean for most engines (even a mildly worn stock one). In closed loop, you'll actually see the car's air fuel ratios (if you have a wideband) switch back and forth between around 14.2 to 15.2:1. It doesn't stay at 14.7:1 all the time, because the narrow-band O2 sensors in the car can only sense something above or below 14.7:1, and they have no idea how far above or below. So they periodically (once every few seconds) switch from rich to lean and get you an average of 14.7:1. If you're watching a wideband, you can feel the idle surge and hunt along with those switches. While you're driving along it's much less noticeable and the switching happens faster.

So in my opinion, the best thing to do is just shut that behavior off at idle, and use a pre-determined value (13.8:1). You end up with a smoother idle, less hunting / surging, and less bucking at cruise. This also gives you enough fuel to work with the increased overlap of a mild cam upgrade without making the car stall all the time.

 

[revhead347]

So sorry you are having trouble. I have never heard anyone say anything good about Bama tunes. I have been a long time customer of jms chips, JMS Automotive Products The owner actually created the SCT chip system. Even with that, OBD 1 stuff is hard to tune. You really have to tinker and see what happens. Add some fuel pressure, add some timing, etc, see what happens.

Kurt