Thank you, so much for your interest and help, I know these are a lot of questions but this is a problem that I most get through, and I thought of posting them in here, since this is the best place to ask when it comes to Fieros.

I was wondering, which computer will be better for my 3.4 DOHC turbo setup.

Choices: 1227727 & 16149396

Ok, perhaps since the 1227727 was originally design to operate under boost it will make a more desirable candidate, or maybe even rather logical, but there still some issues that would have to be work out, such as the EGR being electric in the 3.4 and the 1227727 using a mechanical one. And more likely even more that I’m not aware of!

Could EGR problem be fixed? Will deleting it have a negative side effect, or not?

On a side solution I thought of using the 16149396, since I already have one, but there are some questions that I have about going this way:

1) First of all, how could the 16149396, be modified to operate under boost successfully, just as well as the 1227727?

2) How hard would it be to reprogram the DOCH computer to make it work under boost, and just as good as the 1227727 one?

And last. But not least.

Which ones will be the advantages, of using the 1227727 over the 16149396? (Could this be fix, to match one another?)

Thanks again!

I have been wondering the same thing with one twist. Would one of these be better than the other or would a Haltech be better yet? Hopefully someone chimes in with some good advice. Thanks in advance for all the useful info to come.

Greg

Yes, lets see WCF?
You guys have already done the math on this, what did you do?

Thanks!

TEC 3 if you have the money... way more tunable.

West coast also sells the Haltec E6GM... That would be the one I would go with....

Go with the Haltec. I have heard the tech support is great, along with the product.

I am not positive on the numbers you're talking about... but for any kind of 60* V6, the turbo grand prix code is the way to go. It supports boost (up to either 2 or 3 bar, I forget off the top of my head), and is definately the cheapest vs the e6k and other aftermarket ones. I highly recommend the gmpcm tuning software if you go that route. Cost you $25. You can get an eeprom burner on ebay for $50 delivered, and then basically whatever the TGP computer costs. You may be able to use the DOHC computer with the TGP eprom, but there may be wiring differences (like for a wastegate actuator solenoid or something) You can alter the fuel map in the GMPCM software to compensate for the larger displacement. I bought it when I needed to fix my stalling problem in my 3.4dohc, and it worked like a charm. Checkout www.gmpcm.com for more details

Yes, its true that all those computers will do wonders, but that it’s the case when money isn't an issue, however I'm trying to keep this project as a low budget project, other wise I could of done a N* conversion instead.

Thanks thou

More opinions, advices? Please shine with your knowledge, you ECU masters!

I have a modified $DF mask (9396 ECM), its done similarly to the $8F (TGP) minus the wastegate. I will be posting it on my site sooner or later, use at your own risk type of thing.

As for which is better, the $8F was meant to handle boost from GM, though the RPM scales are really not ideal for the DOHC engine; also if you have an electric auto tranny it will not control it. $DF is a nice mask and meant to go on the DOHC, but no boost. Be fore warned, either ECM tuning is a ***** since hardly a single table or value is near being right.

quote Originally posted by THE BEAST: Where are the GM computer Tuning Gurus, go?

They are all out playing with their Haltech's

The GM ECM's are far better than the aftermarket. The aftermarkets are just more accessable for many people.

The TGP computer (1227727) program has a switch in it which should allow it to operate the digital EGR valve commonly found on the 91-93 3.4 TDC engines. The TGP computer is also set up to interface with a 2-bar MAP sensor stock which would accurately read boost up to 15psi. You could probably run more boost than that but the ECM just wouldn't see it. I have done a couple of chips in the past for people running the TGP ECM on the 3.4 TDC engine. The 1227727 is capable of running the 3.4 TDC/DOHC engine just as good as the 16149396 computer, the only difference being the 16149396 computer is set up to interface with either a 5-speed manual, or a 4T60-E, and the 1227727 does not have electronic tranny controls so you are limited in that respect.

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power corrupts. absolute power corrupts absolutely.

Custom Chip Burning | Fiero Engine Conversions | Turbocharging | www.gmtuners.com

Why not a nice little GN/TTYPE/TTA, or a SY TY/Turbo Sunbird computer? they would definatly work, and with the mass air sensor/map combination they are slightly self tuning. All they might need is some code modification witch is fairly well documented. Especially in the GN/TTYPE/TTA compter.

quote Originally posted by Fierobsessed: Why not a nice little GN/TTYPE/TTA, or a SY TY/Turbo Sunbird computer? they would definatly work, and with the mass air sensor/map combination they are slightly self tuning. All they might need is some code modification witch is fairly well documented. Especially in the GN/TTYPE/TTA compter.

What do you think Darth Fiero, TK, anyone?

I wouldn't consider a GN/TT 7148 for anything other than the 3.8L Turbo.

I would most likely work with the 7727 and GPT code for a turbo charged DOHC or switch the stock 9693 code over to 2 BAR (would require scaling in a couple of places). The 9396 DOHC code does have the provisions for the extended RPM range although it not as good as it could be. Depends on the trans too.

The 7749 is an option if it's switched over to drive DIS but no 4T60E support is available.

Decisions, desision........

On the other hand, it's easy for me to talk since I won't be doing it.

Terry

[This message has been edited by TK (edited 03-24-2004).]

According to the GM DIY ECM sites, the 1227730, 1227749, and 1227727 are all essentially the same computer. Appearantly you can use the same mem-cal in all three and they will all work. I have heard that the 1227749 has an additional output driver compared to the other two but have never checked myself. So essentially you could use any one of these ECM's so long as you are using a chip that is set up to run the DIS and 2-bar map sensor.

You cannot use the 1227148 GN computer in place of these other computers because it is set up to run the unique DIS system only found on the Buick engines. Besides that, I don't know why you would want to anyway, the GN computer is just as slow as the stock Fiero computer with a 160baud ALDL data rate. The 7730, 49, 27 computers all send ALDL data at 8192baud rate plus there are many aftermarket scan tool programs out there (like Datamaster) that will interface with these computers.

As far as I know the EGR is the only issue you need to consider when trying to use the 1227727 ECM with the 3.4 TDC engine, if you could call it an issue. According to my tuning software there is a switch in the $8F chip (3.1 Turbo) that will allow that computer to control a digital EGR valve so I don't know what the problem would be.

[This message has been edited by Darth Fiero (edited 03-24-2004).]

One more suggestion, 3800 Series 1 SC computer (the Bonneville ECM) Basically it woud control a boosted engine and a 4T60-E. You would probably only need to adjust the spark tables and probably tweak the fuel tables for the decreased displacment, but increased boost and flow characteristics, as well as raise the redline. The only thing is you would have to convert the 3.4 DOHC to SFI (easy using the bonneville harness) and add a Mass air. Any thaughts on that?

DIS is handled in the ignition module not the ECM. The ECM setting are just set to work at the values needed for DIS.

quote Originally posted by Fierobsessed: One more suggestion, 3800 Series 1 SC computer (the Bonneville ECM) Basically it woud control a boosted engine and a 4T60-E. You would probably only need to adjust the spark tables and probably tweak the fuel tables for the decreased displacment, but increased boost and flow characteristics, as well as raise the redline. The only thing is you would have to convert the 3.4 DOHC to SFI (easy using the bonneville harness) and add a Mass air. Any thaughts on that?

My thoughts are it would not work quite right. Starting with the 3800 series I which came out back in 1988, GM implemented something called "fast start", or a high resulution crank sensor. Actually, the crank sensor has 2 sensors in it, one to monitor 3x signal and one for the high resolution sensor which is 24x or something. The ignition module on the 3800's intercepts both the crank and cam position sensors (3 signals total) and then sends that info back to the 3800 PCM. The 2.8/3.1/3.4 DIS module is only set up to interperate 1 crank sensor signal. Besides that when it comes to a turbo engine, using a 2 or 3 bar map sensor is a lot better for monitoring boost than using a MAF. I am using a MAF sensor on my 3800 Series II TURBO engine and the PCM has no idea how much boost I am pushing. I can only adjust timing and fuel up to the max flow for the MAF sensor so anything more than that is just the same value. Looking at the TGP chip, you can adjust fuel and boost individually up to 190 kpa independantly of each other. Plus, if you were planning on running more than 15 lbs of boost, you could rescale the tables in the TGP computer to work with a 3-bar map sensor. But for most people a 2 bar sensor would work just fine. In my professional opinion, don't try to reinvent the wheel on this subject. It is a lot cheaper and easier to use existing hardware (and software) which is tested and proven to run your particular engine type. If you try to use a 3.8 or 3800 computer you are going to have to completly rebuild the timing and fuel tables as well as all other operational charateristics just to get your engine running; that is if it will run your engine in the absence of the hi-res crank sensor and cam sensor (which might be taking the reference points different than what they are on the 3800). You can't always adjust all of that stuff in the chip so keep that in mind.

Thanks every one specially those who have fallowed this discussion closely giving the best of their unconditional knowledge!

Let me tell you that I'm impress with your extensive knowledge on this matter, and that in the future I will be glad to seek your help again, (if you don't mind of course), also receive my true thanks to you guys!

BTW, I forgot to mention that my car uses the 5 speed manual. For those who thought about working around the computer code for the newer auto trans.

Wheres those smileys that bow? Darth you are the man. I also think that the 1227727/1227730's are the best for turbo DIS V6 applications. I just wanted to hear what you thaught about it and the alternatives. To be honest though, I'm suprised you didn't use a 148 GN computer on your car. Basically the 3800 is the same as a 3.8, especially one that's turbo'd. Didn't know the DIS unit was unique to that motor though. The sensors are all on the crank pulley as far as I can remember with exception to the cam sensor. So its do-able, But of course that can all be avoided with the 1227727/30. I Have yet to have any sucsess with getting the 3.4 DOHC to run well with the 1227727, but that has alot to do with inexperience, and a lack of knowlege of the AUAF $8F and ARZW $6D codes. After I froze the block, I discovered someone had the hack of the $8F mask. Too late for me. But I am looking to supercharge the 3.4 DOHC, so there is quite a bit of relavance for me here now. Thanks Darth, You sure know your GM EFI's!
Fyi, 16194396's and 1227727's are almost perfectly interchangable, Besides the automatic transmission control. I used to switch them for the weekend's so I could attempt to tune it.

[This message has been edited by Fierobsessed (edited 03-25-2004).]

You are right Fierobsessed, Darth Fiero is the MAN, and I think everyone will have to agree with this, TK doesn’t do so bad himself either.

Cheers Fiero, friends!!

Darth Fiero do you have any, advice on what turbo used?