Just an FYI, I have to point out Darren Freed as the rightful reverse engineer of the OBD 1.5 computers. It took the guy years to do it. Some time ago, his hack was available on his college web page. It is one of the best hacks I have seen of a code, especially one with SFI. His work made me change my mind about which code I would use on my Fiero. He too is (was?) a Fiero guy.
Not saying that Darth doesn't do really good work, but this hack was not his.
After reviewing the hack, I am convinced that the OBD 1.5 computer is the best computer for ALL 3.4 DOHC applications from 94-97. With some work, even boosted.
91-93's still have to stick with the 16149396 or 1227727 / 730 computers because they lack most of the critical sensors for SFI. But hacks are just as available for these computers.
I still don't see the practicality in the Haltech, or other aftermarket computers, EXCEPT for the fact that they are easier to modify and don't have such a steep learning curve. In the end you still won't have the drivability, the features, and the cost effectivness of the factory ECM's. Then what if it breaks? its another $1,000. As opposed to $25 at the u-pull it.
That being said, it's still fairly difficult to try to dumb down a 94-95 ECM to not run SFI, and run off a MAP sensor. It doesn't even have a MAP sensor at all, and one cannot be hooked up to it without some serious understanding of the code, or some special hardware. I am hoping to hook up a MAP sensor just so that it will report to the ALDL stream along with my WBO2, I am using the transmission temperature input to do this dirty deed with the WBO2, but I need another Analog port for the MAP. This is why it's difficult.
Sounds like fun!
Does anyone know where to get a hold of any of the disassemblies?
I have a question about headers for the 3.4 DOHC. I have a '96 engine I plan to put into my project car. I am having trouble finding a front manifold up here in Canada for the 3.4 DOHC to replace the rear one as I want to run the exhaust in the stock Fiero route versus out the rear side of the engine so I just decided I would build a set of headers for it instead. Always wanted to build a set anyway. I now have a decision to make around what type of header to build.
I have done some reading on the web around the design aspects etc. and I also went back through this thread and saw procarnut's header setup as well as what fieromadman drew up in CAD and I have narrowed down to 3 options in my opinion for headers.
Here is what I have gathered and my own opinion on the options before me.
Log Headers. Essentially, build a header set that look a lot like the stock 2.8 manifold or 3.4 exhaust manifold where each port comes out into one tube running into the connector/crossover pipe into the rest of the exhaust. Easiest to build, and you get some hp increase from removing the stock cast manifold restrictions but not a lot.
Shorty Headers. These are pretty much what procarnut did for his build. A lot like the log style but each port runs into a collector so you remove the mixing and backpressure from the other ports with the log style. You still have unequal length primaries so you don't get optimized tuning. More difficult to build than log but you will get more hp increase. Not sure how much to expect.
Long Equal Length Headers. Best of the bunch but much more involved in designing to the proper rpm range, peak torque curve, with more complex bends to make sure all are equal length both sides of the engine. I have to assume it will give the best hp increase since you are tuning to optimize for road or race performance whatever your application.
Obviously, the long headers would seem to be the obvious choice overall but my question is:
Is it worth the extra work to build these for what you will gain in hp and sound etc.? I have also read that tuning these long headers can be a lot of work after installing to make sure you compensate in the ECM etc. for fuel, air against the more free flowing and tuned headers. I had not planned on porting the heads or intake at this time as I want to get the engine in and working to start with. I can always play during a later winter when it is stored.
If I do go with the long, tuned headers, from my reading I would think I should set the tube length to optimize at peak torque, which I believe is about 4200 rpm? This was stated the best for road driving, and racing useage would be peak rpm range rather than peak torque. Any feedback on whether this would be the best approach if I do end up going with long, tuned headers?
Regardless of shorty, log or long header build, I planned on using 1.75" primary diameters that collect into 2.25" collectors/crossover pipe that then mate into a 2.5" diameter for the rest of the exhust run. I have a high flow cat and magnaflow muffler. Thoughts on this as well?
I look forward to the replies and experience you can all provide.
Originally posted by Emc209i: Yep, that and this particular forum. What do you need that you can't find?
So you deleted your very well informational post??? Wow. One minute I miss my old Fiero, the next minute and I remember why I left. It's this attitude that almost makes me glad I'm out of Fieros...
[This message has been edited by Silicoan86 (edited 05-23-2009).]
I have a question about headers for the 3.4 DOHC. I have a '96 engine I plan to put into my project car. I am having trouble finding a front manifold up here in Canada for the 3.4 DOHC to replace the rear one as I want to run the exhaust in the stock Fiero route versus out the rear side of the engine so I just decided I would build a set of headers for it instead. Always wanted to build a set anyway. I now have a decision to make around what type of header to build.
I have done some reading on the web around the design aspects etc. and I also went back through this thread and saw procarnut's header setup as well as what fieromadman drew up in CAD and I have narrowed down to 3 options in my opinion for headers.
Here is what I have gathered and my own opinion on the options before me.
Log Headers. Essentially, build a header set that look a lot like the stock 2.8 manifold or 3.4 exhaust manifold where each port comes out into one tube running into the connector/crossover pipe into the rest of the exhaust. Easiest to build, and you get some hp increase from removing the stock cast manifold restrictions but not a lot.
Shorty Headers. These are pretty much what procarnut did for his build. A lot like the log style but each port runs into a collector so you remove the mixing and backpressure from the other ports with the log style. You still have unequal length primaries so you don't get optimized tuning. More difficult to build than log but you will get more hp increase. Not sure how much to expect.
Long Equal Length Headers. Best of the bunch but much more involved in designing to the proper rpm range, peak torque curve, with more complex bends to make sure all are equal length both sides of the engine. I have to assume it will give the best hp increase since you are tuning to optimize for road or race performance whatever your application.
Obviously, the long headers would seem to be the obvious choice overall but my question is:
Is it worth the extra work to build these for what you will gain in hp and sound etc.? I have also read that tuning these long headers can be a lot of work after installing to make sure you compensate in the ECM etc. for fuel, air against the more free flowing and tuned headers. I had not planned on porting the heads or intake at this time as I want to get the engine in and working to start with. I can always play during a later winter when it is stored.
If I do go with the long, tuned headers, from my reading I would think I should set the tube length to optimize at peak torque, which I believe is about 4200 rpm? This was stated the best for road driving, and racing useage would be peak rpm range rather than peak torque. Any feedback on whether this would be the best approach if I do end up going with long, tuned headers?
Regardless of shorty, log or long header build, I planned on using 1.75" primary diameters that collect into 2.25" collectors/crossover pipe that then mate into a 2.5" diameter for the rest of the exhust run. I have a high flow cat and magnaflow muffler. Thoughts on this as well?
I look forward to the replies and experience you can all provide.
Thanks Don
Don, not sure you can use the second manifold on the front of the engine. A few years ago, I tried the same thing. Bought a new manifold and then discovered that on the 96-97 motors the heads were so differant front-to-rear, that it would not bolt on. The early motors can do this, but the later ones cannot.
Now you could build somekind of aluminum block that was about an inch thick to help the "transition" into the manifold from the head, but I think it would cost a bunch.
Here is a pic of my headers. They were built by someone here on the forum, and I got them 5 years ago, so I don't have his name anymore, but I believe spending the money on them would be a good thing. I remember a few years ago, you could get lazer cut flanges that match the heads on Ebay, then you would just have to have someone do your bending/welding.
Rob
Before Jet Hot coating.
After Jet Hot :-) .
------------------ 88 TTop coupe (96 3.4DOHC/5 speed) 03 Vibe GT. 6spd (stock) 05 GTO, LS2, 6spd (not stock) 84 SE "Vert" (oh boy, what did I do now)
[This message has been edited by qwikgta (edited 08-11-2009).]
man I am sorry to ask this because I KNOW it has to have been discussed already. I cannot find what I need in the HUGE collection of information and I don't know my ass from a fuel injection (mechanical retard). I need to replace the 2.8l from my 84 fiero. Since I am doing this I figure I might as well put something a little better but not overkill. I was thinking of either a really nice 2.8l with cam, or a 3.4l engine. But I have no idea what to buy and the mechanic I am having do the work is just your basic engine guy (i guess). Can anyone point me to the right thread where I can find: a) a good 2.8l with cam for sale b) what 3.4l engine will fit (from what make/model/year car c) all information needed to give the mechanic to put in the 3.4l engine
hey guys, long time since i posted in this thread. Well i finally put my decklid on the beast and guess what i found. there is no way in hell i can check, let alone put oil in the beast w/o removing the decklid. what all has everybody else do to get around this.
hey guys, long time since i posted in this thread. Well i finally put my decklid on the beast and guess what i found. there is no way in hell i can check, let alone put oil in the beast w/o removing the decklid. what all has everybody else do to get around this.
dan
I used another rear cover (the one without a fill neck) and welded an after market neck on it. I have an extra modified one if you're interested.
Putting oil in isn't that big a deal at all. Just use a funnel with the snake tube. Just don't expect it to be that easy to change those spark plugs.
For the dipstick, There isn't any real easy solutions. I made a custom one out of the two ends of a stock one, welded to a 3/8" fuel/brake tube that I bent with a Electricians bender to make it a "S" shape. Works good. It exits right behind the cam carrier end cap.
91-93 had no Cam Position Sensor on the front cam box. 94-96's fronts do have the sensor and in 97 (or so i am told) that the lifter diameter changed. All rear cam boxes are the same, save for the diameter change in 97. they are ALL interchangeable, fitment wise. Just beware of the change in the sprocket pitch in 96-97's.
ok, i am having issues with the beast taking forever to start, i mean like ten minutes. found fuel pressure regulator completely destroyed so i replaced it and still had same issue. once started the car will run, stall, run, stall, run, stall. once it gets warm she runs forever. unfortunatly i haven't/can't get or keep it running long enough for any codes to set to see where to start looking for issue. any ideas???. I am really considering putting the duke back in, at least that was driven on the street, 5 years with the dohc and it hasn't left my garage yet.
MS, whats up, just passing you a pic of the motor you sold me YEARS ago. She's up and running fine. Finally got her painted (all one color) before the cold hit.
Cheers.
Rob
.
------------------
88 Coupe, TTOP, 3.4 DOHC and a GT clip
[This message has been edited by qwikgta (edited 01-25-2010).]
wow...that WAS several years ago... the funny thing is I just bought ANOTHER DOHC as a backup... got a steal of a deal on one I couldn't pass up.
What color red did you paint the manifold? your swap looks SWEET! I'll get you some of the one I purchased..
Tell me how you worked the stock fiero coolant pipe setup?
VERY unique color on your formula.. I would have never chose that color but it does look good!
Are your wheels beretta GTZ wheels? The reason I'm asking is I've looked around for a beretta GTZ lately to use as a daily driver, maybe not a good idea after reading up about the Quad4...
I'm about to swap out the cradle to an 88, yours is an 88 formula right. Any issues fitting into the 88 cradle?
[This message has been edited by msweldon (edited 01-25-2010).]
I thinks its just standard "Red" heat engine paint. I want to say it is FORD red. It will do until I can get it powdercoated.
Tell me how you worked the stock fiero coolant pipe setup?
For the pass side I used a stock hose, I think it was a driverside 2.5L one. My car was a 88 coupe w/ 2.5L not a V6. I had the hose laying around the garage. For the drivers side, I cut the trunk lid support (similar to the cut we make on the pass side) and used a 90' hose to a stock 2.5L thermostate housing cut down, then a "off the shelf" hose that was the closest I could find. I made a template out of a cardboard tube and some aluminam foil. It worked.
VERY unique color on your formula.. I would have never chose that color but it does look good!
Thanks, I copied a color that I saw in HOT ROD magizine for thier "Project F bomb"
Are your wheels beretta GTZ wheels? The reason I'm asking is I've looked around for a beretta GTZ lately to use as a daily driver, maybe not a good idea after reading up about the Quad4...
Yes, Betetta GTZ rims. I am running a 205 front and 225 rear tire, but I need to run a 5mm spacer on the rear, I don't like the way they fit. All 4 rims are 42mm offset, and that does not work with the 88 rear.
I'm about to swap out the cradle to an 88, yours is an 88 formula right. Any issues fitting into the 88 cradle?
Again, mine is a 88 coupe but I had NO/NO fitment issues. Plenty of room. Did remove the stock dogbone mount, but I dont' think I needed to. More for looks. Also, I used the WCF poly mounts (all three) and with the 88 engine motor mount the motor fit perfect.
Ill take more pics to show some of the fitment stuff.
OK, posting it here first. I have an '88 Formula with the DOHC w/ getrag sitting in my mom's garage in Houston. It has sat there since October when I went to do the first plug and wire change since I bought it and found out the #2 cyl was cross-threaded. I kind of want to fix it, but I'm busy fixing my GT first. If someone wants to take it off my hands let me know. I also have a spare motor and tranny here in Ft. Worth along with various other spare motor parts that I collected to do a swap before I bought the car.
Are you concerned at all about using the engine lift bracket for your "dog bone" mounting point? It has broken on a few other people. You have poly mounts so it may not break on you.
If anyone still checks this thread. I am looking for the part numbers for the tools used to de-pin the 96401 ECU and also the fiero C500 searching found me zilch on the topic. Does anyone know?
[This message has been edited by FieroWannaBe (edited 07-13-2010).]
The 282 is a sportier and better geared transmission. The four speed is not "hard on the engine", I don't know where you got the idea. The G6 6 speed has horrible first, second, fifth, and sixth gears.
If you care to research, there's a great thread at RFT on transmissions matched to the LQ1.
The 4T60 with paddle shift will feel mushy, but sportier than without the paddles.
The 282 is a sportier and better geared transmission. The four speed is not "hard on the engine", I don't know where you got the idea. The G6 6 speed has horrible first, second, fifth, and sixth gears.
If you care to research, there's a great thread at RFT on transmissions matched to the LQ1.
The 4T60 with paddle shift will feel mushy, but sportier than without the paddles.
Hard on the engine as in at cruising speed down the highway the rpms are a bit high in 4th..
What is the gearin like in the 4t60? Does it match up nicely? The "mushy" could bee fixed with a shift kit probably for harder, stronger shifts
Originally posted by L67: The G6 6 speed has horrible first, second, fifth, and sixth gears.
I presume you mean the MT2 and not the MU9 which has different 3rd-6th gears "for performance." The F40's primary platform though, is behind a turbo ecotec. But it does come bolted behind a 3.6 DOHC in the G6. First is pretty long, indeed. Second through fifth though, are pretty close to what they are on the MG2 5-speed Getrag, while sixth is "more economy on the highway." If you want the 6 speed, and to pull on someone in 4th gear though, get the MU9 instead of the MT2.
Originally posted by HausFiero: Hard on the engine as in at cruising speed down the highway the rpms are a bit high in 4th..
~>=80% of all engine wear occurs on cold start. If you have good oil at the correct operating temperature, 5000rpm and 2000rpm will net nearly the same wear. So in respect to wear being linked to the gearing, its hearsay. What you'll be loosing is a nicely geared overdrive and fuel economy. Do consider though, that the DOHC has: 6 rod bearings, 4 main bearings, 4 intermediate shaft bearings, and 4 tappet cams sitting in two aluminum cam tower; if you abuse this engine, things will get very ugly very quickly.
quote
Originally posted by dobey: I presume you mean the MT2 and not the MU9 which has different 3rd-6th gears "for performance."
No personally I avoid both. If you like to shift, its the transmission of choice, but gearing isn't great for either, and lots of time going through the gears - particularly in town.
[This message has been edited by L67 (edited 08-03-2010).]
That would depend on the driver, but even if it were as fast or faster shifting than manual transaxle, you have to take into account parasitic loss of the automatic. It will certainly feel slower with only 220btq to play around with. Look up D2's old turbo setup that he bought from Chris West. The team at WCF installed the paddle shifters and tranny controller, I'm sure if you could get into contact with anyone on that team they would give you their opinions.
That would depend on the driver, but even if it were as fast or faster shifting than manual transaxle, you have to take into account parasitic loss of the automatic. It will certainly feel slower with only 220btq to play around with. Look up D2's old turbo setup that he bought from Chris West. The team at WCF installed the paddle shifters and tranny controller, I'm sure if you could get into contact with anyone on that team they would give you their opinions.
Iv never heard of parasitic loss from an auto transmission.. Can u go into a little detail?
As for the 220 hp feeling weak, if I do a 3.4 dohc swap I'm goin all out.. Turbo'd to make about 400 hp
Originally posted by L67: No personally I avoid both. If you like to shift, its the transmission of choice, but gearing isn't great for either, and lots of time going through the gears - particularly in town.
Have you actually driven a car with either one? Based on the gear ratios, I doubt I'll be going through the gears any more than I do now with the Getrag, my Mini, or my S-10. The only big difference is 1st gear, which I'll just end up getting through faster, since it'll be behind an LS4. Or I may just start off in 2nd plenty, in traffic. We'll see.
But beyond wishing 1st gear was more usable, I haven't seen any complaints about the other gears from anyone using the F40 trans. And Zac88GT was autocrossing his N*/F40 car.
