some of you may have followed my 96 3.4 dohc w/automatic swap into my 88 gt. well today i put it to the test to see what it would do. i had the unbelivable chance today to run side by side with a imaculate stone stock 88gt w/auto to use as a comparison, he was running consistant 16.8s in the quarter and my run with him i did a 15.0. my cars best for the day was the last run during eliminations where it did a 14.89.
as you can see by my 2.2 60 foot times that my car is not a blaze of fire out of the hole. i have yet to hear the tires squeek on dry pavment. i think with my setup i am in dire need for a looser torque converter,the stock one is just to tight. the engines bottom end is a little soft but when it hits 3500rpm the exhaust gets loud and it suddenly takes on a different attitude and starts pulling hard all the way to the 6300 rpm shift point. it almost feels like a nox charge is hitting the engine. i also brought my stock 99 gtp w/3800sc engine to run a few times and it was running almost identical times as the fiero was. anyways wow! that was fun

Engines kinda known for making power in the upper RPM's isn't it?
High stall converter, 3000-3500 rpm?
Whats the redline on the 3.4 DOHC motor?

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http://www.geocities.com/fierorulz/fieropage.html

hey Mike, when I told you today about using a higher stall converter from say the stock 2.5 Fiero, I forgot to mention that you may run into an issue in which you might bump up against the rev limiter in the PCM before the trans shifts because that stock 2.5 converter will probably slip about 200rpm or so more on upper edge of the RPM range compared to what you are using now. I honestly can't say what your stock PCM has for a rev limiter because I don't know of anyone getting inside of those YET.

Anyway it was great seeing some fellow Fiero owners at Cordova! Oh, and in case anyone is wondering about the reaction times, cordova was running a .000 tree today so we basically had to leave on the second to last yellow in order to get a good R/T.

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1987 Fiero Coupe 3800 Series II Intercooled Turbo (12.79et @ 106.6mph)
1987 Trans Am GTA 5.7L Superram 4L60-E (13.1et @ 109mph)

http://dtcc.cz28.com
GM EFI chip reprogramming & 3800 Fiero Conversions

[This message has been edited by Darth Fiero (edited 10-12-2003).]

It definately Doesn't feel like a shot of the sauce.... you'd scream off the line with all that torque @ 1500-2k rpms!

Good to hear that TDC's make decent #'s being stock though, I'll likely go for the project when I get the SE!

dra> I had a good idea what to expect with this engine when i did this swap. with the size of the ports and 4 valves per cylinder i knew this was not going to put out any real power until it was in the upper rpm range. the red line is rated at 7000 rpm and the computer is programed to shift at about 6300. but i was trying to look to the future when i considered this swap, i believe this engine has a lot of potential if it is fed some boost. I would like to keep the auto trans but it needs a much looser converter. i have a 98 cavalier z24 that has a 2.4 dohc engine w/auto and this car has a very loose converter, something like this is what i need if i am going to keep the auto trans behind my 3.4 engine.

darth> i kinda was thinking about a 4cyl converter. now i am using the 4t60e trans and this tranny has the gears shifts controlled by the pcm. now i may be wrong but does'nt the pcm control the shifts with info from the engine, like rpm, throttle position ect. does the pcm use any feedback from the trans at all besides the vss? by the way, i really enjoyed seeing you're car run the quarter. that car is a true sleeper, nothing gives away what lurkes under the hood.

quote Originally posted by mike kaas: dra> I had a good idea what to expect with this engine when i did this swap. with the size of the ports and 4 valves per cylinder i knew this was not going to put out any real power until it was in the upper rpm range. the red line is rated at 7000 rpm and the computer is programed to shift at about 6300. but i was trying to look to the future when i considered this swap, i believe this engine has a lot of potential if it is fed some boost. I would like to keep the auto trans but it needs a much looser converter. i have a 98 cavalier z24 that has a 2.4 dohc engine w/auto and this car has a very loose converter, something like this is what i need if i am going to keep the auto trans behind my 3.4 engine.

The question about it making power in the upper RPM range was kinda rhetorical LOL. Have you checked into getting a custom torque converter made? I'm not sure what a "loose converter" means but I'll assume you mean a high stall converter. I used to dable in autos when I was running RWD front engine pony cars, mainly dodge challengers. Not real familiar with the FWD auto transaxles, but isn't there a way to shift manually and make the ECU (ECM, computer, whatever) ignore it's shift points? With the old torqueflite trannys we just switched to a manual valve body and a 2500 stall torque converter. Gave one hell of a launch when hooked up to a 440CI motor and a nice 5:26 rear gear, was bad about twisting the uni-bodys but was a real hoot when you could get it to hook up!
I have been looking for a swap for my 88 since the suspension rebuild was completed and the 2.5L was dieing but kinda ruled out the 3.4DOHC because of the attention I thought it might demand, not because of any lack of potential. I'm looking for a nice torquey everyday driver, maybe 4.9 or SBC but still wrestling with the issue.
Good luck and I'll be keeping an eye out for updates.

quote Originally posted by mike kaas: darth> i kinda was thinking about a 4cyl converter. now i am using the 4t60e trans and this tranny has the gears shifts controlled by the pcm. now i may be wrong but does'nt the pcm control the shifts with info from the engine, like rpm, throttle position ect. does the pcm use any feedback from the trans at all besides the vss? by the way, i really enjoyed seeing you're car run the quarter. that car is a true sleeper, nothing gives away what lurkes under the hood.

From my experience, the PCM you are using only uses TPS and VSS inputs to determine shift points. There are RPM shift point tables in most of the other PCM's I have delt with, but I have found that these tables have no effect on the shift points. I think the PCM might use them as a backup should the VSS fail or something. Anyway, I know of people swapping in higher stall converters into LT1 equipped T/A's and Camaros and are having the same problem without tuning. If the PCM shifts the trans at a certain VSS reading every time, swapping in a looser converter will allow the engine to spin a little faster before it hits the same VSS reading and shifts... Now, you can find out where you rev limiter is by putting the trans in LOW1 and running the engine up all the way until you hit the rev limiter. I would guess that it is probably around 6500 rpm or so on that computer. If your trans is shifting at 6300 rpm now, and your rev limiter is at 6500, then you should be ok swapping in the looser converter, but it is going to be close. The worse that will happen is that you would bounce against the rev limiter at every WOT shift but that shouldn't really hurt anything, if anything it will be a little easier on the trans as the shift will occur while the engine power is cut, but don't quote me on that. There are too many unknown variables.