With all of the final drive ratios out there, I am wondering what would be best for my kit car.

Specs:
3800sc series 2 or 3
widened suspension
19x11" wheels on back
Mainly daily driver, 50% freeway driving
Want good mix of power and mpg

Thanks guys.

look for 99+

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87 GT
series 1 3800sc (7.597 @88.53 1.579 60ft)

Look here... http://en.wikipedia.org/wik...ransmission#4T65E-HD

Thanks guys. I guess I am asking for experience. Has anyone setup a 3800sc/4t65 and with they had another final gear ratio? I don't want to regret getting the wrong tranny.

The 3.29 ratio is the favorite on the heavier GM cars, not sure what the best ratio is for the lighter Fiero?

3.29 overall final drive ratio would work best in just about any car that is going to weigh 2800 lbs or more (which includes a Fiero with a 3800 SC swap).

The trouble is most of the 4T65-E HD transmissions came with an overall final drive ratio of 2.93. That was with using a 3.29 ratio differential and 37/33 chain sprockets. Only the 2004-newer 4T65-E HD transmissions that came with 3800 Series 3 SC engines and had the TAPShift option got the 3.29 overall final drive gearing (they used 35/35 chain sprockets).

You CAN take a 2.93 4T65-E HD trans and put the 35/35 chain sprockets in it which will make it have a 3.29 overall final drive ratio. But it requires partial disassembly of the trans. In my opinion, it is WELL WORTH the upgrade considering how much of an acceleration performance increase it will give you. It also will not cost you much in the fuel economy department. Of course, you will need to have the PCM custom programmed to work with the new gearing, but that isn't a problem.

1997-02 4T65-E transmissions are all compatible with the same model year 3800 PCMs. Starting in 2003, GM changed the design of the 4T65-E transmission a little (electrically) which makes any 2003-newer 4T65-E INCOMPATIBLE with an earlier PCM. So keep that in mind as well.

If you get a 97-02 4T65-E trans, I would recommend using 1998-2000 programming in a compatible PCM.

If you get a 2003-newer 4T65-E trans, you will need to use 2003-newer PCM programming (in which case I would recommend using 2003 Grand Prix programming if you are going to use a cable-op throttle body).


-ryan

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OVERKILL IS UNDERRATED

Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com

Darth,
That is exactly the answer I was looking for. Now, I have the 3800sc series ii in the shop, but hasn't been torn down. Would it be a good option to find a low mileage engine and tranny from the 03 on up family? Is it cheaper to change the chain, or buy a low miles 03+ tranny for the 3.29 35/35?

quote Originally posted by mram10: Darth, That is exactly the answer I was looking for. Now, I have the 3800sc series ii in the shop, but hasn't been torn down. Would it be a good option to find a low mileage engine and tranny from the 03 on up family? Is it cheaper to change the chain, or buy a low miles 03+ tranny for the 3.29 35/35?

You won't find an 03+ 4T65-E HD with the 35/35 chain sprockets easily. Like I said, those were only offered with the TAPShift option (04+ Series 3 SC applications only), and the TAPShift function only works with the 3800 Series 3 PCM (unless you run an aftermarket transmission controller) which comes with its own share of issues when trying to use it in a Fiero swap. You could use a TAPShift capable trans with a non-TAPShift capable PCM, but the TAPShift won't work.

ALL OTHER 4T65-E HD transmissions including 03+ came with the 37/33 chain sprockets. Non-HD 4T65-Es are commonly found with 35/35 chain sprockets and you could install the HD differential and related parts into it easily enough if you want to go that route instead.

Remember, if you get an 03+ 4T65-E, then you must use an 03+ PCM/programming. And I can only recommend cable-op throttle body systems for Fiero swaps due to the problems many people have had when trying to use DBW Series 3 systems in Fieros. The only 3800 SC cable-op PCM/programming compatible with 03+ transmissions is for a 2003 Grand Prix GTP.

if you need anything specific get ahold of morads parts the parts are used but everythings in great shape. i dont have the number right off but look them up that tap shift came out of the comp g gtp's

GTP,
I called them twice in the last 3 days. Nothing good to speak of.

Darth,
I guess I will focus on a 97-02 4t65hd. Found one for $689 with 30k. Might try that one. Thoughts?

I switched from 2.92 to 3.29 chain ratio due to the fact that the GMR chain only comes in 3.29...

I would love to have my 2.92 back...

Good to know DH. Mine has the 2.92s doesn't it? (02 gtp)

02 GTP should have come with 2.93 overall final drive ratio stock.

I don't know what car DH is talking about but if he is talking about not liking the 3.29 overall final drive ratio in his turbocharged Fiero that runs 10's?, then that's like comparing his apples to your oranges (since you are using a 3800 SC that I'm assuming won't be making near as much power as his turbocharged 3800 did).

Let me put this another way. If you have a basically stock 3800 SC / 4T65-E (w/ 2.93 ratio) powered Fiero that runs low 13's or high 12's in the 1/4 mile, then I bet you are barely getting into 3rd gear before you cross the 1/4 mile mark. This means you are only really using 2 gears for acceleration in a drag race. For something like this, using a trans that has 3.29 overall gearing would be much better. It would give you better performance without hurting fuel economy all that much.

Now if you are making some serious power and your car is so fast in the 1/4 mile that you are running out of gear (and usable engine RPM) before you cross the 1/4 mile mark, then it may be a good idea to convert the trans to higher (lower, numerically) gearing - or install a taller tire.

Which brings me to the next question. Exactly what size tire are you going to have on the back of this thing? (please give metric tire size or overall diameter). I assume since you said you were using 19x11" rims on the back, you'll have more than trashbags on them for rubber. Which means you'll probably end up with a taller tire than most people run with these swaps. If this is indeed the case, you are certainly going to want to have the 3.29 overall final drive gearing in the transmission you use.

I am talking about my fast car, but the fact that it has the same RPM limitations as a stock 3800 has... I would just suggest that the 2.92 would be a better option for someone looking to get the most out of their setup.

GM did it for a reason, guys with GTPs do it too. At the end of the day it really has proven to make little to no difference on these turbo/supercharged cars where the powerband is flat / tapers off with rpm.

The 2.92 offers the best MPG, and IMO a better feeling first gear (which is where you are doing your playing around at). I was not commenting on anything to do with top speed in 3rd gear.. as that is a side effect but I have been able to solve it easily enough so far... Its more about the 1st gear to me though.

200whp or 600+whp, I would want the 2.92s every day of the week.

Darth,
Darn good point. The tires are 285 35 19s (26.9" vs fiero 25"). I am not sure what the 7+% in diameter increase feels like, it makes sense that it would make a difference. The GTP had 26.5" tires and the power was not enough. I plan on making them a touch taller next time to match the front height. The question now, if I tear into my tranny, what should I replace while I am changing the chain??

I have a 2008 3.29 4t65e with a S3 and I really like it a lot.

I called Dave at Tripleedgeperformance. He said to get the $799 kit to make the tranny like new. He said it had everything needed. Does this sound like the right kit if I plan on rebuilding it myself?

quote Originally posted by darkhorizon: I am talking about my fast car, but the fact that it has the same RPM limitations as a stock 3800 has... I would just suggest that the 2.92 would be a better option for someone looking to get the most out of their setup.

Even if we assume someone is limited to say 6000 rpm with a 3800 SC, a vehicle weighing 2800 lbs or so or more that has a stock or lightly modded 3800 SC will benefit from having a 3.29 overall final drive ratio trans; especially if they are running taller than stock diameter Fiero tires on the rear.

quote GM did it for a reason, guys with GTPs do it too. At the end of the day it really has proven to make little to no difference on these turbo/supercharged cars where the powerband is flat / tapers off with rpm.

GM ran the 37/33 chain sprockets so less engine torque was put thru the transmission. This helped the transmissions live longer. Also, these were all used in FWD cars stock which always had traction issues with these engines that made a lot of torque. Given that, I can see why GM used the 2.93 gearing. But Fieros don't suffer from such traction issues, which means you can benefit from having the 3.29 gearing; if we are talking about performance. For you to say "at the end of the day it really has proven to make little to no difference on these turbo/SC cars" and have you apply that to every possible build out there makes me think you don't have any idea what you are talking about. Now if we were talking about a car that ran 10 sec in the 1/4 mile and it were running out of gear by the end of the 1/4 mile; or if we were talking about an L67/4T65-E swap done to a Trike that only weighed 1800 lbs wet (yes, I have built harnesses and made tunes for some of these), then I can see a reason why you wouldn't want 3.29 gearing. But some of the fastest GTP builds are using 3.29 and some are even using 3.69 overall final drive ratios in their transmissions. Why would they be doing that if you say they don't need it?

quote The 2.92 offers the best MPG, and IMO a better feeling first gear (which is where you are doing your playing around at). I was not commenting on anything to do with top speed in 3rd gear.. as that is a side effect but I have been able to solve it easily enough so far... Its more about the 1st gear to me though.

You get no argument from me on the highway fuel economy issue. 2.93 gearing will get you better fuel economy than 3.29's. But it won't be by much. But when it comes to acceleration; if you are going to be using more than 1st gear, then 3.29's can be a big help. After all, in a 4T65-E it is a big ratio drop going from 1st gear's 2.921 ratio to 2nd gear's 1.568 ratio. And 3.29’s will certainly help acceleration in 2nd and 3rd gears.

quote 200whp or 600+whp, I would want the 2.92s every day of the week.

I have to disagree with you here. You are talking about two completely different animals when comparing a 200whp car to a 600whp car, especially if we are talking about the two engines being used in the same car. An engine capable of putting 600 hp to the ground is going to be making a ton of torque so it doesn't need "better" gearing to move the car.

If you have two identical cars that both make 200whp and weigh the same, the one with 3.29 gearing will beat the one with 2.93 gearing in a drag race every day of the week assuming traction isn't an issue in either case.

quote Originally posted by mram10: Darth, Darn good point. The tires are 285 35 19s (26.9" vs fiero 25"). I am not sure what the 7+% in diameter increase feels like, it makes sense that it would make a difference. The GTP had 26.5" tires and the power was not enough. I plan on making them a touch taller next time to match the front height. The question now, if I tear into my tranny, what should I replace while I am changing the chain??

Going from a 2.93 ratio to a 3.29 ratio is roughly a 12% change. I've built a few 3800 SC / 4T65E 2.93 powered Fieros that used stock 25" tires and they felt pretty good. But doing the same swap to a Fiero that used taller rear tires (than stock) always felt to me like it could have used a trans that had 3.29 gearing. Another thing to consider here is what the weight difference is between your 19x11" rims with 285 35 19 tires on them and what a stock 25" overall diameter Fiero tire and wheel package weighs? If your 19's are significantly heavier, then that is more rotating mass that is going to suck up more power just to turn it. And in that case, you would certainly benefit from running a 4T65-E that has 3.29 overall final drive gearing.

-ryan

[This message has been edited by Darth Fiero (edited 02-02-2012).]

quote Originally posted by mram10: The question now, if I tear into my tranny, what should I replace while I am changing the chain??

I suggest getting the following parts from a GM dealer as they have been upgraded through the years and are known problem parts:
New hardened pump drive shaft (new design, hardened vs non-hardened)
New hardened 4th input hub (new design, hardened vs non-hardened)
New OEM (not aftermarket) PCS (pressure control solenoid)
Shift kit if you want (can't get this at the dealer)

To do all this, you need to remove the pump, valve body and channel plate (channel plate for FULL shift kit only). This can be more than some people can do.
You have to remove the pump and valve body to do everything except the full shift kit. If you don't do the full shift kit, it's not too bad, but still requires some skill and memory.

You will need a channel plate gasket if you remove the channel plate (so only if you install a full shift kit).

[This message has been edited by 1fatcat (edited 02-02-2012).]

quote Originally posted by mram10: I called Dave at Tripleedgeperformance. He said to get the $799 kit to make the tranny like new. He said it had everything needed. Does this sound like the right kit if I plan on rebuilding it myself?

You might want to call Dave back because I just got off the phone with him and it didn't sound like he was under the impression you were going to be changing the chain sprocket ratio; and you'll need more parts to do that.

Anything you get from Dave should be all the updated stuff (like what you would get at the dealer).

Thanks for the input guys. When I said 7%, I was talking about the difference in tire diameters, not gear ratio, just to clarify.

Darth,
Thanks for taking the time to talk to Dave about this. I will call him back and figure it out. Since I do not have my engine done yet, would it be a better option to find a gen3 engine and tranny(04 gtp maybe) with the 3.29s and the 35/35s as a package from Morad? Not trying to continually bounce back and forth, but I want to make sure this is the best way for the money possible before I do it. After the kit car, I have an 88 waiting for a new setup, so I want to learn all that I can. Thanks again guys.

Update: Just got done talking to Dave at Triple Edge. He said I should get the $800 kit with a new torque converter and sprockets. A total of $1000 to do this sucker with my labor. Thoughts?

[This message has been edited by mram10 (edited 02-02-2012).]

quote Originally posted by mram10: Thanks for the input guys. When I said 7%, I was talking about the difference in tire diameters, not gear ratio, just to clarify. Darth, Thanks for taking the time to talk to Dave about this. I will call him back and figure it out. Since I do not have my engine done yet, would it be a better option to find a gen3 engine and tranny(04 gtp maybe) with the 3.29s and the 35/35s as a package from Morad? Not trying to continually bounce back and forth, but I want to make sure this is the best way for the money possible before I do it. After the kit car, I have an 88 waiting for a new setup, so I want to learn all that I can. Thanks again guys. Update: Just got done talking to Dave at Triple Edge. He said I should get the $800 kit with a new torque converter and sprockets. A total of $1000 to do this sucker with my labor. Thoughts?

You cant use the 04 trans due to the tap shift crap.

It would be best to run a stock converter IMO, I love the stock HD converters myself.

I would like to add that I have ONLY driven supercharged 3800s for the last 8 years... I have some experience in the field of gear ratios and what feels better than others, and how many people i know that have regretted changing from the 2.92s.

quote Originally posted by mram10: Thanks for the input guys. When I said 7%, I was talking about the difference in tire diameters, not gear ratio, just to clarify. Darth, Thanks for taking the time to talk to Dave about this. I will call him back and figure it out. Since I do not have my engine done yet, would it be a better option to find a gen3 engine and tranny(04 gtp maybe) with the 3.29s and the 35/35s as a package from Morad? Not trying to continually bounce back and forth, but I want to make sure this is the best way for the money possible before I do it. After the kit car, I have an 88 waiting for a new setup, so I want to learn all that I can. Thanks again guys. Update: Just got done talking to Dave at Triple Edge. He said I should get the $800 kit with a new torque converter and sprockets. A total of $1000 to do this sucker with my labor. Thoughts?

If you want a built trans you might check at clubgp.com and talk with Tim King ( I believe ) was either clubgp or 3800pro.com one...

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87 GT
series 1 3800sc (7.597 @88.53 1.579 60ft)

DH,
What size tires are you running? I am putting a bone stock 3800sc in there, with the possibility of a turbo in the near future. It seems to me that the 2.92 would be sluggish with the bigger, heavier tires, but that is why I am asking you guys.
How often should I replace my torque converter? Dave said if it has over 100k, it is a good idea to spend the $150 on a stock TC. I did find remans on ebay for $90 though. What would you do?

JB1,
I will go over there and see if I can find him. Thanks.

quote Originally posted by Darth Fiero: Non-HD 4T65-Es are commonly found with 35/35 chain sprockets and you could install the HD differential and related parts into it easily enough if you want to go that route instead. .

X2.... I got 3.05 Gear Ratio in my Non-HD converted to HD..
Ha ha ....TOP that

Nos,
Now that is a great idea. If you guys are in my shoes with this 120k tranny, what option would you choose for a BUDGET alternative that will last?
The purple dinosaur always has great advice !

[This message has been edited by mram10 (edited 02-03-2012).]

quote Originally posted by mram10: Nos, Now that is a great idea. If you guys are in my shoes with this 120k tranny, what option would you choose for a BUDGET alternative that will last? The purple dinosaur always has great advice !

man that's a Hippo..NOT Barney..

BUDGET...Get a NON-HD and use that.
I'm pretty sure you can use 2 Manual Fiero axles for a direct Fit if you mount the trans in the middle and it should be stronger than a Getrag 5 speed.

Well, of coarse it's a purple hippo

Would there be any differences in the end?

quote Originally posted by mram10: Well, of coarse it's a purple hippo Would there be any differences in the end?

Way Cheaper Price and no Custom Axle !!!

Nice.

quote Originally posted by nosrac: man that's a Hippo..NOT Barney.. BUDGET...Get a NON-HD and use that. I'm pretty sure you can use 2 Manual Fiero axles for a direct Fit if you mount the trans in the middle and it should be stronger than a Getrag 5 speed.

The manual axle may work for the pass side. A stock fiero automatic driver axle is used on the driver side. This is all assuming his kit car is not modified at all.

Custom axles are NOT a big deal, nor are they really even an extra cost.

quote If you have two identical cars that both make 200whp and weigh the same, the one with 3.29 gearing will beat the one with 2.93 gearing in a drag race every day of the week assuming traction isn't an issue in either case.

This could not be more wrong. The trap speeds will be different in a 3800sc situation, but the quarter mile times are completely the same due to the completely flat power band. Its been tested time and time again, to the point that your "theory" is just crazy talk. You really need to lay off the google and actually start doing stuff before you go out and confuse everyone to death.

quote What size tires are you running? I am putting a bone stock 3800sc in there, with the possibility of a turbo in the near future. It seems to me that the 2.92 would be sluggish with the bigger, heavier tires, but that is why I am asking you guys.

I run with 26's most of the time, I do have some 25s and I do not notice any difference while driving it, mostly because the 25s are a bit heavier wheel/tire combo.

I have 07 z06 corvette tires and wheels on the car. They are way heavier than the 15s I pulled off it. The rear will be custom spacers (2-1/2"), so the axles should be fine IF I can actually line up the motor and tranny the way it needs to be. First time, so It might even be backwards when I am done

quote Originally posted by darkhorizon: This could not be more wrong. The trap speeds will be different in a 3800sc situation, but the quarter mile times are completely the same due to the completely flat power band. Its been tested time and time again, to the point that your "theory" is just crazy talk. You really need to lay off the google and actually start doing stuff before you go out and confuse everyone to death.

What are YOU smoking? I've been doing this since BEFORE you even had a driver's license! I didn't need to search google for anything; I've done it before it was even available on a google search. I don't know what 1/4 mile times you are looking at but I am talking about Fieros here. And every one I've seen with a stock or lightly modded 3800 SC that had 3.29's BEAT a similar swapped Fiero that had 2.93's in both 1/4 mile ET and in MPH. So I don't know what timeslips you are looking at (sandbagged or otherwise)...

I will grant you that putting 3.29's in a FWD car such as Grand Prix GTP may not gain you any 1/4 mile performance because that gearing can hurt your launch due to traction issues (easier to spin the tires with 3.29 gearing than with 2.93 gearing). Again, Fieros don't usually suffer from this problem and can take advantage of the better gearing during an acceleration contest. The 3800 SC engine does make a pretty flat power curve, but it doesn't fall off as quickly and as early like something like the 4.9 Caddy V8 does.

I told you before, if this guy had stock 25" diameter Fiero tires on the back of his car and a stock-bodied (and weighted) Fiero, then 2.93's might not be a bad idea. But he already said he had a kit car (emailed me and said it was stretched) which tells me it is going to be significantly heavier than your run-of-the-mill Fiero with 3800 SC swap; + he had 19x11" wheels on the back of it to top it off which tells me he is going to have a lot more rotating mass back there. He is going to want 3.29's if he is concerned at all about performance.

I don't know why you get on these kicks that you do, DH; but I honestly think you are just putting crap out of ass to argue with people you don't agree with. You are smoking crack if you think 3.29's are worthless. They're not in all cases; certainly not for what this guy is doing and not for what most people who do Fiero 3800 SC swaps are doing. Just because YOU REGRET doing something with your car doesn't mean that same situation applies to everyone. Perhaps someday you'll learn that.