Hey you all,

I'm looking for information on 4th Gen F-bodies. Specifically, I'm interested in the diff options, gearing differences (rear end and tranny), 1LE vs. base model specs, and any other differences from model year to model year.

For example, I know the '93s are speed density, not mass air. Are there any differences there from a performance or maintenance standpoint? The '93s also had a slightly different T-56 tranny, as I understand it. Were '93 and '94 models not available with 3.42 rear gears? Would a 150 mph speedo indicate that the car has 3.42's? No governor? I remember my old roommate's '94 T/A didn't have the "GT" package and as a result had the 115mph speedo, governor, and maybe even 3.23 gears (instead of 3.42s).

I know in '96 they went OBD-II with dual cats. They're also rated at an insignificant 10 hp more than the '93-'95 models. Of course, in '98 the LS1 came out with much more power. However, the LT1s are obviously still very compeitive in F-Stock, despite the power deficit, iron block, and smaller front brakes. Any particular reason for this? Or are the right people just not running LS1's? (IMG:http://www.frrax.com/rrforum/style_emoticons/default/unsure.gif)

So, needless to say, I'm intersted in LT1 vs. LS1 differences, too. But, I'll likely stay with the cheaper candidate, i.e. the LT1.

I should point out that I'd mainly be interested in F-Stock, so update/backdate concerns are of less importance. I'm not sure if/when I'd move to ESP.

Thanks in advance,
Tommy

What?
Tommy are you thinking of moving to an F-body???
When did this come about? LT1's make great FStock cars. Originally I was unconvinced of this until I put some seat time in Franks LS1. After that experience, whether its setup related or not, I really like my car much better on the cone courses. They're also more affordable!
I can answer some of this, I'm sure others will fill in and/or correct me:
'93's came with either 2.73 rear gears and the M28 3.36 1st gear t56 (less desirable and less common)
or 3.23 rear gears w/ the M29 2.97 1st gear t56.
All '94-'02 cars had the T56 and 3.42 rear gears, 1st, 2nd, 3rd, 5th, 6th were different ratios than the '93 trans. (can't recall the numbers) although the LT1 & LS1 transmissions are not interchangeable. There are other gears and such with automatics but I don't even pay attention to those.
If I were shopping for an LT1 to eventually modify I'd stick to the '94-'95 LT1 due to the MAF vs. speed density and the OBD I vs OBD II, but thats just me.
1LE's are interesting cars although they aren't something to hold your breath for in finding. base Z28's and Formulas will do just fine.

Hey Morgan,

Yup, I'm considering a move to an F-Body. It may be the most cost effective way to race a nationally competitive car on the cheap. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/smile.gif)

Anyhoo, thanks for confirming my thoughts on the '93 tranny. I need to find out those tranny ratios. I'm curious how it compares to the standard T-56 with 3.42s. The '93 (with 3.23's of course) may still be worth considering. Is there any easy way to determine if a car has 2.73's vs. 3.23's other than counting the driveshaft's revolutions?

I'm curious why you prefer your LT1 over the LS1. Was it low/mid range torque? Did it somehow handle differently? What were your impressions?

Thanks,
Tommy

Honestly, I prefer the LT1 over the LS1 as well. Part of it is due to the low end torque of the LT1, but it's also related to the weird braking issues with the LS1 (aka "LS1 axle hop").

There should be an RPO that distinguishes between 2.73 and 3.23. I'd have to look it up when I get home, however.

Oh, and the 2nd through 6th gears in the '93 are the same as in the '94-97 transmissions. It's just the first gear that's different.

Karen

go here
http://www.1le.net/
also click on manual gear box
http://www.f-body.org/tech/tech.htm

As far as the car comparisons go, We both had the same basic setup. Similar alignment, both have 35mm solid front bar, both have Koni Singles, Both with Hawk HP+ (but different brakes). I've even used the same tires on both cars, 710's, A3S03's, and Victoracers. For what ever reason my car just felt sharper. It transitions a bit better and the turn-in in mine is a tad quicker as well. Steering does feel a bit more responsive. Maybe I just take a while to adjust to different vehicles, but it sure felt like home when I hopped back into mine after a couple months off. Although looking at LS1 dynos vs LT1 dyno curves I wouldn't expect there to be a whole lot of performance difference. In fact the LS1 does have a higher peak but at a higher RPM. Down low it is respectable as well. The LT1 torque curve isn't a curve, its damn near table top flat. You should see my dyno plot, its flat from ~2000rpm all the way up to 4500+ rpm at around 274RWTQ. Anyway, seat of the pants feel my LT1 does feel better coming of the slower corners but the LS1 did scream down the longer & faster sections. Whatever the reason for the differences I no longer plan on ever buying an LS1 F-body.
If you are really serious about it then maybe you should arrange to have a couple co-drives in both types of properly setup cars and make up your own decision.
By the way, mine still has the worn out 139K+ mile suspension bushings on it.

I'm tired of being 60 hp short of a LS1. It doesn't matter what I do to my LT1, it will never have the power of the LS1.

I don't buy the more torque in the LT1. How many autocross's do you run where your RPM drops below 2500 rpm?? Not many, at least not here.

Look inside the glove box for a GU5 code for the 3.23 gears.

Give me more power!!!!!!!!!!!!!!! :drive:

I didn't really buy it either, but I could swear I felt a SoTP difference between the two.

I think the low-end torque is better in the LT1. The power starts to "come on" sooner in the LT1 than the LS1, and I think there are enough "slower" turns at most events (even National level stuff) that it can make some difference.

When margins are less than a tenth, any difference matters. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/dry.gif)

Karen

I thought that as well, and I'm not argueing with you. But, when I dynoed my car, it dynoed at 300 ft lbs or higher from 2500 rpm to 5200 and that seems to beat the 274 ft lbs listed earlier in this thread. This is my 2002 Z28, stock with a lid. The 2 graphs are 3rd and 4th gear. 4th is the higher line (I was just checking).

http://home.columbus.rr.com/trackbirdz28/i...201%20small.jpg

[edit] Remove the worlds largest dyno sheet and show it as a link [/edit]

Christ almighty guys, let try and resize those pics (IMG:http://www.frrax.com/rrforum/style_emoticons/default/tongue.gif)

Agreed ....

If it's too small, I can make some adjustments.... (IMG:http://www.frrax.com/rrforum/style_emoticons/default/rant.gif)

I linked it off my site. I forgot it was "huge". I can't resize it at work.....

Changing link.....

Actually they're all different except 4th (which is still 1:1).

I'm too lazy to look them up but the 93 M29 tranny actually has the same ratios as the Z06 transmission except for 5th and 6th.

IMO the differences between a 93 and a 94-97 aren't worth mentioning. Technically the MAF system is better but i've driven both and couldn't tell any difference. At least with a 93 you get better transmisison ratios.

Tommy,

Welcome, time to ditch that Bimmer for something with torque (IMG:http://www.frrax.com/rrforum/style_emoticons/default/biggrin.gif)

To check the rearend ratio just look at the option codes which are on a sticker in the glovebox.

GU2= 2.73
GU5=3.23
GU6=3.42

However the 2.73 cars are pretty rare so there is ~90% chance any 93 six speed car you find will have 3.23's (which is good because then you can switch them for 3.42's and stay legal in ESP).

If you have any questions about 93's vs. 94+ feel free to e-mail me (or ask here). I think I have all the differences memorized by now (IMG:http://www.frrax.com/rrforum/style_emoticons/default/smile.gif)

Tommy Regan....... I knew it was you. Tommy R, Austin TX.... (IMG:http://www.frrax.com/rrforum/style_emoticons/default/smile.gif)

You'll get all kinds of info here, most of it's even good (unlike a lot of places!).

Maybe I missed it, but is this for F-stock? I assume so because of the "race on the cheap" idea.

My take. Buy either one, both can win. LS1's have more HP, LT1's have better torque belowabout 3500 rpm than a LEGAL F-stock LS1 does. And because of the gearing, you will at times be down there (well, maybe not in Texas....). Karen's right, the brake-hop issue doesn't rear it's head in an LT1 either, and it's cheaper to buy. Of course it's more ragged out, and if you get a '99+ LS1 you need not worry about limited slips wearing out like you do on '98 and earlier cars so that's a Pro in the LS1 column.

I'd not recommend a '93. The gearing is a non-issue because those cars all had 3.23's even with a 6-speed where the later cars have 3.42's with 6-speeds. Also the fact it's a one year only car causes some glitches, like the front brakes are different and that sucks when it comes time for pads.

What you wanna know??? I got lots of opinions. But in the end, frankly it's 6 of one, and a half-dozen of the other. (IMG:http://www.frrax.com/rrforum/style_emoticons/default/wink.gif)

Edit: I'll add I think the reason LT1 steering feels/is faster is two reasons. The steering wheel is smaller which helps quicken it some. And the LS1's have a version of Magnasteer, which is pretty numb and might be slower too, don't know that for sure, but I doubt it.

The ladies man is interested in F-bodies! (IMG:http://www.frrax.com/rrforum/style_emoticons/default/laugh.gif)

Check out the FS nationals results:
http://ww2.scca.com/soloresults.php?ID=55

Only 2 LS1's in the top 10! And only one trophied (way to go Frank!).

IMO the LS1 gains you little on an autox course.

I don't care what one has dynoed at. You can SEE THE DIFFERENCE ON COURSE. The LT1 doesn't give up much if anything on course. Torque makes up for the HP deficet.

Example (I've got to use it since it was my best ever event at Peru). Sam and I leave at the same time. Both .5somethings at the light. Sam's LS1 vs my LT1. We hit the turn around the same time. And were close enough each time, I'm not convinced of any power advantage on an autox course.

Sam's car did have issues that event but mine did to, although much less severe.

Lonnie,

I agree that seems to be the case. What I was trying to say is that LT1's feel like they have more low end grunt to me and yet, I make more torque at 2500 than most of them seem to. Meaning, the LS1 isn't lacking low end grunt, but it feels like it is (compared to the LT1). I was trying to explain that the numbers say the LT1 does not have more grunt on the bottom (on paper), but they sure feel like they do. I'm open to explanations/suggestions as to why that is.


This was what I was replying to. I was 300 to 317 ft lbs from that power band and the 300 ft lbs held on until 5200 rpm. That's 26 to 43 ft lbs in my favor (depending on the LT1's peak, I only have that info to use). And my car seems to dyno lower than most 2002's I've seen.

I didn't say LT1's were bad, slow or anything else. I was just making an observation that the numbers and the way they feel don't seem to match up. That's all, nothing else.

Overall I think it's a moot point as far as time on course, although I might recommend LT1 just because it's cheaper. I think the LT1 feels like it has more torque because of the good ol butt dyno. The LT1 pulls hardest around 2800-3000 rpm while the LS1 pulls hardest around 4000. Because the LS1 pulls harder at 4000, it feels weaker at 3000, which it is but not by that much.

i have a 93, and have no desire for an LS1

The LT1's biggest problem is the optispark.

Otherwise is is a pretty strong motor. I believe it is more durable then the LS1.

There is no doubt the LS1 has more power, but the LT1 has more roots int he 350 motor. So, you can interchange more parts and they will be less expensive.

If you can put a cam that is well matched 1.7 rockers in an LT1 then you'll (roughly) have the power of an LS1.