Cale Sahl

iTrader: (2)

I have seen quite a few hardtop Heritage Edtition/Z03 Z28s with red body/black stripes, but hardly any with t-tops. Mine is a t-top, and the last one I remember seeing in person was 16 years ago. Just curious

scottmoyer

Most people opted for the 5.7L when they got the Z03 Z28 and TTops weren't available with the 5.7. Also, if people wanted the 5 speed, by 1992, most people were ordering the car with the performance axle. When you order the performance axle, you couldn't get ttops. People thinking that they are buying a limited edition car will usually order the options that make it special to maintain it's value.

Cale Sahl

iTrader: (2)

That's what I think, too. Spec-wise, mine is a 'dog' compared to the other performance options. 205hp 305ci, 2.73 axle, but it's a hell of a cruiser so I don't complain too much (and it has 93k original miles)

RockinGTA89

nice camaro! My uncle had a heritage camaro convertible long time ago. I was like only 12 at the time, couldn't even see over the dash on passager side. Always thought it was large car when i was kid and loved it. It's a shame why they had to go the route of "if you order a performace axle ratio then no ttops." I would think by 1992 the vehicle's structual integrity would strengthened, (at least a little) to support the 350 option or 5spd with performance axle.
I mean, look in 1989 the GTA T/As were equipped with the L98, 3.27, and in a convertible (ASC conversion) or in a ttop form. So i'm kinda scratching my head on 90-92 years...

scottmoyer

PM me your VIN number and I'll see if I can get you numbers on how many 92 Z28s had TTops and heritage edition RPOs.

AmorgetRS

iTrader: (6)

It was a weight issue, not a strength issue.

RockinGTA89

AmorgetRS, I'm trying to understand this...
if it was a weight issue, what does that affect? The government's GVW penelties?
I've heard of such where if the vehicle weighs more then a specific rating then there's a charge to the corporation for doing so. (Kinda like a gas guzzler tax if you will)
Otherwise, i couldn't see much of a total weight difference between certain components on a vehicle to make it a issue. Correct me if i'm wrong, but I don't think there's much of a weight difference between a 305 and a 350 engine. Both are cast iron blocks, or the differentials weather it be a 9bolt or a 10 bolt. As for tranmissions, this is the only factor were i can see a difference, I'm sure the T5 tranny is much lighter then the 700R4.
The other weight issue I would believe is that the convertible option it's self, such as the added undercarrage support and the added components needed for the convertible top, but not much else....

AmorgetRS

iTrader: (6)

Here is a thread that should answer most your questions on it:

https://www.thirdgen.org/forums/hist...0-pontiac.html

The 350 was more than just the engine, it included an oil cooler and other things that added to the weight.

I am not sure where convertibles came into this, but as I recall, there are no factory "Vin 3" convertibles with 350s. All the Verts with 350s are the non "factory" ones.

RockinGTA89

Thanks AmorgetRS,
That link did answer a few questions, as i now know what you mean about the weight. It was indeed to meet the CAFA restrictions.
However that still doesn't answer my question in regards to why Cale's car couldn't be had with a performance axle, i mean the 305s can't be much more (weight wise) then the 350 cars. Sure the 350s got the KC4 engine oil cooler and without the CC1 Ttops, it's understandable that it would have to compromise from being penelized for the added weight.
However, I can't see why a 305, MX0, CC1, performance axle 3.27, 3.42, 3.45, etc. to be part of the package. Sure, if the 2.77 is a open diff then i can only see it saving a mere few lbs over a limited slip. But i don't think the weight savings is that dramatic.
Another question is, was it allowed to have a 305,5spd, CC1 tops, and performance axle in 91-92 models? I mean if you have the T5, that would shead some weight and i would think it would help to have the ttops & performance axle combo, available.

Unless CAFA had much more strict regulation for the 91-92 model years, then that would make more sense.
Or is it perhaps the 91-92 camaros weighed more then previous model years causing GM to find more ways to cut even more weight to pass CAFA weight restrictions. ( I can see the added air bags being as such added weight)

I read somewhere in the attached link that the weight was measured to the tightest kgs. So I can see that GM was very weight conscious.

I just find it interesting that the '89 model year (for the GTAs especially) were able to get all the goodies: L98, KC4, N10, GW6, WS6, AQ9, CC1 (glass i might add), UQ1 radio controls, and not be penelized for the added on weight as it would to previous years or years afterward.
I found out on my GTA's window sticker the shipping weight was 3,519lbs, however the GVWR weight stated on the vehicle's sticker as front: 2177lbs/ rear:2100lbs, making it a total of 4277lbs. Now i don't know what the weight regulations was for '89, but i don't think it can't be that much going into the following years....
I'm not trying to add to the complication to this thread nor do i want to continue on the attached post, I just find it a bit weird and kinda of a joke, because eventually many owners end up doing their own thing with their own car (besides who cares about weight at this point of time unless your fuel economy minded.) Like if i was Cale, i would of swapped that 2.77 and put in something more peppy, like a 3.27 or 3.42. In such experience, when i had my '87 T/A with the 305TPI, 700R4, CC1, 2.77 combo...it was a dog like he said, but when i bought my GTA, there was a much bigger oomph and i loved it! But to each their own opinion, which i spoke out mine.
However if Cale's car is original and it was built that way, i'd probably keep it that way being that i love original cars.
Speaking of which Cale just out of curiosity, do you have rear disc brakes or drum brakes on your car?
I also read that there was a possible weight difference, concerning to having either/or...

As for the convertible part, I'm thinking of something else and that would just throw it off topic....my bad

okfoz

Keep in mind that everything is a calculation, For example, The rule of thumb is for every 10% in weight reduction you get 8% better Fuel Mileage.

John

AmorgetRS

iTrader: (6)

The rear axle ratio doesn't change the weight, however it without a doubt affects the fuel mileage. So worse mileage from the performance axle + the added weight of the CC1 t-tops pushed it over the edge. Also, I am not sure you could get the performance axle without adding the dual cats, which meant more weight. The air bag system in 1990 added weight, too, as you mentioned.

As far as the performance axle, 305, 5-speed, t-top question for the Firebirds the answer is yes. I have a GTA and a Formula that are both examples of such. For Camaros I don't know the answer to that.

As far as the 89s, they did redo the code in the ECMs and improved it. This may of lead to enough of a fuel mileage gain to offset the extra weight added. Also, the CAFE requirements may have been lower in 89 then in 90.

Shipping weight and Gross Vehicle Weight are not the same. Shipping weight is basically what the car weighs. GVWR is is maximum recommended fully loaded weight for the vehicle, at least as I understand it.

http://en.wikipedia.org/wiki/Gross_vehicle_weight_rating
As far as who cares about the weight/fuel mileage, ask the government. It isn't as if GM just decided these things, these things were forced on them. What is done after the car leaves their hands isn't up to them.

okfoz

I agree.
It could be that the Dual Cats is what allowed the T-tops in 1989, that with the Aluminum drive-shaft may have been a means to offset some of that in the heavier cars. I suspect The Dual cats specifically were added to the "mandatory option list" with the perf axle to allow some of the other options that people wanted, the extra expense was probably calculated to be outweighed by the added options people could purchase with these items. A less restrictive exhaust not only improves power, but it would improve efficiency. As like anything that is restrictive, it may have helped in freeing up power than hurt for the weight.

I think you may have hit upon something that I had forgotten, The Airbag system would have taken that weight that would have been otherwise available for some other options. I bet between the extra wires, computer, airbag, added dash padding and sensors it probably weighs around 20#-30# (just a guess).


CAFE never goes down... The Government has a hard time backing off regulations once they are in place. The target I think was 22mpg or 22.5 mpg average by using a formula based on city & Highway driving. I want to think it was 25/75 or 20/80 But I do not remember. I bet I could find it if I wanted to, I do want to remember it was skewed to the Highway side of MPG.
how true that is. The govenment does many things that are good, other things they think we are too stupid to actually know what is good for ourself.

Also I did a little digging, Below are curb Weights for Camaros
IROC-Z Coupes - Info From MVMA Specifications, Standard Equipment
1982 - 2961# (Z28, LG4 & M39) Guessing not specified
1983 - 2974# (Z28, LG4 & M39) Guessing not specified
1984 - 3186# (Z28, LG4 & M39) Guessing not specified
1985 - 3319# (LG4 & M39) Guessing not specified
1986 - 3278# (LG4 & M39) Guessing not specified
1987 - 3225# (LG4 & M39) Guessing not specified
1988 - 3229# (L03 & M39) Guessing not specified
1989 - 3099# (L03 & M39)
1990 - 3319# (LB9 & M39)
1991 - 3242# (LB9 & M39)
1992 - 3273# (LB9 & M39)


IROC Convertibles - Info From MVMA Specifications
1987 - 3284# not specified
1988 - 3352# (L03 & M39) Guessing not specified
1989 - 3285# (L03 & M39)
1990 - 3400# (LB9 & M39)
1991 - 3323# (LB9 & M39)
1992 - 3377# (LB9 & M39)

I am not sure what happened in 1989 to decrease the weight so much, both the Coupe and Convertible had a significant decrease in weight...

RockinGTA89

thanks for your input guys, i find it very insightful. I musta picked the ideal year to own a GTA then, otherwise i couldn't have my cake and eat it too!

As for what i'm saying in regards to who cares factor, I know the government cares, but i'm saying for those who like to tinker with their cars, we're not always the type to be fuel conscious wise then performance wise. Although i know i'm one who likes to have as much power and be economical at the same time. I've also heard before about: for every 10 percent of weight reduction equals 8 percent in fuel savings. Which is something i always like to keep in mind. Currently i'm trying to find ways of improving gas milage on my 93 s10 and found a few...

Also, thanks for clearing up about the vehicle weight. I always had a bit of the time understanding the GVW decal on the door. I always wanted to weigh my car for accuracy but never got around to it before i sold it.

I'm interested to know what the ECM coding of the 89s made it different from other years. However i don't have the time or the know how to go about it, unless someone here has tinkered with them units and would like to shed some light about their programming.
I do however, remember i was able to get some reasonable mileage from my GTA on the highway. Something around 500 miles on a full tank and a 1/2, when i drove my GTA into michigan and back into IL. I thought it was rather remarkable when i got about 100 miles on a 1/4 tank which i was cruising about 65ish....not bad for a stock motor and drivetrain.
Even after 20 something years later, i'm still finding these thirdgens fasinating from facts, historic points, and stories from people who own them....

okfoz

When I purchased my 89 Formula 350 Convertible, I filled up in Asheville, NC, Filled up somewhere in KY, and then filled up in MI, about every 320 miles. That is the best I ever did. I calculated the MPG and I ended up with 25.xx or so... I figured that was pretty good for averaging 70Mph

Now my 87 Formula that I have done too much to, added 3.73 gears, Full exhaust, cam, etc etc, I can only go about 280 miles before getting nervous. I can make it from Flint, MI to Dayton, OH on a tank for the Trans Am nationals... I got a lot better mileage with my 2.73 and LG4, but that was no fun... burning rubber is much more enjoyable.