Hey guys, I have a quick question. Yes, I searched but I couldn't really find the answer I'm looking for. Anyway, I have a '91 Z28 'vert. 305 TPI with a 5 speed. Anyway, everyone is always telling me that vert's are so much slower (like a second in the 1/4) because they're so much heavier. Yeah, so if you haven't guess my question, exactly how much slower woul my car be then say a hardtop/t-top 5 speed TPI of the same year?

 

Run....60'....1/8..MPH.....1/4....MPH
0....2.280...9.863..69.63...15.302...86.63<@ SLP Day-Rest were another day
1....2.304...9.845..73.56...15.222...92.40
2....2.284...9.853..73.22...15.242...92.06
3....2.327...9.905..73.25...15.254...92.57
4....2.327...9.891..73.00...15.260...92.49

Relatively stock (exhaust/fuel pump/shift kit) @3760 lbs w/ me in it and about 50lbs of crap. (I weigh 200.)

Mine is an auto though....

BTW, the LCA's and SFC's aren't installed yet even though they're in my sig. THey're just sitting in my room till my LCA relocation brackets come in.

 

i have an Auto Week movie about the convertible z28's. They said the convertibles and the hardtops weighed the same due to the fact that the convertible doesn't have the heavy rear hatch.

 

Another question, My car doesn't have dual cats, which I think is the reason I've read that a 91Z vert' 5 speed with dual cats has 225 HP. So, if mine doesn't have dual cats, how much HP did my car come with? ...And I don't really see how another cat could make 20 HP, so am I missing something?

 

convertibles are heavier, and the extra cat in a dual cat setup isn't making any horsepower, it's that the whole exhaust is allowed to flow more freely because of the way it's routed

 

So, if I was to put a flowmaster American Thunder 3" cat-back on it (which I did) what would your best estimate of my HP be?

Another things, I'm thinking of getting headers as my next mod...What HP would they give me?

Sorry for all the questions..I'm pretty new at this stuff. I'm only asking because I'm sick of all these kids at school who always ask me how much HP my car has, and me only being able to tell them over 200. I just want some closer figures. Anyways, thanks for the help

 

My V8 Vert Z28 weighed 3760 w/ me in it.

My V6 Hardtop 92 Firebird (w/ GFX) weighed 3600 w/ me in it.

 

couldn't tell you, you'd have to route that question to the exhaust forum, they could probally tell you without thinking about it how well it flows...

 

For the weight, Speedemon171 is the closest here--I have a '91 T/A convertible and the only extra reinforcement are these gay ASC installed riveted in rocker plates that are made of 0.080" steel. I would bank on the fact that the hatch glass is heavier than the additional reinforcement. All in all I'd say they are pretty close--but you guys have me interested. I may need to compare the T/A's weight with my '91 Z28 T top.

 

I'll post the scale ticket if anyone wnats to see it.....

 

I believe your weights; 160lbs difference between the cars is most likely due to V6/V8 differences. Equipment level plays a role too--I have a 1988 Road and Track Mustang vs. Camaro issue and it has a number of tests in it. Here are some as tested weights:

Loaded 5.7 Iroc: 3645

Stripper 5.0 5spd Iroc: 3485

V6 Sport Coupe: 3325

There's also a test of an Iroc convertible against a Mustang convertible (they're even on the cover), but the buttmonkies didn't list any stats like wieght for them. The sport coupe wasn't totally bare bones, either.

Ironically, I subtracted the SC's weight from the stripper 5spd Iroc and came up with exactly 160 lbs. Your weights (w/o you in the car) are 3560 for 'vert and 3400 for the V6 hdtp. So your convertible weight is right inbetween the Irocs in the mag, and your V6 was only 75lbs heavier than the mag's V6. Depending on how much gas is in the tanks of a cars weighed plus any difference in options makes up the differences. So, if anybody doesn't believe your weights, I can also take digital pics of the articles and post them. Interesting note; the loaded 5.7 is HEAVIER than your convertible!