ZR1 '90 vs TPI '90 ??

[johnny]

Ofcourse I know the mayor difference between those vehicles. But are there some hidden differences? Why is it that a ZR1 so much better is in handling than a TPI?

Are there chassis differences? Or differences between the rear and front axles? Maby they used a stronger or stiffer bodycomponents?

If I put a ZR1 engine into a 91 corvette and change everything, it would not behave like a real ZR1. How come??

 

[KANE]

Ofcourse I know the mayor difference between those vehicles. But are there some hidden differences? Why is it that a ZR1 so much better is in handling than a TPI?

Are there chassis differences? Or differences between the rear and front axles? Maby they used a stronger or stiffer bodycomponents?

If I put a ZR1 engine into a 91 corvette and change everything, it would not behave like a real ZR1. How come??

Wow... I would start with the fact there is a lot more "meat" in the tail. The rear end is wider. The tires are wider. Then, little components are different in small ways all over the suspension. The sum makes the ZR1 handle like it is on rails.

If you want an imposter, buy the ZZ383 motor, machine an LT4 manifold to fit it, and keep the hood closed. At 425 HP, with a few suspension mods and a careful choice of wheels, no one will really know the difference on the street or on the track. Most people (maybe even all non-vette folks) can't tell the ZR1 from an LT1 anyways.

Personally, the ZR1 is a better car than the C5 base model in terms of uniqueness, collectability, and resale. As for being a practicle car, I think the C5 wins on the merrit of the cost of parts and proven track record for reliability (a 4.5k uber-production engine versus a 20K mercury marine super-car motor). Don't get me wrong- I'd love to have a ZR1, but I'd rather drive a C5 everyday though.

 

[johnny]

Thx for your responce. I know the difference in driveability between a normal c4 and a normal c5, because I had those both. I did drive a ZR1 wich coilovers. So what you say is:

The ZR1 id the same car like a normal C4, but it handles better because of the wider tail. There is nothing like:

a lighter hood
heavier car
diverent gravetypoints
wider rear axle

thx!

 

[Aurora40]

Hmm, I recall magazines of the time thinking the Z-51 L98 Corvette handled a lot better due to it's lighter and better distributed weight. And the L98 had a lot more meat down low in the powerband for cruising around. Though the Z would ultimately dominate in most any race due to the increased power.

 

[KANE]

Thx for your responce. I know the difference in driveability between a normal c4 and a normal c5, because I had those both. I did drive a ZR1 wich coilovers. So what you say is:

The ZR1 id the same car like a normal C4, but it handles better because of the wider tail. There is nothing like:

a lighter hood
heavier car
diverent gravetypoints
wider rear axle

thx!

Well, the ZR1 was not the completely different kind of car that the 2006 Z06 is to the C6. I would say a ZR1 is as close to a C4 as a Z28 is to a base Camaro. Engine, axles, suspension, weight dist., stuff like that.

 

[johnny]

How much heavyer is the ZR1 compare to the TPI? And where is that weight located? I have heared that it is the engine. If so, why it the engine much heavyer, it is aluminum.

 

[8388]

Four cams, twice as many valves and rockers, longer serpentine style timing chain. It all adds up.

 

[johnny]

Four cams, twice as many valves and rockers, longer serpentine style timing chain. It all adds up.

Thx.....how much weight is it actually?

 

[Aurora40]

How much heavyer is the ZR1 compare to the TPI? And where is that weight located? I have heared that it is the engine. If so, why it the engine much heavyer, it is aluminum.

This is yet another advantage of pushrod motors that you rarely hear magazines mention. An iron blocked/aluminum headed L98 weighs less than the DOHC all aluminum LT5. In addition, the L98 has it's weight lower, so it has a lower center of gravity. An all aluminum pushrod motor is incredibly light.

The ZR-1 was about 200 lbs heavier than the regular Corvette.

 

[Wegone]

A motor with a flat power band up to 7K rpms and a 3 inch wider rear to cover the 11 inch wheels were the only big difference plus a ZR-1 came with all options, all the main running gear was the same as or could be ordered on a base model.

 

[ZRXMAX]

Why a ZR-1 handles better ? Good question... As you study all the changes in spring rates, sway bar sizes, shocks, etc throughout the production run of the C4... It really is no secret much tweaking has been done through factory changes alone... I know it is heavier in the front end due to the heavier motor ( about 40 lbs ) and related frame componets... It seems to sit a bit lower also in the front... BTW... their is no difference in the width of the differential... it only appears that way due to the offset of the wider rear wheels...

 

[johnny]

Why a ZR-1 handles better ? Good question... As you study all the changes in spring rates, sway bar sizes, shocks, etc throughout the production run of the C4... It really is no secret much tweaking has been done through factory changes alone... I know it is heavier in the front end due to the heavier motor ( about 40 lbs ) and related frame componets... It seems to sit a bit lower also in the front... BTW... their is no difference in the width of the differential... it only appears that way due to the offset of the wider rear wheels...

Thx again for this reply.

So, you say that the 200 lbs is allover the car. The extra weight of the engine alone is only 40 lbs, that's not much. The wider rear, the bigger rearwheels, bigger swaybars make the ZR1 heavyer.

When I drove the ZR1, I could not feel much difference in the weight, compare to my custom C4. The ZR1 handles very well.

To optimize the ZR1 I could do:

Use a lightweight hood and maby some other bodyparts (save 100 lbs)
Use carbonfiber seats, without the electricseatengines (save 70 lbs)
Lexanrear window (save 40 lbs)
coil-overs instead of leafsprings (save 40 lbs)
lightweight racewheels (save 10 lbs)
battery relocationkit
no spare tire ( save 30 lbs )

Lose some weight myself and take a skinny girlfriend too

 

[ZRXMAX]

Thx again for this reply.

So, you say that the 200 lbs is allover the car. The extra weight of the engine alone is only 40 lbs, that's not much. The wider rear, the bigger rearwheels, bigger swaybars make the ZR1 heavyer.
It seems GM was putting on the beef each year... all the little improvements added weight... the 90 ZR-1 was the lightest... I don't think that rear clip and different doors really added much weight... However... ZR1 doors are specific to that model...

When I drove the ZR1, I could not feel much difference in the weight, compare to my custom C4. The ZR1 handles very well.
Good point, they do seem well sorted out... I wonder how they compared with the 1984 Z-51 cars in the slalom ? That would be the defining test imho...

To optimize the ZR1 I could do:

Use a lightweight hood and maby some other bodyparts (save 100 lbs)
I was quoted 56 lbs for a Toledo Pro hood in fiberglass... I don't think you can knock more than 30 to 40 lbs off in the hood alone... Perhaps if you did a lot of carbon fiber stuff you could get to 100 lb reduction...
Use carbonfiber seats, without the electricseatengines (save 70 lbs)
Now it feels like a race car with those seats! lol !!
Lexanrear window (save 40 lbs)
I don't need a rear window defogger anyway ! Got a price on that piece ?
coil-overs instead of leafsprings (save 40 lbs)
I wasn't aware the weight savings were that big... everything I have ever heard regarding the weight saving were pretty minor... but the handling and ride height adjustments are a bonus...
lightweight racewheels (save 10 lbs)
That is big... reciprocating unsprung weight is times 7 at speed... like losing 70 lbs...
battery relocationkit
Or... a lightweight battery... have heard of an 11 lb battery before... 29 lbs lighter than my Optima... I still need to move mine behind the passenger seat...
no spare tire ( save 30 lbs )
That is why I have 24 hr towing service... but I still keep the spare... some other guy might need it on the side of the road...

Lose some weight myself and take a skinny girlfriend too

I could stand to lose 30 lbs myself... however... the girlfriend would cost me half of everything ! :-(

 

[johnny]

Not that I have this idea, but you could take a convertible chassis and build a ZR1 convertible out of it. Use the grandsport flares for the rearwheel off-set.