ZR-1 Top Speed

[Jeffvette]

Wow, what a ****ing match

Curtis hit 201 during the ORR race in Texas. His mods: P&P on the plenum and injector housings, coilovers which lowered the car, and the absence of side mirrors.

The Aerobody by Callaway does more than just the nose. It's a complete package that allows the air to flow more smoothly over the entire car.

 

[ZR1Pete]

I believe it was just under 400 rwhp. His speed was recorded by either radar or gps if I'm not mistaken. This was done, at one of those high speed events here in Texas similar to the Silver State Classic.

There you have it 400 RWHP and coilovers to get you to 200MPH or 475-490 FWHP depending what % you use.

 

[locobob]

Thought Curtis had headers as well. Also remember something about a good tailwind or being on a downhill stretch, could be wrong, it's been a while since I read his post on ORR. Lots of factors involved with topping out. I'd say Curtis Wards experience was an example of everything coming together just right. Probably more of an aberation than the norm.

The Grandsport ought to be capable of low 170's I would think. I recall a mag article where an LT1 managed 172mph but most put the figure in the high 160's. Obviously an LT4 car would best an LT1 in top speed.

Z06 is gear limited to around 174mph.

 

[redc7z06]

I think everyone is forgetting one thing about being able to do 200mph, HP is key but also weight. You want to hit 200 with less HP, lower the weight of the ZR. Start with the hood, lighter wheels, no spare, lighter weight seats, get rid of the heavy headlights, you get the idea.

 

[Jeffvette]

I think everyone is forgetting one thing about being able to do 200mph, HP is key but also weight. You want to hit 200 with less HP, lower the weight of the ZR. Start with the hood, lighter wheels, no spare, lighter weight seats, get rid of the heavy headlights, you get the idea.

Mass has a big part in acceleration but a very, very small part in top speed. Top speed depends largely on Power and Drag (and Gearing but here optimum gearing is assumed).

 

[redc7z06]

Ok, so a 400lb ZR-1 with a stock LT5 engine can't do 200mph.

 

[Rob]

I think everyone is forgetting one thing about being able to do 200mph, HP is key but also weight. You want to hit 200 with less HP, lower the weight of the ZR. Start with the hood, lighter wheels, no spare, lighter weight seats, get rid of the heavy headlights, you get the idea.

I agree. Weight is key.

 

[8388]

Yes weight is an important factor, but not as important as air dynamics on the big end. Tie a parachute to that 400lb ZR1 with a stock LT5 and you wont go too far.

The point to all of this is that a 400 rwhp stock bodied ZR1 is capable of seeing 200 mph if certain conditions are applied.

Here's an example : the same car with the nose raised up 2" may struggle to reach 180 mph while the same car that has had the front lowered by 2" glides right up to 200 mph add a tail wind to the scenario and it's that much easier.

I have experimented with this exact scenario in real life, and those measly 2" on the front of the car can make all the difference in the world at high speeds.

Unless you have a full blown race car, with all the advantages of wings and spoilers, you want a certain amount of weight to help keep the car stable at those speeds.

 

[Jeffvette]

Ok, so a 400lb ZR-1 with a stock LT5 engine can't do 200mph.

Not if it has the Cd of a mac truck. Aerodynamics play more of a roll with top end speed than anything else.

 

[DRTH VTR]

Mass has a big part in acceleration but a very, very small part in top speed. Top speed depends largely on Power and Drag (and Gearing but here optimum gearing is assumed).

I totally agree with this post. Mass affects acceleration F=MA, but is not a factor in the top speed calculation. Mass will only affect inertia to any significant degree.

 

[redc7z06]

Geez guys I said "You want to hit 200 with less HP, lower the weight of the ZR." I never said anything about changing the Mass or Cd of the car. I agree with lowering the car can help and all that. My point is you can help a little on the top end if you also lighten up the ZR.

 

[Hib Halverson]

Ok.
I retract the "crack smoking" remark.

It really was made more in gest than anything else. I should have added a smile but then, maybe folks here can be a little less thin-skinned, too.

Anyone who says that a "lightly mod'ed" ZR1 will go 200 either misunderstands anecdotal information they've been given, has in accurate information, is just ignorant of fact when making that stuff up or is intentionally distorting facts.

There's an anecdotal post elsewhere of Curtis Ward's car going 200 mph and needing about 400hp at the wheels to do it. My guess is Curtis' car makes more than 400 at the wheels but, for the sake of discussion...400 at the wheels is between 470 and 500 hp, depending on what conversion you do and to get an LT5 to that performance level requires more than "light modification." If you're doing it with an engine having less power than that, then the car's aero could be modified or atmospheric conditions or terrain features need to be more favorable than normal.

"Mild mods" are bolting on an aftermarket exhaust, putting in a K&N filter, changing plugs or plug wires bolting on tires and wheels...that kind of thing.

Stuff like pulling the top end for porting, resetting cams, converting to coil-overs, installing nitrous oxide are not mild mods.

People are talking about weight. Forget weight---at least forget it as a key factor in the speed. The key to top speed is horsepower, gearing and aero.

When were talking about C4s going over 165, aero is pretty important, both to attaining the speed (for example, extending the front air dam, raking the car slightly and pulling-off the side mirrors is probably the same as 30hp) and having the car handle safely once you get there.

My guess is a legitimate 200 mph (near sea level, flat ground and no wind) ZR1 would need at least a six mile straight, at least 500hp and an engine capible of making max power at 7200, the right axle ratio, the car raked slightly, side mirrors off, rear bar disconnected, tires safe at 200mph and the driveline and tires balanced perfectly.

 

[rkreigh]

Mr wards car did this feat with some pretty SERIOUS mods as mentioned.

ported plenum, headers, race tires, coil overs, roll cage, light seats, ect....

I believe he mentioned he had a bit of help from a tail wind too.

curtis can hopefully post. it's not at all ez to run 200, and the tires and safety equipment are the LAST thing you want to overlook at that speed.

lowering the car and taking off the mirrors definitely helps the aero, man I sure miss that car!!

curtis definitely proved the potential and durability of the stock bottom end (and heads for that matter) on that car. 108K+ miles, most of 'em hard, car had headers, BIG 3" straight pipes and NO muffs. sounded like tearing metal at WOT, I will never forget the performance and sound that car made at BG

 

[ZR1Pete]

I believe he mentioned he had a bit of help from a tail wind too.

curtis can hopefully post. it's not at all ez to run 200, and the tires and safety equipment are the LAST thing you want to overlook at that speed.

lowering the car and taking off the mirrors definitely helps the aero, man I sure miss that car!!

I remember reading he had done one run with the wind and one aganst the wind.

 

[malc350]

This is not just a Callaway owner's wishful thinking

but I have road tests where Callaway Twin Turbo Corvettes run over 190 mph with 382-403 HP, depending on where you read it.

Callaway advertise a top speed of 191.5 mph in my Callaway owners manual though it states this is with the optional (expensive!) aerobody fitted.

I hae a road test of a "European spec" 1988 Callaway Twin Turbo tested (with electronic timing gear) at 193 mph (see my website). This car did not have the aerobody but had a larger front spoiler and removal of air con and lightweight seats (to save weight which would help handling & acceleration rather than top speed).

This car was advertised at 382 hp but estimated to be around 400 due to some "mild engine massaging by Callaway" but who knows what the real story is?

In a nutshell I have always thought that Callaway Corvettes (and actually all C4 Corvettes) are very efficient in terms of the top speed in relation to HP. I guess they're very slippery.

BTW I have seen Callaway's 450 hp "Supernatural" (normally aspirated LT1 based conversion) advertised at 200 mph though this semms a little optimistic to me...

 

[vettl83]

Question here guys, what did Calloway do to get 256 mph out the car he called the Sledge Hammer? I saw it auctioned off on tv at one of those high end auto auctions. They claimed it was totally streetable, and on a C-4 platform. The winning bid was just over 200K. Later 84 CF 91 ZR-1

 

[DRTH VTR]

Question here guys, what did Calloway do to get 256 mph out the car he called the Sledge Hammer? I saw it auctioned off on tv at one of those high end auto auctions. They claimed it was totally streetable, and on a C-4 platform. The winning bid was just over 200K. Later 84 CF 91 ZR-1

That was no stock machine. It had about 900 HP. It just sold in the last Barrett-Jackson auction. It sold for less than I thought it would.

 

[vettl83]

Thanks Jim, do you believe it's streetable with that kind of horse power? Wonder what they did to get that many ponies? Thanks, 84 CF 91 ZR-1

 

[froggy47]

That's a neat link Jacko, thanks. As for a ZR1 doing 200, I trust Hib's comments. Unless you've done it you're just bench racing.

 

[SurfnSun]

As for a ZR1 doing 200, I trust Hib's comments. Unless you've done it you're just bench racing.

Thats a little closed minded. Ive never driven my Callaway to 190+, will it do it? Absolutely. I know of a Callaway set up similar to mine that ran 197....I don't call that bench racing.