LU8

I came across these UK magazine test times. I think they are interesting in terms of what a showroom car can do, given that Corvettes and other fast cars tested by Car and Driver, Road & Track etc. are often prepared, even though magazines request normal cars. I recall Car and Driver's 30,000 mile 1985 Corvette automatic report, where they discovered as they were just about to give the car back a bunch of GM repair orders stashed in the storage compartment showing that the car had been through a few transmissions, and had the odometer tampered with before C&D got the car.

In any case with the cars tested below they were obtained from the Belgium agent, so I would say there's less chance they were improved prior to testing. I have thrown in early and late C3s for comparison.


1968 L68 427 4 speed 0-60 6.1 seconds top speed 145 mph (Motor)
1984 TBI Automatic 0-60 7 seconds top speed 139 mph (Motor)
1984 TBI Automatic 0-60 7.2 seconds top speed 138 mph (Fast Lane)
1984 TBI Automatic 0-60 6.6 seconds top speed 142 mph (Autocar)
1986 TPI Stick 0-60 6 seconds top speed 151 mph (Autocar)
1989 ZR-1 (380 hp) 0-60 5.6 seconds (Autocar)
1992 LT1 Automatic 0-60 5.8 seconds top speed 162 mph (Performance Car)

The LT1 car did a 14.3 second 1/4 mile at 100 mph.

Around the same time Autocar tested the 1986 Corvette, they also tested a BMW M635CSi (M6) and got 0-60 in 6 seconds and 150 mph top speed.

I have long thought the TPI cars to be great value for money, and recalling when the LT1 350 came out many thought it wasn't much slower than the ZR-1, so I have always had doubts over the ZR-1's power rating. That said, I should state in the above Autocar tests the ZR-1 beat the 1986 car in 30-70 mph acceleration 4.5 to 6.3 seconds.

c4cruiser

With different drivers in the same car or a similarly-equipped car, it could be hard to get consistent results. And if the same car was used, it could be that the car could have used some "attention" to generate some consistency. I recall reading reports that the various magazines pretty much beat the cars to death, then tried to fix them on a shoestring budget.

As far as the ZR-1, the ones I have driven are certainly faster than L98 or even LT1/LT4 cars. What I liked about the ZR-1 is that the speeds come up so smoothly so you really don't notice the climbing numbers, just the consistent acceleration. Look at the records that were set by the ZR-1 back around 1989. 175+ for 24 hours with nothing but stops for gas, driver changes, and whatever scheduled maintenance was required based on mileage.

Another thing I had read about the early ZR-1 cars was that the advertised 375HP wasn't really the actual rate across the total production of the early engines. Some engines would hit the 375, others came in at 400HP and more.

I did get a chance to see 170 in a '90 ZR-1. I also had a '92 'vert that I was able to just get to 160 on a trip thru Montana (where it wasn't breaking the law at the time! )

LU8

Agreed, and it's certainly true that with each engine upgrade the Corvette picked up a much higher top speed. I think that's where the real gain is, more than the traditional 1/4 mile figure. To get some perspective all C4s are 350ci small block 3,300-3,600lb cars, in terms of the performance expected from such cars. Big top speed and refinement gains over the C3.

I think it was just nice to see a different set of test reports, which apart from driver and condition changes, were on showroom stock cars.

Lt4-396

Whoever was behind the lt1 that did a 14.1 needs to learn how to drive.

ghoastrider1

my best run, at Indy test and tune wensday, stock auto, was 14:151 @ 97.27. 1986 coupe.
Perhaps I had better tires than in 86. I had to start off the line at off idle. Any RPM try just put the tires up in smoke. Oh, its a Z-51 if that counts for anything.
Thanks for posting this, interesting read.

ghoastrider1

LU8

Motorweek got the worst ever time for an automatic TBI car, 7.9 seconds 0-60 and 15.8 1/4 mile.

However, the show noted their torque converter took a long time to start working.

Engine for engine I would say the C4 gains 1 second across the board and 15 mph on a C3 for same power. From lighter weight, better rear suspension design and aero body. Plus improved tires.

LU8

Sorry, the LT1 got a 14.3.

They were wintery conditions, the Jag V12 got 14.4 and the Porsche 928 GT 14.0 on test. The 928 was the only stick shift.

Tom400CFI

ZR-1's power is there....it's "hidden" in 0-60 times by it's weight. It weighs a couple hundred more lbs than the OHV cars. If you run all the cars in the 1/4, then compare the trap speeds....you can see the ZR-1's hp.

cv67

Depends on the driver and DA
Never seen an LT1 car do better than 14.0
Z never got anywhere near the claimed 12.9 time

Tom400CFI

I've gone 13.75 here in UT; 4500' elevation/7000' DA typically. I can't imagine why someone from either coast should be able to do better than me. A lot better. These 14.0x numbers are kooky ...for stick shift LT1's anyway. Maybe a 2.59 rear'd auto would run 14.x's.

Lt4-396

With a 6speed the lt1 is a low 13 second 1/4 time. A lt4 is capable of running very high 12's.

Those times must be with a auto with the 2.XX rear.

DGXR

With the gradual increases in horsepower, better drivetrains and slick body shape, I'm not surprised at the top speeds of the LT1/LT4 cars. I still can't believe 4th gear in my ZF6 is good for anything between 20-105 mph. That seems nuts to me but I really love it

And it's well known that the ZR-1 official horsepower ratings were low. Some experts and experienced drivers have estimated the factory numbers were 75-100HP too low and some of the cars were putting out 475+ HP. Again it's just their educated guess... who knows. I want to look up C4 ZR-1 dyno runs but aint got time for that.

Tom400CFI

You're saying the opposite of what LU8 said. Neither is right. The ZR-1 made just about what GM said it did. Again...trap speed tell the story. No sand bagging with the ZR-1.

ghlkal

Interesting read. Thanks OP

This seems reasonable to me

The LT5 in the ZR-1 may have been just a little under-rated, but I agree that the 90 made about 375 stock. Yes, compare the trap to see the difference in the cars.

LU8

To bear out the point about trap speed, check out this Motorweek 1985 TPI stick vs auto comparison. Great ETs but unusually low trap speeds, from this I feel the TBI and TPI cars achieve their times using good tire traction, and engine torque. The automatic's torque converter would take full advantage of the torque, and the stick shift car's 4+3 had that very short 1st gear.


The better breathing LT4 and ZR-1 350s do indeed show their prowess at the top end. Adding 20 or 30 mph to top speed is no mean feat, so I'm not bagging either LT4 or ZR-1. It's just that sometimes I think the established magazines work with the automaker to spice up a new model's reputation with performance claims that are a little optimistic.

When Joe Chubbs Oldham got 14.68 and 15.14 out of a non a/c 1974 Dart Sport 360 and Nova SS 350 I believe that because the cars were running 3.55 and 3.42 gears respectively, and by 1974 no one was going to go to the trouble of preparing these cars. They weren't new models, and high performance in 1974 wasn't something anyone was really into by that time.

93Rubie

I've ran a slew of 13.4's and 13.5's in less than ideal conditions at Keystone Raceway Park. Trap speeds in the 103-105 range. 6 speed manual of course.

ghoastrider1

love to see a list of all years corvette and their 1/4 times and speeds. I think a few folks might be surprised at how well their mild mannered c-4s do against the old school brutes. The advNCE IN ELECTROnics has done wonders versus brute hp.

cv67

At stock l98 l98 ot lt1 could take down most old musclecars/at least stay with a good percentage of em..a stock 89 would have killed my 69 rs ss given the 70 Z28 a run for its money

Know what would smoke about anything back then til the GNX came out?

Dodge lil red express pickup. Thing hauled *** for what it was, think it was a 14 sec truck would walk an L82 all day. For its time was impressive

. Late 70s.....

Tom thats a real good time for UT

Tom400CFI

Fastest muscle car of the late '70's!



Thanks!

Old Jim (RIP) would only give me 14.40's in the betting POOL when I first got it. No faith, I tell ya! Well, old Jim had to EAT SOME CROW.


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