LT1 performance

[wulf]

I drive a 1992 LT1 4 speed automatic coupe in bright aqua metallic which was imported from Florida to Germany where I live - a great car!
However, I could not reach so far the acceleration pereformance for 0-60mph which is stated by the test in "car&driver" (5.0 s, 6 speed manual) nor the specs provided by the manufacturer (5.7 s). My time is 6.8 s with ASR on. Since without ASR a significant wheel spin arises, I thought it would be better to switch it on. Three questions: 1. has anybody measured or read in a test what the acceleration to 60 mph, quatermile time and top speed for the 1992 LT1 with 4 speed automatic is? 2. Is it due to the automatic transmission that my car accelerates not as fast as a manual transmission? 3. Should I switch the ASR off for better results - what procedure results in the best acceleration.
It would be great to hear your experience, results etc..

 

[vettepilot]

WULF,
Glad to hear that you are enjoying the Corvette experience in Germany. The times you speak of from the manufacturer are usually the result of many tries to get the right combination of launch RPM , wheel spin, bogging of the engine, and in the case of the automatic, effectively applying throttle to achieve the most effective acceleration characteristics. Also the fuel has much to do with LT1 performance, as it does with any high tech engine. What grade fuel do you have available and using in your LT1. Is it at least 92 octane or better? Also, the road surface may make a big differance when one is measuring 10ths or 100ths of a second.
How about temperatures, your still experiencing some cold weather aren't you? The colder weather will help produce more HP because of the higher air density, but it will reduce the traction of the tire compound substantially.
I think as the weather gets warmer, you may actually see an improvement in your 0 - 60 times. The ideal conditions might fall in the area of 65 - 75 Deg. F or 18 - 24 Deg C.
Stan
From USA

 

[wulf]

Hi Vettepilot,

thanks for advice: I will have to wait a few weeks until we will have again warmer day temperatures, but then .. you know ... If you state they are trying many amny times - how many times are too much for my automatic transmission etc what is possible without hurting my Vette? By the way I use 95 octane fuel!
Take care

wulf

 

[Edmond]

And you'd also have to figure in altitude as well right?

You'd also have to figure that since the car is older, it most likely wouldn't perform with the same numbers as it did when the car was new.

 

[wulf]

Dear BullWinkle:

I have gotten a mail from LT1vettepilot who has experience with two LT1s: one 60000 mls one with 160000mls on it, both having 300 hp. The latter with higher milage is obviously faster and feels stronger ...

wulf

 

[Edmond]

If the theory is that the older it gets, the stronger it gets, that's good cause I'm getting there!

Yes, the auto would be a significant difference from the manual because you have to wait for the car to shift, which is sometimes a pain in the rear end. I hear the LT1 is an excellent motor and hope to own one some day.

 

[Edmond]

Wulf,

Being that you're in Germany, do you get to "stretch the legs" more than the boys here in the US?

 

[Full Bull]

bullwinkle...i spent two years in Europe, in Itlay...and frequently traveled into Germany. The autobahn is known worldwide for having "no speed limit", but threre's more more myth to that than fact. While there are segments of the autobhan where the speed limit is significantly higher than any thing here in the States, I'm not aware of any where there was no speed limit.

That said, i don't recall seeing more than one or two cars pulled over with a cop car behind them. Maybe I just was paying too much attention to the road to notice (you learn real quick to do that when traveling at 130 mph...stuff happens real fast)...but, it didn't seem that there was much attention paid to speed limits.

I know many times that i was passed by an assortment mercedes, beemers, and more than a few euro-spec fords...all blowing by me like i was sitting still...and i'm doing 120-130 (flat out in my SAAB) !! My guess is that they were doing 160+

Bottomline...yep, you can go a LOT faster in Germany, and some of the other euro countries than you can go here in the good 'ol USA. That said, Spain, Britain and others were as bad, if not worse, on speeding than we are here....

 

[Edmond]

Let me ask you this...

How in the world did you manage to get a Saab up to 120? That is a feat within itself.

What is a Euro-spec Ford? I'm sure they have different crash safety and emissions standards than us. Just like some Euro cars go through a few changes before we see them over here.

 

[Drewser]

Uber alles

I lived in North Germany for 2 years and have been on MANY white knuckle rides on the autobahn, mostly in taxis. They FLY and since they are mostly Mercedes, they can fly. The autobahn for the most part has suggested speed signs. Even on the side streets the speed is only suggested. The polizi have enough to do without messing with speeders. One big difference over there is that if they pull you over for dui, they can take a blood sample, and if you refuse...they take it by force.:eek BTW--the fastest I ever went on the autobahn was between 270 and 280 kPH (about 165mph) and it was on a motorcycle (hard to read going that fast and my attention was elsewhere). The taxis routinely go over 200kph (120mph). Some crazy taxis over there and since they get paid by the mile it doesn't make sense to go slow.
--Drew

 

[vettepilot]

I lived and "worked" in Fulda, Germany in the late 70s thru 81, at that time there were no speed limits on the autobahn, but there was talk about establishing them. As soon as you hit the city/town limits the speed limit was 60KPH, (about 31 MPH) usually enforced by way of radar activated cameras, FLASH... gotchya! Ticket arrived a few days later in the mail. OK, a trip to the local Bundaspost pay the fine, and you were on your way hoping you weren't accessed points.
Outside the city limits it was as fast as conditions allowed, but if you had an accident, you were driving too fast for conditions, pretty simple system.
Also, if you hit a farm animal, even a chicken, you paid for the chicken you hit, the eggs it could have laid, the chicks that could have hatched, the eggs they could have laid, the chicks they would have hatched... etc.

 

[Drewser]

Fulda!

I got my air assault wings at Fulda gap! Yes, go as fast as you want BUT, you have to pay for what you break, and they have this nasty habit of planting trees about 5 feet off the roadway about 10 feet apart so that if you do lose it you are a meat puppet. With all the black ice up north it pays to be careful. One thing I really like about the roadways over there is that if a farmer (or anyone for that matter) makes a mess on the road, ie. loses his load or tracks mud or dirt clods on the road, they have to clean it up. They also have an enforced law over there (which is unenforced here) of stay right except to pass. In other words, no going slow in the fast lane. Another thing that would keep most cars off the road in America is that if car has rust on it--it fails inspection. Bald tires, fail. If not everything works, fail. Here, if it starts and gets to the bmv under its own power then you get your tags. I miss the beer too.
--Drew

 

[Edmond]

pilot,

Just imagine if you could open up the Z06 over there! I could just picture them saying, "Damn American sports car!" Look what it's doing to us!

 

[Don Martin]

Wulf,

I have a 92 Corvette coupe with the A-4. My times are the same with ASR on or off. I use a G-tech Pro performance meter. My tires are GSC's and they too spin if I keep it to the floor. To get the best times with ASR off you must practice and since every road is not the same and I proved to myself that the times are the same on or off I just leave it on.

Your times 0-60 are very slow if correct. Just tell us however how you measured them and if you converted them from Meters / sec. Also what are your times with ASR off?

Times will vary with barometric pressure, humidity and temperature. I do not agree that 65F is the best temperature.

My 92 has the G92/ZO-7 options so the rear drive is 3.07 and not the standard 2.59. Tell us what your codes are and we will help you with finding out what your ratio is.

I get 0-60 in 5.2 secs in cold, dry high temps. The 1/4 mile time is about 13.6 sec at 108 mph. If I had stickier tires I would get better times I am sure but its fine now. It ranges up to as slow as 5.6 sec in hot, humid and low pressure.

We also need to know what rpm your tranny shifts at and what your tires are.

Once after servicing I found the accelerator cable laying loose off the cresent. It was not opening the throttle all the way. My times were 6.7 sec I bet. I could be a lot of things. But times in the 6's are way off for a engine that makes 300 HP!

Auto's are just as fast as manuals in Corvettes and with regular drivers, like me, they are faster with the auto.

 

[wulf]

Hi Don,

thanks for advice and the offer to examine my cars equipment: VIN 1G1YY23P5N5113235 WA-L 979609796143 ist this what you have been asking for?

It would be great if you would have any chance to find out what rear axle ratio my car has. By the way, it was imported from Florid in 1992 form Jim Gregg, Sunset Chevr. Inc. 1800 Bay Road, Sarasota, FL 34239 phone 813 366-7800 or -2484. I do not know whether this dealer still exists ...

Would be great to hear from you again!

Wulf

 

[69MyWay]

Wulf,

You need to click on the specifications link here in the forum and print off the RPO and option labels for your car for that year model.


Then, look on the bottom side of the center console lid and compare notes. You will find your axle ratio right there.

 

[wulf]

Hi 69MyWay

its good to know where I can find the specs of my car - thanks!
Is there anybody out there who has changed the rear axle ratio in an LT1 who could share his experience with me: what is the improvement in acceleration to 60 mph and quatermile? what is the decrease in top speed (you know, we have some "Autobahns" here which have no speed limit ....

Wulf

 

[Don Martin]

Wulf,

We need the codes from underneath your console cover. There is a lot of stuff there and it takes awhile but do it but it's worth it.

There was a "Bright Aqua" posting on the Corvette Forum who also complained about upshift problems at very high speeds on the Autobahn with his C-4 with the A-4 tranny. Is that you? I recall that complaint being that the Corvette driver had to floor it to get the A-4 to downshift at very high speeds to keep up with the fastest cars on the Autobahn. It sounds like you have the opposite problem.

In any case list the codes but for very high speed driving to get mileage I have no experiance. But someone here must.

Also find out your RPM's at high speed. Perhaps the tranny is downshifting into "D" out of "OD".

 

[Don Martin]

Wulf,

You can get a lot of testing data at http://corvetteforum.net/c3/superfast80/index.shtml

But in any case a Lt-1 C-4 should do 0-60 in about 5.7 sec or better if it's close to 100% operating condition.

As to your question on top speed vrs say a 3.07 axle and the A-4. I think my 92 with such a combination will do 135 mph in D and maybe 160+ in OD.

In summary first I would find out what you have and then make sure it's up to normal tune. If that's not acceptable for high speed driving then I would shop for another car. It's really easier and more effective than modifying yours.

 

[twiget]

Originally posted by BullWinkle
What is a Euro-spec Ford?

I'd guess a Euro-spec Ford would be an Aston Martin, or Jaguar.

Wulf,

Keep in mind that the numbers obtained by the car magazines and GM where done so with the use of professional drivers and the best possible circumstances.

Jason