No luck on the general board; let's try here.
When the winds subside, I'll take my 1,200-mile baby for a top-speed run on a deserted road (60 miles long :D) near my house, but I have some questions about what could happen.
Third gear is good for almost 165 mph at redline (75 @ 2730 rpm). Shifting to 4th would drop rpms to around 3,950 (84 @ 2000 rpm). As a comment, ALL A4s will always drop to 3950 from redline in 3rd, regardless of gears; only the speed would change (a 3.15 would be 3150 rpms @ 75).
At 4K' of altitude, my guess is my car won't pull to redline in 3rd, but hopefully not too far below (150-155 is my guess). What do you think??

Assuming it hits redline at 165 (for sure at sea level, huh?), can the engine pull in 4th from 3,950 at that speed? Peak torque is at around 4,500 rpm, but it's almost identical from 4 to 5K. Does the engine pull hardest at peak TQ or HP? We might be 'gear' limited at 165, due to that HUGE gap.
By the way, what's the % error in our speedometers? What's the true speed at, say, 100 mph indicated?

Thanks for your comments guys. Don't want to lug my engine in 4th at WOT if it won't pull.

JC

 

Holly poopie. . . :crazy:

The car will certainly keep pulling in 4th; however, are you crazy? The stock coupe will take you right up to about 185-190. . .do you have any idea what will happen if something runs out in front of you or if you hit a bump just right, uh, err, maybe I should say just wrong?

:blueangel: :blueangel:

 

I don't need a 'grandpa' lecture man :cuss; I'm 41, and just crazy enough to speed where it's 'safe' (you can get killed in a track too buddy, and is there a top-speed oval track in your town?). Ask for more info before jumping to conclusions; people go over 200 mph there every weekend. I only top out my cars and bikes there once; nice to have it out of your system.

Second of all, 190 on an A4?? In your dreams buddy. An MN6 at sea level, under perfect conditions, tops out at 172. A 3.15 A4 might go a little faster than the 2.73, but never close to the MN6, which is geared to pull top speed.
I just don't think 4K rpm can pull above 165 mph at altitude.

JC

PS. DON'T LOOK at the 'what's your top-speed?' tread posted over the general side recently, or you'll have a heart attack.

 

Hey jack butt, do a search on archived conversations and you will see plenty of forum members that have A4's above 170. In fact, if I recollect, I have even seen A4's with 3.42's get to 170+ and have stopped before hitting the limit. Theoretically, the 2.73's would have the tallest gearing and thus the highest top speed. However, at that point you are probably drag limited as opposed to gear limited. In other words, you couldn't reach the top speed potential of the gearing because the drag coefficient is too high.

Regardless, since you are 41, you probably have been out of school too long to recall the mathematics behind these calculations. So, to make it easy for yourself, why don't you just look up some top speed calculators where you can plug in the gearing and it will provide the top speed. :jester

:troll :troll :troll

 

Hey "Grandpa" !!!!!!! Maybe you should just give him a ride in that super mod'ed vette of yours if he wants to go fast!!!!!! :lol: :lol:

 

At least I went to school butthole. If you have nothing better to do than insult people on their own posts, and on a subject you don't know what the hell you're talking about, do it on another board.

Moderator, could you please put this guy in his place? There's always one everywhere you go. I apologize for the language everyone, but this is a CORVETTE forum; if this guy is insulted by top-speed talk, he should buy a yugo.

JC

 

:lurk:

 

I hate being the voice of reason...:nonod:

Look, a stock A4 will not touch 170. A modded A4 will go very fast, all depending on the mods. I don't doubt that many people on this board have run their A4's to pretty colossal speeds, but they were not nearly as close to stock as GRAY_VETTE. So please stop arguing about it. My guess is that at 4k' you'll get around 155, maybe close to 160. Mine hits the wall around 155-160 and creeps up the rest of the way from there (M6 Coupe)

As for the relative wisdom of top speed running, well...it's a very polarizing issue. Some say it's crazy/dangerous, some say it's exciting and reasonably safe under the right conditions. If anyone has ever succesfully convinced another not to run fast by flaming them on a message board, please inform us because that would be a first. If anyone has ever succesfully convinced another that running fast is not suicide by arguing with them on a message board, please inform us because that would be a first.

:cuss = :nono:

 

:lurk: :lurk: :D

 

[QUOTE]

Look, a stock A4 will not touch 170. A modded A4 will go very fast, all depending on the mods.

:yesnod: :yesnod: :yesnod:

Yes it will.... :cool:

 

Please do a search on archived threads. You will see several A4's that have gone on past 170.

Mathmatically, the 2.73 will have a higher top speed than the 3.15, 3.42, 3.73. As you move to the shorter gearing, you increase the acceleration rate while sacrificing top-end.

By the way, if you do the search you will find cars that are not significantly modified. I do not believe that different gears, torque converter and new intake or exhaust will not cause the top speed to increase. If anything adding more gearing will simply cause the top-end to decrease. However, for most on this forum it is reasonable to sacrifice top-end for better 1/4 mi. times.

----------------
Oh, otherwise, I am sorry for my previous post. I had too much to drink and the "grandpa" thing set me off. Sorry. :grouphug:

You want to run your car to its limits, have at it. Before modifications, I had my car to 153. . .didn't have the rocks to go any faster (A4 that had 2.73's). For this reason, it is simple for me to throw the :bs flag on your call of 150. When I hit 153, it seemed like the car had plenty more to go.

 

When my car was stock and around at 25k miles I did the 'top-speed' test.

I was in OD the whole time and hit 168 before I ran out of real estate. The
car was still pulling too. It was the first and last time I did that. No idea
what rpms I was at. My eyes were on the road with 2-hands on the wheel.

:cheers:

 

Hum!!!! Risky thread! but here goes! I have a little 98 rag top A4 with all the bolt ons, headers, X pipe, corsa, Rockers, Hall tech maf mods, Thermo. Every thing but heads and cam... (sooooo I ain't stock) My base line dyno showed that I got a pretty strong C5 right from the get go, and I was able to pull a strong 305+ RWHP out of the box and before the mods. Must have been a wednesday build. She took the bolt ons well and the Mods just got her stronger!

As far as high speed safety, look, you can get killed at 60MPH. If you have an open streach and the time is right and the traffic and conditions are good Gopher it. My rule is as long as I am absolutely positive I can't hurt anyone else but myself.

Having said that, I did manage to pull a ticket at around 165, almost went to jail and still paying for it on my insurance (a little over a year ago long story). So add the law factor to your safety issues. The ticket said 100+ cause he could not get a clock on me as I smoked him so badly. Never even saw him pull out!

Having said that, with the mods I can buzz right by 170 (top up and really noisy) I was suprised on the 4th gear pull, and would have gone further but the gonads shrank, and the testerone failed at that point.

I think she would be good for the 180-185 range, but at 170 I could feel the drag really comming on! and unless you are carrying in excess of 475-500 HP you are not going to get much over 190-195, and 200 is out of the question. On the dyno I saw 190 before dyno shut down, but who cares!

The highway was clear and straight for roughly 5 miles (3 lane), the car is in perfect condition. No traffic either on my side or the other. The run craps are good for this kind of run as you have a much lower chance of a catostrophic tire failure due to junk. The time was around 6:30 AM on a sunday (sunrise) The cop, well, he was behind me and just came on a exit ramp and was hidden by a bridge when I nailed it he was just pulling in behind me, but because I was concentrating on where I was pointed I didn't look in the mirror again till I was getting out of it a little over 170! About 2-3 miles back I saw the flashing lights. I just hit the emerg. flasher pulled over and waited for him! Those motorolas are pretty fast, I knew I had earned the felony traffic stop award, and did not what him to think I was running.

He did not take me to jail, he did write me up, the judge did hammer me ($300 and no traffic school which means I really get nailed on my insurance, 1 year left)

Do not take this a a whine, my rule is if you can't handle the time don't do the crime!!!

I have not bee over 140 since and granny the car on the streets, and pretty much do a lot of autocross and open track.
My suspension is set up Hotchkis sway bars, Lowered 1.5" or there abouts (max on stock bolts), F45 adjustable stock shocks) ERadi speed rotors, Hawk pads SS lines and Brake Bias spring.

Sooo yes a A4 with 2.73, can run pretty fast, yes I do have mods.
Jer

 

I've hit 172mph in my '98 vert with an A4 with the help of some juice.

Chan :cheers:

 

:eek: Your lucky your top didn't get sucked off. :yesnod:

 

Respectful disagreement never offends, and that's what makes these boards great; let's keep it that way :thumbs:.

Let's start with a known fact: highest measured top-speed of a stock vette was achieved on an MN6 coupe, and it was 172 mph (sea-level, cool air, etc.). With the typical error of 6%, that translates to an indicated speed of 182. Gearing that allows any higher speed than that is useless for top-speed purposes (unless you're going to heavily modify your engine).
Now, let me list the 'theoretical' top speed for each of the ratios mentioned above, and things will start to make sense:
2.73 = 252 mph
3.15 = 213 mph
3.42 = 188 mph
3.73 = 160 mph.

As it can be seen, the 2.73 4th gear is useless for top speed for obvious reasons. By the same token, the 3.73 is too short (numerically higher). That leaves us with the 3.15 and 3.42 as the 'better' ratios. The trade-offs are well known: higher ratio will accelerate quicker, but consume more fuel and cruise at higher rpms. As you can probably guess, the 3.42 is the performance champ ratio: it'll be quicker than the 3.15 and 2.73, and still be able to achieve top speed close to redline, right at the HP peak (ideal scenario). There's even 6 mph left to squeeze with some engine modifications. My personal preference would be the 3.15, as it strikes the best compromise of performance vs fuel economy; I just couldn't wait 2 months to get one.
As a final note, what kills our car's performance is that we only have 4 gears, and worst of all is the HUGE drop in rpms (over 2K :eek:) from 3rd to 4th at redline. This is more of a problem the faster you're going when it happens, and why the 2.73 will always be the slowest of all. The engine just can't pull too much at 165 mph under 4K rpms. It'd be like going uphill on your bicycle in top gear: you could go way faster, but just can't pedal fast enough.

Changing subject, I'm with TGrits10: 160 tops. I'll give it a try Monday morning, and post the results. The beauty of that road is you have infinite visibility; it was mainly built for the border patrol. Last time I traveled it in my bike didn't see a single car for the 60 miles, and average speed was in the triple digits :D.
We always take risks when doing these kind of things, but I'm fully aware of the consequences, and do it responsibly: always alone in the car/bike, alone on THAT road (no other road is completely safe for me AND others), vehicles always are in perfect mechanical condition (including tire pressures), and am in a good state of mind. If you think about it, there's much more risk of a crash in an intersection than opening up my car on a deserted road. Forget about risk of crashing while skiing, walking, driving, etc. Just living is a risk: we could get cancer :cry!! Life's too short guys; enjoy it (responsibly) while you can.

JC

 

Good post Gray,
I do a lot of autocross and open track and you would wonder why I stay with the 2.73s? Well first on the autocross circuit, I virtually never come out of first gear except on some courses with longer straights, and with my mods and running the lower profile 315 Hoosiers on 17" rims she pulls like a bandit out of the turns, I am right in the middle of my torque curve. On open track I never get to 4th, and again, it just pulls well. No doubt the smaller diam. tires are a big help. The guys with the lower gears have to shift way too much. Also they find themselves in some awkward RPMs is some cases. I just pop it in first and nail it.

My wife and I like to go east out to the desert highways and just cruise. Bakersfield up to Needles, or to Vegas. Absolutely some fantastic high speed cruising highways out there. On some of those highways I have had double bottom trucks pass me at 100. I use the car every day for work, and can't beat the gas milage. I am not a drag racer, soooo

On the autocross ckt I run A Street Prepared and with the Western States Corvette Council, 2 years of points champion and last year took second. Not racing this year, due to work and building a 76 Shark.

Will be back next year.

For me it is the perfect all around set up! Will curb the high speed stuff, too expensive and getting too old!

The officer that nailed me above could have been my son!!!

Take care
jer


[Modified by BlueDragon, 1:30 PM 5/9/2003]

 

Ya know it gets really noisy and there was a lot of daylight around the windows, good thing the blow out tabs are there. As for the top coming off? I thought about that, and it actually seemed pretty solid! Boy that would have been a rush, hey?

That was one of the reasons I backed out of it, and of course the cop had a lot to do with it. But I lifted and then looked in the rear view!

I think the worse part is when my wife found out! She still gets pissed when she thinks about it and it has been two years!!! I don't think I will ever live it down. When you can't grab what hurts grab your head!!:cry

How can I put it?? a significant emotional event?? LOL!

 

good post i like it hot :lurk: :lurk: :lurk:
it is amost as fun as :auto: fast. :lolg:


[Modified by low flyier, 3:51 PM 5/9/2003]

 

LMFAO!

Never seen a 41 year old snap so quickly. Prolly a sign that he's having a *cough* crisis.