My Vette Vs Grand National (Video and questions)

[vettered91]

Last November I'd change the cam, springs, and did a home porting job to my Vette. My ET was before that swap 14.8 almost every time with street tires at 20psi, launching at idle (I did not have traction). The local Racetrack is at 5200 ft altitude.

Last December 17th I went to test the new mods, and there it was; a Grand National with NOS, Slicks and some more mods. It was the fastest car that night... until my babe arrived!!!

We just did two runs and here are the numbersthe guy didn't want more)

1st run
Vette: Grand National:
T. Reacc. 0.517 0.568
T. 60ft 2.277 2.130
ET 13.653 14.080

2d run
Vette: Grand National:
T. Reacc. 0.653 0.502
T. 60ft 2.260 2.203
ET 13.718 14.184

Like before the cam swap the tires where at 20psi (street tires), I'd launched at 800 (my new idle speed). As you can see I went from 14.8s to 13.6s. The new cam is a 224°/230° with .486"/.503" (with my stock rockers)

Now the questions:
¿Do you think you can go down that much the ET with just the cam swap or my homemade porting and polishing helped a little bit?
¿What should be my ET with slicks and a 2000rpm launch?
¿What ET should I expect at sea level?

Here's the link to the video Vs the Grand National from a friend (right click, save as......)
http://www.camaro-transam.com/videos/redlt1vsgrandnational.mpg

here another video, same night Vs a Stang:

https://store.cybercable.net.mx/docs/vette02.mpg

That night my vette was the fastest car!!!

 

[Edmond]

Those slicks will take some good time off your ET. But I would worry about having too much traction and not being able to handle it.

As for what you would run at sea level instead of a mile up, I'll look and see if there is a formula online. I'm sure there is because they always talk about doing adjustments in the test mags.

 

[lov-n-life]

You should be able to convert everything to standard day conditions (sea level, 59 degrees, I forget the humidity level) and do some fairly accurate calculations. I'm an aircraft mechanic by trade, but have been out of it for almost 3 years. I forget what the formulas are, but we used them to calculate % of engine performance. If you know what your engine is supposed to be producing at standard day conditions (HP and TQ at the wheels), you can calculate what you are running at the track and the figure your engines efficiency percentage vs standard day conditions and then figure what you would run if you weren't a mile up in the air. That made my head hurt... I'll see if I can find the formulas online. :L

Added: Here is a website that explains this... in a bit more detail.
http://www.grc.nasa.gov/WWW/K-12/airplane/airprop.html

 

[koolaid117]

Those are two excellent videos! Congrats on the fast car!

 

[G Winter]

You should be able to convert everything to standard day conditions (sea level, 59 degrees, I forget the humidity level) and do some fairly accurate calculations. I'm an aircraft mechanic by trade, but have been out of it for almost 3 years. I forget what the formulas are, but we used them to calculate % of engine performance. If you know what your engine is supposed to be producing at standard day conditions (HP and TQ at the wheels), you can calculate what you are running at the track and the figure your engines efficiency percentage vs standard day conditions and then figure what you would run if you weren't a mile up in the air. That made my head hurt... I'll see if I can find the formulas online. :L

Added: Here is a website that explains this... in a bit more detail.
http://www.grc.nasa.gov/WWW/K-12/airplane/airprop.html

Now that link made MY head hurt!;squint: :eyerole

 

[vettered91]

Those slicks will take some good time off your ET. But I would worry about having too much traction and not being able to handle it.

Thanks Edmond, I don't think I know what you mean. I had real big problems not having traction (fish-tailing) in the past. With traction my main concern is my Dana 36 because right now I think I'm at the edge.

That made my head hurt... I'll see if I can find the formulas online. :L

Added: Here is a website that explains this... in a bit more detail.
http://www.grc.nasa.gov/WWW/K-12/airplane/airprop.html

Thanks for the link, ¿Can you explain it to me? :confused Hahahaha (just kidding)

Those are two excellent videos! Congrats on the fast car!

Thanks, I'm very proud of it because I did everyting with my own hands (and blood!!! hahahaha!)

Now that link made MY head hurt!;squint: :eyerole

:crazy Yep! but I almost understand what's in it!!! :L

 

[vettered91]

Sorry all about the

thing!!! (it goes beyond my knowledge) :ugh


EDIT: Fixed

 

[PLRX]

Funny, I feel like going out and look for anything to race. Awsome videos!! Congrats on being the fastest car of the night. The rustang had nothing on you

 

[vettered91]

Funny, I feel like going out and look for anything to race. Awsome videos!! Congrats on being the fastest car of the night. The rustang had nothing on you

That car is the fastest street-rustank in town (14.7)!!!

Here a video where it races against a LT1 TransAm the same night (it was the last nigh of the year before the track closed for Christmas vacations):

https://store.cybercable.net.mx/docs/trans01.mpg

 

[MoeJr]

Excellent run Vettered91. I do not know how much of a difference in ET 5200' makes but that GN is one sad example of a car. I would imagine at that altitude a stock GN would run mid 14's as turbo cars suffer less than NA cars with altitude change. However with Mods and NO2 he shoulda been able to crack off 12's. Musta had a couple plug wires off or just a really bad tune on that car. Around here most stock LT1 A4 vettes and Stock 86/87 GN's run about the same times high 13's to low 14's. I had an 87 GN and had mostly bolt on mods except a small cam and ran 12.34 at 114 with no nitrous as I hate the stuff.

I bet here in the NE that Vette of yours would come close to touching 12's.

:bar

 

[Edmond]

vettered91, just put a / like [/quote] when you want to close the quote. For instance:

[ quote = Edmond] Hello [ /quote ] I inserted spaces between everything there. Eliminate the spaces and you get

Hello

What I meant is that it's questionable whether the tranny and gear can handle the much better traction you'll be getting.

 

[rrubel]

Why does that Mustang sound like it's upshifting and downshifting constantly? Or am I hearing both cars?
[RICHR]

 

[G Winter]

Why does that Mustang sound like it's upshifting and downshifting constantly? Or am I hearing both cars?
[RICHR]

I heard the same thing. I wondered how many gears were in that trans.

 

[vettered91]

Around here most stock LT1 A4 vettes and Stock 86/87 GN's run about the same times high 13's to low 14's. I had an 87 GN and had mostly bolt on mods except a small cam and ran 12.34 at 114 with no nitrous as I hate the stuff.

I bet here in the NE that Vette of yours would come close to touching 12's.

:bar

Thanks for the info MoeJr, just to give you an idea how are some ET's; down here the LT1s are arund the 15.2's, the stock Z06's are around 13.7's and the stock 2004 RT4's 14.3's! Before that night, all the GNs I've seen where in the magazines!!! I used to know some people call them "Corvette Killers". Before the race I was thinking "Oh boy, I'm lost" for the way it sounded and jumped to the stage line.
You can see how hard was to catch him at almost half the track! But you're right, he should be faster than that! (I'm glad he wasn't )

 

[vettered91]

Why does that Mustang sound like it's upshifting and downshifting constantly? Or am I hearing both cars?
[RICHR]

No rrubel, what you hear all the time is the Stang. I think when he saw me getting away so fast he stepped in the clutch a couple of times in desperation trying to get more speed???

What I meant is that it's questionable whether the tranny and gear can handle the much better traction you'll be getting.

Thanks Edmond, I think you're right! I'm not too sure how much more traction my rear axle can handle (and my wallet!!! hahahaha), besides my Vette is my everyday car. Maybe I should not get slicks, but how about some Drag Radials? I just wan to get my vette's real ET once!!! (or... twice?) Do you think it can become addictive? (all I've ever wanted when it was stock was just a little more speed)

 

[G Winter]

Why does that Mustang sound like it's upshifting and downshifting constantly? Or am I hearing both cars?
[RICHR]

OK now I think clutch slipping.

 

[rrubel]

OK now I think clutch slipping.

Except that's not usually what a slipping clutch sounds like. I've had them in a couple cars (incl. the Vette) and it usually only slips when you first let the clutch out.

This sounded to me like he had an auto and kept shifting from D to 3rd and back.

And the vid with the F-body had the same sound from the Stang.
[RICHR]

 

[vettered91]

Except that's not usually what a slipping clutch sounds like. I've had them in a couple cars (incl. the Vette) and it usually only slips when you first let the clutch out.

This sounded to me like he had an auto and kept shifting from D to 3rd and back.

And the vid with the F-body had the same sound from the Stang.
[RICHR]

I know for sure it's a manual.

Here's the last one! :L :https://store.cybercable.net.mx/docs/vette01.mpg

 

[G Winter]

I have had clutches slip in higher gears. sounds like when it slips he lifts a little to let it grab.

 

[vettered91]

Sorry all about the

thing!!! (it goes beyond my knowledge) :ugh


EDIT: Fixed

Thanks Bob, I miss those friday nights listening to Radio Canada!!!