C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Time slip vs Draggy

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Old 09-22-2019, 03:14 PM
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Krusty84
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Default Time slip vs Dragy

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*Edit* The GPS device is called the 'dragy' (not draggy, sorry)
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Last edited by Krusty84; 09-23-2019 at 05:54 PM.
Old 09-22-2019, 03:51 PM
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STL94LT1
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Impressive!!
Old 09-22-2019, 11:24 PM
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Krusty84
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Originally Posted by STL94LT1
Impressive!!
Thanks!

It's a fun car. Needs more diet, gear, a little more tuning and better DA.
Old 09-23-2019, 09:04 AM
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bosshog8
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You're not the first person to verify the accuracy of a dragy (as I'm sure you know). I own a dragy and after using it, reading all the info and accounts like yours, I feel confident to consider the results as accurate and equal too the drag strip.
Old 09-23-2019, 09:29 AM
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QCVette
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These are great for evaluating changes/mods. A before/after comparison takes the "seat of the pants" guesstimating out of it.
Old 09-23-2019, 12:27 PM
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Tom400CFI
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Damn....that's pretty accurate.

AMF!....Rocky Mtn Racway!
Old 09-23-2019, 02:30 PM
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ctmccloskey
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I am still using my 20 year old GTECH Pro as it does the same stuff and is very, very accurate.

The phone software may be inexpensive and okay for general purposes but I like the additional things the GTECH does as well. The torque and HP curves are great but the shift light that is "feeling" your engine and tells you when to shift for the optimum times has helped "learn" my Corvettes.

The GTECH is more expensive but for that quality of equipment you will pay more. I ran the Gtech and then made adjustments or repairs and ran it again right away to see if there was any difference. That i how I knew my Cat-back system and a new Hi-Flow catalytic gained me just shy of 14 hp. Even carburetor changes can be tested right away. The most important thing about the GTECH is it needs a precise weight for your Corvette before anything can be measured. I went to the local landfill and got weighed with car empty of junk with 1/2 tank of gasoline. I had to do the same with my C3 to get it's "REAL" weight.

Truck-stop scales are better and more accurate but they charge to weigh your vehicle. Check out the GTECH and see what that baby can do, I suspect you will be impressed! I want the Road racing version so I can practice auto-crossing better.

Best regards,
Chris
Old 09-24-2019, 08:17 AM
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93 ragtop
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Originally Posted by ctmccloskey
I am still using my 20 year old GTECH Pro as it does the same stuff and is very, very accurate.

The phone software may be inexpensive and okay for general purposes but I like the additional things the GTECH does as well. The torque and HP curves are great but the shift light that is "feeling" your engine and tells you when to shift for the optimum times has helped "learn" my Corvettes.

The GTECH is more expensive but for that quality of equipment you will pay more. I ran the Gtech and then made adjustments or repairs and ran it again right away to see if there was any difference. That i how I knew my Cat-back system and a new Hi-Flow catalytic gained me just shy of 14 hp. Even carburetor changes can be tested right away. The most important thing about the GTECH is it needs a precise weight for your Corvette before anything can be measured. I went to the local landfill and got weighed with car empty of junk with 1/2 tank of gasoline. I had to do the same with my C3 to get it's "REAL" weight.

Truck-stop scales are better and more accurate but they charge to weigh your vehicle. Check out the GTECH and see what that baby can do, I suspect you will be impressed! I want the Road racing version so I can practice auto-crossing better.

Best regards,
Chris



I purchased a used Gtech about 6 months ago. Been playing with it, testing 0-60 mainly..... To be honest, my biggest problem has been finding a piece of road to test on. One that is flat, not too much traffic, and hopefully somewhat cop free!!
Hard to find that in northern Va. at least my part...
Old 09-24-2019, 01:03 PM
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Krusty84
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I have a nice one way service road a few miles from the house. It is about 36' wide (2 lanes and a nice shoulder), flat and no one can really see you from any direction other than behind you. The highway is elevated to the left and you can't see the service road from there unless you are in a semi truck. The right side of the road is airport property and is vacant and filled with brush and whatnot. Other than this spot, I don't really know of a spot that wouldn't attract attention.

Last edited by Krusty84; 09-24-2019 at 02:22 PM.
Old 09-25-2019, 06:42 AM
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93 ragtop
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Originally Posted by Krusty84
I have a nice one way service road a few miles from the house. It is about 36' wide (2 lanes and a nice shoulder), flat and no one can really see you from any direction other than behind you. The highway is elevated to the left and you can't see the service road from there unless you are in a semi truck. The right side of the road is airport property and is vacant and filled with brush and whatnot. Other than this spot, I don't really know of a spot that wouldn't attract attention.



The county I live in, is over 400,000 in population....
But I sure am impressed with the accuracy of the dragy.....
Also, IMO if you are pulling 1.99 60ft times on street tires and a manual trans.... well, that is some good driving!!
BTW what was the DA on that run?
Old 09-25-2019, 09:44 AM
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Originally Posted by 93 ragtop


The county I live in, is over 400,000 in population....
But I sure am impressed with the accuracy of the dragy.....
Also, IMO if you are pulling 1.99 60ft times on street tires and a manual trans.... well, that is some good driving!!
BTW what was the DA on that run?
Manual trans (TKO 600 5spd) w/ Toyo R888R 275/40/17 tire at about 22-24 psi. It was basically dead hooking all night. I was a little afraid of giving it more rpm as the track is about 60 miles from home and I watched a C6 spit its diff right out the back around 10pm. I think I can get at least a 1.8 maybe even better out of the car but I need quite a bit more practice. The LS7 clutch setup is great but there isn't a lot of play in the pedal and once it starts to grab, it just grabs.
The DA was in the 2150' - 2650' range. The dragy app puts it at 2641' and the DragTimes.com calculator puts it at 2141' for that run. I don't really know what to believe as some of the guys at the track were trying to tell me it was in the mid 70°s but I don't think it got to that temp until ~6am. The run posted above was at midnight. I ran 12.0 - 12.1 all night at 120.xx w/ ~2.0-2.1 60' times and I starting running at about 7 pm and I made my last run at midnight. I tend to believe the DA was pretty steady like the dragy app reported all night. Between ~2641'-2780'.
Old 09-25-2019, 11:10 AM
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DMITTZ
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Great times Krusty!

Looks like your making great use of that LS motor
Old 09-25-2019, 11:30 AM
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Hello again, 93 ragtop,

I live in Fairfax County and you are right there are "limited" places you can do it. I go to shopping mall parking lots or school parking lots for 0-60 runs. I find that going from 40-60 gives me a good indication of whether I helped the car or made it worse. Even a good 40-60 run might show important information regarding the engine. My C3 is a big block and tire spin is a HUGE issue so for me I like rolling starts or gentle starts to gets a good idea of how the engine is running.

How did you get your cars weight? Did you get it weighed or are you using the GM information? My C4 weighed less than GM suggested a Coupe would weigh and so did my C3 convertible. I weighed my car at the Ox Road landfill as they have a fairly accurate scale. I have seen far more accurate weight measurements from truck stops but they cost money.

I have done some runs in large open parking areas where there is no chance of hurting someone. The old Kena Temple in Fairfax had a huge parking lot and was perfect as it was empty several days a week. A good part of the Fairfax County Police department knows about my Corvette and have been very friendly. The local police might help identify a place you can do some runs like that, as long as you don't go too fast or get reckless. Sometimes they are really helpful. The only time I had issues with our local law enforcement was passing their station outrunning a Kawasaki 600 at triple digits, not a good move or even a bright one. One of the officers showed up at my house and suggested I be a "bit more careful".

Three officers looked at my engine one day and they were all telling me how their cars were no match for this C3 427 powered Corvette, I smiled and suggested that I was smart enough to know that you can't outrun a radio.

Good luck,
Chris

P.S. Whatever you do, don't do any timing with other cars around! Here in Virginia they confiscate cars caught drag racing on public roads. They are very serious about it so every time an Asian car pulls up and revs their engine I just laugh at them.
Old 09-25-2019, 11:49 AM
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Tom400CFI
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Originally Posted by 93 ragtop
Also, IMO if you are pulling 1.99 60ft times on street tires and a manual trans....


I've pulled a 1.9 60' time, but not here in UT. I had to GO DOWN TO VEGAS to have enough TOWAK, do it.
Old 09-25-2019, 09:42 PM
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With that MPH, better air and a little better 60’ your car has mid 11s or better written all over it.
Old 09-26-2019, 09:23 AM
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Krusty84
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I definitely think the car has more mph and better ETs ahead of her. I also need to mess with my shift points as I was really ringing her out and shifting sooner, especially out of 1st gear, ought to help my mph.

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