litevette

The first time I ran the 1/4 I did 12.8 twice. I was a cylinder down, was running the stock torque convertor and my 60 ft sucked (2.0 and a 2.1).I knows there's gobs of other factors, but how much do you think I can shave off my times if I am running on all 8, install a 2200 stall and get my 60 ft. down to 1.7? What will/can I run with these improvements?

PRNDL

are you going to do it all at once? I would sequence to measure incremental improvement.
1. tune it so it is running properly (ie, 8 cylinders)
2. Next I would buy a set of drag radials to work on 60 ft time.
3. maybe next I would change the TC.

But, I believe imrovements in 60 ft time are supposed to nearly double reductions in 1/4 mile et, so if you go from 2.0 to 1.7 you may actually drop your et by .5 secs.

VETDRMS

Are you sure you were a "cylinder down", if that is truly the case the car would run like crap.

What were your incrementals, and your MPH?
Have you had this dynoed?

litevette

Yes, I'm sure I was a cylinder down because it wasn't running well and had a steady popping coming only from the passenger side tube. I'll have to get back with you on the incrementals. I'm not where the slips are right now. No, I haven't had it dynoed yet. I think it's probably around 400 at the flywheel.
As far as trying slicks, I didn't spin at all. Also, this was my first run down a strip in any car ever, so my reaction is what was lagging.
If I can shave off a 1/2 second I would be soooo happy!
Maybe once tuned I will need slicks.

danboback

I maybe way off base here but 12.8 on your first time is pretty good! What kind of motor do you have in that thing? I find it hard to believe running on 7 cylinders and still get that time. I am not trying to call you a liar, but if you were running on all 8 your 1/4 would be like 11.2! I would really like to know the spec of your motor, it sounds like a beast

VETDRMS

Well, I would make sure its tuned up before you go back, did you have a mis-fire or was it fuel related? Popping can be many things, including incorrectly set valves.

Do you remember your MPH? Assuming you don't have traction problems and the chassis is set up correctly it can be a good indicator of potential ET.

I just started drag racing last summer and LOVE it, but you'll go crazy and empty your wallet just as fast as you'll become obsessed with getting that next tenth... It looks like your at or near sea-level, so you have the benefit of "good" air, I think with some practice and getting everything tuned up you'll be able to knock .5s off your ET.

PRNDL

It will be very difficult to get your 60 ft time below 2.0 on street tires. Drag radials aren't exactly slicks, but the same idea in that they are tires I will only use on race days.

Your reaction time won't affect 60 ft time or your et. That is a common misconception (shared by me too! ). The et and 60ft timer doesn't start until your car moves past the staging light.

SpyderD

1.) I very much doubt you were not "a cylinder down". You were probably misfiring at low RPM's due to a running to rich or something. It likely did not effect you at WOT.
2.) Don't expect better than 2.0 times on street tires. It ain't gonna happen. Be happy if you get anything under 2.1 or so. Your 60 foot times DO NOT suck.
3.) I read your combo on a previous post and you are running very good times for your combination. As Clint Eastwood says - "a man's gotta know his limitations". For a street driven vette, street tires, stock bottom end, I would say you are close to it. You have a well tuned vette - you can play with timing and carb settings and maybe you can tweak out another couple 10ths.
4.) Better converter? Unless you have slicks it probably won't help with those 60 foot times. What may happen is you will get less traction.

litevette

It was a stock 300 h.p. motor. I put a Holley 600 cfm carb, Edelbrock Performer intake (middle "plane" ground down approx. 3/4"), Edelbrock Performer RPM heads and Comp cam (part #12-246-3). The motor is all stock other than that. It breathes better due to hooker side exhuast and electric fans free up a little horsies. I also have underdrive pullies. I really think the #'s are good because the car is now so light.
PRNDL - I didn't know that! Makes sense though.
VETDRMS - Yes, I need to check the valves. Also, my speed was 110 the first run and 109 the second time at the trap. I sure hope I can knock off .05!!!

VETDRMS

YES, you CAN run a decent 60' on street tires, it just takes a little more finess than slamming the pedal to the floor.

Case in point, I have ran a 1.761 60' on 245/45/17" Falken GRB-FK451 ZR Rated Radials.

That trap speed is an indicator of mid-low 12 potential. I have run a 12.3x @ 110mph on a day when the density altitude was 7600' :puke:.

In a properly setup chassis you can run low 12's with 110mph trap.

Sounds like it runs pretty good, I would be happy with those results considering the mild combo. How much does the car weigh? Driver & Gas Included?

SpyderD

1.76 is drag radial territory, but who knows. All I know is I see 2.3's and 2.4's all day on other cars with street tires. I ran constent 2.03-2.1 and I was very happy. It's also very dependent on the track prep at the individual dragstrip.

One thing that may help is to reduce tire pressure in the rear tire. Also instead of increasing the torque converter you may want to consider going to lower rear gears in the differential. may help your launch (or it may cause you to spin more).

Litevettt - What RPM do you launch at? What RPM do you shift at?

litevette

I'm not sure, but would like to know. I estimate that I lost around 3-400 lbs. (maybe a lttle high?) I'm so new to this and just getting the car together. There's alot of questions I have about it to (weight, actuall horsepower, etc.)
SpyderD- I will try letting a little air out. Hope that helps. As far as my launch RPMS, I was only up to about 500. Being new, I was afraid of inching forward and red lighting.I hope you are wrong about the torque convertor, I've already bought it.
I can't wait to try some of the other tactics you guys/gals have been suggesting. I think it's so cool being able to draw on others experience with these cars.

litevette

1st Run 2nd run
R/T .227 .274
60' 2.151 .2060
330 5.652 5.555
1/8 8.416 8.329
MPH 89.10 88.47
1000 10.818 10.747
1/4 12.854 12.802
MPH 110.78 109.71

SpyderD

Oh hell there are so many little cheap tricks to try to squeeze out another 10th here and there. Some work, some don't. Here are some ideas:

1.) Dialing in the carb - changing out jets and accelorator pumps at the track to squeeze out that maximum air/fuel mixture.
2.) Same thing with timing - experiment with 34 vs. 36 total timing, experiment with different curves.
3.) Cold air in the intake. Isolate your air filter from the engine heat or rig up something to bring in fresh air. Cold air is your friend!
4.) Rig up some sort of cowl air setup - get a combination of cold air and a bit of ram air effect.
5.) Again related to a cooler intake - rig up a pan in the lifter valley to keep hot air splashing against the intake, or a heat plate between the intake and carb.
6.) "Cool cans" for the gas lines - basically a can of ice water that the gas lines run through between the pump and the carb. I told you cold air is your friend.
7.) K&N air filters, also a K&N device called a "stubstack" (do not use if it lowers your air filter/carb clearance).
8.) A quart less oil - for less friction HP loss generated in the oil pan.
9.) Run with a 1/4 tank of gas - less weight.
10.) Cut back your spark plug tips - supposedly good for a couple HP.
11.) Synthetic oil - good for a couple HP.
12.) Carb spacers - usually help high RPM, sometimes hurts low RPM.
13.) Take the valve covers off and tweak the valve lash to maximize RPM. Be very careful here, you don't want your pushrod flying off OR your a valve hitting a piston. Make sure your pushrods are the right length, make sure your valve lash is set right.

Those are only a few I can think of at the top of my head.
You launch at 500RPM? Dude your idle speed sould be larger than that. You can experement with different launch RPM's to see what works best for you but I still don't think you will do much better than 2.0 60 foot times. Even with a stock convetor you should be able to hold it at 1,200 RPM and brake. A stock 2,200 convertor is a good choice however, still street friendly.
You never said what you shift at. I assume you manually shift the automatic - play with different shift speeds (within reason!!!). With your cam and lift you are probably getting maximum HP at 5,500-6,000 RPM. If you are shifting only at 5,200 RPM you are leaving alot of HP unused.

Edit - just thought of another one. You will probably benifit from a 650 or 750 carb with your horsepower, in fact I am suprised you only have a 600. Get a double pumper. That may be the kick in the pants you need to get that extra half second. Just be prepared to shell out more for gas on the road.

Glensgages

litevette:
you're making some crazy smoke there, running 110 MPH trap-speeds with what you run.


My '79 Z28 has an 8"/4500 converter, 4.10s, and 28" x 10" Dragways Specials on it, and it runs short-times of 1.84-.86 while deep-staging, which kills your ET off the line (probably go 1.78 leaving both-bulbs lit?).

An ET-slip in front of me looks like this:
0060' -1.851
0330' - 5.319
0660' - 8.216
MPH -- 84.73
1000' - 10.723
1320' - 12.850
MPH -- 104.76

Note that you got 4-5 MPH on me at both 660' and 1320':
I think if you can go 1.8-ish, 12-forties are in reach (if the rear-end lives)
Maybe forum-member SolidLT1 (I think that is his name) will check-in, as he runs 12-thirties with ease.....

SpyderD

I think he's shifting too soon. I had this same problem the other week racing in the dark. I got my best trap speed but missed my best time by about 2/10ths. Turns out my tach shift light was set at 5,000 RPM, I was just watching for the light, not the tach reading. Raced again last week, made sure my tach light was set at 6,000 RPM, similiar trap speed, better time by 3/10ths.

Glensgages

SpyderD:
here's a story regarding "shifting too soon".....

I've run the car in it's current configuration for many years (12+), and I've found that even-with the CompCams' 292H grind, it runs no-quicker-or-faster shifting at 6500 than it does shifting at 5800, which is what shift-light 'chip' I run.

2 years ago, I was out for Opening Day, just running to half-track, and my buddy, who built the 355" motor, and has told me since 1990 to "shift it at 6500 and trap at 7000" was in my pit-space:
out-of-the blue, I tossed him the keys, and said, "We've been tinkering on this Z28 since I bought it new in 1978, and you've never, EVER, made a pass in it..... GO FOR IT, DUDE!!!!! "

He does the burn-out, deep-stages, lights come down, and he clicks-off the best-ever run for the car in the cool, crisp April air, 12.774 @ 109.72 MPH, shifting (he later claimed) at 6500 RPM.....

Although I'm sure he thought the higher-shift points resulted in the quicker/faster ET/MPH, as I put the car back on the trailer, I peeked at the 1/8-mile time he'd run, which was 8.171 @ 85.05 MPH:
I'd run 8.112 and 8.123 on MY 2 squirts, shifting at 5800.....

litevette

I need to print this page out. Awesome information! I'm going again tomorrow night and will do the following: Launch at higher rpms, shift higher (was at around 5800, will now shift at 6-6100) and of course run the extra cylinder that was "down". I want to see what that does first. Hopefully by next week I can get the time to tune the carb and valves, and play with the timing. My next step will be to see what I can do about cooling the air and the intake and rejetting the carb. I'll probably have to build something to acheive that. As far as the carb goes, I've got a buddy with a 650. I'm sure he'll loan it to me some time so I can see if it makes any difference. I might need to get a box to fire the additional fuel, but want one anyway just to make sure I'm burning up whatever I'm dumping into it.
SpyderD- How and where would I cut the plugs?
Glensgages-What can I do to help my rearend live? Will Royal Purple help?

VETDRMS

Litevette: I'm looking forward to your results tomorrow. I think the rear end is a little stronger than most people give it credit for. As long as everything is in good working order and you do not "shock" it (ie dumping the clutch at 5000+rpm, or a transbreak) it can live through quite a lot of abuse. The key is to pre-load the drivetrain prior to the "hit".

The first thing I would do is install Spicer solid u-joints along with u-joint caps as opposed to u-bolts.
I run Royal Purple MAX gear 85-140 in my diff with the GM posi additive. Also, you should consider safety loops (dragvette makes them) as I believe they are required per NHRA rules for our cars faster than 12.99. The "DragVette" suspension kit also helps with some geometry issues. I recently installed their kit and will have track results when the strip opens in a couple weeks.

Good Luck, and have fun.

C3 Stroker

I had the experience of running "one cylinder down" my 1st trip to the strip last year (one plug wire had burned completely off at the plug I later discovered)......the car ran 12.49 in the 1/4.......after correcting the problem, it ran 11.81. ......so don't be surprised at a big improvement.