|
By speedpro56 - 12 Years Ago
|
Street tires suck on the track don't they Charlie? Ha!Ha!
|
|
By yehaabill - 12 Years Ago
|
|
Y-Guy Charlie: 15's are o.k. especially when you look in the "Muscle Car" mags and see street Hemi's & etc. running 15's. Keep it up and get Tony to do the pictures...
|
|
By MoonShadow - 12 Years Ago
|
|
Nice going Charlie. You're getting there. Chuck
|
|
By pegleg - 12 Years Ago
|
|
Charlie, This will sound counter-intuitive, but it works. The harder you run the street radials, the better they hook. I run around 45 at the Pure Stock races.
|
|
By pegleg - 12 Years Ago
|
|
Yes. BUT once they break loose you're done. You'll still need to slip the clutch on the start. The track prep is a major part, many tracks don't do a lot of prep for T & T. Our local track is really bad in that scenario. I was usually 2 to 3 tenths slower at home as opposed to Columbus or US 131.
|
|
By mctim64 - 12 Years Ago
|
Sounds like a good time Charlie. Nice to know the truck is faster than the Firechicken. 
|
|
By Glen Henderson - 10 Years Ago
|
|
That is great Charlie, what is your rpm limit?
|
|
By pegleg - 10 Years Ago
|
|
Tachometer problem?
|
|
By pintoplumber - 10 Years Ago
|
|
You forgot and shifted into 5th.
|
|
By CK - 9 Years Ago
|
This is a great link regarding traction.
http://www.how-to-build-hotrods.com/tuning-4-link.html
|
|
By MoonShadow - 9 Years Ago
|
|
So spinning the two tries was a little something new. Perhaps you are making more hp and its effecting your traction. Time to get serious about that. Chuck
|
|
By John Mummert - 9 Years Ago
|
|
I'd be surprised if a 2" 4hole spacer helped at the dragstrip. Probably feels good on the street with added power at low rpm but high rpm power will likely suffer.
|
|
By CK - 9 Years Ago
|
|
I've heard great things about the cal-tracs. Alternatively Nascar uses truck arms, these seem interesting.
I would consider an open spacer for the drag strip and maybe for the street if your wheel spinning there too.
And consider if your having traction issues now, when you do change the diff and both wheels become engaged be prepared to slip and slide when it spins, especially in the wet.
Taller diff gears could help too if you plan to stick with low rpm torque.
I'm pretty keen to fit my posi too.
What cam are you running again?
|
|
By tomfiii - 9 Years Ago
|
It is slick at times ,but workers just tell you to adjust your vehicle to track!
|
|
By yehaabill - 9 Years Ago
|
Charley, I made set of Cal-Trac copies and they stopped all the axle hop...I haven't tried them at the strip yet
I've got a small engine/electrical problem we're trying to iron out........check out the latest issue of :Hot Rod"
nice hi-dollar "Slick" in there....
|
|
By charliemccraney - 12 Years Ago
|
I made it tonight. Didn't do as well as I hoped but I did get a personal best, 15.609 @ 91.06mph
There's still more in it. I left the traction bars in the safe position, still street tires, no burn out, no posi. I tried a launch at only 1500rpm and it just spun so I reverted to the get it rolling and floor it technique.
I also think I will need a much shorter gear for racing. By the end of the night I wasn't bothering with shifting to 4th and was going through the traps at around 6100rpm in 3rd.
Reaction times were much better than they were at Columbus last year.
I tried to make a couple runs shifting like I did at Columbus to get an idea if the traction bars and lowered rear are helping at all but I couldn't come close to the 15.95 I did in Columbus. On the way home, I remembered that I had jets with me. It was probably 15 degrees cooler than it was in Columbus so a change there may have done something. The elevation is only a 100 foot difference.
After the last run, the valve train seems to have gotten a little louder but it didn't get any worse during the 50 mile trip back home. I'll take a look at that this weekend.
Tony was there in his duster. I think his best was 14.6. Oh, and I put the truck on the scale, 3675lbs with me in it.
I had a real good race against a '91 S10 with a 283. I was just planning to do some testing during that race but when I saw how close we were I thought "I think I can beat him" but it was too late. My "testing" slowed me down too much. that race he ran 16.187 @ 89.16 and I ran 16.223 @ 86.91. His best for the night was 15.5. Our reaction times were .003s apart. Me, .179. Him, .182. It was a good race. We talked for a while in the pits. I thought it was cool that it wasn't a 350 and it was period correct where the engines were concerned.
The announcer guy liked the truck apparently. I couldn't hear him but people were telling me that. I think it had more to do with being a unibody than anything else.
|
|
By Hoosier Hurricane - 12 Years Ago
|
|
Way to go Charlie. When you get the traction problem solved you will be well on your way to winning rounds in competition.
|
|
By charliemccraney - 12 Years Ago
|
They sure are bad for launching. I'm sure I can get more out of them by putting the traction bars in the position which is better for traction and playing with the preload. I just don't want to break something and have to have it towed home. I need to get a ramp truck.
I don't have the power to have the problem you have with street tires once I get moving, though.
|
|
By charliemccraney - 12 Years Ago
|
You mean the pressure?
I was comparing things last night and my 60 foot was generally worse than in Columbus. They didn't have the track prepped very well since it was just a test and tune. Hopefully that's the reason. I was hoping to see some improvement there with the traction bars and lower rear - but it probably simply need some tuning in that area, too.
|
|
By charliemccraney - 12 Years Ago
|
I went again last night, but with the Firebird. The only significant departure from stock is the Hooker cat back. Everything else is stock or stock replacement. 305 TBI, 5 speed, 3.08 posi, WS6 (for those not familiar with GM stuff, that is performance suspension, different springs, wider wheels/tires, bigger roll bars). The best was16.848 @ 83.16. It has the same launching problems as the truck. I was expecting it to leave better. Street tires suck. The weight with me and some other stuff was 3590 and the tire size/gear ratio combo works out to about the same as the truck so I had the same issue, not enough track to get into 4th. So I can say that my truck is faster than my "sports car" in a straight line, anyway.
We swapped the cam in Tony's Duster last weekend to something smaller with more overlap and swapped to a lower rpm intake, from performer rpm air gap to a performer. The plan was to make it less peaky but to try to keep the averages pretty close and make it more street friendly. It seemed to work. He only slowed 4/10s, 15.1s (the 14.6 above happened when the water/power steering pump belt decided to retire. 14.7s were consistent) and says he's much more happy with the driveability. There's an electrical gremlin with the ignition so he put it away for the night before trying different shift points and launch rpms. So it may be even closer to what he ran last time.
One race was pretty fun. It was a turbo 4cyl of some kind. I could hear the turbo and blow off valve when he shifted behind me and then after about the 1/8th he blew by me, ran 13 something. When I got my time slip, it turns out that he was asleep, a 1.6 second reaction time and mine wasn't great so I got about a 1 second head start and that was the best run of the night for me. Up to the 1/8th I was thinking "why did you waste money on that rice burner?" After the 1/8th I was thinking "open mouth, insert foot." Sometimes I forget they can be fast.
|
|
By charliemccraney - 11 Years Ago
|
|
charliemccraney (9/21/2012)
After the last run, the valve train seems to have gotten a little louder but it didn't get any worse during the 50 mile trip back home. I'll take a look at that this weekend.
So apparently "this weekend" is 4 months later. I finally took a look and the valve train looks fine for once! Valve noise and exhaust leaks sound pretty similar so I'm going to pull the headers to see if I find any sign of an exhaust leak but I can't find my 5/16 socket for the header bolts today. I'll pick one up later in the week. It's been 4 or 5 weeks since I've driven it and I need to run the fuel through and fill up with fresh stuff, anyway.
|
|
By charliemccraney - 10 Years Ago
|
I got a new best tonight, 15.263 @ 91.08mph. Also a best 1/8th and 60'. It was busy and I got there late and only got two runs but both were better than before.
The changes since my last best are bringing the total timing in 800rpm sooner and disconnecting and plugging the vacuum advance. I discovered the vacuum advance trick at Columbus last year but had not yet tried it with higher shiftpoints. I shift lower at Columbus.
Up next is a 4.11 gear.
|
|
By charliemccraney - 10 Years Ago
|
|
What do you mean? I was shifting at 5500rpm. I haven't tried higher but lower and it slows down.
One thing I thought was weird is my previous, I was going through the traps at about 6200rpm but last night is was only about 5700rpm. Since the mph was the same, I don't really get that.
|
|
By Hoosier Hurricane - 10 Years Ago
|
|
Charlie:
Have you changed tire sizes since the earlier runs? That'll change rpm. Also, were the previous runs at the same track? Clocks could be set up differently from track to track.
|
|
By charliemccraney - 10 Years Ago
|
Same tires, same track. I guess it could be the tach or my memory.
|
|
By charliemccraney - 9 Years Ago
|
Haven't been back, yet, just documenting changes since the last run before I loose track. Hopefully it will be enough little things to get me into the 14s.
No rear gear change, yet. Thought it might be worthwhile to tune some more.
Changed from 20w50 conventional to 15W40 synthetic blend oil.
Installed Innovators West Damper.
Installed smaller diameter water pump pulley. This one hurts power.
Indexed spark plugs.
Corrected rocker geometry.
Increased secondary jets 2 numbers.
Changed carb spacer from 1/2" divided to 2" 4-hole.
Installed a 14" air cleaner assembly, which does not work with the K&N Stub Stack I have been using.
|
|
By charliemccraney - 9 Years Ago
|
I made it to Atlanta Dragway tonight. It was a pretty inconclusive night. No improvement. In fact, it is slower.
It was very busy and I could only make two passes. Both times I spun and had to let off, which killed the 60'. My best run of the night had better 60'-1320' times than previous runs with similar et's, so maybe that means something. I'm also think it was just spinning easier, which means I need to tackle the traction, and at least get posi before I go back.
|
|
By charliemccraney - 9 Years Ago
|
Spinning is nothing new, but it seemed to be happening more easily, even on the street.
My friends had not arrived for my first run, so I did that with the spare tire, some tools, and a few spare parts, maybe 150-200lbs extra, and my 60' was .200s better than the unloaded 2nd run. MPH and et was about the same. If it were a better, more experienced driver, that would definitely mean something, but I'm not that good, yet. There is still the chance that the result suggests traction is at least a part of the issue.
Of all the things I've changed, the only things that are really ambiguous are the secondary jet change, carb spacer change and required air filter change to fit the spacer. Those are easy enough to put back to the old configuration for testing. Everything else, with the exception of the water pump pulley should increase output.
Thanks for the link, CK. This truck will probably not have a 4-link ever, so I won't be able to put much of that to use. I do have what I think are the best traction bars available, Cal-tracs, and when setup with the right combination of parts, these handily get vehicles into the 11's, faster than I ever plan to go in the truck. They do have a few adjustments to play with, which I will play with at some point, but not like a 4-link. First I will get some form of positraction so that both wheels can contribute to the forward motion. Hopefully that will be enough for now that traction can be eliminated as a reason it is slowing down. That will be a good, relatively easy winter project, so I can try to get back to the track soon after it opens next year.
|
|
By charliemccraney - 9 Years Ago
|
I had considered that. It's so close to the end of the season now, and so busy that there really isn't much time for tuning, so I picked what I thought would do what I wanted and it didn't. My hope, given that I know I do not have the traction for any kind of launch, was that the 4-hole spacer would help me get off the line quicker, and perhaps all of the other things would at least keep the top end the same as before.
I have lots of spacers now, so I hope to get there during a less crowded day to try different ones.
Looking back at past time slips, this run is one of the slowest 60' I've had, 2.703 (best 2.428) but near the top in mph, 89.94mph, 1.14mph slower than my best.
|
|
By charliemccraney - 9 Years Ago
|
I have the repop blower cam.
I'll test spacers some day, but the next trip to the track has to have everything the same, with the exception of positraction. I'd also rather address a traction issue with something that increases traction, rather than doing something that decreases torque. My plan, ultimately, is to inject and turbocharge, so I'm going to need the traction. May as well take care of it now. I've contacted Moser, and their 31 spline axles will do the job for my plans.
Not concerned about slipping and sliding as it will do that just fine right now. Hopefully, by it's very nature, positraction will reduce the number of instances of that slipping and sliding.
The gears will definitely need to be shorter for racing, and since I have a 9", I can easily swap between street and strip gears. I suspect that I will also need shorter gears for the street, to fit the power band of the engine and tall overdrive better.
|
|
By charliemccraney - 9 Years Ago
|
I thought you had those when you were at Columbus. They eliminated the wheel hop, and that is a good thing.
|
|
By charliemccraney - 8 Years Ago
|
Nothing significant to report. Just documenting changes and discoveries.
I noticed that the front driver's side brake was dragging. Turns out the caliper pins, bushings and sleeves need to be lubricated now and then. Lubed them and no more dragging. Went ahead and did the passenger's side, too.
I don't know if this was taking place during my last trip to the track but if it was, it was slowing me down.
Edit 04/29/16
I noticed that it still wasn't rolling like I thought it should even after lubing the caliper pins. I remembered something else I had not done in a while, adjust the parking brake cable. Now it's rolling a lot better. Gotta remember to think of the whole package
Limited slip added about a-month-and-a-half ago
Edit 06/28/2017
Last summer - winter, I made and installed a windage tray, crank scraper and oil pickup primarily to address an oil pressure drop at high rpm. The engine does seem more responsive.
I'm thinking that since I've made so many changes since my last good run, I'm going to do a couple more things that should help. At this point I won't know what hurt or helped, anyway.
Edit 09/13/2017
Made a sort of antenna delete since the radio does not currently work and I could not hear it if it did.
Filled in the plenum slot of the Blue Thunder intake. Smoothed transition from carb to ports / plenum. Improved port match between intake and heads.
Edit 10/18/2017
Reinstalled K&N stub stack. This was used during my best run so far, but it was not installed at the very last run because it would not fit with the new air cleaner base. I figured out how to make it work with the new base so I figured I would include it in the updates.
Edit 4/27/2018
Installed 17" aluminum rims and tires. New tires are 25.7" diameter. Old tires were 28" diameter. About equivalent to going to a 4.03 rear gear. New tires should be better in all aspects, including traction.
Edit 4/25/2019
Installed Holley 670 because the 570 developed idle problems. The engine does need something bigger, anyway.
|