Thanks guys, We cut another 2 tenths off

We tried timing and air pressure changes tonight.
The first pass was with everything the same as 2 weeks ago except 4.11 gears instead of the 3.50's . It went 12.38 at 104.89. 2 weeks ago it went 12.53 at 103.71.
We turned the timing up to 40* with 8psi in the slicks and ran 12.34 3 passes in a row at 104-105mph.

Here's the best of the night.
60ft - 1.64
330ft -4.91
1/8 - 7.71 at 86.68mph
1000ft - 10.19
1/4 - 12.34 at 104.39mph

Do all the times and mph look about right or am I lacking somewhere?
I'm still learning how to read these time slips.
I have some videos but I don't want to bore you guys with the same truck on the same track. They look like my past videos.

7.70 should be right at 12. flat 1/4 mile

Randy

very nice Mike ..... keep on plugging !!!

the Coug wrote:7.70 should be right at 12. flat 1/4 mile

Randy

Wind Resistance Killing it?

Nice job Mike. Post them vids up anyway, It don't matter if they're from the same track, look at mine. Same truck, same track, different dates. My truck runs a little off from the conversion charts also, 2 weeks ago, when I ran in Spokane, my 1/8 mile times were from 6.17-6.24, which according to the calculator, should've been running mid 9.50's to mid 9.60's. I ran a 9.73-9.81. Could be in the gearing, or any number of things. More than likely, it's aero.






Doug...

dfree383 wrote:

the Coug wrote:7.70 should be right at 12. flat 1/4 mile

Randy

Wind Resistance Killing it?

NNOOOOOOO! It's only like driving a chest freezer down the track.






Doug...

MY small block car ran a 12.34 @ 109.55mph. should go a little faster with some tuning. leaves a little slow and shifting at 7400 rpms.

Ace

ThndrChkn wrote:Nice job Mike. Post them vids up anyway, It don't matter if they're from the same track, look at mine. Same truck, same track, different dates.
Doug...

Ok Doug.

105 mph in the 1/8th is pretty fast for a brick.

Nice runs Mike, glad you got her going. Maybe you can make the Bash with the truck next year.

Kerry

There's a whole lotta spin off the line, if you can get it to stick off the line instead of spinning like that you should be able to cut your times down a lot more.

When looking at some of the video it in slow-mo or frame advance, it's not doing too bad considering this is just the first few outings on the truck. Yes there is some spin and/or some bounce, but it's not like it's spinning it's nutts off & zinging the siht out of it.

It's probably a good idea to start thinking about adding a roll cage in the future to help stiffen the back of the chassis. You can see a whole bunch of frame and bed twisting/flexing gymnastics going on out back when viewing the clip in slow-mo or frame advance.

Keep after it.

Good job Mike, hope mine runs that good

Kerry, I would love to bring it to the bash next year.
The big holdup will be a reliable tow vehicle for the trip.

Dave we have noticed the bed has twisted a little since I statred.
Would a 8pt roll bar setup stiffen the chassis enough?
I also have 175lb coilover springs in the rear. Would a lighter spring help?

mike

Is the MPH low for the ET? I remember my old car running 13.30s at 97-98MPH in the 1/4. It was a dog on the hill, it got it all done on the front half of the track.

f250mike wrote:Would a 8pt roll bar setup stiffen the chassis enough?
I also have 175lb coilover springs in the rear. Would a lighter spring help?

Well obviously both a simple roll bar or a more involved full roll cage is going to stiffen the frame better than having nothing at all. But deciding between the two can be a hard choice if your not going fast enough to where the rules say you "must" have the full cage. In that situation the simpler roll bar might be enough to get the job done. But I'm always of the opinion that more bars is more "gooder" & think a full cage is better most of the time (even if it's not "required") if for no other reason than it's already in the car if you decide to step up & go faster in the future.

As for the 175 lb springs, if they are allowing the shocks to sit at the manufactures suggested center-to-center installed height while the truck is also sitting at full weight ride height, then they might be in the ball park. But if the current spring rate causes the shock's C/C measurement to sit either too high/too low with all the weight on the suspension, then the spring rate might be off. In the one clip the suspension did look to initially hit the tire/sidewall real good, which can be a sign that the springs are just light enough that they compress/release a good-usable amount of energy. But you could also see a similar effect even if the spring choice was a little too stiff & a looser shock extension dampening setting was used as a crutch for the stiff spring.

Only way to get a better idea of how close the current spring rate might be is to measure everything to see where the shock C/C is at vs the ride height. And even if the 175's turn out to be an "ideal" spring rate, you can still invest in some other spring rates too if you want & do some more track testing to see what happens. Testing different setups is part of the fun (or part of the headaches & stomach acid ).

I went to the track again yesterday afternoon and improved a little more.
60 ft= 1.61
1/8= 7.65 at 87.36mph
1/4= 12.21 at 106.12mph

Now I think it's time to start working on the rear suspension.
The hop, bounce or whatever you want to call it is still happening at the starting line.
I'm going to order some lighter springs and mess with the ladder bar adjustments some to see if I can fix it.
Also going to talk to a buddy about designing and bending me a 10pt cage.

I know where my limit is as far as rpm and shift points after a little testing yesterday. The best runs are shifting at 5600 with a max rpm of 6000.
Tried shifting at 6000 and the max rpm was 6400 and it ran out of power short of the 1/4 mile . Won't try that again.

way to go. congrats on new time. bob