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This is 2nd gear from a computer simulation. I am talking about Acceleration in G's an RPS Rate Change.


Stan




>>>>---_Gear_Change_1_->_2
___________________________________Force____Aero_____Rolling__Elapsed___________Accele
[email protected]_____dynamic___Resist.___Time______Total__ration_RPS_Rate_Hood_Scp
__________________ft/sec__Torque___Wheel__Drag_-_HP____HP______(ET)____Distance_in_G's__Change_Pressure

_8458.3___80.29__117.761___851.9__5511.8____17.051____7.547___1.1483____79.426___2.315_____0.0___.1145
_8550.0___81.16__119.038___851.0__5505.7____17.612____7.629___1.1655____81.458___2.312__5342.5___.1170
_8650.0___82.11__120.431___849.9__5499.0____18.237____7.719___1.1842____83.700___2.309__5335.1___.1197
_8750.0___83.06__121.823___845.8__5472.2____18.877____7.808___1.2030____85.977___2.297__5307.6___.1225
_8850.0___84.01__123.215___841.6__5445.4____19.532____7.897___1.2219____88.291___2.285__5280.2___.1253
_8950.0___84.96__124.607___837.5__5418.6____20.201____7.986___1.2409____90.644___2.273__5252.6___.1282
_8954.5___85.00__124.670___837.3__5417.4____20.232____7.990___1.2417____90.751___2.272__5251.4___.1283
_9050.0___85.91__126.000___833.4__5391.9____20.886____8.075___1.2599____93.036___2.261__5225.2___.1311
_9150.0___86.86__127.392___829.2__5365.0____21.586____8.165___1.2791____95.467___2.249__5197.6___.1340
_9250.0___87.81__128.784___824.4__5333.8____22.301____8.254___1.2984____97.939___2.235__5165.6___.1369
_9350.0___88.76__130.177___819.5__5302.3____23.033____8.343___1.3179___100.453___2.221__5133.4___.1399
_9450.0___89.71__131.569___814.7__5271.1____23.780____8.432___1.3374___103.011___2.208__5101.4___.1429
_9481.0___90.00__132.000___813.2__5261.4____24.014____8.460___1.3435___103.812___2.203__5091.5___.1438
_9550.0___90.66__132.961___809.8__5239.8____24.542____8.522___1.3571___105.612___2.194__5069.3___.1460
_9650.0___91.60__134.353___805.0__5208.4____25.322____8.611___1.3769___108.257___2.180__5037.1___.1490
_9750.0___92.55__135.746___794.4__5139.9____26.117____8.700___1.3968___110.956___2.150__4968.1___.1521
_9850.0___93.50__137.138___783.8__5071.4____26.929____8.789___1.4171___113.722___2.120__4898.9___.1553
_9950.0___94.45__138.530___773.2__5002.8____27.757____8.879___1.4377___116.556___2.090__4829.6___.1584
10007.8___95.00__139.334___767.1__4963.3____28.243____8.930___1.4497___118.224___2.073__4789.7___.1603
10050.0___95.40__139.922___762.7__4934.4____28.603____8.968___1.4585___119.460___2.060__4760.5___.1616
10150.0___96.35__141.315___752.0__4865.8____29.465____9.057___1.4797___122.435___2.030__4691.1___.1649
10250.0___97.30__142.707___740.7__4792.4____30.344____9.146___1.5012___125.487___1.998__4617.0___.1681
10350.0___98.25__144.099___729.4__4719.2____31.241____9.235___1.5230___128.618___1.966__4542.9___.1714
10450.0___99.20__145.491___718.0__4645.8____32.156____9.325___1.5452___131.832___1.934__4468.7___.1748
10534.5__100.00__146.668___708.5__4583.9____32.942____9.400___1.5642___134.614___1.907__4406.0___.1776
10550.0__100.15__146.884___706.7__4572.5____33.088____9.414___1.5678___135.131___1.902__4394.5___.1781
10650.0__101.10__148.276___695.4__4499.1____34.037____9.503___1.5907___138.518___1.869__4320.1___.1815
10763.0__102.17__149.849___683.8__4424.3____35.132____9.604___1.6171___142.452___1.837__4244.1___.1854
10874.7__103.23__151.405___672.2__4349.4____36.238____9.704___1.6437___146.453___1.804__4168.0___.1893
10988.0__104.31__152.982___660.6__4274.2____37.382____9.805___1.6711___150.628___1.771__4091.6___.1932
10999.8__104.42__153.146___659.4__4266.4____37.502____9.815___1.6740___151.068___1.767__4083.6___.1936


 

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I know this is not a pro stock run by any means.
After the car is moving Gs go down as each gear has less mechanical advantage and you get closer to 1to1 output.
at launch on my car get to a little over 2Gs .
 

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I know this is not a pro stock run by any means.
After the car is moving Gs go down as each gear has less mechanical advantage and you get closer to 1to1 output.
at launch on my car get to a little over 2Gs .
what are your actual ET Slip ET incrementals and MPH's for that Graph ???
 

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This is my 10.00 index car.
at 1 Foot i get GForce Max = 1.8735
what was your GForces near 1320 FT finish line ??
i get in the 0.24 GForce range

from old RacePak Data on a SS/IA 1968 Camaro
we were getting 1.96 = max GForce
when it ran
1.330
4.058
6.377 = 105.86 MPH
8.402
10.132 = 129.86 MPH .. he let-off too early near 1320



 

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2.00 is max on this run. 1320 about .29
for a Clutch/ManualTrans/Flywheel
2.00 Gforce or slightly more would be achievable at Launch

i modeled a Converter/Automatic Trans on the SS/IA Car
and it too can sometimes Launch as high as 2.0541 GForce
at 1 Foot Rollout

Thanks for the Graph + the GForce Data :)
 

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Nick, what grade would you give your engine program up to this point? Keep up the good work and I look forward to watching Shane in Brainerd.
 

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Discussion Starter #5,891
Nick, what grade would you give your engine program up to this point? Keep up the good work and I look forward to watching Shane in Brainerd.
Hello NWroten,

You actually had a pretty good question that I hadn't really thought about before. To give it an actual letter is kinda tough to do. I can't say that any engine builder ever has an A. I feel if you give something an A, then mentally you must think that's all there is to do with it.

At the beginning of the year when we first went out. I would of given myself an F even though everything was new. Jeff had a lot to learn still and the tuneup was still off. Once Shane started running, we got a better idea of where we stood and even at that point. I'd only give myself a D cause I felt I was way behind still. The biggest problem with where I was at back then and trying to get to where I want to be was simple. Money! I just needed more of it to try and improve on everything.

We had a couple of good outings and maybe the grade came up to a C since we were making progress. But the real tell tail to the whole things was when we were in Norwalk. Shane had a new car which was Skillman's old car from last year. Now qualifying did not at all go very well or as planned but we at least stayed in the #16 spot. We at least got some good data on Q4 before the transmission dead-headed going into 5th gear. Actually the data was so promising that we figured out two things. One, we have a lot more potential that we have shown all year long. Two, that there is a definite issue with Shane's old (Blue) car. We still got beat 1st round on Sunday and it was not a pretty run and there was still performance left on the table. But in saying that, we ran the back half and in speed right with the top guys. The promising thing about it all was that the engine we ran in his car all weekend long was the very 1st original engine I built here at the new shop. The one I had under the bench was better but we wanted a base line first with the new car before changing engines. But like I said above, we never made a good base line pull to change it. So moving forward looks a lot more promising and I guess as of right now I'd give myself a C+ or B-. I still have a lot of things I want to try and do when the funds allow me to do that.

Unfortunately now that the performance shows promise. Shane had to withdraw from racing on the Western Swing. He and Auzmet have a big contract that they are trying to finish up which is taking up pretty much all of their time. So in order for us to keep racing as time goes on, he has to take care of business now. The plan is to be back out there by Brainerd and hopefully we will all see you there...

Nick
 

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we ran the back half and in speed right with the top guys
It seems like the trap speeds have become more erratic with the rev limiters. Has that adversely impacted your ability to use speed as an indicator of power? Or do you ignore the timing slip trap speed and calculate it from accelerometer data?
 

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It seems like the trap speeds have become more erratic with the rev limiters. Has that adversely impacted your ability to use speed as an indicator of power? Or do you ignore the timing slip trap speed and calculate it from accelerometer data?
Pete, there is no doubt that the rev limiters can and do affect the final mph. But we get so much data on everyone's car for each qualifying and elimination pass. You can pretty much still figure out who is where. Unless you are on the rev limiter for a long time at the end which does happen at times. The 1/4 mile speeds are still a pretty good indicator of power for the most part...
 

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Great to see the Tuck’s doing well and living their (and our) dreams.
Unfortunately, Shane had to skip the Western Swing cause of work obligation with Auzmet down in New Zealand. Hopefully we will be back out by Brainerd again...
 

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Got a question about compressed spring ....free spring remaining. How close to zero is within reason?
Wouldn't this be called "clearance to bind" or "clearance between coils"?

I don't believe there is any ONE answer for a "general" question. There are far too many variables that are going to affect the clearance needed or wanted.

For a definitive answer, the only accurate method to determine this would be to put your specific combination on a Spintron and see what it wants.

Any specific information given for your combination should be treated as a suggestion.

There are some theories that can be used for suggestions. Such as, the closer to .060" clearance the better.



Cole
 

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.060 is what I've always shot for in the past. This one came out .058 intake and .047 exhaust to coil bind. 540 BBC 18 degree Big Chiefs Blower at 40 psi and 9k max. The intakes I can live with but the exhaust got me nerves up.
 

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I asked PAC about their beehive springs 1-1.5 years ago, and they said shim them as close to 0.060 as you can.


Maybe Nick and Bob will stop in and reiterate their experiences.
 

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Very much its application specific. The beehive and conicals we run tighter. Our typical bracket .900-.950 lift stuff we are about .080 seems to be happy. The 500 depending on the cam design and a few other factors, anywhere from .090 to .145. It also depends on the brand, some brands qc is horrible, and the information on the box about bind height can be off significantly. We crush every spring we use on every motor on our computer spring tester/dyno so we know its actual solid length. Even the sportsman stuff.

I wouldnt run my stuff that close at that rpm BTW. We are normally .080 from theoretical lift with a psi dr1248ml or dr1249ml.

Another interesting tidbit i found the hard way.
Some manufacturers over ratio the rocker to account for flex. Most everything ive seen gets back the lost flex lift with rpm, as the pole vault pole eventually straightens out...lol. So a printed rocker of 1.70 can be as much as a 1.78 actual. Ive seen this destroy a few motors, one a 632 prostock, and one other was a friends 540 blower motor. it went solid and pushed the adjuster up through the alum rocker.



this is just how we do it here. I know others do things differently, but ive had success doing it like that here.
 
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