IHADAV8.com - Turbo Buick Tech, and Nonsense
General => IHADAV8 Playground => Topic started by: Scoobum on September 19 2014, 10:51:48 PM
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Tonites Run:
Distance-1/8th Mile
Temperature-51 Degrees
Humidity-60 Percent
ET-7.03
MPH-101.16
60 Foot-1.73
PL Data:
Boost 23
1st Gear Fueling-807
1st Gear Timing-28.9
1-2 Shift Point-5150
Flash Stall-3975
1-2 RPM Drop-650
2nd Gear Fueling-760
2nd Gear Timing-28.9
2-3 Shift Point-5775
3rd Gear Fueling-744
3rd Gear Timing-27.9
Trap RPM-5600
VP 112 Race Gas
TT 110 Race Chip
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What % slip do you compute at the line? Pretty quick!
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What % slip do you compute at the line? Pretty quick!
Steve...if you're referring to convertor slip, I don't think there's a calculator for 1/8th mile...unless you know of one?
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Just find one that computes mph from rpm, rear gear, and tire height. Then compare that mph to what the timing lights computed which is not quite exact. . Or use the slip computed by Pl if your third gear switch is working
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the PL number depends on your speedometer reading right for the tires you are running...tho
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Man you a layin it down . Mph looks great. A few degrees cooler and you're gonna have a 6 sec slip. Nice work.
I notice the 1-2 shift is several hundred rpm less than than the 2-3 shift(5160 vs 5775). Is this planned? I do like that I doesn't make the shift to 4th.
How tall are your rear tires? I am assuming you are using stock 3.42 gears.
This is where I'd like to be. Great you are already there. I have a pattern to follow.
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Steve...here's a comparison to my quickest run of 6.90 at 101.58. That run was with 28 PSI on a 1.61 launch. Last nites run was only 23 PSI...on a 1.73 short time. Had the car of launched harder I may have eclipsed my best ET. The changes that were made over the winter was I added a FMIC, switched from alky to race gas...and had the heads extensively reworked. I'm betting the heads are giving me the biggest improvement. The bottom line is I'll blow my quickest ET and MPH out of the water with boost and high gear fuel thrown at it.
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Man you a layin it down . Mph looks great. A few degrees cooler and you're gonna have a 6 sec slip. Nice work.
I notice the 1-2 shift is several hundred rpm less than than the 2-3 shift(5160 vs 5775). Is this planned? I do like that I doesn't make the shift to 4th.
How tall are your rear tires? I am assuming you are using stock 3.42 gears.
This is where I'd like to be. Great you are already there. I have a pattern to follow.
Good eye. The track had a big oil down...and it broke loose on the 2-3 shift. At that point it was point and shoot...as I was sawing on the steering wheel and pointing it to the middle of the traps. Rear tires are 28"...with the 3.42 gears.
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Here's the build if anyone's interested:
Stock short block...stock pistons...stoc k rods...stock crank. Balanced rotating assembly.
Big valve reworked 8445 heads...212/212 flat tappet cam...stock rockers.
Champion Racing stock appearing intake...Steve Monroe TB
CEA 6262 JB turbo matched with a 16930 convertor
TT chip and Translator
Stock welded headers
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Boy she's quick! I need to research me a set of 28" tires for the rear.
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Hey scoob,
How much fuel did you have to take out of 1/2 gear to get that low of a a/f ratio? My first gear is in the 870/880 range, second gear is down a bit in the 830/850 range with the default parameters of Eric's chip. I'm only pushing 20 pounds of boost right now as third gear is in the 770/780 range and I'm getting about 1 degree of timing retard at the 2/3 shift. I would really like to work the tune out for first and second before adding any more boost.
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Hang on Jason...and I'll go out and check the SM for low gear fuel...back in 5.
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Brad, here is what keeps jumping out at me. 5100 rpm, with no slip, should equal 136 mph. You pulled 101 mph. 101 mph with NO slip should be about 4150 rpm. Add 10% for converter slippage, and you get about 4600 rpm.
I used this calculator http://www.angelfire.com/fl/procrastination/rear.html (http://www.angelfire.com/fl/procrastination/rear.html) and then cross checked it with another one.
Now, that shows you have about 35% slip in the drive train instead of the 10% I would have guessed with the non lock up converter. Now we have some error because the mph on the strip is calculated from the time thru the traps and not instantaneousl y but we don't have that kinda error.
It seems to me that either the converter is bad, or the tranny is slipping like mad under load....one way, or the other, you could not run a quarter mile without a couple more gears. I think I would ask someone smart about it.
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I ran the slip at 28 percent. I follow Dusty Bradfords posts like a hawk. He says convertors don't fully couple till the 1/4 mark...or well into the run...if I read his post correct. When I use to run the 1/4 the car would consistently run 11.5 at 121...and the slip checked in at 10 percent...so I believe what Dusty is saying about fully coupling. He could likely build a convertor that would fully couple at the 1/8th...instead of the 1/4. As I'm putting more HP to it...the MPH is rising...so it doesn't appear as if I'm 'blowing through it' as of yet. I'll have the car out again on the Thanksgiving weekend next month. Lets see what the MPH is with 2 pounds of boost added. I'm expecting 103.X. What do you think Steve?
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Jason...the low gear fueling is at 113...which means I pulled 11.7 percent fuel out of it.
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Steve...a couple other things. This is the governor from Norbs' old 200. He lightened it to shift higher. Another thing Dusty mentioned about AC convertors is that they couple better with higher RPM's...so I left Norb's governor in.
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Steve...PL is showing me letting out of it at 5600...which is likely 1 second after going through the traps. 1/4 is showing me coast through it at 11.8 at 83 mph.
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No doubt he is right on the coupling. Your comment about the 1/8th makes sense.
The stall still seems high for that converter, tho. I think it is costing you a bit.
I agree that you will pick up a couple mph. The car looks like a 10.8 car from the mph
Without a dyno test, or beating the heck out of the car, it is hard to be exact, but I would guess 5600 is a good shift point for that cam. If PL shows the rpm still increasing at a good rate up to 5800, then that is good and my guess is off :D
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Jason...the low gear fueling is at 113...which means I pulled 11.7 percent fuel out of it.
Thanks brad!
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Steve, I need your advice on this. PL picked up 1.2 KR going through the 1/8th mile trap. Should I pull 3rd gear timing...or add 3rd gear fuel...or both?
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It looked a tad lean so I would add 2 numbers if the air is the same next time
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Another thing. When I hit recall on the SM...it showed 0 KR...so why did PL pick it up...and not my SM? Not complaining... just curious. Oh...and I saw one green light come on on the knock gauge.
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SM looks at timing retard once every 1.4 seconds. Pm looks at it about 24 times per second.
Knock alarm may look at knock counts instead of timing retard and has no filtering applied
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SM looks at timing retard once every 1.4 seconds. Pm looks at it about 24 times per second.
Knock alarm may look at knock counts instead of timing retard and has no filtering applied
Thanks so much for the explanation. :)
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Great time! That is moving and great mph. Took my car to the track on August long. First pass and lost my boost controller. So, I decided to just run it with 14psi. I went 12.09@112mph and my lock up converter wasn't working so I figure that should be an easy 11.7 with the converter locked. First time I took the 4.1 to the track it went 12.39@114 running pig rich, locked the converter and went 11.9@116, then I started leaning it out and went 11.9@116 without the converter locked.
This summer has been horrible. The snow only melted in June and then it rained every weekend. And for some strange reason the weather is really nice this week, 26'C yesterday went for a ride on the RZ and 21'C today, so I fixed my boost problem just got back from a spin. Suppose to be 27-31'C tomorrow. :rock:
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That thing is honkin', Brad!