Re: Time slip analysis....? Rocky's inching toward the 10's
[Re: Streetwize]
#1606779
04/14/14 05:15 PM
04/14/14 05:15 PM
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Joined: Jan 2003
Posts: 6,591 Canton, Ohio
Sport440
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My analysis is your 60 fts. about .2 off Your 1/8 98.6 MPH shows you have some power. If its got the power to run that MPH, its got the power to get a 1.5 60 ft. Your right, for its slow 60 ft. it does come on hard at the 1/8. But then it does die off some on the second half. You gained 20.58, and 20.94 on your two passes. Typically a normal car at that 1/8 MPH would be netting 24.5 MPH or so on the back half. Could that be all just the Aero effects??, not sure really. Rocky doesnt seem to have a problem getting to 99 MPH with a slow 60. I feel its more the just a aero problem. You get that 60 ft. where its got the power to be and find another mph or two on the back half and you will have your 6.9 and 10.9 duel purpose street car. That 1/8 mile 99 MPH tells us that. Nice cool ride, fast too. Just needs dialed in like the rest. EDIT, Just did the math from 99 mph to 120 difference between a .65 and .5 CD with the same 25" frontal area. The difference was 43 HP If I would of used the frontal area of a Duster it would be more like your 50 Hp number that you stated. 50 HP is plenty enough to knock down your back half MPH compared to a more normal back half. But thats no cause for your .2 slow 60ft.
Last edited by Sport440; 04/14/14 06:03 PM.
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Re: Time slip analysis....? Rocky's inching toward the 10's
[Re: Sport440]
#1606780
04/14/14 05:40 PM
04/14/14 05:40 PM
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Joined: Jan 2003
Posts: 9,924 Weddington, N.C.
Streetwize
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Mike, Thanks! That's the kind of analysis I need. 98.66 SHOULd equate to around 124 but (if the Aero .5 vs .65 is real and it's truly like 45 hp (or 500 extra pounds) maybe it's not really that far off. What areo factor is the wallace calculator based on? (I'm assuming a .5). I'm only going through the traps at just under 6000, I'm assuming about 11% slip. If it were an A body pure race combo I'd be using an 8" converter and be hitting 1.5's all day long. So a shorter tire will increase the wheelspeed inthe traps and use more "sweet spot"....so the combo is leaving some on the table but for 1/8th mile "fun brackets" (since it's showing signs of at least being consistent) it's almost perfect as is The motor pulls hard, it feels like it's going downhill at the shift points but it does need that bigger lift cam...I'm probably leaving 30 on the table I'm sure....but I'm not really "missing it" like I would be if it was a Pure race car to me...it's funny. If you look at the linear HP Drag curve just for accelerating from 100 to 120 at a .65 vs a .5....it's significant for 4 seconds. You also sense the drag as soon as you let off the power, it's like a Sail...I hardly need the brakes
Last edited by Streetwize; 04/14/14 05:52 PM.
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Re: Time slip analysis....? Rocky's inching toward the 10's
[Re: Streetwize]
#1606782
04/14/14 06:08 PM
04/14/14 06:08 PM
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Joined: Jan 2003
Posts: 6,591 Canton, Ohio
Sport440
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Quote:
Mike,
If you look at the linear HP Drag curve just for accelerating from 100 to 120 at a .65 vs a .5....it's significant for 4 seconds...
Bobby, yep just did and Edited my post before I saw this. Used 99 to 120 .65 vs .5 like you suggest. The difference was significant enough for your slower back half MPH.
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Re: Time slip analysis....? Rocky's inching toward the 10's
[Re: Streetwize]
#1606784
04/14/14 06:22 PM
04/14/14 06:22 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
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Val-haul-ass... eventually
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Quote:
... 98.66 SHOULd equate to around 124...
Then an E-body probably isn't aerodynamically "optimum" either, considering I never saw more than 122 w/ that sort of 1/8 MPH.
How does an 85" wheelbase "brick" handle at almost 120 MPH? /
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Re: Time slip analysis....? Rocky's inching toward the 10's
[Re: Streetwize]
#1606789
04/16/14 11:42 AM
04/16/14 11:42 AM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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Quote:
Brad, If you watch the car go from behind it tracks as straight as a rail, the steering is really slow so it's not over-correction prone or 'twitchy'.
Thats what I do on short wheel base cars.. I use a longer steering arm to slow the steering.. its easy to over steer a short car
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Re: Time slip analysis....? Rocky's inching toward the 10's
[Re: Streetwize]
#1606791
04/16/14 12:11 PM
04/16/14 12:11 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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Quote:
That's it exactly, mr P
On a short WB car your really driving the Pitch or the 'yaw' rather that steering it, it my ears are perpendicular to the lane I'm doing ok.
You can see in the video it tracks straight. I was really suprised to see the front tires are barely skating the asphalt for the first 40-50 feet, that tells me the motor wants a little more vert....not sure if I'm going to give in to it or not. I might try going to a dual plane to pick up 1/8th mile ET but I'll bet it may slow the mph on the big end. It's vexing....slowish out of the hole, goes like heck through the middle and then the air brake dynamics kick in on the top!
If your not above 6400 rpm then the dual plane would help... and maybe even if your a bit higher because of the time you would be up there... I know all to well about aero.. we use to load a truck with a vertical wall that we could crank up to load it HARD... pushing a wall around takes plenty of power... and depending on the size of that wall(frontal area) it starts taking effect at lower speeds
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Re: Time slip analysis....? Rocky's inching toward the 10's
[Re: Streetwize]
#1606793
04/16/14 01:14 PM
04/16/14 01:14 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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Quote:
... if my ears are perpendicular to the lane I'm doing ok.
Better not race w/ a head cold! You'll never know WTH is going on w/ your equilibrium all stuffed up.
Quote:
You can see in the video it tracks straight.
That's cool. I'm spoiled 'cuz The Mopig drives like it's on rails on the big end. Once I got the car to leave straight (CalTracs settings & rear tire pressure fine tuning), it became a pretty easy car to run down the 1320.
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Re: Time slip analysis....? Rocky's inching toward the 10's
[Re: Streetwize]
#1606794
04/16/14 08:05 PM
04/16/14 08:05 PM
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Joined: Jan 2003
Posts: 9,924 Weddington, N.C.
Streetwize
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Well I pulled Rocky back in the Garage, this weekend I might get a wild hair and swap the cam...so easy in this thing I can probably do it in an hour or even less
Torque should be as good or better and top end should hopefully pick up some via significantly increasing the duration above .550-ish lift.
Old
261/268 107LDA/105ICL .585/.570
New
260/269 .668/.645 108LDA/104ICL
Head flow I/E
.100. 72/65 .200. 144/108 .300. 219/146 .400. 273/174 .500 301/205 .600. 312/212 .700. 316/236
Last edited by Streetwize; 04/16/14 08:30 PM.
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Re: Time slip analysis....? Rocky's inching toward the 10's
[Re: justinp61]
#1606796
04/16/14 08:28 PM
04/16/14 08:28 PM
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Joined: Jan 2003
Posts: 9,924 Weddington, N.C.
Streetwize
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Both Solid Rollers but I'll bet I could probably even run hydraulic rollers on the old cam....it's really an Endurance style circle track (allegedly 358" Nascar Trucks and IROC Daytonas) cam with 360 oiling grooves on the 2 & 4 journals....it would probably make an awesome street roller cam for my new 440 incher
Last edited by Streetwize; 04/16/14 08:38 PM.
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