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#3301
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Just let me know when you're ready to line them up! I'll even leave the A/C on! You'll love the tailights. All 169 LEDs.
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Bob Woodard Brighton, MI 2012 SRT8 Charger - 12.70 @ 111mph |
#3302
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Ill take some of that! Where do I sign? Just to be fair I will leave my ac on too!
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Nothing is impossible if you break it down into possibilities. It's all a matter of "Want to". |
#3303
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Remember when the SD first came out. There was a track test,I think there were 4 cars total. A Laguna,a Charger, and forget the rest. Lets just say the SD was tops by a wide margin. Move Over Pontiacs Are Racing(MOPAR). :-D
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#3304
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Just so you're clear Jay, we're running top end, not just 1/4 mile! LOL
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Bob Woodard Brighton, MI 2012 SRT8 Charger - 12.70 @ 111mph |
#3305
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They tried to do a comparison test on the new Charger with a G8 but there were none to be had. GM killed them! Times they are a changin!
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Bob Woodard Brighton, MI 2012 SRT8 Charger - 12.70 @ 111mph |
#3306
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Or, Move Over Pontiacs Approaching Rapidly
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1973 Formula 400 4 spd 04C build date Norwood assembly plant. |
#3307
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super duty piston info needed
i have been getting conflicting info on what piston i can use for the 73-74 sd rod.does anyone who actually built or has a sd engine know what piston brand i can buy with part # if possible to use with a factory sd rod? any help would be appreicated.thanks brian
bmwjmw@verizon.net |
#3308
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Received my new Hemmings Muscle Machines magazine yesterday and it has a nice write up on the 73-74 SD-455's.
Enjoy, Brew |
#3309
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Good article. I just don't understand how it says that with a good driver a sd455 is good for high 13's on the 1/4, which I truly believe. But then it goes on to say that some sd expert thinks the 290hp net rating to be correct? Am pretty sure the net total is alot higher than 290hp.
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#3310
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Quote:
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#3311
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Quote:
Subtract approximately 22-25% (auto) or 12-15% (stick) from factory net HP ratings to get an approximation of RWHP numbers.
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Regards, "455HO" Lloyd 2008 GMC Sierra Denali 2WD Crew, L92 6L80E, Silver w/ Ebony guts, 14.26 @ 98 |
#3312
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Quote:
So you are saying the "real net on a 73 is 22% less than the 290? Thats interesting, I stand baffled , Thanks for setting me straight ! |
#3313
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The article does not go into whether the rating is based on crank or rear wheel measurements, I know it's always being stated as crank measurements in all publications I've looked at. Therefore if the "expert" is to be believed, 290hp minus 20-25% loss at the wheels, would not equal 1/4 times in the high 13's. not even high 14's for that manner.
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#3314
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Quote:
NO vehicle that I'm aware of is rated at the wheels. The "SAE Net" HP and Torque ratings began in 1971, and most manufacturers advertized their vehicles with BOTH the old "SAE Gross" and "SAE Net" ratings Then for the 1972 model year the SAE Net ratings became the law, and if I'm not mistaken ALL manufacturers were required to advertise the Net ratings ONLY. A couple of Pontiac examples: 1971 L78 400 4V was rated 300 Gross HP, and the 1972 L78 (with dual exhaust) was rated 250 Net. The 1971 LS5 455HO was rated 335 Gross HP, and the 1972 was rated 300 Net HP. That is also why you'll notice that for a few model years after 1971 engines were rated differently when equipped with single or dual exhaust. Until duals went away . . . The major differences between gross and net ratings are that engine is required to pump it's own coolant and fuel, turn it's own alternator and other accessories, and breathe through it's as-installed air cleaner and exhaust system.
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Regards, "455HO" Lloyd 2008 GMC Sierra Denali 2WD Crew, L92 6L80E, Silver w/ Ebony guts, 14.26 @ 98 |
#3315
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For horsepower comparison purposes, leave the 1/4 mile ET out of the conversation. Too many variables like traction, gearing, torque converter stall speed (on an auto), etc.
1/4 mile TRAP SPEED is a MUCH better all-around indication of REAL, to-the-wheels horsepower (vs. the total vehicle "race" weight, of course). Another real world example (that's not TOO far removed from a stock SD455) would be my Formula. I Don't wish to bore everyone with all the details, but is a 467" 455, ported 7F6 heads, VERY mild solid lifter cam, STOCK HO intake, SD Q-Jet, stock Ram Air system, R.A.R.E. 2.5" outlet exhaust manifolds into an OLDER 2.5" PYPES exhaust system (not the better new system with the free-flowing muffler), TH400 with a GM converter, 3.08 gear, etc. 3925# "race" weight. On a conservative engine dyno (and running stock 2.25" SD455 exhaust manifolds) we got a best of 430 corrected HP. Later, on a conservative (Mustang, eddy-current) chassis dyno we got a best of 299 corrected RWHP. A 30% loss on my car, due in part to the restrictive single muffler. My car runs a consistent 105 - 106 MPH 1/4 trap speed, in the heat.
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Regards, "455HO" Lloyd 2008 GMC Sierra Denali 2WD Crew, L92 6L80E, Silver w/ Ebony guts, 14.26 @ 98 |
#3316
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The difference between net and gross is pretty simple. Both are measured at the crankshaft. Gross is the engine only with no accessories hooked up and running free air intake and exhaust. Net ratings are done with the correct vehicle exhaust system, all accessories, and the correct vehicle airbox or filter system in place. It takes power to turn the accessories, therefore a lower number.
If you'll notice, the 73-74 SD-455 HP was rated at 4000rpm. The engine continues to make power well past that rpm. Probably made 350ish at 5200 would be more correct. There is a new SAE rating system that the manufacturers started using 5-6 years ago where you actually do a net rating with a witness from SAE that certifies all of the parts of the engine. It levels the playing field between all of the manufacturers. You MUST rate your engine HP +/- 1% of what it makes on rating day.
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Bob Woodard Brighton, MI 2012 SRT8 Charger - 12.70 @ 111mph |
#3317
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Quote:
Your point about the "rated" HP RPM for the SD engine is a point I most certainly meant to make, and completely forgot. Thanks for chiming in!
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Regards, "455HO" Lloyd 2008 GMC Sierra Denali 2WD Crew, L92 6L80E, Silver w/ Ebony guts, 14.26 @ 98 |
#3318
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Hey Jay, I'll take some of that action and I will do it in the 1/4 mile! And I'll leave my A/C on too with the top down!
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Dick Winkles 1970 RAIV GTO 4-speed 1974 Original owner Z-28 4-speed 2008 SRT10 Viper Very Orange (was SD TA!) 2015 Challenger Hellcat 6spd (was SD TA!) |
#3319
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Interesting read, thanks for all the clarification! Lloyd, Bob...
I do seem to remember the lower numbers being better suited for insurance companys?? Oddly enough a mild 455 can pull 500 lb ft of torque , hehe thats higher than most trucks of that era :P |
#3320
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Holly Bat Caves its Dick Winkles
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