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I finally got the car dyno'd and am very happy with the result - 325.1 horsepower at the wheels. I am the original owner and no mods have been made to the car. The "official" factory rated horsepower for this car with the CME is 335, about 40 horsepower less than it actually has. Other than the occasional minor piston slap (which the Pennzoil Platinum helped reduce) she still runs very well despite 155,000 kms.
Sorry, I forgot to add my sig.
These engines are very much underated, as you've just found out.
Now you have a baseline,,,,when does the modding start? :D
I agree with FBJ. Let the mods begin. The LS1 was always underated and getting to 400 rwhp is no more then a phone call to your parts supplier and a Saturday afternoon. These cars, SS & WS6, were ment to run in the 12's right from the start. The only problem is the 10 bolt rear and a couple of minor things like window motors but overall I like my SS more then a Vette. JMO
To the o p i basically have the same car, same ext color and int color. mines an 02 w/cme and blackwing air lid 345 hp. Love the color its just hard to keep clean
Yep I have an 02 SS vert that is identical and SLP loaded, CME, Lid, mats, portfolio, cover, etc...I've really grown to dislike the color, it's as bad as black :lol: Can't take the darn thing around the block without feeling like it needs wiped down again.
Nice dyno number. Any track times with her?
My Z is now a DD and I basically gave up on trying to keep it clean anymore. I do like the color though. I still get comments on it even when it's dirty.Quote:
Originally Posted by Firebirdjones
And it put down 306/323 and the rear wheels as a stocker.
Sig shows what the car did as modified.
That's pretty close to what I put down factory. 324/338 at the wheels. I had mine dynoed to see that everything was working as it should.Quote:
Originally Posted by Ed's 01 SS
My 00 SS is factory 320hp. On Bluecat's Dyno it laid down 295 stock with SLP lid before his tune. A few keyboard clicks later 306hp to the wheel. I was surprised that it lost 25hp from the flywheel to the road. Always good to have a baseline number.
Actually they loose quite a bit more. The numbers GM puts on these production cars isn't really that close and shouldn't be used as a comparison for real world dyno's.Quote:
Originally Posted by danjo11
There is a pretty large difference if you dyno the engine alone vs a chassis dyno. Of course correction numbers and dyno's vary but generally the engine on a dyno has no accessories to run, usually gets a carb hat for outside air, in a controlled room, and for ease of hookup generally runs an electric water pump since the accessory drive in most cases in non existent.
I've seen nearly 100hp difference from engine to chassis dyno on a couple of my cars. By the time the engine is in the car, running all accessories, heat soaked, surrounded by a hot engine compartment, air cleaner assembly installed, full exhaust, turning the transmission, driveshaft, rearend, wheels and tires, it all robs alot of HP.
A perfect example of LS engines was GM High Performance several years ago running the LS1 crate engine on an engine dyno with no accessories similar to what I described above, and right out of the crate it made right at 400 hp at the flywheel. So when you put it in a car and you see all these examples making 300-330 HP on a chassis dyno, it starts to make more sense. GM sandbagged the advertised HP numbers just like they've done for the last 40 something years.
Agreed, they grossly underrated the LS1 and I do not know why because every time you open a magazine you see someone else has the HP lead. Mustang, Corvette, Viper, Camaro they leap frog every month.
Quote:
Originally Posted by Firebirdjones
And that 100 HP diff you wrote about is why almost all the cars from the late 60s had so much over-rated advertised power. When you see a 330 HP, 410 ft-lb torque 400 Firebird from 1968 run a 1/4 mile time of mid to high 14s @ 102 MPH, it makes sense when the 4th gen cars with about the same curb weight run a full second (or better) and 6 MPH faster. And the new cars get 28 MPG highway. And don't overheat. And stop more than once before the brakes fade. And go around corners so much better. And (on and on).
GM didn't want the F-body to be on par with Chevy's flagship car, the Corvette.Quote:
Originally Posted by 2002ssslp
They just don't have the character, or collectability, or a growing increase in value every year,,,,,Just jabbin :DQuote:
Originally Posted by Too Fast
Alot of the gross ratings back then were still a bit conservative but not nearly as bad as some of the cars today. That's why NHRA quickly refactored alot of cars in class racing because they were clearly running quicker than their factory HP ratings would suggest, which is how they are initially classed.
The DZ 302 rated at 290 HP actually made 350-360 hp with a good tune but the 70 LT-1 that came out a year later rated at 360 hp (370 HP for the vette) actually makes nearly right on that HP number. Just depends on the car in question I think.
My 69 SCJ mustang is a perfect example of a low (fudged) HP rating on purpose. Only 335 from the factory but in 68 when they were first introduced they cleaned house in Stock Eliminator and NHRA quickly refactored them at 380hp or something like that. Many more examples too.
My 70 ram air formula 400 was factory rated at 345 hp. I rebuilt it to stock specs with alot of attention to detail, nothing ported, and stuck to the pure stock rule book where I wanted to run the car. They basically stick to some of the NHRA stock eliminator rules where they allow up to a .060 overbore (these engines are getting old :wink:) and they have a certain rod and piston part number that is allowable per NHRA that mimics a stock piece similar in weight and CC's. They do allow a bump (up to 1.5 points) in compression as well to compensate for cc'ing your heads, decking the block, and the overbore.
I decked the block and CC'd the heads a little tighter (slightly milled), but I chose to go only .030 over, and I chose to keep the compression down to 10:1 (slightly below stock) to try and get away with pump gas most of the time since it's also a driver. So you could say mine is slightly detuned, still runs a stock blueprint camshaft, stock heads, carb intake etc....
It dyno'd at 384 hp (I believe give or take, I'll have to look at the sheets, it's been 14 years ago) I know it was 380-something.
Anyway, a few years after, I had already been racing the car, had a sharp tune in it, have the car so well dialed in I could pretty much predict what ET it would run on any given day and weather condition when we rolled in. It was deadly consistent. They had a chassis dyno on the premises one day at the Tri-Power Nats, and after racing that day we decided to throw it on there for giggles (it was only $35 for 2 pulls). Made 301 HP and 355 TQ with a flat 13:1 AFR throughout the pull. Made another pull without shutting the car off and it duplicated the first pull to the button. That's why the car is so consistent going rounds, it just doesn't fall off when it's hot.
Anyway, long story short, it's a good 80+ HP off of the actual flywheel HP it dyno'd. Pulling through a 400 turbo with stock converter, and the original 12 bolt rear.
Yes but in the 60s they used a gross horsepower rating and sometime in the mid 70s they started using a net horsepower rating. The gross ratings were always way higher then net ratingsQuote:
Originally Posted by Too Fast
Ah yes, FBJ, the character. You must mean the overheating, ill-handling/ill-stopping/flexable chassis. J/K! Some of the best looking cars came out in the late 60s/early 70s, why are some of today's cars copies of those. I like the old cars with a modern suspension and brakes.
I have noticed my WS6 is starting to get some heads turning, it's 12 years old now. But not as much as my 68 Le Mans drop top, and I'm sure you know this with your classic rides. What you say about HP ratings is true, some were underrated back in the day but most were not at all representative of what the engine made in actual car trim. And like slimss reminds, those numbers were gross. I think it was '72 when it went SAE net.
Yep, the only difference is the gross resembled no accessories or any other HP robbing add ons. Pretty much how every engine is still dyno'd today. Net ratings are with all drive accessories included, usually the air cleaner, all robbing some power. They went to net ratings in 72, with lower HP numbers but engines remained assentially untouched from the previous 71 model year with a few acceptions.Quote:
Originally Posted by slimss
I don't really experience any of those "ill" problems you speak of. If in tip top shape they are trouble free daily transportation for me ;)Quote:
Originally Posted by Too Fast
I'm a bit opposite,,,,don't care for modern suspension and brakes on an old car. Pro touring doesn't do it for me, just another fad. I like em' as they rolled of the assembly line and I drive em' that way without a complaint.
Some of you geezers have gotten soft :D
^^^Damn now I'm part of the geezer crowd. Speaking of which, the Good Guys are in town this weekend. At least I'm not a member of AARP!