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Discussion Starter #1 (Edited)
Factory rating is 300hp, but this being said:
Our trannies use up about 23% of the power the motor is putting out.
So 300hp net with a 23% drivetrain loss is 231whp, correct? How many here have dyno'd 231whp on a dyno without any modifications of any sort? I have done some research and see that number is being achieved with mods like induction and exhaust, but not factory stock.
The original N* was rated 275hp so ~211whp, which seems more realistic assuming about 20whp is being gained from induction and exhaust mods = 231whp (which should have been the factory number).

So question is was the 25hp added to the newer N* real, or was it just for print? I would like to see dyno sheets for all N* if you have any, both 275hp version and 300hp version. Or if anyone has more details to this I have overlooked, I am open ears (or eyes in this case:bouncy:) Thanks for any input or opinions.

Links to some of my research:


http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/100904-few-numbers.html?highlight=dyno (and with more smoothing that would have showed even less)
http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/75675-so-i-put-my-sled-dyno.html?highlight=dyno
I would expect an L37 to put down 210 or so...
Hot Rod did a dyno test of a stock 300 HP mid-90's Eldorado a few years ago, and it put out around 216 HP or so.
Which is exactly in line with my 275hp theory?
 

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The Northstar Tuner
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Factory rating is 300hp, but this being said:

So 300hp net with a 23% drivetrain loss is 231whp, correct? How many here have dyno'd 231whp on a dyno without any modifications of any sort? I have done some research and see that number is being achieved with mods like induction and exhaust, but not factory stock.
The original N* was rated 275hp so ~211whp, which seems more realistic assuming about 20whp is being gained from induction and exhaust mods = 231whp (which should have been the factory number).

So question is was the 25hp added to the newer N* real, or was it just for print? I would like to see dyno sheets for all N* if you have any, both 275hp version and 300hp version. Or if anyone has more details to this I have overlooked, I am open ears (or eyes in this case:bouncy:) Thanks for any input or opinions.



http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/100904-few-numbers.html?highlight=dyno (and with more smoothing that would have showed even less)
http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/75675-so-i-put-my-sled-dyno.html?highlight=dyno

Not all PCM programs are created equal
 

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Discussion Starter #3 (Edited)
Not all PCM programs are created equal
I agree, but GM created them all to equal 300hp and it seems they don't stack up?

In 1999 the Ford Mustang Cobra was rated 320hp and people complained that their dynos didn't show that power, and Ford was required (or heavily persuaded) to recall all the 32v Cobras that year and install better exhaust, so why didn't Cadillac do the same if what is said is in fact true? (Sorry 50% of my posts have reference to a Mustang) :(
 

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I agree, but GM created them all to equal 300hp and it seems they don't stack up?
I know better than that.
Trust me
I have about 50 on paper and they are all different. I am mostly looking at z or w rated tires. I have some odd country programs, but I have about 50 different ones. Most of them are just for 2000 to 03. If I started pulling up S and H rated tires I would be over whelmed.
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I put together a DHS that ran against a VIN 9 car. It is Bert's Kill so you will have to wait, but that 275 horse is no 275 anymore. Nothing internal in the engine.
 

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Discussion Starter #5 (Edited)
I know better than that.
Trust me
I have about 50 on paper and they are all different. I am mostly looking at z or w rated tires. I have some odd country programs, but I have about 50 different ones. Most of them are just for 2000 to 03. If I started pulling up S and H rated tires I would be over whelmed.
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I put together a DHS that ran against a VIN 9 car. It is Bert's Kill so you will have to wait, but that 275 horse is no 275 anymore. Nothing internal in the engine.
You are going to a different page, I know there are different spec cars. Issue is they were ALL rated 300hp, so they ALL should have made at least 300hp. We all are in agreeance that one of the biggest hinderances on these cars as far as making power is the factory PCM tune. But GM says their shitty tune (no matter the speed spec) is good for 300hp (231whp) and it is not.
 

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You are going to a different page, I know there are different spec cars. Issue is they were ALL rated 300hp, so they ALL should have made at least 300hp. We all are in agreance that one of the biggest hinderances on these cars as far as making power is the factory PCM tune. But GM says their shitty tune (no matter the speed spec) is good for 300hp (231whp) and it is not.
No
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That is my point.
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A engine that was on the dyno was rated at 300. It was not certified.

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please read this paper
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http://www.sae.org/certifiedpower/details.htm
.
 

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Discussion Starter #10
You posted again before I could even reply to the first, slow down:bighead:

But you said it yourself, which of the 50 tunes was applied to those test motors?
 

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You posted again before I could even reply to the first, slow down:bighead:

But you said it yourself, which of the 50 tunes was applied to those test motors?
All I know is that I have one slick program.
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I am working on some for 99 and prior.
 

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So what really is the rated HP of a vin 9 1996 North*? & am I wasting my time trying to use this motor for my project ,when I already have a 235_250 motor in it already????
 

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I think that what AJ is saying (regarding the SAE ratings) is that both ratings are correct. The older L37 Northstars are rated at 300 hp. The newer L37 Northstars are rated at 292 hp, UNDER THE SAE J1349 spec. It's like gross vs. net ratings. Or old EPA MPG ratings vs. new EPA MPG ratings. Both old and new are "correct" in that the results are accurate to the method. The methodology was updated to try to better replicate real world conditions (in both examples, hp rating and EPA MPG rating).

The rating of a VIN 9 1996 Northstar engine is 300 hp. Will you see that at the wheels? Who knows -- it depends on the condition of your transmission and fluid, the weight of your wheel/tire package, etc. But there are too many unknown variables in a chassis dyno to know FOR SURE what your engine makes. We can guesstimate that the transmission consumes 23% of the hp. What if it's only 20%? What if it's 25%? At 20%, 300 = 240 hp on a chassis dyno. But at 25%, 300 = 225 on a chassis dyno.

The only true measurement would be to dyno it at the crank, just as Cadillac did, and find out. Otherwise, you're just spinning your wheels, so to speak, trying to ascertain how much hp your transmission consumes to figure out how much hp an engine might make. Keep in mind also that an engine with 80,000 miles won't likely make the same power numbers as a new one.

In other words, I would totally believe a street-driven car with 50,000 miles putting down a number of 215 hp on a chassis dyno, even if the engine is supposed to put out 300 hp. Maybe the transmission is eating up 27% of the power (81 hp). 215 hp + 81 hp loss = 296 hp. If the difference between the rating and the actual output is only 4 hp, as in this case, I'd be impressed.
 

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The G-Tech Pro says I put down 242. I will have a whole folder full of dyno slips soon. :) just hang on.
 

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Another question you have to ask is what were the conditions of the test for the 300hp and 275hp ratings? Is this installed in a simulated vehicle? With factory induction and exhaust? Are all the accessories installed? (water pump, alternator, power steering, AC compressor)

I don't know the answer to that... I know they recently changed those conditions, and the 4.4L SC N* was rated at 469hp then changed to 440hp. Same engine. 29hp "disappeared". Or maybe it was vice versa.
 

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I don't know the answer to that... I know they recently changed those conditions, and the 4.4L SC N* was rated at 469hp then changed to 440hp. Same engine. 29hp "disappeared". Or maybe it was vice versa.
Yeah, it was vice versa. It was originally rated at 440 hp, and when re-run using SAE's new guidelines, it came out to 469 hp. For some reason, the new spec was favorable to that engine, but some other engines "lost" power. Some Toyota engines "lost" a sigificant amount of power (10%).

In the FWD Northstar world, the 300 hp engine "lost" 8 hp and 8 lb*ft of torque with the new SAE spec, and is now rated at 292 and 288 respectively (from 300 and 295 originally).

The 275 hp engine didn't "lose" any hp, and "lost" 5 lb*ft of torque with the new SAE spec, and is now rated at 275 and 295.

Again, none of these engines actually "lost" power. It's simply using a new measurement. It's like getting on an exercise bike and setting the resistance to zero, and seeing how many RPM you can turn (which you could convert to hp). Then set the resistance to maximum and then re-measure. Your strength didn't change, but the test conditions did. That's all.
 

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Well when a car owner wants to go faster they go buy performance parts, but that's not an option for us :crybaby:

Does anyone here have a Northstar in a different vehicle controlled by a manageable ECM?
 

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Well when a car owner wants to go faster they go buy performance parts, but that's not an option for us :crybaby:

Does anyone here have a Northstar in a different vehicle controlled by a manageable ECM?
I run mine on a 99 SLS program. I hope to have mine very tunable soon. I made the wrong choice on power plants. I had a 2000 and a 99.
 

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I thought even older SAE ratings were at the crank, not the wheels, put the engine on an engine test stand like GM, Ford, etc all have to do in order to get SAE cert and see what it runs under a given ambient/load combination. Until then trying to 'estimate' drive line losses or arguing the 'true' hp level of the engine is a futile exercise...

just my .02
 
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