The_Raven Posted February 9, 2004 Report Share Posted February 9, 2004 Howyadoin, As mentioned elsewhere, I'm getting a '96 SLS. This of course has the 275HP "Y" or LD8 engine. As I recall the final drive ratio is different between the "Y" and "9" (L37) motors, and the "9" motor has hotter intake cams, which, along with higher shift points and redline, is largely responsible for the higher HP rating of the L37. I seem to also recall reading that the motors are not a direct replacement due to PCM differences. So the question is, can I swap the intake cams from a '96 L37 into my LD8 to take advantage of the aggressive profile, or would the shift in the torque curve be negated by the different final drive ratio and different shift points? Or would the hotter cam just screw up the PCM anyways? -Mark P. Salem, MA "Refined Sugar" - '96 SLS, 175K "...the Caddy is dedicated to relentlessly -- and comfortably -- converting time into distance." -J.J. Gertler Link to comment Share on other sites More sharing options...
Bruce Nunnally Posted February 9, 2004 Report Share Posted February 9, 2004 You'd need the PCM change as well I think. Best to enjoy the car as it is, but if you want the other drive train I think you'd have to go all the way and get engine and transmission and PCM. Probably work as well to get an STS instead. Bruce 2023 Cadillac CT4-V Blackwing Follow me on: Twitter Instagram Youtube Link to comment Share on other sites More sharing options...
tjtjwdad Posted February 9, 2004 Report Share Posted February 9, 2004 Bruce, I'm inclined to agree. Once you start down that slippery slope you can find the domino theory real quick. Jim White Link to comment Share on other sites More sharing options...
Matlock Posted February 9, 2004 Report Share Posted February 9, 2004 The job can be done, but the L37 engine is much much slower with the 3.11 final drive than the LD8. The torque of the L37 is a lot less at any given point in the rpm band. In fact, the engine does make more HP, but only at the higher rpm's that the LD8 doesn't even reach. The L37 300HP does sell because it says 300HP, but the LD8 275HP is actually quite a bit more powerful. The actual difference in the 0-60 and 1/4 mile times of the SLS LD8 and STS L37 is very very small, in fact some SLS's will outrun STS's. The SLS engine seems to respond better to modifications, as in you drop more time in the 1/4 than an equally modified STS. Plus, the SLS is A LOT better on gasoline. The only thing is the top speed limiter of 112 on the SLS that may be an aggrevation for you. The STS will most likely come with a not-so-much-better 130mph. If you want to modify, forget the cadillac northstar in a production car. You may just wreck it and get frusterated. Try something else that actually has factory sponsored modification parts. If you are happy with the already great performance characteristics of the Northstar, maybe install a K&N air filter and some mufflers and enjoy the drive!! Good luck with your ride! It looks sweet! Link to comment Share on other sites More sharing options...
Bob D Posted February 9, 2004 Report Share Posted February 9, 2004 >The STS will most likely come with a not-so-much-better 130mph. < The STS's that came with 'Z' rated tires from the factory will hit 150 mph. Been there, done it.. Without too great effort I might add.. '93 STS.. opened, dropped, wide...fast. Link to comment Share on other sites More sharing options...
JasonA Posted February 9, 2004 Report Share Posted February 9, 2004 The swap is possible, but in agreement with the above posts, you won't get any benefit by swapping ONLY the camshafts. The L37 engine (the STS version) is less powerful anywhere but above around 5000-5500 rpm. Thusly, it has the much shorter 3.71 final drive to compensate for it. If you change cams, which will loosely "convert" your engine to an L37, you'll really bog down because that engine won't like the 3.11 final drive that's in your car. The LD8 (the SLS version) has the low-end torque characteristics to really shine with the taller final drive, and it gets great mileage on the road (30+ mpg). And indeed, some particular SLS cars will outrun some particular STS cars (all within production tolerances). The performance is so close, it's not worth compromising your driveability and mileage, in my humble opinion. Jason(2001 STS, White Diamond) "When you turn your car on...does it return the favor?" Link to comment Share on other sites More sharing options...
tjtjwdad Posted February 9, 2004 Report Share Posted February 9, 2004 I'm inclined to agree with the rest of the post. Don't sell the SLS performance short. When I drove the various models when I was looking I always thought the 275 HP engine was more peppier. I chose a STS not because it had 300 HP but because I prefered the subdued look and fog lights on the front end, it handles much better than the SLS and on par the STS' were better equipped. Bob D; The STS's that came with 'Z' rated tires from the factory will hit 150 mph. Been there, done it.. Without too great effort I might add.. Will these thing really run 150 MPH? Talkin' about your head on fire and your a@# a catchin'. Anyway mine has W rated tires as I have not heard of any 2001+ with Z rated tires. Jim White Link to comment Share on other sites More sharing options...
Bob D Posted February 10, 2004 Report Share Posted February 10, 2004 Bob D; [Will these thing really run 150 MPH? Talkin' about your head on fire and your a@# a catchin'. Jim White Yep...But only out on ranch land...no driveways, no other cars. no nothin. You can see all the way to the horizon forward and aft..A nice flat, long open stretch. It shifts from third to fourth at 130, and climbs right up to peg the speedo. Just held it for a few seconds, and backed off. Done it twice. '93 STS.. opened, dropped, wide...fast. Link to comment Share on other sites More sharing options...
Jan Olsson Posted April 29, 2004 Report Share Posted April 29, 2004 Bob D; [Will these thing really run 150 MPH? Talkin' about your head on fire and your a@# a catchin'. Jim White Yep...But only out on ranch land...no driveways, no other cars. no nothin. You can see all the way to the horizon forward and aft..A nice flat, long open stretch. It shifts from third to fourth at 130, and climbs right up to peg the speedo. Just held it for a few seconds, and backed off. Done it twice. I have a friend with a -84 Toyota Supra and invited him for a test drive when I´ve only had my STS for a week or so... You should have seen the look on his face when it shifted to the fourth gear at 130 mph... Link to comment Share on other sites More sharing options...
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