: Northstar VS NHP VS The other thing



USSBlackPearlUSMC
12-21-10, 04:47 PM
What is the differnce (FWD) on the Northstar and NHP.
275hp x 300 ft
300hp x 295 ft

Is it a PCM or is there mechanical differnce?

Also VVT was not put on because of a space issue? Has anyone tried to retro fit it?

Also what is the differnce and interchangbilty of the 4.6 and the 4.4?

ltdltc
12-21-10, 05:07 PM
The LD8 is tuned for more torque, while the L37 is tuned for responsiveness. LD8 get a 3:11 drive ratio, L37 gets a 3:71 ratio. Other then the heads, drive ratio in the transmission and slight tuning parameters the engines are identical.

The block for the LH2 is longer not to mention that it is mated to the 5L40/6L50 transmissionS. The 4.4 is a supercharged variant of the LH2 known as the LC3.

Retro fitting a LH2 into a K-Body is not really possible.

Superjim
12-21-10, 05:42 PM
What is the differnce (FWD) on the Northstar and NHP.
275hp x 300 ft
300hp x 295 ft

Is it a PCM or is there mechanical differnce?

Also VVT was not put on because of a space issue? Has anyone tried to retro fit it?

Also what is the differnce and interchangbilty of the 4.6 and the 4.4?


The 275hp and the 300hp (actually 292 for 2006 and newer) have different cams.
They also have different final drive ratios.

They use the exact same ECM and TCM...but they are tuned different.
For instance...on the Performance Sedan TCM...if I am accelerating around a curve really fast...pulling a good bit of "G" force.. and I let up on the gas for a bit...it WILL NOT upshift..it will stay in the lower gear, because it "KNOWS" I may need to accelerate again.

the 292hp '06 and newer are the exact same "SPEC" as the 2005 which was rated at 300hp.

The difference in HP is because they used a new way to measure the HP which is supposed to be more representative of real world HP.

Jim

USSBlackPearlUSMC
12-22-10, 08:56 PM
Thank you Gents!

tedcmiller
12-27-10, 10:52 PM
Actually the "300 HP" Northstar has always been 292 HP. The Federal goverment stopped advertisers from rounding up numbers (which they did whenever the opportunity presented itself). So Cadillac always called the 292 HP Northstar a 300 HP engine even though it really wasn't. The statement that the 275 and the 292 HP Northstars are identical except for cam timing is correct. The lower HP version (275) does have a little more torque. When the Feds stopped the roundup game, Cadillac quit talking about the 300 HP engine (which it really wasn't) and simply referred to it as the high-performance engine. They even removed the "300 HP" label from the engine cover.

This might have occurred around 2006 but I don't know for sure. I do know that Cadillac was still advertising the 292 HP engine as a "300 HP" engine in 2004 (my wife's 2004 DTS had "300 HP" on the engine cover) but her 2008 high-performance DTS has no HP rating on the engine cover.

Superjim
12-27-10, 11:36 PM
My 2006 says NHP on the cover.
I assume that stands for NorthStar High Performance

Jim

tedcmiller
12-29-10, 03:04 PM
You assume correctly. But the HP on the NHP engine (my wife's 2008 DTS engine cover says the same thing) has always been 292.