View Full Version : Data on the northstar

02-10-06, 12:06 PM
Where can I find any information on the North* Example compression ratio for 93 94 95 96 97 98 99; Cam sizes for the same years; I know the intakes were changed in 1995, was this the reason it gained 25 hp or did something else happen! The Data I need is all for the Vin 9 motor. Thanks

02-10-06, 12:40 PM
a service manual for the engone would tell it all, i believe compression is around 10.5 to 1 or so, as far as gaining 25 hp?? i know thats the difference between the vin 9 and y motors because of an intake cam and computer difference i beleive. the biggest change for the intake was it went all composite not aluminum among other changes hope this kinda helps

02-10-06, 02:35 PM
If I had my service manual with me I could tell you everything from ring end gap, to intake lobe lift specifications for the '98 model year (basically the same until 2000) and so on. Unfortunetly, my service manuals are back at home and I'm waiting for my parents to ship them down here. I think it's a 10:3 compression ratio on the pre-2000 engines.

The 25hp gain between the LD8 (Y) and L37 (9) engine comes from the lift and duration on the intake lobes for each intake cam. The LD8 uses the same sizes for both intake and exhaust, while the L37 uses a larger cam profile for intake and retains the LD8 sized exhaust cam profile. The LD8 also uses a 3.11:1 final drive ratio, making 300 ft/lb torque at 4000rpm, and 275hp at around 6000rpm or so. The L37 uses a shorter final drive ratio of 3.71:1 because it makes 295 ft/lb torque at 4400rpm, and 300hp at 6200rpm. Less torque higher up in the power band requires the shorter final drive to make up for it.

In 1995, the northstar went from the metal intake to the composite plastic intake similar to the LSx series of engine, which gained a 5hp increase in both the LD8 and L37 engines. This resulted in the jump from 295hp to 300hp in the L37, and 270hp to 275hp in the LD8.

If your just looking for a general summary of differences between the 1995-1999 engines, then the only REAL difference between the two would be the larger intake cam profile on the L37, and the shorter final drive ratio of 3.71:1. Those are the two biggest difference between the two engines, since internally, they are basically more or less the same. They also share slightly different PCM programming, because of these differences.

02-12-06, 12:11 AM
yah. what he said:thumbsup: