: Y / 9 What's the Difference?

04-27-05, 12:23 AM
Who knows and who can tell me what the difference is between the "Y" and "9" N*s?

Is the HP rating a difference in the mechanicals or the ECM? Are the head/cam profiles different? Compression ratio...where does that extra 25 hp live?

04-27-05, 01:22 AM
The 9 engine has a more aggressive intake cam profile that the Y engine. The other big difference is in the final drive ratio. The 9 engine's transmission uses a 3.71:1 ratio, while the Y engine's transmission uses a 3.11:1 I believe. That's pretty much it I think. Bbob knows every minute detail, he'll probably post a reply to this.

04-27-05, 10:16 AM
I believe the PCM is programmed a little differently as well.

04-27-05, 12:53 PM
From all I've read, the bottom line is that the "Y" engine (275HP) produces its' torque a little lower on the RPM scale, and hits it peak a little lower as well. That, coupled with the final drive differences, makes the Y guy a teensy bit "faster" off the line, and gives it just a tiny skooch more in 40-60 MPH and 50-70MPH type manuevers. But the "9" engine will take the same car slightly higher top end, all other things being equal.

Assuming identical cars, I'd rather have the "Y" engine - I do more driving at 40 to 80 than I do at 140+ :)

Or did I read the Final Drive ratios backwards??? I can never remember...

04-27-05, 10:07 PM
The Y engine will pul harder off the line, mostly because they develop their torque a little lower, and therefor have more usable power at lower RPM's. The Y's 3.11:1 final drive ratio is better for higher top speeds. On the other hand, because the 9 engine has such a short final drive ratio of 371:1, it can rev faster, and make up for the torque being higher up in the power band. If you on the highway, the 9 engine will pull harder, simply because the short final drive ration, allows it to transfer more torque to the wheels, at highway speeds. It's not as good for top speeds though, since the engine has to work harder, to maintain the same speed that the Y engine does. I think if I was going to just drive the car around town, I would buy a Y engine car, since it's a little more "user friendly" when leaving stoplights. From what people say, it's a little more well mannored at lower cruising speeds. Since I do drive really fast on the highway, the higher peak hp, and shorter final drive of the 9 engine, is perfect for passing people, and acceleration at higher speeds.

04-27-05, 11:50 PM
Why did any of the cars get 3.11s? Since 3.73 cars are still drag limited at around 150 it's not for a higher top speed or anything. Better economy?

Night Wolf
04-28-05, 12:11 AM
Why did any of the cars get 3.11s? Since 3.73 cars are still drag limited at around 150 it's not for a higher top speed or anything. Better economy?


with the Vin Y engine, it has more torque and at a lower RPM, so the taller gears can be used.

Which is why the Bonnie GXP is as fast as it is off the line... it has the Vin Y with the 3.73 gears... more torque and at a lower RPM *plus* the short gears.

3.11 isn't all that bad... considering my '93 DeVille has 2.73 with the 4.9....

plus the Y is more of an "old people" enigne... in that most of the older people got the base model, or luxury model of the car, not the touring models.

but difference in the enigne alone is just the cams and computer

04-28-05, 07:54 AM
plus the Y is more of an "old people" enigne...Hey, watch it there.. :dance: I'm an old people.. LOL... :D