: Difference in 275HP & 300HP Engines



dslivingston
10-03-03, 09:10 PM
Could someone please tell me the difference in engine specifications in the 275HP & 300HP NorthStar engines use in the 2003 Cadillacs.

Thank You,
David Livingston
dlivingston@sc.rr.com

ShadowLvr400
10-03-03, 09:21 PM
Base motor, 275@5600 horse 300@4000 torque
Touring motor, 300@6000 horse 295@4400 torque

The difference is done be slightly different cams and timing. Not much else. The Base motors are mated to a 3.11 gear ratio, touring gets a 3.73.

Elvis
10-03-03, 10:25 PM
I wonder how much of that "difference" you could really feel under normal driving conditions?

The Caddy salesman told me he couldn't really tell. And since he said it while I was sitting in a DTS, I tend to believe him. He also said that the DTS would blow the doors off of a stock '96 Fleetwood.

ShadowLvr400
10-03-03, 10:51 PM
2 Things. 1, if you drive like I do, you'd probably notice the difference. 2, The Fleetwood, in 95, 96 with the LT1 350, will not give up a thing to the Northstars. I have a buddy with a Caprice, (basically same car) and with exhaust, intake, msd ignition, and 150,000+ miles on it. Runs mid 14's. Like a 14.5 The differences in accel will be the LT1 powered cars off the line, but the Northstar fed cars a bit farther down the track.

Elvis
10-03-03, 11:02 PM
I would never bet against ANY of the modified LT1's on this forum!

Chuck C
10-04-03, 10:59 AM
Here's the difference....the Touring (300hp) motor has more balls than the 275 hp....it's all due to that nice gear ratio.

:burn:

ShadowLvr400
10-04-03, 03:29 PM
Here's the difference....the Touring (300hp) motor has balls....it's all due to that nice gear ratio.

:burn:

Trying to indicate my 275 horse version has no balls? :mad: You might be surprised what more torque earlier in the power band than the ETC can do.

Chuck C
10-04-03, 09:19 PM
Trying to indicate my 275 horse version has no balls? :mad: You might be surprised what more torque earlier in the power band than the ETC can do.

phil, didn't mean to step on your toes there...i edited my original message too. Nice car btw.

ShadowLvr400
10-04-03, 11:21 PM
No worries Chuck, I wasn't deeply offended, just a bt annoyed. So hard to get sporting respect with a Caddy. Though the autocross did pretty well. Btw, will I be able to host the vids on here?

jonrodman
10-11-03, 09:53 PM
Here's the difference....the Touring (300hp) motor has more balls than the 275 hp....it's all due to that nice gear ratio.

:burn:

What are the shift points for the STS and SLS, and ETC. I have a 96 STS with supposedly the STS engine. It shifts 1st to 2nd between 6500-7000 RPMS at 45-50 MPH if I am on it. I was surprised that the speed was that high. I would have guessed that with 3:76 gears it would be shifting closer to 25 or 30 MPH. It is fast, but what are other people experiencing for shift points.

Based only on the shift, does anyone think I have the SLS or STS drivetrain? The car I have has had a lot of work done on it. I am still trying to figure out what I have.

Jon
96STS

jonrodman
10-11-03, 10:35 PM
I would never bet against ANY of the modified LT1's on this forum!

People go nuts on the 5.7 L Chevy's. There is every conceivable modification available. Some of those 5.7s can make more than three times as much power as a Northstar. They could have Nitrous, Superchargers, Turbo chargers, custom aluminum blocks, stroker cranks, and there are 32 Valve heads available. With some modifications people rev them up to 8000 RPMs. The Northstar is a great engine, but so far to my knowledge people have not been modifying them very much.

I would love to see a turbo kit come along. I am sure someone has probably installed a 5.7L in a Seville.

Jon
96STS

CBOYLE
10-12-03, 12:08 PM
Could someone please tell me the difference in engine specifications in the 275HP & 300HP NorthStar engines use in the 2003 Cadillacs.

Thank You,
David Livingston
dlivingston@sc.rr.com

wife drives a 1999 sls (275hp) i have a 2001 dts (300hp)
i agree with the difference is BALLS.
even with the weight of the dts it is still a rocket!
wish i could persuade her to a drag race!
charlie

jonrodman
10-12-03, 04:37 PM
No worries Chuck, I wasn't deeply offended, just a bt annoyed. So hard to get sporting respect with a Caddy. Though the autocross did pretty well. Btw, will I be able to host the vids on here?

I would love to see the autocross videos. Are they available on the web somewhere?

dkrj
10-12-03, 06:56 PM
What are the shift points for the STS and SLS, and ETC. I have a 96 STS with supposedly the STS engine. It shifts 1st to 2nd between 6500-7000 RPMS at 45-50 MPH if I am on it. I was surprised that the speed was that high. I would have guessed that with 3:76 gears it would be shifting closer to 25 or 30 MPH. It is fast, but what are other people experiencing for shift points.

Based only on the shift, does anyone think I have the SLS or STS drivetrain? The car I have has had a lot of work done on it. I am still trying to figure out what I have.

Jon
96STS

i have a 97 sts and it shifts the same between 6500 & 7000rpm 1-2 shift.

jonrodman
10-12-03, 07:20 PM
i have a 97 sts and it shifts the same between 6500 & 7000rpm 1-2 shift.

Do you know what speed are you traveling when your 97STS shifts at 6500-7000 rpms? Is it around 45-50 mph or less?

ShadowLvr400
10-12-03, 08:07 PM
I would love to see the autocross videos. Are they available on the web somewhere?

I'm trying to beat my friend into tracking down the cord for his camera. He moves into his new house like next week or two. After that, I should be able to get the cord, and then copy it to computer. So, give me some time to bully him into it.

dkrj
10-12-03, 08:19 PM
Do you know what speed are you traveling when your 97STS shifts at 6500-7000 rpms? Is it around 45-50 mph or less?

didn't look but next time i will and i'll let you know. it should be the same because as far as i know speed and rpm are gear ratio related.

ShadowLvr400
10-12-03, 08:30 PM
I think he was asking for the shift points of 1-2. Like engine rpm, and vehicle speed. I have a feeling that with the 3.73 touring version, it'll be 6800 rpms and 42-45 mph. The non touring version, like my eldo is 6200 rpms and 45 mph.

jonrodman
10-12-03, 08:30 PM
didn't look but next time i will and i'll let you know. it should be the same because as far as i know speed and rpm are gear ratio related.

Yes, you are correct - they are gear ratio related. I am not sure what engine and transmission mine has. This would be a way to verify. I know it feels fast, but it appears as if the engine has been removed and replaced. I figured that if yours shifted at the same speed and rpm then I probably still have an STS engine and transmission in it.

My car appears to be a "theft/recovery" vehicle. It was missing several parts, had a borken window and door handle and a lot of items were unplugged as if someone had started parting it out. I don't know any history on this car, and wanted to verify that I have the 3:76 gears. It has shaped up to be a really nice car. I am hoping that someone did not replace the STS engine with an SLS. If they did, it still runs great, but I would like to know.

ShadowLvr400
10-12-03, 08:35 PM
My car appears to be a "theft/recovery" vehicle. It was missing several parts, had a borken window and door handle and a lot of items were unplugged as if someone had started parting it out. I don't know any history on this car, and wanted to verify that I have the 3:76 gears. It has shaped up to be a really nice car. I am hoping that someone did not replace the STS engine with an SLS. If they did, it still runs great, but I would like to know.

Check the VIN. The.... 8th? (Someone confirm please) digit should be either a 9, or a Y. 9 is touring, Y is base.

jonrodman
10-12-03, 08:38 PM
I think he was asking for the shift points of 1-2. Like engine rpm, and vehicle speed. I have a feeling that with the 3.73 touring version, it'll be 6800 rpms and 42-45 mph. The non touring version, like my eldo is 6200 rpms and 45 mph.

Hi Shadow,
That is the answer. That answers that. It sounds as if they both shift at around 45 mph, but the 275 hp version shifts at 6200 rpms and the 300 hp version shifts at around 6800 rpms.

It is going to be an estimate because shifting is not an instantaneous event. Mine starts shifting at 6500 but sometimes before the shift completes the tach is up to 7000 and the speedometer is up to 50 mph. Sometimes the shifts are snappier than other times. Traction has something to do with it also. Sometimes the tires lose traction for a couple seconds.

Jon
96STS

jonrodman
10-12-03, 08:44 PM
Check the VIN. The.... 8th? (Someone confirm please) digit should be either a 9, or a Y. 9 is touring, Y is base.

Good idea, Yes it is the 8th space and the codes are correct.
In my case I was not sure if it still had the original engine or if it had been replaced with soemthing different.

Jon
96STS

jonrodman
10-12-03, 08:47 PM
Check the VIN. The.... 8th? (Someone confirm please) digit should be either a 9, or a Y. 9 is touring, Y is base.

Hi Shadow,
On the VIN number issue, is there any way to tell by the VIN if the vehicle has the 130 mph speedlimited computer or the 150 mph computer?

I know, look on the sticker on the drivers door, but if someone was shopping on ebay or autotrader, could it be determined just from the VIN?

Jon
96STS

ShadowLvr400
10-13-03, 05:47 AM
On the 130 or 150 limiter, I don't know. But being the guy that I am, my response is find an open highway with no cops, and see. :) How do you think I found out about the evil 112? Found that out in under 4 days.

dkrj
10-13-03, 06:32 PM
Do you know what speed are you traveling when your 97STS shifts at 6500-7000 rpms? Is it around 45-50 mph or less?


checked this morning, shifts just over 40mph. hope that helps.

jonrodman
10-13-03, 07:51 PM
Check the VIN. The.... 8th? (Someone confirm please) digit should be either a 9, or a Y. 9 is touring, Y is base.

You are completely correct on the VIN. It is the 8th digit, and the Y and 9 info is correct also.

Jon
96STS

JOENH
10-14-03, 07:31 PM
Thought I read somewhere ina Caddy Tech pub that the only difference in performance was larger headers/exhaust manifolds and gear ratios.

Budabear
03-09-04, 09:18 AM
I recently sold my 1995 SLS with 275hp and replaced it with a 1994 STS with 300hp. While 275hp is not at all shabby you can tell the difference with your eyes closed when you step down on the gas pedal of the STS. Both car were quick but my STS is FAST! When extra acceleration is needed my STS takes off like a rocket which the SLS wasn't capable of.

I loved both cars but I knew there was a reason why I wanted the STS.

Geno Castellano
03-09-04, 10:00 AM
The only mechanical difference between the two engines is the cam timing - and the fuel and spark mapping that goes with it. On the 93-99 engines only the intake cams are different. On the 2000 and later engines the intake and the exhaust cams are different.

The 3.71 final drive is put with the L37 engine to make up for the slight loss in low end torque with the L37 and it works well since the L37 can pull off the higher RPM upshifts.

The really nice performance package is what's in the new GXP Pontiac. The LD8 engine coupled with the 3.71 final drive (for the first time in production) and with a very low backpressure exahust system so that even the LD8 engine can pull off the 6500rpm upshifts. ;)

capn
03-10-04, 09:54 PM
... more than three times as much power as a Northstar

WHAT? ive seen a N* make 2500hp is there a chevy that makes over 7500 hp?

dloch
03-12-04, 04:59 PM
The only mechanical difference between the two engines is the cam timing - and the fuel and spark mapping that goes with it. On the 93-99 engines only the intake cams are different. On the 2000 and later engines the intake and the exhaust cams are different.

The 3.71 final drive is put with the L37 engine to make up for the slight loss in low end torque with the L37 and it works well since the L37 can pull off the higher RPM upshifts.

The really nice performance package is what's in the new GXP Pontiac. The LD8 engine coupled with the 3.71 final drive (for the first time in production) and with a very low backpressure exahust system so that even the LD8 engine can pull off the 6500rpm upshifts. ;)
Will a 2000 and later motor work in a vehicle that is pre 2000?

Is there a way of telling the difference by looking at the number on the valve/cam cover?

joeveto
03-13-04, 08:31 PM
I can't speak to the 350's in the Caddy's. But I've got two Vettes with the small block Chevy, and they are nice.

But I have to say, I love this Northstar engine. The sound is like nothing else I've heard. A multivalve V-8. A Freaking Multivalve V-8!. Damn. At times, I wonder why I even have a stereo. My C3 has most of your standard hot rod goodies (flat tops, hot cam, headers, etc.), and yes, it's a lot faster than the Caddy.

But unless it's a sunny day, 70 degrees, and I have no particular place to go, I'll take the Caddy every time. With the Caddy, I can have it all. It's a hoot. The first time my wife rode in the Caddy, she said "I can't believe a car this big is this fast..." This is the same woman who drag raced with me, in my C3, at Beach Bend raceway, in Bowling Green. She knows quick. Her C4 is quick. But the Caddy impresses her.

These are great cars, whether you're talking about the 5.7's, or the 4.6's. Doesn't matter.:worship:

156MPH
03-15-04, 04:21 AM
that is why i have shorter tires

STS 310
03-15-04, 05:38 PM
God forbid an SLS engine! GEEZ!
The extra 25 hp aint goin to help if you cant drive to begin with. Amen and so forth.

Pimpin_Whity
03-15-04, 10:35 PM
i have a question. is there a way to change the gearing on a regular eldo and make it like the etc (not the engine just the gears)?

joeveto
03-16-04, 12:20 AM
i have a question. is there a way to change the gearing on a regular eldo and make it like the etc (not the engine just the gears)?
You can change tire height. If you go with a shorter tire, you'll have effectively lower (higher numerically) gearing. A taller tire will have the opposite effect. But I don't suggest doing this. First, your speedo will be off. Second, your car is going to handle rougher, and it's going to do so with a suspension not set up for it. Last, your car is going to turn higher revs on the freeway, and use more gas in the process. Also, you might confuse the computer and trip a code or two.

Honestly, for the modest reduction in performance (if any) I'd rather have the 275 horse engine. I'd like to use regular fuel and have an engine with more torque, at lower revs, that's turning slower on the freeway.

The optimal, but more expensive way to swap out your gearing, would be to find a transaxle out of a donor ETC.

Pimpin_Whity
03-16-04, 03:16 PM
You can change tire height. If you go with a shorter tire, you'll have effectively lower (higher numerically) gearing. A taller tire will have the opposite effect. But I don't suggest doing this. First, your speedo will be off. Second, your car is going to handle rougher, and it's going to do so with a suspension not set up for it. Last, your car is going to turn higher revs on the freeway, and use more gas in the process. Also, you might confuse the computer and trip a code or two.

Honestly, for the modest reduction in performance (if any) I'd rather have the 275 horse engine. I'd like to use regular fuel and have an engine with more torque, at lower revs, that's turning slower on the freeway.

The optimal, but more expensive way to swap out your gearing, would be to find a transaxle out of a donor ETC.thanks. that's what i was thinking. is the gear ratio difference in the tranny or in the diff?

Anthony Cipriano
03-17-04, 04:12 PM
thanks. that's what i was thinking. is the gear ratio difference in the tranny or in the diff?

The difference in the gearing is in the differential - but that's inside the transmission. In a transverse engine, front wheel drive setup like the FWD Cadillac Northstars the transmission is really a "transaxle" as it contains the transmission and the final drive. You can take the transmission apart and change the final drive ratio but that would be difficult and expensive and then the car would set trouble codes as it would see the wrong ratio.