: northstar governer/limiter



mattbruz
02-12-10, 11:50 PM
i did 120mph in my 93 caddy etc and about crapped myself:eek:. is there a limiter on this car??

Ranger
02-13-10, 10:19 AM
Limiter will depend on what speed rated tire the car came with.

Beaudreau
02-13-10, 03:55 PM
OMG, I did 120+ in a '60 Mercedes 220 Sb when I was 15 and I am 51 now and have been much faster in other cars, but I was on the Autobahn! My little Saab would go off the speedo and do 5500+ RPM's which was about 137 MPH, but I drove others that legitimately went 190! Still, I would like a real answer to your question, the tire thing makes sort of sense, but I would like to know the factory limit set with different tires! I think that we all know that most, if not all cars are speed limited in this day age of electronics and honestly none of us has reason to go fast as we can even when limited, but it nice to know info!

Submariner409
02-13-10, 05:25 PM
The speed limiters set into the ECM (OBD-1) or PCM (OBD-II) correspond to the speed ratings of the original equipment manufacture (OEM) tires supplied on the car as delivered. That info is on the tire rating sticker on the driver's door or may also be found by decoding the RPO (Regular Production Option) list on the underside of the spare tire cover. Use the RPO sticky post at the top of the main car model pages.

The rating letter speeds can be found by a deep search in www.tirerack.com or maybe a Government DOT site, but basically you'll see the below 3 or 4 in a 1990 - 2005 Cadillac (and they're model dependent: the base models are set lower than the higher rated models in the same body style):

S = 112 mph
T = 118 mph
H = 130 mph
W/Z = 145 ++ mph (look this one up)

My car is (was) H-rated (limiter since removed) and would top out at 132 mph (GPS). The fastest I have now had it to is 144 (GPS).

Submariner409
02-13-10, 07:10 PM
FWIW, here's the current lineup of U.S. DOT tire speed ratings by letter (and the Z-tire breakdown):

L = 75 MPH
M = 81
N = 87
P = 93
Q = 99
R = 106
S = 112
T = 118
U = 124
H = 130
V = 149
W = 168
Y = 186
Z = "in excess of 149 mph", BUT note the suffix in ( ) -
.......225/50ZR/16 = 149 mph
.......205/45ZR/17 (88W) = 168 mph
.......285/35ZR/19 (99Y) = 186 mph

My Cooper CS4-V tires, stamped 235/55/17 (99V) are 149 mph rated tires.........so where 235 is the section width in mm, 55 is the sidewall height as a percentage of section, and 17 is the rim diameter in inches, then (99V) is the speed rating.

www.tirerack.com, "shopping tools", "tech center", "how to read tire speed ratings..........." (Matter of fact, read as much as you can take......)

ryannel2003
02-13-10, 09:21 PM
I topped my 2000 STS out at 129MPH and it was smooth as silk. The wind noise was crazy but otherwise it was an enjoyable experience. I've done it about... oh 4 or 5 times since then :sneaky:

YouTube- 2000 Seville STS Top Speed

Submariner409
02-13-10, 10:01 PM
:highfive: Fun, Huh ??? When there's no one else around.

I hope someone notices the rate at which fuel "range" drops when that engine is drinking gas at several quarts a minute...............

Also that you can hit 130 in 3rd...... and the temp never moved a hair..................

Skiller.
02-14-10, 03:36 PM
Amazing..

I now have Goodyear Eagle GT V-rated tires on my car (149 mph), yet it's limited to 112 :(

Rarely would I ever go above that (I only hit 112 once), but it would be nice to have no limit.

Sub - what's the process/cost to remove the limit?

robertcopeland69
02-14-10, 09:04 PM
Amazing..

I now have Goodyear Eagle GT V-rated tires on my car (149 mph), yet it's limited to 112 :(

Rarely would I ever go above that (I only hit 112 once), but it would be nice to have no limit.

Sub - what's the process/cost to remove the limit?

i would love to know this myself.thanks

mattbruz
02-14-10, 09:22 PM
lmao "top speed fuel cut-off". i love cadillac center console messages. i found out that my car tops at 150 due to the rpo on the side of the drivers door

Submariner409
02-15-10, 11:07 AM
Go to http://westers_garage.eidnet.org/index2.htm and look at the "Price List" tab for your car, then read the "Shipping" information. I think they now get $500 for their work - email them with your specific question. They do quite a business........

Then spend an hour in there reading - there's more info in that site than you imagine..........

codewize
02-16-10, 11:24 PM
I run my DTS over 100 regularly. She sits solid as a rock and it's no different than driving her at 60. Never hit the limiter because OH I don't have one LOL.

No seriously I never seem to have the room to go that far but a little over 100 happens now and again.

BlackCaddy87
02-18-10, 02:01 PM
My car would shut off at 130 before the chip. I've seen 147 on the hwy and 150 on the dyno both still in 3rd gear

Submariner409
02-18-10, 03:06 PM
Remember that FWD Cadillacs with the earlier ECM can be "chipped" and "tuned". FWD Cadillacs with the later PCM cannot; it takes a PCM reflash to change parameters.

I believe the change was around 1996 with the switch to OBD-II (OnBoard Diagnostics protocol -II).

BlackCaddy87
02-18-10, 03:53 PM
g3R4BU8HebM

Notice the tach only about 5500 in 3rd at 132? Can't remember what the rpms were at 150 in 3rd but she was screaming

ponyboyt
02-19-10, 11:07 AM
my GPS has sat at 149 since June when i blew my first engine. That one burned a bit of coolant, had to top up once a week. The stuff was like downgraded nitrous it seemed like.... ive since not had my GPS in MPH and havent had the car up to 200km with this engine, but something tells me it wont do it. Too many issues and lack of high rpm power. I seem to remember the car was in 4th though when i burried the needle.... (250km/h?).

Me n Jake talked about this before, and checing my door last night revealed an H rating. Ive never seen the car cut off, but i have doubts about my PCM... TCS/ABS lights on, i get 145 speed limited randomly, and randomly the car wil use 1st gear. So im guessing randomly it shuts off the limiter :)

(1997 STS)

Submariner409
02-19-10, 12:10 PM
If you're getting a 145km/h (90 mph) speed limited message that's suspension/brakes related and the first gear thing sounds like a transmission shift solenoid fault.

If you topped out at close to 250km/h that's about 155 mph, so it appears there's no speed limiter in your PCM - something has been changed because H-cars are limited to a nominal 130 mpg (210km/h).

caddydaddy
02-19-10, 01:04 PM
I had my 2000 STS up to the speed limiter of 130 MPH, once. It takes too long to get there, so now I ride the motorcycle when I wanna go fast! :)

ponyboyt
02-19-10, 03:23 PM
yep i know all that. My ABS pump is seized, i have a new one. It isnt always speed limited, just does it a few times a week. Randomly though, i will get first gear. Buggy car i guess.

BlackCaddy87
02-20-10, 04:01 AM
i just realized how much money i had in my caddy only in repairs...what a shame

Superjim
02-21-10, 09:47 AM
Remember that FWD Cadillacs with the earlier ECM can be "chipped" and "tuned". FWD Cadillacs with the later PCM cannot; it takes a PCM reflash to change parameters.

I believe the change was around 1996 with the switch to OBD-II (OnBoard Diagnostics protocol -II).


Sub, I know you probably already know this... but 2006 and newer NorthStars can be tuned by EFI Live or HP Tuners software.

Both the Engine Control Module and the Transmission Control Module can be tuned.

Mine has been tuned.
I like it.
It is "H" rated.
No limiter on it now.
I have had it to 144 but ran out of room and had to slow down.
It was still pulling pretty good. :)

Texas Jim

caddydaddy
02-21-10, 10:02 AM
i just realized how much money i had in my caddy only in repairs...what a shame

But I'm sure you love the Caddy anyways! :D At least I do, especially when I step on the loud pedal! :lildevil:

Superjim
02-21-10, 10:12 AM
But I'm sure you love the Caddy anyways! :D At least I do, especially when I step on the loud pedal! :lildevil:


Yes sir...thats one of the things I really enjoy. :thumbsup:
I love the sound of the NorthStar when you stand on it. :)

Texas Jim

mattbruz
02-24-10, 09:34 PM
i havent pushed my car to its limit yet.. only because its my only transportation and i have no funding for another. but im sure i'll get to test it when i have to rush my wife to the hospital when she goes into labor.. i'll make the pooper troopers eat my dust... at least for a little bit before they send the chargers out on me. i pray it doesnt rain that night. i dont see that many of the 93-95 eldos. its like somethin happened to them and the l37 besides the production of the ld8

is there any remedy for a burnt/cracked valve in the engine?

caddydaddy
02-24-10, 09:42 PM
is there any remedy for a burnt/cracked valve in the engine?

Yes, replace the valve and repair the seat if needed.

mattbruz
02-24-10, 10:37 PM
Yes, replace the valve and repair the seat if needed.

thank you