Yesterday I had a conversation that brought up the subject of the governors on our XLR's. It was mentioned that at 155 mph that the XLR's fuel pump will automatically shut down as that is the speed at which the governor kicks in ..... :skep :skep Since a couple of our forum members have hit that speed (some say even faster) .... no one has ever mentioned having that happen to them ... so, then when I picked up my car yesterday, I asked my tech about the govenor .... he told me he did not know at what speed the governor is set - or if it is even set at all .... I bet if I went back and searched that there is probably more for me to find .... but, I'd like to hear some of the rest of you guys comment on this and what you may know on that subject.....:yesnod

I don't think that the fuel pump shuts down, I think that you just reach a maximum speed. Hans and Standby reached a maximum speed of 158 twice on Rendezvous I.

Oh Ruth Ann, I'm so disappointed, I thought this was going to be about Arnold Swartzen......whatever. LS

You will find 155mph (or around there) is what most auto makers limit their cars to. I've been told everything from tire ratings to an informal "gentleman's agreement" between automakers. (search the web for 155 gentleman's agreement) I've even heard a funny story about it being a requirement because the police don't have cars to catch you. I don't have a for-sure answer.

In the XLR, fuel pump is not going to "shut off" per say as some cheaper cars - your car is just going to stop going faster. The XLR is drive by wire so the computer just won't let it go any faster, but you should be able to maintain 155mph (or 157?) without any worries of the pump shutting off. I've never hit the one in the XLR. From reading around it looks like the V gets a 170 limit...

I know my SC430 stopped accelerating at 155 too (this one I hit a lot), again the fuel pump didn't stop - I just wasn't allowed to go faster. At around 110mph the tire pressure light would come on if the tire pressure wasn't within like 2psi of spec.

From previous discussions here - I am pretty sure that the exported XLR's don't have the limiter.

UPDATE: Check out this link - it even has an XLR in it: http://www.forbes.com/2006/11/22/fastest-cars-american-forbeslife-vehicles-cx_dl_1127speed.html - the last paragraph sums it up "Finally, you might notice that tenth place on our list is a four-way tie among models with top speeds of 155 mph. This is because many sports car manufacturers electronically limit their vehicles' top speeds to keep the cars' equipment safe for use. Historically, a gentleman's agreement in the auto business limited performance cars to a top speed of 155 mph, and many automakers still stick with that (mainly out of practicality; it's easier to certify a car's tires and other systems to go 155 mph than to go 205 mph). Mercedes-Benz's hot-rod AMG cars adhere to the 155 limit, as do BMW's M cars, Cadillac's newest V-Series hot rods, Ford's new Shelby GT500 and Jeep's new Grand Cherokee SRT8."





Yesterday I had a conversation that brought up the subject of the governors on our XLR's. It was mentioned that at 155 mph that the XLR's fuel pump will automatically shut down as that is the speed at which the governor kicks in ..... :skep :skep Since a couple of our forum members have hit that speed (some say even faster) .... no one has ever mentioned having that happen to them ... so, then when I picked up my car yesterday, I asked my tech about the govenor .... he told me he did not know at what speed the governor is set - or if it is even set at all .... I bet if I went back and searched that there is probably more for me to find .... but, I'd like to hear some of the rest of you guys comment on this and what you may know on that subject.....:yesnod

Im so thankful my RUF BTR C-4 has no limit. Its been rated at 205mph Iv had it at 185 a few times but with over 40 speeding tickets I am being a bit carful! Ya right!!LOL. Ive had the red X at 120 + a few times but it is the wifes and shes usually in it so I dont push it too hard. Her feeling are" hell lose your license I dont care just dont ask me schlep your dupa around for you"!!! I bet some geeks have a great way to program an "Over-ride" on these cars computers! jim

Guess I or Hans would be the only ones so far to really answer this question.
It has a sight warble when it hits 158 to let you know it isn't going to offer anymore speed. A BG tech could probably explain exactly what takes place because I just haven't had a chance to climb under the car at that speed.
BobYesterday I had a conversation that brought up the subject of the governors on our XLR's. It was mentioned that at 155 mph that the XLR's fuel pump will automatically shut down as that is the speed at which the governor kicks in ..... :skep :skep Since a couple of our forum members have hit that speed (some say even faster) .... no one has ever mentioned having that happen to them ... so, then when I picked up my car yesterday, I asked my tech about the govenor .... he told me he did not know at what speed the governor is set - or if it is even set at all .... I bet if I went back and searched that there is probably more for me to find .... but, I'd like to hear some of the rest of you guys comment on this and what you may know on that subject.....:yesnod

I know I don't want to meet a woman driving 155 mph coming towards me! So just forget about Ruth Ann, Or I'm telling your husband what your planning.

Well, here was my thinking ..... let's say you were on your way to BG, say to attend a R3 .... and you wanted to just sort of see what your car could do .... and all of a sudden, right before the sheriff pulls you over .... your fuel pump quit :eek ... Would the car start right back up again??? :glol

I know I don't want to meet a woman driving 155 mph coming towards me! So just forget about Ruth Ann, Or I'm telling your husband what your planning.

Ahh, Galen .... would you really tell???? :angel :angel

Well six of us got pulled over and not a one tried to take off. Guess you just got to shoot the sheriff. Wasn't there a song, oh never mind.

Well six of us got pulled over and not a one tried to take off. Guess you just got to shoot the sheriff. Wasn't there a song, oh never mind.

Valentine's Galen, ..... I think we all need new Valentine's! :glol

Well, anyway, I'm thinking from all of the replies that the car doesn't stop from lack of fuel ...... Where is cadillac tech when we need him? Oh, yeah, I forgot, he's out of town having a great time without us! :cry :D :D

The front starts to get a bit light at 150+ anyway and like Bob says you wil know it hits the limiter but the fuel doesn't cut out. If you wnat to hit the duece on the way to Rednevous III you can take my Benelli or Bimota :crazy

The front starts to get a bit light at 150+ anyway and like Bob says you wil know it hits the limiter but the fuel doesn't cut out. If you wnat to hit the duece on the way to Rednevous III you can take my Benelli or Bimota :crazy

Kent .... you scare me!:eek :eek :jester

Every SVT product I've ever owned was limited in top speed, luckily the aftermarket chip/tuners were able to remove the speed limiter. My wife and I can attest to the fact the 2003 Cobra will exceed 160, unfortunately the speedo pegs and its SOTP from that point on. :glol

I would assume the tuner folks who are working on custom tunes for the V are looking at removing the limiter.

Every SVT product I've ever owned was limited in top speed, luckily the aftermarket chip/tuners were able to remove the speed limiter. My wife and I can attest to the fact the 2003 Cobra will exceed 160, unfortunately the speedo pegs and its SOTP from that point on. :glol

I would assume the tuner folks who are working on custom tunes for the V are looking at removing the limiter.

Okay, mswaim ........What did you just say? :confused It's like trying to read a foriegn language .... okay, okay ..... I know I am a rookie car girl .... :cry 10-7 :jester

Okay, mswaim ........What did you just say? :confused It's like trying to read a foriegn language .... okay, okay ..... I know I am a rookie car girl .... :cry 10-7 :jester

I was just going to ask the same question, thanks for asking first, now I don't feel so alone in this mans land. Don't these guys realize we don't speak mens car language????:cheers :cheers :cheers

I was just going to ask the same question, thanks for asking first, now I don't feel so alone in this mans land. Don't these guys realize we don't speak mens car language????:cheers :cheers :cheers

Hmmm, well, PD and you're right ..... they need to teach us what SVT and tuners and those things are .... and, I know .... we can teach them how to shop :party

How do you like that? I've hijacked my own thread??!! :eek :eek :eek

Hmmm, well, PD and you're right ..... they need to teach us what SVT and tuners and those things are .... and, I know .... we can teach them how to shop :party

How do you like that? I've hijacked my own thread??!! :eek :eek :eek

You are awesome!!!!! :thumbs :thumbs :thumbs

The limiter or govenor implementation still intrigues me ...

If damage is caused by going faster than 155mph on tires, engine, or whatever - the warranty considers those speeds as racing / or abusing.... and that voids the warranty anyway ..... my tech said that he had a car come in and the computer showed that he had been doing 140+ when the engine blew .... and he said at that point the guy just bought himself a new engine . :eek ... so, we can have the power .... but I guess if you play you have to pay .... so why limit the speed at which you can play?? :confused

What portion of the post did you not understand. Is it the SOTP? Come on now, that's an easy one..........

SOTP = Seat OF The Pants!

Custom Tuned Chip = http://www.need-4-speed.com/autologic.htm

Of course, you need to know the lingo - are you dealing with an ECU, ECM or ECC? And don't forget your TCU's, TCM's and the ever-popular TCC's.

ECU = Engine Control Unit
ECM = Electronic Control Module
ECC = Engine Control Computer
TCU = Transmission Control Unit
TCM = Transmission Control Module
TCC - Transmission Control Computer

You will need to know your Open-Loop from your Closed-Loop operation (well, of course. Everyone knows that!)


Okay, so I was kidding - you don't need to know any of that stuff. Just call the custom programmer and tell them what you want. Remove the rev limiter? Okay! Remove the top speed limiter? Okay! Turn the cooling fans on sooner? Okay! Raise line pressure in the tranny and firm up the shifts? Okay! Provide closed loop operation tables to maximize engine power while avoiding lean conditions; especially if you choose to bolt on a 100-200 horse shot of nitrous. :thumbs Okay!

And if choose to go hand-held programmer, you simply input the changes you wish to make, and at the same time record your factory settings into the tuner tool so you can swap between your custom tune whenever the car goes in for service.

The XLR and V are both governed at 155 and it is electronic, so it is very accurate. Occasionally, momentum can take you 1 or 2 mph over, but it settles in at 155.
You also get a "Maximum Speed" reading on the DIC.

Hhhmmm. now I wonder how he knows that???????:glol :glol

How the speed is actually limited is through the injectors. At speeds below 155 the fuel delivery system allows for the fuel delivery to increase through the injectors as needed. At 155 the fuel delivery is supplied to the injectors, and they pulse the spray in a limited fashion to keep that speed regardless of throtle position.

Of course many factors such as forward momentum can cause the vehicles odometer to read over the 155 maximum. This is the operation for all XLR models.

www.Cadillac-XLR.com (http://www.Cadillac-XLR.com)

Thank you
Allen

Now this intrigues me. I don't see why this should void the warranty unless you remove the limit and go above 155mph.

So if you blow up your engine, make sure you clear any codes before you take the car in for service. It sounds like a code got set when the engine blew and saved a snapshot of the input sensors.


The limiter or govenor implementation still intrigues me ...

If damage is caused by going faster than 155mph on tires, engine, or whatever - the warranty considers those speeds as racing / or abusing.... and that voids the warranty anyway ..... my tech said that he had a car come in and the computer showed that he had been doing 140+ when the engine blew .... and he said at that point the guy just bought himself a new engine . :eek ... so, we can have the power .... but I guess if you play you have to pay .... so why limit the speed at which you can play?? :confused

If you tamper with the engine/electronics to exceed 155, then your on your own.
But I don't believe they can void a warranty for driving a vehicle the way it was built to perform.:nono

The real concern is if the insurance companies get access to that stored information.

If you tamper with the engine/electronics to exceed 155, then your on your own.
But I don't believe they can void a warranty for driving a vehicle the way it was built to perform.:nono

The real concern is if the insurance companies get access to that stored information.

If you don't get a ticket .... or have an accident .... how can an insurance company use that stored information against you??? :confused Wouldn't you have to be a liablility first?

All I know is; custom tuning is now available for both the XLR and the V and there is no better way to maximize the potential of either engine. Also, no better way to enhance bolt-on items such as intakes, exhaust, nitrous, etc. , especially if the tune is developed with the car on the dyno. Many of the aftermarket tuners are advertizing substanial gains across the power band on the V. :thumbs

All I know is; custom tuning is now available for both the XLR and the V and there is no better way to maximize the potential of either engine. Also, no better way to enhance bolt-on items such as intakes, exhaust, nitrous, etc. , especially if the tune is developed with the car on the dyno. Many of the aftermarket tuners are advertizing substanial gains across the power band on the V. :thumbs

There he goes again, PD .... :eek
We are just going to have to buy ourselves some automotive text books so that we can talk to the big-boys .... :jester :jester

If you really want to learn more about what's being discussed here go to one or both of the following tuner software sites:

http://www.hptuners.com/

http://carputing.tripod.com/LS2main.htm

These are the industry standard tuning packages.

If you really want to learn more about what's being discussed here go to one or both of the following tuner software sites:

http://www.hptuners.com/

http://carputing.tripod.com/LS2main.htm

These are the industry standard tuning packages.

Hmmm, Pegasus .... I looked at those web sites ... I think I will stick to driving my XLR and let the technicians take care of fixing it! :yesnod :cheers :yesnod

It's not a matter of "fixing" it but rather achieving the full potential of what is truly an impressive performance vehicle. Out of the box it's a great car, but with a little tweaking it becomes a fantastic machine.

It's not a matter of "fixing" it but rather achieving the full potential of what is truly an impressive performance vehicle. Out of the box it's a great car, but with a little tweaking it becomes a fantastic machine.

Yep, I agree, and excuse my bad choice of words ... :o
I had not heard that any of the forum had done any tweaking to the performance of the engines ... except for the intake/exhaust .... or maybe I've missed that. :confused

A good tuner with access to a dyno should be able to pull another 35-45+ hp from an XLR-V such as Bob's where he has improved the volume of air available.

Direct from engineering:
GM Powertrain Position on this one.


We engineered and validated the car to perform up to and including 155 mph top speed. As such we included a speed limiting calibration that controls the car through powertrain management to no more that 155. (I believe we use the same controls as we do for maximum RPM engine protection which is a combination of spark and fuel control of the engine.)
As you may recall, the XLR is available around the globe, and in the European market there has been a gentleman's agreement to reserve operation above 155 to extreme sports cars.
We would strongly discourage any defeating of this element of the calibration as it would put the car in a condition that we never tested or validated it to.

www.Cadillac-XLR.com (http://www.Cadillac-XLR.com)

Thank you
Allen

Quite frankly, the speed limiter is not a big issue, to me it's the rev limiter I would want to dump, along with any torque management programming and on the "V" I would want to remove any waste-gate actuators that may be pre-programmed to a certain threshold.

:cheers I'm with you on this one. Since I get a lot more air then most because of the removal of that rain shield, each gear warbles, which means I've got more hp or air pushing into the supercharger, so I now shift it out before it can warble. I use the word warble cause it sounds like a fart after Thanksgiving. I wish I could tach higher, but when I shift, it doesn't drop off as you might think it would. Still strong pulling power.
bob



Quite frankly, the speed limiter is not a big issue, to me it's the rev limiter I would want to dump, along with any torque management programming and on the "V" I would want to remove any waste-gate actuators that may be pre-programmed to a certain threshold.

Most modern supercharger applications include a waste gate or some other bypass to prevent what they feel would be overpressurizing the engine.......:rolleyes

Once that critter kicks, all boost is lost until it re-engages. It usually will pop off right as the engine builds to redline and you are in that sweet spot where you are ready to shift - and just as it jumps into the next gear, you lose about a 100 hp as the boost drops to zero!

Ever since Ford began using Eaton superchargers on their SVT Lightnings and Cobras, owners have figured out how to bypass the problem and maintain constant boost; which also leads to ear-to-ear grins at stop lights!! :thumbs :glol