wht89reatta Posted May 18, 2011 Share Posted May 18, 2011 I was thinking while i was on my way to work, its all highway, how often does one break the triple digit speed point? I find myself doing it about twice a month and only for short bursts, about 5 miles or so. Is this normal? Link to comment Share on other sites More sharing options...
D-a-n-i-e-l Posted May 18, 2011 Share Posted May 18, 2011 Normal...... no, needed YES Link to comment Share on other sites More sharing options...
KDirk Posted May 18, 2011 Share Posted May 18, 2011 Normal for those of us who like to do things "our way"; which is probably why we own a car like the Reatta to begin with. I don't get much chance to do this where I live, since you have to be about 1.5 hours out of town to get a rural stretch of straight flat interstate to pull it off (at least somewhat safely) without being hassled by the cherry tops. That said, when I went to pickup my 88 a few weeks ago, I was driving my Deville up to the pickup location on I-70 in Kansas. I've never hit the top speed limiter on that car in the 8 years I've owned it and decided to try. Now, by the owners manual, it is supposed to shut off at 112MPH (top speed for T-rated tires) but I hit 116 and it was still accelerating. Since I was coming up on a slight hill, I backed off not knowing whether a trip-ending straight to jail traffic stop awaited me beyond the crest. Now I don't know if the manual is wrong, or if a previous owner modded the ECM to remove the limiter - which I think is pretty unlikely on a car like a Deville. In any case, I probably could've hit 120 but ran out of road where I was comfortable trying. One of these days...[Alice, to the moon!].KDirk Link to comment Share on other sites More sharing options...
padgett Posted May 18, 2011 Share Posted May 18, 2011 Km ? Link to comment Share on other sites More sharing options...
Guest Kingsley Posted May 18, 2011 Share Posted May 18, 2011 I have heard or read that the Reatta is electronically limited to 120 MPH or so. If correct, how is it wired? Do not believe I have seen this menioned on the Forum before. Link to comment Share on other sites More sharing options...
KDirk Posted May 18, 2011 Share Posted May 18, 2011 Kingsley, this is a function of the ECM. When the electronic governor (top speed limit) is reached, the ECM begins trimming fuel supply to force a reduction in speed. Obviously, the ECM knows how fast the car is going by monitoring the vehicle speed sensor (as does the BCM and IPC for that matter). The process is pretty much the same in all modern computer controlled cars that have a set top speed limit. The only way most cars come "wide open" is if they are factory supplied with Z rated tires (good to 155MPH I believe) and then the ECM is set to remove the limiter. The 300HP version Northstar equipped STS and Eldorado had this as an option for at least a few years. On my Deville, hitting the limit (supposedly) places a message on the driver information center (a text display within the main instrument cluster) that states top speed has been exceed and instructs you to reduce speed. I believe it is also supposed to sound the chime to get your attention. This is why I was trying to hit the limiter, just to see what it did. Since I was getting concerned about a speed trap beyond my view, I backed off before I got to the big prize. Now I wonder if I inadvertently changed the speed limiter myself some time ago when I reprogrammed the IPC to "think" it was in an Eldorado in order to gain additional engine data displays in the driver information center. I think the Eldo was limited to 120 or 125 for the 95 models, since you could get a better tire package than on the Deville. So, maybe that's why it didn't kick in at 112 like I was expecting. Thing is, I thought this was implemented entirely in the ECM (or PCM in 1995 terminology) so I don't know for sure.I rather doubt I will ever hit the ceiling in a Reatta, 120 is just a bit too fast for me to be comfortable on public roadways. That would be 55 over the limit on most semi-rural interstates (65 zones) and a sure trip to the clank if caught by a small town smokey. I like to go fast, but I don't need to risk that aggravation just to say I did it. KDirk Link to comment Share on other sites More sharing options...
Rawja Posted May 18, 2011 Share Posted May 18, 2011 I'm pretty sure I did an indicated 124MPH in my old '89 at some point. Didn't feel like a limiter was kicking in. Prolly was going a smidge faster as I was running 225/60R15s on 'er. Link to comment Share on other sites More sharing options...
wht89reatta Posted May 18, 2011 Author Share Posted May 18, 2011 I can officialy say that Ihave topped my 89 reatta out at 121 about 4 years ago. this is the fastest i have ever gone and it was only for about .2 miles. I have never run into a cutoff issue with either my 89 reatta or riviera but i do believe they are both rated to be cut off at 125.Thanks guys for letting me know that im not alone. Link to comment Share on other sites More sharing options...
Guest Kingsley Posted May 18, 2011 Share Posted May 18, 2011 Kevin - nicely covered. Thanks to you and others and hopefully of inerest to others on the Forum. Link to comment Share on other sites More sharing options...
Bushwack Posted May 18, 2011 Share Posted May 18, 2011 I've gone as fast as 95 with the top down but the cowl shake/suspension became a concern (as did my nerves). On the flip side, went 130+ in both the Lexus and Corvette with ease. Each time, I felt like an irresponsible teen-ager (ahh..those were the days). Link to comment Share on other sites More sharing options...
wht89reatta Posted May 18, 2011 Author Share Posted May 18, 2011 Bushwack it sounds like you might have something loose in the front end or your tires might be just ever so slightly out of balance. Link to comment Share on other sites More sharing options...
padgett Posted May 18, 2011 Share Posted May 18, 2011 Speed Limiter is just a single byte (0-255) in the Memcal PROM in the ECM. Frankly I would not want anything leaning out the mixture at a very high speed. There is a second byte for restoration but if (a) is never reached ( has no effect. Link to comment Share on other sites More sharing options...
Bushwack Posted May 18, 2011 Share Posted May 18, 2011 Bushwack it sounds like you might have something loose in the front end or your tires might be just ever so slightly out of balance.I was thinking that. I had the tires re-balanced and also an alignment the following week. But haven't taken the car at such speeds since. Link to comment Share on other sites More sharing options...
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