I don't think it's required. My SVX (92 model year only) had no speed limiter, and was power limited at ~140-145 mph. Similarly, the LS1 F-Bodies that came with the uprated tires had no speed limiter either, and will top out from ~155-170 mph on power, depending on who you ask.Sypher wrote:actually most cars have a speed limiter on them when they are manufactured. I have yet to see one without it. I guess it's either a government required thing or that it's the manufacture's safeguard agaisnt people overworking the engine...LS1Leader wrote:
3) Might as well do it. Didn't realize that there was a speed limiter at all on 'Vettes.
Why 91?
Not really... some rookies want to copy the high octane table over the low octane table, so that even if the car detects knock, it doesn't run rich, etc. This is great if you've already got a perfect tune and always get good gas, but it eliminates the safety factors built into the whole anti-knock system. While this may be nice if you don't have a tuning tool handy and always want to make sure you're running in a fully optimized mode, it's impractical if you can tune it right back to the way it was before the knocking (i.e., by having a backup copy of your most optimized tables), in the case of knocking mucking your "good" tune.
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I've seen reputable people doing mail order tunes who ask you if you want it optimized for premium gas. Hopefully, that doesn't simply mean deleting the low octane fuel maps. I was expecting that they'd have better optimized maps that they could replace the stock high octane maps with. Of course there's always the issue of memory. Maybe they want to add higher (like 93-94) octane maps and don't have room to do so unless they delete the 87-88 octane maps.
I don't know how much RAM (or PROM) my 99 PCM has. My guy says the 99-02 OS files are all 512kb or less. The 03-04 OS files are about 1mb. Yet, he seems confident he can upgrade me to the 2003 OS. The 04 OS wouldn't work because the chip wiring is different. The 01-03 PCM is a different part # than the 99-00 PCM, but the wiring is the same. My guy's own car is a 00 Camaro and he upgraded himself to the 02 OS as he wasn't sure about 03 at the time. He now seems to know that 03 would fit on my chip. I guess if we find out that it doesn't during the install, we can always start again with 02 instead.
I don't know how much RAM (or PROM) my 99 PCM has. My guy says the 99-02 OS files are all 512kb or less. The 03-04 OS files are about 1mb. Yet, he seems confident he can upgrade me to the 2003 OS. The 04 OS wouldn't work because the chip wiring is different. The 01-03 PCM is a different part # than the 99-00 PCM, but the wiring is the same. My guy's own car is a 00 Camaro and he upgraded himself to the 02 OS as he wasn't sure about 03 at the time. He now seems to know that 03 would fit on my chip. I guess if we find out that it doesn't during the install, we can always start again with 02 instead.
I haven't heard of memory being an issue. My understanding is that tuning for premium gas would simply overwrite the current high octane table. Either way, mail order from a big company wouldn't be my recommendation. At worst, I would get the car remotely tuned by a personal tuner. But even that would require that you have the tuning software and can load the tuner's data in and provide the tuner with more outputs as feedback to further improve the tune.
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My 1993 Geo Prizm LSi 5 SPD says it requires 91 in the manual:
http://www.supload.com/free/Manual.jpg/view/
http://www.supload.com/free/Manual.jpg/view/
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A Geo that drinks fine spirits . . . I've never seen that!Louisville Slugger wrote:My 1993 Geo Prizm LSi 5 SPD says it requires 91 in the manual:
http://www.supload.com/free/Manual.jpg/view/
2007 Mazda3
Mods: 15% tint, Eibach ProKit
2006 Ninja 636
Mods: NOS & sidecar
Mods: 15% tint, Eibach ProKit
2006 Ninja 636
Mods: NOS & sidecar