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Discussion Starter #1
at what speed does the computer cut out the spark on the 91 caprices? i have seen on websites for police vehicals that a 91 with a 305 was able to do 124 mph but i know my car shut down way before i hit 124 mph. so how fast is it allowed to go?
 
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Discussion Starter #2
a buddy of mine has a '91 with the 305........stock exept for a shift kit, civilian model......it cuts off at about 108-110 i would guess
 
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Discussion Starter #3
If it's not a 9C1 or a Caprice LTZ, then it'll have a 108 mph limiter --- which you would experience anywhere from 106 to 109 mph indicated. IF you have a 9C1 or LTZ that got H- or V-rated tires (per the driver's door sticker), then it will have a 130 mph limiter for H-rating, and probably 147 for the V-rating.

There were two years (1991, 1992 I think) that MSP tested LO3 9C1s with both 2.56 and 3.08 rear ends. The 2.56 cars went 128 and 124 mph (in 3rd gear) while the 3.08 cars went around 114 (probably in 4th).

4th gear with a 3.08 rear end is like running an equivalent 2.16 rear end, so you can see that a 2.56 rear end car in 3rd (at 1:1 ratio) has an rpm advantage of 256/216, allowing the engine to rev closer to the rpm for peak power (around 4200 rpm for the LO3).
 
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Discussion Starter #4
what about in over drive? will it still cut out at 108? if i ever get my trans rebuilt i will have the part put in that will allow the car to shift into overdrive when i am at wot. will the car still cut out?
 
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Discussion Starter #6
Speed limiters came about with OBDII, 1994.
The only limiter on 91-93 would be 305CI,OD trans.,and a rear gear that is way to tall.Most of the civi. 305 cars had 2.56s.
 
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Discussion Starter #7
<BLOCKQUOTE>quote:</font><HR>Originally posted by xnchp9c1:
Speed limiters came about with OBDII, 1994.
The only limiter on 91-93 would be 305CI,OD trans.,and a rear gear that is way to tall.Most of the civi. 305 cars had 2.56s.
<HR></BLOCKQUOTE>

OBDII------1996 :D
 
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Discussion Starter #8
I sold my 1994 civi-LT1 108mph speed limited Caprice about 6 months ago. Trust me I spent 6 years working around OPTI-SPARK,CAM DRIVEN WATER PUMP and OBD II. I thought buying a LT1 car was great(I sold my 92 Caprice 305tbi with a 3.42 gear swap, TBI spacer,1.6 rockers, dual exhaust, transgo shift kit,and Hypertech thermomaster chip to finance the purchase)so after replacing my 2nd optispark and battling OBD II(Unfortunatly I didn't know about this sight and Brian the PCM reprogramer) I recently purchashed a 93 9C1 and am back at my good old fashion hop ups.
 
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Discussion Starter #9
<BLOCKQUOTE>quote:</font><HR>Originally posted by xnchp9c1:
Speed limiters came about with OBDII, 1994.
The only limiter on 91-93 would be 305CI,OD trans.,and a rear gear that is way to tall.Most of the civi. 305 cars had 2.56s.
<HR></BLOCKQUOTE>

Very little here is true.

1. Speed limiters were installed in almost all cars back in the 1980s, through to today, and they had nothing to do with OBD2.

2. OBD2 (or OBD-II) was first installed in the 96 Bcars, not 94.

3. The speed limiter installed at the factory (almost always as part of electronic programming in the ECM/PCM) will be exactly related to the tires installed at the factory - so check your driver's door jamb sticker.
 
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Discussion Starter #10
Kdrolt- 147 mph on V-rated tires on a 91-93 9c1/L03? No way. Not even with an L05. My 92 9C1/L05 hit the peg at 133. Isn't 147 is the block on 94-96 9C1/LT1s?

xnchp- As for OBD-II, that did NOT exist till 96, which has already been stated, I think you mean OBD-I (Unless for some strange reason you put an OBD-II system in your car, which would obviously explain why you had problems with it).
 
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Discussion Starter #11
<BLOCKQUOTE>quote:</font><HR>Originally posted by LT1KICKER:
147 mph on V-rated tires on a 91-93 9c1/L03??? No way. Not even with an L05. My 92 9C1/L05 hit the peg at 133. 147 is the block on 94-96 9C1/LT1s.<HR></BLOCKQUOTE>

<sigh>

I never said that a 91-93 w/LO3 could reach 147 mph. I said that the speed limit installed in the car (in the ECM or PCM) will be related to the speed rating of the tires installed at the factory.

1. non-9C1, non-ZO9, non-WX3 (civilian Bcars) 91-96 models.
108 mph limiter with all tires. Note that most civilian Bcars got S-rated tires, and that's where the 108 mph number came from.

2. ZO9 model conversion, 91-93 models, with either LO3 or LO5 (1993 only)
probably got 130 mph limiter, no matter whether H- or V-rated tires. The ZO9 model probably wouldn't exceed 130 mph anyway.

3. 9C1 with L99, 94-96 models.
120 mph limited regardless of tire (H or V).

4. 9C1 with L03, 91-93 models, H-rated tires
130 mph (even through the max speed was 128 mph).

5. 9C1 with LO5, 91-93, H- or V-rated tires.
130 mph for H-rated, 147 for V-rated (even though the max speed was 133 during 1992 MSP test)

6. 9C1 with LT1, 94-96, H- or V-rated tires.
130 mph for H-rated, 147 for V-rated (even though the max speed was 141 during 1994 MSP test)

7. WX3, LT1, 94-96, Z-rated tires. 154 mph limiter, due to driveshaft critical speed, even though the bone stock car max speed was 142 based on magazine tests, and 145+ mph on anecdotal comments from owners.

The rule-of-thumb, in case you didn't get it, is that the speed limiter of the car NEVER exceeds the speed rating of the factory-installed tires.

In most cases the speed limiter equals the tire speed rating (and why I said it was related to it). I leave it to you to figure out why this is true in most cases.

In other cases the speed limiter is lower than the tire rating (L99 9C1s for example, H rated tires, 128-130 mph ability, but 120 mph limiter).

A search on the topics of speed limiters, and top speeds will reveal that much, if not all, of the items above have been posted before.
 
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Discussion Starter #12
I love how friendly this forum has become. Thank you for the clarification.
 
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Discussion Starter #13
i hope i can spread a little light on this topic by saying when i had my 92 LTZ with a L03 motor and the stock 3.23 gear in the rear i hit 115MPH on the high way and it had alot more pedal to go and was no where near toping out as far as i could tell and it did come with 235/75 V rated tires stock and thats what i had on it thank you LaTerZ...
 
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Discussion Starter #14
My very anemic '91 LO3 can get to just over 100 before the engine isn't doing any good any more, but it isn't cutting out.
 
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Discussion Starter #15
<BLOCKQUOTE>quote:</font><HR>Originally posted by McThag:
My very anemic '91 LO3 can get to just over 100 before the engine isn't doing any good any more, but it isn't cutting out.<HR></BLOCKQUOTE>
I have the L03 /w 2.56 rear end as well.
As far as I can tell it either pulls spark or reduces (not cuts) fuel to keep the car from going faster.
I had mine up to the limiter (hard to tell exactly at what speed that was since I have an 85MPH speedo but kdrolt's 108 sounds right) and it just stopped accelerating, with the trans locked up in 4th.
My GP cuts fuel completely when it reaches the limiter, causing it to suddenly cut out... scared me first time it happened - thought the distributor chain broke for a split second).
 
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Discussion Starter #16
OK, so how do we go about getting rid of the limiter???
 
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Discussion Starter #17
If I tried to drive my 200,000 mile Caprice 120 miles per hour, my pistons would fly out of the motor going 220!
 
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Discussion Starter #18
I eliminated the LO3 and added an LT1 and got rid of the speed limiter that way. :D

The car now pulls to 120 according to the tach (speedo only goes to 100). I chickened out before the motor quit pulling.
 
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Discussion Starter #19
my caprice has been to 138mph ....Before I owned it and when it was 100% stock except for SS rims....The kid said he would never do it again :D Wuss.....

I personally have only gone 125 in it...Highwys around here arent long enough before they start to curve, or the good ones are patrolled by tons-O-cops.. :rolleyes:
 
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Discussion Starter #20
myne is stock and cut out at the high 20s. just did it not to long ago on the highway chasing my dumb ass friend who was driving stupid to tell him to slow down......
 
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