I bought my car right before winter so i never got the chance to go top speed.
But awhile back i remember seeing a post about a speed limiter in lower output f-bodys...
now since i have a low output f-body i was wondering if this speed limiter
came stock on a 1989 formula 305 TBI. or did it even come stock on f-bodys ..

thanks for the input- Corey

 

112 MPH was the limit on my 92 RS 305 TBI.
I believe it was dictated by the speed rating of the tires that came on the car.
Yours is probably the same.
-Rich-

 

my 89 RS 305 TBI topped out at 107.

 

how do i get rid of this???? a chip or is there
some kind of wireing i can unhook?

 

Some chip suppliers get rid of this in the chip.
Mine is a custom from Ed Wright at Fastchip.com.
Otherwise, there is a way to fool the Vehicle Speed Sensor.Do a search on that(VSS),I think you'll find something.
-Rich-

 

try this link: https://www.thirdgen.org/newdesign/tech/unlimited.shtml

 

Yeah, only way to get rid of it is with an eprom. The fuel cut off was around 110mph on every TBI f-body.
You can disconnect the vss from the ecm with a simple inline switch but this isn't a good way to do it. The problem is that the ecm looks at the vehicle speed to make adjustments to timing, fuel, tcc lockup etc. There is no point of going faster than 110 unless you're at a track anyways. If that's the case then you should get a custom eprom.

 

115

 

115 cutoff and 110 resume in some, 108 cutoff and 106 resume in others. So it's around 110

 

the top speed is controled by the speed sensor..there is a tech article about how to bypass it with a switch...maybe my sensor is going bad but ive had my cars pin pegged to the trip meter...it has no problem going past the 115 mark ive done it several times...when im pegging on the trip meter the rpms are still going up...lol what the hell is wrong with my car

 

Okay, this is starting to annoy the crap out of me. The vss sensor tells the ecm what speed the car is going. If it's more than what I just listed and you have a stock eprom then you won't go any faster than the speeds. TRUST me, it's impossible and I can prove it to you. If you want me to send you an eprom with the limiter down to 60mph I'll bet you $100 your car will either sputter and not go faster OR if you keep the foot down the car will actually die. I have something I like to call my valet eprom. I burned it with a 45mph top speed and it works great.
Some people think that if they install bigger tires then they'll go faster. That's true, but so will your vss sensor is still locked up with the ecm. They feed off the same signal.
If somebody thinks they have a funky eprom send it to me and I'll look at the speed limiter and tell you what I find. So far I have yet to find a stock eprom with more than 115mph limiter.
If you can go noticably higher as in 120mph or faster displayed on the speedo, then please prove it to me.
Sorry for being a grump but this kind of stuff ticks me off. The BEST way to prove the speed is to simply hookup winaldl and datalog what speed the ECM see's, not just the speedo. The speedo is an analog device that can be off from what the ecm actualy is "seeing."
If I get a chance to drive a stock Lo3 again I'll test and datalog this proof myself.

 

soon as the weather clears up ill get on the highway and take a picture of it pegged for you. if its controlled by the speed sensor will the mod in the tech article really work? as in will it allow your car to go as fast as you want...also i hear in some cars that the OD is the gear that is governed...like in the new Zs...i did all mine 110+ in 3rd

 

it's actually 112(according to the General).. In trying to figure out how in the hell they came up with that.. I did some testing... on 4 diff. LO3 F-body's.. noticed the same thing in all of them.. just before you redline in 4th gear.. you hit the limiter.. that might not be the reason.. but it sounds better to me.