Why does my car top out at 120????

stunner6910

New Member
Oct 31, 2003
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south texas
It was friday night or better said, saturday morning(4:30am) and i was driving home. There's about a 12 mile strip where it's like a dessert, so I took the long way home and decided to see how fast my car would go. It went up to 120 and didn't move from there, why?? My first mustang hit the 150 and kept going a little more, and so did my second mustang. Both cars were mildly modified like exhaust and cai and gears. What will I need to remove the speed limiter from this car??
 
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stunner6910 said:
Why does my car top out at 120????

Do you have 4.10's? If so, that would explain it, LOL...

What were your RPM's at when you were crusing at 120? Also, did the needle on the tach just get to a certain point and slowly come to a stop, or did it "bounce" back down like it kept hitting a limiter?
 
yup, back when i had the stock 2.73's in my car i would try to top her out. fuel cutoff at around 127mph. no one knew why. ive heard other stangs going up to 140-150 no prob but mine wouldnt go that fast. i know with the tweecer i should be able to bypass that but i wont cause i dont wanna go that fast anymore plus i have the 4.10's too....its kinda a spur of the moment thing but it was still kinda annoying.
 
When I had my 2.73's my car would barely get to 120 and stop accelerating at about 125 in 4th gear. With the 3.73's, I could take it up to above 150. Ive been to 145 but let off, It was still accelerating.
 
Numbles said:
When I had my 2.73's my car would barely get to 120 and stop accelerating at about 125 in 4th gear. With the 3.73's, I could take it up to above 150. Ive been to 145 but let off, It was still accelerating.

Mine did the same thing with the 2.73's, it would hit 120, and then just crawl to 125. It felt like a Civic launching. Now with the 3.73's, I was able to hit 140, and that was with a 5th gear pull, starting at 100.
 
Silver95Stint said:
It shouldn't top out at 120 even with 4.10's. You should be able to hit at least 130 without problems.

You're absolutely right; I have 4.10's and I can hit 130mph but that's about it. I was just kidding in my first post. ;) I figured it was either some kind of limiter on the AODE cars, or just sucky stock gearing.
 
but i still don't understand why it does this. my first car only had a complete exhaust system and cai. it wouldn't ****** out til after 150. my current car is the same thing vert, 95, aode. i have no problems whatsoever with this car, it runs great but i just dont understand this dilemma.
oh, and zero, it did not hit the limiter
 
Maybe aero drag into a head wind. I have a 87GT and have been 4500 rpms in 5th with 2.73's down a slight grade. I would say maybe honest 150mph but the speedo only goes to 85 so I may never know. It will do 100mph in 3rd around 5500, only know that because of running at the strip.
 
vert maybe? i don't know man, i've taken my old AODE hardtop up to 135. this car i hit 150 easy, and it kept pulling so i don't know how fast it can go. was your engine still pulling revs or was it was just out of power? like did it feel like there was nothing left in it?
 
stunner6910 said:
it felt like it just couldn't go anymore, but i know for a fact that it was not a rev limiter.

What you are describing is exactly what happens when you have stock gearing and a stock or near-stock engine. The wind resistance gets pretty high at those speeds and your car simply doesn't have enough power to push itself any faster against the wind with those gears.

stunner6910 said:
i don't know maybe it needs something

It does. MORE POWER! (or better aerodynamics) Steeper gears would help too.

An S-Trim should do the trick nicely. ;)
 
I have the same problem. In total stock form top speed 122mph. Then with all the mods listed below still top speed of 122mph :( . At the track the car got .2 quicker but the speed stayed the same with the gear swap :bang: Others on this forum had better experience though :shrug: So, I am thinking that with minor bolt-on's there isn't enough HP gain to get the car moving faster. So, either forced/NOS induction is needed. Or, H/C/I swap is in order.
 
JJ95GTID said:
Fact is I don't care that my car only goes 122mph. I just want to get there quicker!

No kidding. I remember when I wanted 4.10's and everybody was like "Don't do it, you won't be able to go 150mph+ anymore!" So what? Big f'n deal! We don't need people going that fast on the streets anyway. My car tops out around 130-135 with the 4.10's but it gets there quick as hell...and I rarely go faster than 100mph anymore anyway. I want to keep my Stang and myself in one piece; imagine what would happen if you had a tire blowout at 140...or if you hit a pothole or an animal in the road. :nonono: