what will my top speed be with 4.10's and my 700rd from a 89 formula with the 305 tbi engine.

 

Not very high.


What size wheels are you running?

 

245/50/16 ws6 rims

 

Id skip the 4.10's. 3.42's would be a better match.

 

You are power limited and not gear limited for your case. Also if you have the still have the speed limiter, but recalibrated for those gears, you will still be at 115. If you do not change the speedo gears your top speed will be about 90.

 

With 4.10's your top speed in third is gonna be a little more than 90 mph. If you are able to shift into OD at WOT you could possibly achieve over 130 mph.

 

i got 4.10s in my 85 ta with a 305 tpi, when i drag raced i trapped at 5600 or 5800 rpms and my trap speed was 87 mph all three runs, so about 90 is correct , my car will shift into 4th automatically but i have no clue how fast the car will go , i have the stupid 85 mph speedo, and the same size tires . i would also like to know what the top speed is.

 

Gearing wise you are right, especially if he can wind out OD. But he is power limited with the LO3 and the motor will never be able to propell him at those speeds. Also, if he does not change his speedo gears or remove the limiter he will bounce off the limiter at around 90 or less beause the car thinks its going 115.

 

I agree about the speedo gears, but 130 isn't all that fast and given a large stretch of road he should be able to hit it with his mods. Back when I was completely stock I bounced off the 112 mph limiter a few times and I know I could have gone a lot faster.

 

Yea I geuss I could see that if he had enough road. If he was in OD with a tire radius of around 14" he could hit 130 at around 5000rpm or so as a rough estimate. It would be a lot easier with lower gears but I be it would be close. Whenever I bounce off my limter I think that if I didn't have it, it would be hard to go past 120 or so.

 

I think I'll just delete the limiter, hook up winaldl, and find out, lol.

 

I tried to see what the top speed of my car was. After around 120, I jammed the pedal all the way down to the floor and the front of the car lifted up and with no airdam and ~6 in. of ground clearence, all the air going underneath caused the front wheels to loose most of thier contact with the ground and I couldnt steer momentarily. Needless to say I wont be trying that again.

 

Now you are talking. Too bad windal has to come to our aids because of our 110 speedo.

I have always felt far more stable in my 3rd gen at speeds. At 115 I feel like I am riding on glass and the same speed in my 95 makes me feel like car is going to fly apart. Tires and suspension make these cars feel awesome at speed.

 

Its really more of an aerodynamic issue. My car sits pretty high and theres nothign to redirect air around the car rather then under it. Far too much air finds its way under the car causing a 'wing' effect. Feels great up to around 100 or so and after that it starts to get squirly.

 

Thats a new one on me. Why is your car so high anyways?

 

Big, fat 65 aspect ratio all season tires and unknown junkyard springs form the previous owner. I hate those all seasons. The sidewall has more compliance then the old yokohama's had. But unlike the yokohamas, I can actually drive in the snow.

 

with enough power at 5500rpm,26"tire 4th gear 4.10 rear should be 137mph and 3rd gear should be 94mph at 5500. at 5800rpm with the same setup it should be 144mph in 4th and 1oomph in 3rd. go to prestage . com and check out there calculaters,you can try all kinds of combinations.