Top End Limits!!??
 

I have a 88GT totally stock except the clutch w/ the gauges that only goto 85 lol and a 2.73 r/e. Tonite i was racing a few cars down the freeway at atleast 110+mph cuz my speedo was tacked at the bottom of the gauges. Anyways i noticed as a approched the yellow line in 4th, i shfted to 5th and it wouldnt go any further than a lil under 3000 rpms. Its like a limitor or something. Is this b-cuz there is really something limiting me from going faster or is it becuz i dont make enough hp to go faster?
Also with my car, how fast am i going when im at this point since i only goto 85 on the gauges.?
thanks
bryan

gear
 

I would say there's nothing wrong with your car, with 2.73 gears and a stock motor, when you hit 5th, that's overdrive and will excellerate more it just takes for ever, Remember top speed is indicative of total horsepower, TORQUE is what excellerates the car, get ya and exhaust system, a 3.73 gear.

A bone stock 88 notchback was tested in a 88 Road and Track magazine with 3.08 gears and topped out at if i remember right 143mph.

I also remember very well a comparison test tween and 86 LX 5-speed and an 86 IROC.......they 86 went 147mph, I ***** you not, maybe your fuel pump is getting errk, some of those early stangs only came with an 88LPH and Ive removed some that had 66LPH, I say tach the living bazeezes out of 4th gear, and really if you havent beat em buy 100 plus mph whats the point?

Have fun, also check and see if your throttle body blade open all the way at WOT...car off of coarse, also until I think 91-up had teflon coatings on the throttle blade to help gunk build up, how about your timing???????

Jay

Jay

Too high a rearend gear and too little power. It takes big power to redline a Mustang in 5th gear. easily twice that of a stock engine if that little. I'd guess about 135-140 mph where your tach was in 4th. when the 89 was stock, it would register 140 topped out. Didn't matter if you were in 4th or 5th.
4th was pegged and fifth wouldn't pull any higher. FYI, Car Craft (in 1988) took a stock (albeit a factory "selected") 89 GT and ran it 147 mph on top.

Ok well i was just wondering what kinda of speed i was pushing with stock 2.73 gears and a 5th gear 3000 rpm mark or 4th at like 5300-5500 rpms..?
i need an intake and exaust and some bolt ons but i need money.. i also need gauges hehe.. any more replays to this, about the rpms and speed?
bryan

well according to the analyzer here in 4th gear 5300-5400 is around 150 mph and 5th gear at around 3000 is around 121 mph.

I had my 88GT with mild mods at about 145-150 according to the stock tach (inaccurate at best) in 4th. I actually slowed when trying 5th. I also have 2.73s i believe.

hey what analyzer are you supposably talking about? Also is that 4th gear @ 5300rpms w/ a 2.73 rear end?
Does anyone know where i can pick up some 140mph or 200mph gauges for a decent price?
And if i switch to 3.73's what speed will i be running in 4th gear at 5300rpms and will 5th gear accelerate more than it does with 2.73's?
sorry about all the questions.
Thanks
Bryan

well i got a ticket for i think was either 145 or 135 at the top of 4th. It should go faster i dont see why it would cut out or slow up like that did u have a full tank of gas???
later

You got a ticket?? In my state you would have gotten a free ride to the jail house. lol

My car a dps car has a 160 speedo, i went 130 in 4th gr just over 5k rpms, not sure, but it was around that, heh, dont like to look down at guages long.... at that kind of speed:D

You hit 130 at about 5grand in 4th with your 3.27 gears or 2.73's? If they were with your 3.27's then if i was running my engine about the same as you i would have been going a lil faster?

Thats not the way it works man, but i believe i did this with 3.08's and 3.27's, a small difference.
because you have 273 does not mean you will go faster on top, you want more gear, not too much, but enough rpms to keep your motor in the powerband, wind drag, or going up a hill has alot to do with it, i bet a car with 3.55's and your car with same mods and 2.73, the other car would pull harder than you at a top speeds of 120+ mph, your motor just has to work harder to spin what the 3.55's or 373 can do easier and faster, now that does not mean your car isnt fast, my car flies with the gear it has, if you want to topend race, you have the wrong car, unless you have turbo/blower, there is an AWD plymouth laser convertible around here that goes high 11's at 124 mph, i have not yet to see any n/a stang's, or f-bods beat this car on topend, he is running some mad boost, so dont worry, you wouldnt have a chance on topend against a car like this, unless you have a power adder, or seriously built roller cam high compression motor.

btw, sorry to get off subject about that awd dsm above, but the topspeed topic remided me of him, i have a vid of him in action somewhere if anyone wants to see it, i'll email it.

OHH all right i see now.. i had been thinking for the longest time the longer your gear the more top you'll have if you have the power but it just takes longer to build up bcuz i saw that if you have 3.73 or 4.10 then you top end lower.

MEDIK418 is right, it is about power! if you have the H.P then you will certianly go faster (higher top end) with 2.73:1 than with 3.73:1 gears. Once you get above 100 mph the air resistance goes up expotentially to the increase in mph. Case in point, a 220 h.p SHO Taurus will out acelerate a 220 H.P Mustang from a 100 mph roll! The reason why is that the Taurus is way better aerodynamically than the Mustang so the wind resistance above 100 mph is less which allows the car to accelerate faster for a given H.P. Actually did this test with a friend of mine with 2 brand new cars, 1993 SHO 5 speed and a 1993 5.0 5 speed Mustang. (we both worked at a Ford dealership at the time and were doing pre-delivery inspections) From a dead stop the Mustang kicked the SHO's ***, More torque, RWD. but from a 100 mph roll the SHO actually started walking away from the Mustang! We shut them both down at about 135 mph. So if you have the H.P. you can pull a hell of a top end provided the car is stable aerodynaically. On our drag car with 4.56:1 gears, 28" tall slicks, No overdrive, C-4 trans, we run it close to 140 mph in the 1/4 mile, it takes 8,000 rpm and about 750 H.P. to do this is 9.7 sec.
Yes sir it is ALL about H.P. if you have no power then go with gear because it will let the engine spin "free'er"