So I seem to be unable to accelerate my car past 250 km/h. I have my foot to the floor, but its like the car is just unable to accelerate past that speed. The car's aero is stock, ride height stock, suspension pretty much stock. Engine makes approx 400 hp crank, estimated. Has anyone got their g's over 250 km/h? What sort of aero mods have you done to get it there? The feeling from the drivers seat is like someone's just slamming on the brakes at that speed. It's not like the power gradually disappears, the car will nose dive like the brakes are being applied. Is it possible the engine isnt' getting enough air? Anyone ever run into this before? I have still like another 1000 rpm of gearing before I run out of gear. TH350, 2.29 rear end
car will not accelerate past 250 km/h
- Thread starter othtim
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Is this a GBody :?: If so, it is your car trying to save your life. These cars are not made to go that fast :lol:
But seriously, it sounds like a spark or fuel issue :idea:
But seriously, it sounds like a spark or fuel issue :idea:
Lol, yeah it does get pretty squirrly at those speeds. Even at the end of the 1/4 im probably doing near 200km/h (i always keep accelerating a bit past the traps so I dont accidentaly let off too soon). im interested in some mods to keep the nose down. It's like i get the feeling that the front wheels aren't doing anything at all. gets pretty scary at the big end. I dont want to be crashing at the big end. its been pretty squirrly up there before, makes me nervous with how it feels. i am interested in ideas on how i can make it less sketch on the big end.
Some type of fabricated front splitter would be beneficial :idea: This would pull the front of the car down lower at higher speeds. The lower you can get the front of the car the better off you'll be 
My dad has done around 160 mph in his Trans Am, and he has said, even when you have more gear and a little more power left, aerodynamics limit you a lot once you get close to top speed.
othtim said:
othtim said:
Say what?
Unless your car weighs 2600lbs I dont think so.
Inspite of that, you are probably experiencing the limits of the car (hopefully on a track). The fastest ive ever been is 225km/h, and what happened was about 220km/h the pressure under the front of the car overcame the weight of the front of the car. This raised the front end of the car just enough to start acting like a parachute. The feeling was the same "hit the brakes" you described. The car would have continued to accelerate but I had to back off. The steering felt like it was not connected, and the sound of the air rushing by changed (probably increased a couple of decibles).
http://en.wikipedia.org/wiki/Drag_(physics)
If you are so inclined, you can figure out what the top speed of your car should be. You need to calculate the drag co-efficient, and the projected frontal area of your car. There is a formula for the co-efficient. Plug those values in to figure out your Drag Force (sounds like a racing superhero league). All this will allow you to calculate your Power required to overcome that speed. You could rearrange the formula to solve for max speed since power is a "known".
Power will be in units of work over time, which will tell you how much fuel you will need to get the power. All kinds of fun stuff in there like reynold's number too. Make sure your units are the same!
This is why there are online calculators for this sorta stuff
Anyway, at that speed you are probably near what your car is capable of. If you can work out the calculations above, you can also determine what kind fuel your car is getting at those speeds, and whether or not its adequate.
Probably not too many people running their "stock" cars to those sorta speeds.
Ha, you're right. Looks like i;'m only doing like 180 km/h. Math fail. And power is really only a known-"ish", lol.
And what youre describnig is almost exactly what I'm feeling, online170. I'll do the math and figure out what the top speed is lol. I've had one hell of a time trying to find any information about top speeds on these g-bodys. Seems like no one does top speed runs in them???!?! I can't see any reason why not??!?!?!? lol. I'll try some mods and see what I can do. I'm thinking like a garden-trim air dam and possibly a front splitter.
Half the problem is so many of my friends have supras and 240's and they can do rediculous high speed pulls.
One of the biggest issues I'm having now is tires...I can't seem to find any decently high speed-rated tires in 15" rim sizes.
And what youre describnig is almost exactly what I'm feeling, online170. I'll do the math and figure out what the top speed is lol. I've had one hell of a time trying to find any information about top speeds on these g-bodys. Seems like no one does top speed runs in them???!?! I can't see any reason why not??!?!?!? lol. I'll try some mods and see what I can do. I'm thinking like a garden-trim air dam and possibly a front splitter.
Half the problem is so many of my friends have supras and 240's and they can do rediculous high speed pulls.
One of the biggest issues I'm having now is tires...I can't seem to find any decently high speed-rated tires in 15" rim sizes.
As far as mods, I'm not sure. Even at 200kph, its extremely sketch. As far as aero, I'm really thinking its just going to be trial and error, like try something and see if it feels more stable at speed. One thing I want to do is switch to a manual steering box, and get some tires that can handle higher speeds. The power steering just feels suuuuuper unsafe at speeds, its like its not even doing anything. And maybe block off some of the front end of the car, and make some kind of air dam. other than that, I dont know - copy nascar?
in drag racing don't you have your car geared so you hit the max revs at or very close after the finish line?
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