1978 Trans Am is wrong!

Wild Cobra Z28

Wild Cobra Z28

371
Wild_Cobra_Z28
OK, I had a 1977 for six years when I was in Germany. It was stock, except the rear gears. It would do over 165 MPH. I don't think I got this one over 125 MPH on the long straits.

I think Sony is assuming the 230 HP is engine HP when these were rated SAE net.

---edit add---

Looks like the car is correct afterall. Please read following posts before replying to this one.
 
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PD needs to fire whoever did research on American cars. Tons of the info is wrong.
But the 125 top speed sounds right maybe a little on the high side.
 
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Wild Cobra Z28
OK, I had a 1977 for six years when I was in Germany. It was stock, except the rear gears. It would do over 165 MPH. I don't think I got this one over 125 MPH on the long straits.


I think Sony is assuming the 230 HP is engine HP when these were rated SAE net.
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I think they are closer to reality than you think. My brother owned a 78 with the Pontiac 400 and It wouldn't touch 165. The speedometer only goes up to 100 so how do you know you went 165? Car and Driver tested a 79 with the top of the line 400 and hit 124 at redline. There wasn't much of anything in 1977 that would hit 165 except a Porsche Turbo 911.
 
71 GS Stage 1
I think they are closer to reality than you think. My brother owned a 78 with the Pontiac 400 and It wouldn't touch 165. The speedometer only goes up to 100 so how do you know you went 165? Car and Driver tested a 79 with the top of the line 400 and hit 124 at redline. There wasn't much of anything in 1977 that would hit 165 except a Porsche Turbo 911.
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As a Trans Am specialist, I can tell you that your statement is 100% correct. A 1978 Trans Am could not reach anywhere near that kind of speed. (165 MPH) Top speed for a 78, 400 4 speed was 123 MPH.

You could not even reach 165 MPH with the last 455, the 1976 Big bird.
 
Badasp5.0
PD needs to fire whoever did research on American cars. Tons of the info is wrong.
But the 125 top speed sounds right maybe a little on the high side.
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No.

About 125 is all you can take one of these without changing the gear ratios. You'll blow the engine if you take then too fast. Change the gearing, and they have enough power to top at least 150 MPH.

The HP curve looks right. Max power is about 4000 RPM, so in a stock one, you are at about 2/3rds max power when you come close to the redline. Kind of a built in safety feature. Change your gearing to achieve top speed at 4000 RPM, and these babies, in real life will go!

I did own a 1977 for six years. I drove it on the autobahns in Germany. Since, I have had a 2000 Z28, and currently have a 2002 WS6.
 
fredyellowone
As a Trans Am specialist, I can tell you that your statement is 100% correct. A 1978 Trans Am could not reach anywhere near that kind of speed. (165 MPH) Top speed for a 78, 400 4 speed was 123 MPH.

You could not even reach 165 MPH with the last 455, the 1976 Big bird.
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You my friend, or no expert.

See my last post.

Try a 2.41 rear axle sometime in a real one.
 
Are*
And yes, top speed of a factory 1978 400 4 speed was 123 MPH.
Now that you know this, feel free to believe in care bears, up to you.
 
71 GS Stage 1
The speedometer only goes up to 100 so how do you know you went 165?
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By how fast I passed the cars with 250 KPH limiters on them, and these people in these 12 cylinder BMW 750iL's didn't want this American car to pass them! I have had several times when I know I was going over 160 MPH. Came across a lot of fast cars over that six year period.

My speedometer would wrap back around, just short of zero before it pegged out.
 
fredyellowone
Are*
And yes, top speed of a factory 1978 400 4 speed was 123 MPH.
Now that you know this, feel free to believe in care bears, up to you.
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Again, gearing makes all the difference in the world.

I do not dispute you claim of a 100% stock car. Mine had 2.41 rear gears put in.

Think about that.
 
Tell me if my math if off, and under this assumption.

Peak power is 4000 RPM

Stock car, at 124 MPH is 5500 RPM, and power curve at at 5500 RPM is 60% of peak power.

160 MPH/124 MPH = 1.29.

It is a square function relationship between power and speed to push a car through the air, i.e. it take four time the power to double the speed.

1.29 x 1.29 = 1.664.

1/1.664 = 0.601.

Looks right to me. The same factory car that tops out at 124 MPH at redline will hit 160 MPH if you change the gears to hit 160 MPH at 4000 RPM.
 
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atiger
Your Trans Am was faster than a 750i 400+hp BMW 6.0 V12? Sounds like a hell of a car.
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Yes it was, but only because the BMW had a limiter that kept it from going faster than 250 KPH (155 MPH). I read someplace those will go over 180 MPH is you disable the limiter.

And they were 5 liter, not 6.

The 6 liter would be a 760iL.
 
Wild Cobra Z28
Tell me if my math if off, and under this assumption.

Peak power is 4000 RPM

Stock car, at 124 MPH is 5500 RPM, and power curve at at 5500 RPM is 60% of peak power.

160 MPH/124 MPH = 1.29.

It is a square function relationship between power and speed to push a car through the air, i.e. it take four time the power to double the speed.

1.29 x 1.29 = 1.664.

1/1.664 = 0.601.

Looks right to me. The same factory car that tops out at 124 MPH at redline will hit 160 MPH is you change the gears to hit 160 MPH at 4000 RPM.
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But the game is not using different gears. The game is using the factory settings which would make it top out at about 125. You're saying the game is wrong when it isn't. Try changing the gears in the game and see what happens.
 
Wild Cobra Z28
Yes it was, but only because it had a limiter that kept it from going faster than 250 KPH (155 MPH). I read someplace those will go over 180 MPH is you disable the limiter.

And the were 5 liter, not 6.
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Just FYI you can respond to people all in a single post, just click "Reply" on each one and they all end up in the box at the bottom of the page. Limits multi-posting, which is frowned upon around here.
 
R1600Turbo
Just FYI you can respond to people all in a single post, just click "Reply" on each one and they all end up in the box at the bottom of the page. Limits multi-posting, which is frowned upon around here.
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Yes, I've seen that accidentally before...

Thanx.
 
71 GS Stage 1
But the game is not using different gears. The game is using the factory settings which would make it top out at about 125. You're saying the game is wrong when it isn't. Try changing the gears in the game and see what happens.
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But I put in the custom transmission, and changed my gearing. You think I would miss that since I am the one explaining the gearing issue?
 
I was sure from the start we were talking about stock cars. If that is not the case, my apologies. All my cars always been 100% stock. As for PD, I doubt they changed an axle on a stock '78 to be all that accurate.
 
fredyellowone
I was sure from the start we were talking about stock cars. If that is not the case, my apologies. All my cars always been 100% stock. As for PD, I doubt they changed an axle on a stock '78 to be all that accurate.
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Accepted.

But... In post 1:
It was stock, except the rear gears.
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I just went to arcade mode, Special Stage Route X, and used 1.00 for fifth and 2.417 for the final. It topped out wrong, then remembered, my tires were not stock either. They were a larger diameter. I had this set for top speed those years back. I then set fifth gear to 0.842, and topped out at 267 KPH (166 MPH) on the level. Just took longer to get there than I remember. Maybe it is correct, as the autobahn is not a racetrack, and several kilometers of straits.
 
QuikSlvr223
Basically you're saying the stock Trans Am is wrong because it has a lower top speed than your modified Trans Am?
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No.

I was saying it was wrong, because after I modified the game car gearing, I didn't see it break 125 MPH on the straits. In retrospect, if you followed my posts, you'll see that I said it may be correct, and the the autobahn is a longer straightaway to get to top speed.

Back to the first post, I assumed they based the car physics on SAE net power than a real car. The engine HP of these cars is greater than the rated SAE net.
 
Wild Cobra Z28
I think Sony is assuming the 230 HP is engine HP when these were rated SAE net.
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SAE net should be pretty close to the actual HP at the crank. You'd need to derate it by another ~15% to account for drivetrain losses.

The real problem with American cars is that PD doesn't take SAE gross into account and derate to account for it. Anything after they switched to net, I would expect to be pretty close to right.
 
The cars in the game are all fantastic and honestly gove the devs more credit for paying and licencing all these cars and taking the time to try the really hard task of recording sound accurately... Its not easy trust me just trying to make good sound samples for my edm music is a pain could only imagine doing cars
 
MrWednesday
SAE net should be pretty close to the actual HP at the crank. You'd need to derate it by another ~15% to account for drivetrain losses.

The real problem with American cars is that PD doesn't take SAE gross into account and derate to account for it. Anything after they switched to net, I would expect to be pretty close to right.
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The real problem is that Kaz hates American cars...
 
kdryan
The real problem is that Kaz hates American cars...
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I doubt that since he's owned quite a few. And to lead a project this ambitious, one assumes he loves every automobile. I don't know where your comment came from.
 
Sephy
I doubt that since he's owned quite a few. And to lead a project this ambitious, one assumes he loves every automobile. I don't know where your comment came from.
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I feel cheated on the vintage Mustangs. :)
 
Wild Cobra Z28
No.

I was saying it was wrong, because after I modified the game car gearing, I didn't see it break 125 MPH on the straits. In retrospect, if you followed my posts, you'll see that I said it may be correct, and the the autobahn is a longer straightaway to get to top speed.
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Ah, now I see what you mean.
 
The Trans Am probably did have somewhat more power than rated for (though whether it had enough power to allow it to go faster than the much more aerodynamic third generation Trans Am Turbo is something I'm pretty iffy on), but I'm not entirely sure how PD is supposed to know the "true" power rating; and there are plenty of cars with far more glaring problems in terms of specification errors anyway.
 
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Tornado
The Trans Am probably did have somewhat more power than rated for (though whether it had enough power to allow it to go faster than the much more aerodynamic second generation Trans Am Turbo is something I'm pretty iffy on), but I'm not entirely sure how PD is supposed to know the "true" power rating; and there are plenty of cars with far more glaring problems in terms of specification errors anyway.
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Well, if they accessed actual torque curves, and any speed test of a stock car at what RPM, they could do an accurate estimation from there.
 

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