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GTA DOCUMENTATION/RESEARCH Want to ask about your GTA's documentation, build codes, or other historical data? Then post it HERE!

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Old 02-24-2011   #1
1badGTA
BAD GTA 88 5.0 TPI/T5
 
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5 speed had more HP than auto? I didnt know!

Ok. I guess I am stupid..
I got a 5-speed 5.0...
I didnt know that the auto 5.0 TPI had 195 HP!
My 5 speed has 220 stock. I didnt realize! I thought they all had 220. All that and Posi with 3.45 gears

Now to go find me an 5.0 auto to race...lol
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Old 02-25-2011   #2
merc3065
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Re: 5 speed had more HP than auto? I didnt know!

it was rated at 195 due to hte auto transmission driveline loss.

5spd will be comparable(not exact) in speed and acceleration to a 350 auto.
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Old 02-25-2011   #3
1badGTA
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Re: 5 speed had more HP than auto? I didnt know!

Quote:
Originally Posted by merc3065 View Post
it was rated at 195 due to hte auto transmission driveline loss.

5spd will be comparable(not exact) in speed and acceleration to a 350 auto.
Cool. On thirdgen.org they always talk trash about 305s. Good to know I could hold my own
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Old 02-28-2011   #4
FrankieRider2
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GTA Year: 1988
GTA Engine: 350 TPI Automatic
Re: 5 speed had more HP than auto? I didnt know!

The later 305s ('91-'92) had as much HP as the earlier ('87-'88) 350s. Not the earlier ones....
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Old 02-28-2011   #5
GTAhot92
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Re: 5 speed had more HP than auto? I didnt know!

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Originally Posted by FrankieRider2 View Post
The later 305s ('91-'92) had as much HP as the earlier ('87-'88) 350s. Not the earlier ones....
My 305 Auto is LT1 Auto fast. The 2;73's suck off the line thou. However yes the early 350's are no match for the 91-92 cars. The earlier cars with the dual cat is another story.
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Old 03-02-2011   #6
eseibel67
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Re: 5 speed had more HP than auto? I didnt know!

Quote:
Originally Posted by merc3065 View Post
it was rated at 195 due to hte auto transmission driveline loss.

5spd will be comparable(not exact) in speed and acceleration to a 350 auto.
Actual flywheel horsepower is higher on 305 manual than 305 auto. Not sure what all the differences are, but cam and tune are different for certain.
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Old 03-03-2011   #7
1badGTA
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Re: 5 speed had more HP than auto? I didnt know!

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Originally Posted by eseibel67 View Post
Actual flywheel horsepower is higher on 305 manual than 305 auto. Not sure what all the differences are, but cam and tune are different for certain.
where did you get this info? I am curious!
As I have said on other threads, she runs hard and rough a bit. Not as smooth as my old 86 auto I had back in the day. a less mild cam would explain it. The owner (who had it since 90) said nothing has been modified and she is stock. Took my friend for a ride who said he couldnt believe the 350 running harder than mine, but again, I am sure the 90 & 91s would beat her. But I dont like the noses on those or the airbag steering wheel. Spring is in the air. Anyone in Columbus, OH would like to meet up for a cruise-in night?
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Old 03-04-2011   #8
GTAhot92
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Re: 5 speed had more HP than auto? I didnt know!

The rated HP variance comes from the transmission power loss.
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Old 03-06-2011   #9
andre#4
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Re: 5 speed had more HP than auto? I didnt know!

I know in 1991 a 305 was rated as follows:

305 with auto 205hp
305 with 5 sp 230hp


I think the 230 number only applies if the performance enhancement group is applied. this package includes a much bigger exhaust system and dual cats. Also included a 140mph speedo and higher redline tach. I think it may have been combined with the disk brakes. and maybe with the performance axle ratio. I don't have the papers here in front of me. (I used to know this stuff by memory...say no to drugs)

I had a 1992 305 5 speed trans am convertible that DID NOT have the performance enhancement group.

it had the tiny exhaust pipe (2") single cat, and it also had drum brakes. It had the 120 mph speedo and lower redline tach too. So I think that was just the basic 205hp motor with the 5 speed and nothing else. I have seen 5 other converts with that setup too. That car was not fast at all. I bought it new and did not modify it.

I used to think that the 5 speed cars all had the performance enhancement group, because they always rated the power higher on the 5 speeds. But these converts prove that wrong. (now, was that a special convertible horsepower downgrade thing to save the roofless structure or was that done on coupes too?)

On he other hand, my 1991 formula 1le with 305 and 5 speed has a raspy angry sounding motor and goes much much faster. That car had the 140mhp speedo, high redline tach, disk brakes, 3" exhaust, dual cats, performance axle ratio.

I don't remember if the fuel injectors were different for the 230hp 205.

Anyway, you have to take into account the performance enhancement group because it makes a huge difference. And check if your car has it before buying it. The cost to upgrade all that stuff will exceed the value of the car.

I know that the 92 convert had a very strong structure that did not flex nearly as much as 350 and turbo converts do, so maybe the lower power and open rear end helped save the structural integrity.
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