why is there 25 more hp in a manual lb9 than in an auto lb9

 

25 hp? Depends on the year, the 5 speed had the L98 cam which has more power. Maybe comparing a Camaro 5speed with ram air (15 for cam and 10 for cold air intake) vs. firebird auto? It's probably not quite that large of a difference in real life, but the cams were different in some (if not all) years.

 

take 1992 camaro for example. The 305TPI auto makes 205 hp, the 5 speed 305TPI makes 230

explain that...im saying its a bigger cam...

 

Actually the auto AND the manual make 205, the manual G92 option makes 230. I've no idea what the G92 package is, but its listed on the tech data page. It includes steeper gears as well.

 

Well, that just it.

Do a search on 305 and peanut cams. More arguing there than u ever want to read.

85 TPI had good cam.

86-89 were not very good cams.

90-92 305 and 350 all got same cam.

G92 5spd(after dual cat intro) cars also got the dual exhaust which was rated at 230 with the 5spd 305 cars, along with the good gears.

There is more to it than that, but that is the basics in a nutshell.

later
Jeremy

 

What 3.8 TranAM said. Lots of argument over the "theory" of what motor should have had what cam (the primary reason for HP differences) vs. what was shoved into the motors IN REALITY by the factory.

In general, agreed with above, that 90-92 305 TPIs probably all got the "good guy" cam and made the higher HP number (although there were still some differences in the exhaust depending on application). The higher and lower HP numbers related to which type of tranny the car got seem to be only what the marketing literature says, not the reality of the situation.

 

You guys are way off the question. The answer is the it take less power to turn a manual trans. An auto has to turn a torque converter and 10 quarts of fluid. You loose up to 20% of horse power through an automatic trans. A manual has to turn 3 quarts of fluid. An auto trans is slipping at wide open throttle. A manual trans doesn't at wide open throttle. Manual trans is faster and gets better gas mileage.

 

I don't know whether those numbers are at the wheels or not, but if you read the chart on the main TGO page (assuming thats correct) then the manual and autos of same years have the same horse power in many cases.