Bigger turbos same boost what would happen?

Ok guys i was just wondering purely because I have too much time on my hands this summer holidays what would happen if you had two exactly same cars but one had a physicaly bigger turbo then the other one and they were running the same ammount of boost. Would the two cars have the same power at the wheels or would the bigger turbo one have more power at same level of boost? Any and all input more then welcome

Ok guys i was just wondering purely because I have too much time on my hands this summer holidays what would happen if you had two exactly same cars but one had a physicaly bigger turbo then the other one and they were running the same ammount of boost. Would the two cars have the same power at the wheels or would the bigger turbo one have more power at same level of boost? Any and all input more then welcome

Power is determined by how much air is flowed by the turbos (lots of other factors of course, but in simple terms to answer your question), not boost pressure.

A car with bigger turbos at the same boost level, will flow more air and as a consequence would be more powerful.

I see. Well makes sence i guess. So any turbo will always flow a set volume of air only at different levels of boost it will be more dense air right? Or am i missing something? Thank you very much for your promt and to the point reply.

I see. Well makes sence i guess. So any turbo will always flow a set volume of air only at different levels of boost it will be more dense air right? Or am i missing something? Thank you very much for your promt and to the point reply.

Yes each turbo has its own flow characteristics, dependant on size/design of turbine used on the exhaust and compressor side.

In simple terms the more air you can compress into the engine (along with more fuel) = bigger bang = more power.

Here are a couple of articles to read that explain the basics.

http://www.streetracersonline.com/articles/turbo/

http://www.streetracersonline.com/articles/forcedinduction/

Would the air also be slightly cooler, as the larger wheel will spin less to make the same amount of boost as the smaller one.

The answers you'll get can only be as accurate as the questions themselves.

You need to define what exactly is the 'bigger' part of the turbo:

1. the compressor housing

2. the turbine housing

3. the compressor wheel

4. the turbing wheel

5. combination of the above (define which ones and by how much)

Otherwise you are in a 'how long is a piece of string' situation;)

A Larger turbo (in all ways) would indeed heat the air less and push a larger MASS of air into the engine. Due to it being a cooler and denser charge.

A Larger turbo (in all ways) would indeed heat the air less and push a larger MASS of air into the engine. Due to it being a cooler and denser charge.

Exactly. At the same pressure and temperature the same amount of air flows, no matter the size of your turbo. The engine has certain air requirements, to get more than that in you have to pressurise it. It's just that a bigger turbo will generally be more efficient at higher flow rates and therefore produce less heat. Less heat = more air in the same volume = more flow.

Thank you very much for your input. And those sites were very useful. This is a great forum with lots of informed members. Will be troubling you guys quite a bit with these questions while i get old enough to insure a supra. Thanks for your help:D

I ran an HKS GT3040 (rated to 500hp) at 1.5bar with no problems. I then swapped the turbo for a GT4067 (rated to 700hp) and at the same 1.5bar she blew a piston and the engine caught fire. So yes, bigger turbo = more power

Gamer, you just like breaking cars.