need help.. under standing turbo charger A/R numbers.

[brent9k]

Im building a flowthru turbo kit for my 1600cc vw sand rail. I want to run the t3-t4 turbo off ebay for $100 bucks. I have seem some posts where some people can get them up to 22psi of boost and others can only get them up to 5 psi on a long run.

Its my understanding the t3-t4 is just the frame size of the turbo,
What i am realy looking for is info on A/R numbers. I see that they range for .48-.70 on both turbin and commpressor.

So if i want it to boost up faster do i go with a lower or high A/R number on the turbin

and do i go high of lower on the commpressor.


thanks

 

[Givemeaboost]

I'm not sure about a/r numbers but I DO know that you shouldn't buy a $100 turbo on E-Bay. They're junk Chinese turbos. I bought one four years ago for $400 and it lasted about 20 hours.

Ken.....

 

[Ryanlilly]

^^ X2, im surprised you got 20 hours out of it. The chinese ebay turbos are garbage.

 

[BigFish BC]

Im building a flowthru turbo kit for my 1600cc vw sand rail. I want to run the t3-t4 turbo off ebay for $100 bucks. I have seem some posts where some people can get them up to 22psi of boost and others can only get them up to 5 psi on a long run.

Its my understanding the t3-t4 is just the frame size of the turbo,
What i am realy looking for is info on A/R numbers. I see that they range for .48-.70 on both turbin and commpressor.

So if i want it to boost up faster do i go with a lower or high A/R number on the turbin

and do i go high of lower on the commpressor.


thanks

your first a/r # is intake side the higher the more air it flows or draws in & fills your motors cylinders.the second # is the exaust side this one will determine how fast it spools ,the lower the # the faster it will spool. but there is a down fall of running to small is that it will make a ton of heat when held wide open for any amount of time.you need to find the best balance of intake & exaust side to make it spool as quik as possible without making to much back pressure & heat.iam guessing you would want something like a 3071 garret but you need all the spec on the motor to get a good idea go here lots of great info.
http://www.turbobygarrett.com/turbobygarrett/tech_center/tech_center.html

 

[milehighassassin]

Agreed on not buying a junk turbo. You can get a great deal on a real T3T4 turbo as it is. Probably $600 or so.

I'll post an ar chart later. I'm on my phone now. Cooling is going to be tough on an air cooled motor. It can be done Porsche did it for years.


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