Thread: Decided on Blowthrough

The turbo will have to spin a lot faster to achieve the same boost pressure if there is a leak in the system. If the compressor cannot move enough air, this will be seen as a drop in boost pressure on the top end. Even moreso than a normal t25 sees.

Even my big GT30 can overspool if I have a big enough boost leak. The turbo will just spin faster and faster in order to achieve the boost pressure before the wastegate will open.

Sorry you are correct. I have no idea what I was thinking. I'm thinking over boost pressure going into the engine and a watching it on a boost gauge. You are right you will over boost the turbo. I'm all screwed up today. Day before long weekend.

Wow so leaks are not only annoying but basically prematurely kill the turbo.

Anyway got this figured out, it was my old stock BOV, with no boost to keep the BOV closed, it would open at 7 PSI. This shows how week the stock avenir spring is! My Greddy like BOV stays closed without a problem.

I noticed this because it did not built boost on Draw Through either. Now I will remove the old stock BOV once I can get a pipe with the right bungs on it

Overall im very happy and will be going to Blow through and see how it holds up. Meanwhile my temporary fix is to have pressure on the BOV via Wastegate lined Teed off.

Newbie question
What are the benefits of blow-through?

• Some say a crispier throttle response, similar to NA
• Open BOV for that beautiful Wshhhhh sound
• Coupler blows off before the MAF, no worries, drive home and fix it
• Leaks wont make you loose metered air (as long as they are before maf)
• Don't need to worry about welding a Valve Cover Breather and 1" recirc hose bung (at least yet)
• You can have a very short Intake pipe, you can get away with just putting a filter over the turbo inlet and all it a day
  

I think the response is where you put the MAF. Closer to the TB and the crisper the throttle response is, but you must maintain a distance to get accurate readings.

My solution is goin to be very very short piping and a pull-through.

How about distance of MAF from throttle body and distance between MAF and BOV?

Is required to have a bend after the MAF before going into the throttle body?

Is it the same or better to put the BOV at the intercooler or on the hot side piping just before going in?

Yup, it all seems to depend on MAF location, not putting pressure into the MAF.

If you have a W2A system, you can have some short piping



At least 12" away from the throttle body, and at least 6" away from the BOV.
It doesn't matter where you put the BOV, as long as it's at least 6" away.

You need to have 8" of straight pipe before the MAF to reduce turbulence.

Now where I was reading about the 8" deal, the site said with tests they noticed 8" before the MAF and 8" after the MAF is needed. They said before MAF needs to be straight, while after the MAF you can have bends, they said that once the air is accounted for, it doesn't matter how you bend it, it will still be the same. I'm guessing they are saying 8" of tubing before the throttle body.