no boost

[IanS13]

ok i have a question it might be stupid to ask at this point but i will ask anyway well today i started the car to see if it would build boost, but it did not am seeing a little over 20 hg vac but when i hit the gas no boost goes to zero, ok here is the problem i don't have a down pipe on the car yet as it is not made yet still waiting for the flange, anyhow there is a second outlet hole on the back of the turbo my best guess would be that this is for an internal waste gate. ok with the being said here goes my second question, if that hole is not caped off will the turbo make any boost. should it not atlest make a very little amount of boost. and if it should why am i not seeing any boost my boost gauge is using a vac line that runs from the bottom of the tb to the egr then to some other part that looks like a egr a bit.

[rn240sx]

1st off, you should tap somewhere else to get vacuum and boost readings. Try tapping off the fuel pressure regulator. If u dont know where that is, follow the fuel rail from the FRONT of the motor goinh BACK towards the firewall. At the end of the fuel rail you will see what looks to be a mushroom looking thing. That is the FPR.. You should see a vacuum line running from it going DOWN toward the back side of the intake manifold. That line itself is the 2nd best place to tap for vacuum and boost pressure. On my ka motor, I removed ALL the emission crap possible and I found 3 open ports that were welded directly to the manifold and they were used for emission feedback. All 3 i was able to get a vacuum and boost pressure signal from..!!! I only used (2) of them. 1 for my boost gauge and the other for my bov.

2nd, if your trying to read boost from a stand still by just reving up the engine, good luck, it WONT happen..!! If your turbo is smaller than a T25, then maybe you will get some boost, but not much.

3rd, on your turbo, your saying that on the exhaust outlet there is a 2nd tiny hole..?? If so, that hole is there for when the INTERNAL wastegate opens, the bypass exhaust gases will pass thru that hole and mix in with the turbine's ex gas..

[IanS13]

well i did not rev it past 3500, so what your saying is i won't see any boost just standing still i have to be driving.

[:: orion ::]

...i won't see any boost just standing still i have to be driving.

Exactly.

Unless you run some tiny, tiny turbo...which is a damn waste anyway.

The motor needs load to build boost...

- Brian

[IanS13]

oh my buddy with his ecplise can build boost all the way to 10psi with his stock turbo, his turbo is small i think it's a 14g or some thing.

[rn240sx]

"oh my buddy with his ecplise can build boost all the way to 10psi with his stock turbo, his turbo is small i think it's a 14g or some thing."

Well, yeah if he's is MOVING he will build boost... But if he's just standing still and reving out his motor, he WONT see any boost..!!!

Another thing.... he can "build" boost all the way to 10 psi".You said that wrong. What u should have said was my buddy can hit 10 psi on his stock turbo. NO OFFENSE to you just trying to help you out..

[SloS13]

, if that hole is not caped off will the turbo make any boost. should it not atlest make a very little amount of boost

umm, i dont think so unless you're dogging the crap out of it which i wouldnt suggest unless you want to melt your firewall or something

[IanS13]

tru

umm, i dont think so unless you're dogging the crap out of it which i wouldnt suggest unless you want to melt your firewall or something

there was a little flame comming out the first time i started it it seems that from turning on the key to check the fuel pressure made my spark plugs wet with gas so it would not start when i got it started a little flame was comming the turbo.