1G exhaust/leak

[ITSME4G63]

Hey guys, I have an exhaust leak between my turbo and exhaust manifold. me and a friend took a sander and sanded both the turbo and and the manifold and its still tehre. I knwo it has to be my exhaust manifold since the turbo was on the car before with a deifferent manifold and it never had a leak. Now, I also have an exhasut leak in my downpipe, the flexpipe is leaking exhaust. When I drive my car, sometimes when I step on it, that stock 10 psi doesnt feel strong at all, another time I step on it and it feels like heaven at the same boost level. Would these exhaust leaks contribute the car to act like this. The engine has 60 miles on it since rebuild, breaking it in. Also, hadnt had time to check with a logger, but would liek a heads up.

 

[mirkoelek]

If its not a big leak between the turbo and the manifold, you shouldnt feel a big power loss. If you have a leak in your downpipe you cant have any power loss, no matter how big the hole is... get a new gasket and problem solved

 

[staticbrainwash]

A couple things could be happening. Try maing a BOOST LEAK TESTER, mucho importante! That way you can see if you've got leakes in vac or boost. Also, try changing all gaskets and pulling off the manny and turbo again and get both mating surfaces milled on the manny and get the turbine housing flange on the turbo milled where it meets the manny.

As said above, you won't have any loss in power from a post turbo exhaust leak. So Boost Leak Test your system then try torquing everything back down and milling the flanges flat if they need it.

Check back after you boost leak test, it could be that simple.

When do you notice power loss most? When cold or at fulltemp?

 

[ian7321]

Are you beating on a newly rebuilt engine? If so do you not care about your piston rings? You know you are supposed to take it easy at least the first 500 miles so that the rings can seat.

 

[ITSME4G63]

Are you beating on a newly rebuilt engine? If so do you not care about your piston rings? You know you are supposed to take it easy at least the first 500 miles so that the rings can seat.

quite the contrary, youre supposed to give it some stick so that the piston rings do seat it fine. But, its not like Im BEATING on it anyways. SOme 2nd and 3rd gear pulls wont hurt it.

The power loss happens randomly, if it was a boost leak then the boost gague wouldnt show me hitting 10 psi when I romp it woudl it? Sometimes I just feel it right away when I shift into lets say second gear, that its not going to have much power and other times it hits right away, either way the boost gague pegs the same way, there just inst much power one time compared to another. Im going to have to find the logger cable and see if what is going on, Ive got a bad feeling it may be the knock sensor getting phantom knock for some reason and I doubt itd be bad it on has 5xx miles on it.

The gasket for the manifold is one I got of of ebay, its a 1/8 thick one and you cant bend it for shit, its cnc made so I doubt something is wrong with it, I have a 2g manfiold at work which im porting out this week and will isntall it on the weekend and see what happenens.

Thanks for the input, id appreciate more.

 

[staticbrainwash]

Make sure you mill the new manny surfaces flat.

And yes, your boost gauge will read 10 all the time no matter what. Do you have an MBC? If so how is it routed? What ends up happening is boost will always try to hit whatever level it is set at. So if there is a leak, it will overwork the turbo to get it to stick at 10. There's a little bit of a way around it to tell if you've got a leak, if you have an MBC DO NOT route it tee-d into the blow-off valve. Route it from the compressor cover or from the compressor outlet elbow. This way you are running shorter line from a safer(and closer to the original) boost source. So if there does end up being an issue you will notice because the system won't be trying to charge through so much line.

 

[ITSME4G63]

Make sure you mill the new manny surfaces flat.

And yes, your boost gauge will read 10 all the time no matter what. Do you have an MBC? If so how is it routed? What ends up happening is boost will always try to hit whatever level it is set at. So if there is a leak, it will overwork the turbo to get it to stick at 10. There's a little bit of a way around it to tell if you've got a leak, if you have an MBC DO NOT route it tee-d into the blow-off valve. Route it from the compressor cover or from the compressor outlet elbow. This way you are running shorter line from a safer(and closer to the original) boost source. So if there does end up being an issue you will notice because the system won't be trying to charge through so much line.

its an old school hks evc, theres a evc box in teh engine bay, which has a vaccum lien running from it to the compressor elbow, from it to the wastegate actuator, and from it to a T that runs on line to the bov and one line to the intake manifold. THank you for the input I will sure to check the hoses if anything, or purchase a boostleak tester.

 

[ian7321]

its an old school hks evc, theres a evc box in teh engine bay, which has a vaccum lien running from it to the compressor elbow, from it to the wastegate actuator, and from it to a T that runs on line to the bov and one line to the intake manifold. THank you for the input I will sure to check the hoses if anything, or purchase a boostleak tester.

Actually you can build a boost leak tester at home depot, lowes, ect for about 5 bucks.

 

[FORMONTOYA]

The power loss happens randomly, if it was a boost leak then the boost gague wouldnt show me hitting 10 psi when I romp it woudl it?

Yes it would as long as the boost leak is not super huge. The turbo will try to hit the set boost pressure. If you have boost set to 10psi and have a leak, lets say it's a 5psi leak, then the turbo will pump out 15psi in order to maintain the 10psi (+ the 5psi leak) you have the boost pressure set at. That's why it's so important to do boost leak test on these cars, IMO at every oil change. Leaks will cause the turbo to work a lot harder in order to maintain the set boost pressure and shorten the life of the turbo.

 

[staticbrainwash]

Getting a nice simple MBC also helps. Less vac line, and more accurate in my opinion. One line from the outlet elbow, one to the WG actuator. Done.

DEFINATELY make or buy a leak tester though. MachV has them, or you can make one for real cheap too. 2" pvc cap, 2"straight coupler, some clamps, and a valve stem. Assemble according to the vfaq.com directions.