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boost leak or turbo lag?

crewchiefpro said:
Previous post said 4 lbs spring, so my guess is it will open at that regardless of the vacuum line connection ( mine does ). A spring that weak could be the whole problem.
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A 4psi spring should keep the wastegate closed until the vacuum line running to it sees 4psi. If you unhook the.vacuum line then the wastegate should never open and boost should continue to rise until you close the throttle. The only exception to that would be if you had excessive backpressure in the exhaust, enough to actually open the wastegate, but if that were the case you wouldnt even be able to get the turbo to spool properly.
 
striker2 said:
A 4psi spring should keep the wastegate closed until the vacuum line running to it sees 4psi. If you unhook the.vacuum line then the wastegate should never open and boost should continue to rise until you close the throttle.
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100% Agree. I have run a low psi spring with and without boost control on multiple setups and not had any problems. Need pictures or diagrams of how everything is setup to be diagnosed, imho.
 
striker2 said:
A 4psi spring should keep the wastegate closed until the vacuum line running to it sees 4psi. If you unhook the.vacuum line then the wastegate should never open and boost should continue to rise until you close the throttle. The only exception to that would be if you had excessive backpressure in the exhaust, enough to actually open the wastegate, but if that were the case you wouldnt even be able to get the turbo to spool properly.
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you know, I forget if the car still had stock exhaust or not. It made boost all the time from a stop or low rpm, but try to get on it in the mid range and it wouldn't make boost as I recall. So another item that needs to be addressed to car the car running the best that it can.
 
yeah the stock exhaust wont cause enough back pressure to cause problems unless it is damaged in some way (clogged main cat, collapsed wall, etc).
 
Hey guys, sorry for the delayed response. I spend the weekend at a relative’s house, and wasn’t able to get on a computer. Thank you BrApple for posting some info during the meantime.

I’m starting to think that the problem is not lag, but more so a leak. However, it’s strange, because the car will eventually hit 8PSI, but it seems that it has to work so hard to get there. My thoughts are the BOV at this point. I’m thinking it has to be stuck open or leaking. Though, would an open BOV make any boost at all? Or is it possibly stuck partially open? Usually, hearing the release of air at a shift would be the giveaway if the BOV were working properly, but being that it’s set to recirculate, I believe I wouldn’t hear any loud blow off at all anyway, right?

In addition, if the boost controller is to blame, it’s definitely a possibility, as I have a manual eBay boost controller. I believe the wastegate spring is 4psi, and the boost controller is set to 7 or 8.

Though, if the boost controller was the problem, wouldn’t the car still get to 4 PSI without any problems?

BrApple said:
Adam, when I was riding along int the car it was making 7~8 lbs of boost. However if you get on it around 3 krpm it wouldn't boost. From a stop it would.
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This^

If I am cruising, and jump on the throttle (WOT), you can hear the turbo spool up, and the boost gauge no longer reads a vacuum, but instead stays at "0PSI" for a few seconds before slowly building boost. This is what initially made me think turbo lag :blackeye:. Though now I am thinking that there might be a leak somewhere, and the turbo has to overwork to build boost.

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Some older pics:

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and this last one, before the motor was put back in:

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Thank you so much everyone! :) the advice means a lot!
 
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Your oil feed/drain should be as close to vertical as possible. In that last pic they are horizontal, which isn't good for two reasons; poor drainage, and possibly bad for the bearing's in the turbo.

Back to the topic: It sounds more and more like a leak somewhere.

What is your A/F ratio when driving, etc.?
 
Whoa. That turbo center center needs to be rotated 90*. garrett states not to run the center section more than 30* iirc.

Is that home depot water piping (used as vacuum housing??) going to the top port of the wastegate???
 
Also it appears the the elbow going into the throttle body is collapsed from too tight of a turn, which will restrict air flow
 
Ha! Wondered where that 'kit' ended up. That intercooler was in my garage for awhile. Wonder where the TiAL BOV went that was previously on there.

Anyway, I'm looking at that BOV as being suspect. If you unscrew the top, are there any washers inside to effectively increase the spring pressure holding it closed? I recall I (and Stazi in the past) had to add washers to our RFL BOV's to keep them closed at idle. If the spring inside that bov isnt firm enoght, i would think it to blow wide open when the the turbo builds some pressure in the intercooler.

Check that out in the near term, in the long term, think about a higher quality BOV. I loved my HKS SSQV. And even reciculated, you should be able to clearly hear the BOV open when venting 5+ psi. I could flutter the gas and still get sound from mine.
 
I still think the wastegate hoses are setup wrong, which I have thought since the previous thread. Every symptoms makes it sounds like the top wastegate port is hooked up and not the bottom. The picture leads me to believe it is also.
 
Ok, lets clear everything up...

1. that water hose was used for mock up to find the correct length of oil return hose for the turbo

2. the wastegate vacuum line is run from the bottom port to a positive pressure source after the turbo on the intercooler.

3. the oil feeds and returns have been rotated to correct degrees after engine was installed INTO the car. many things were modified after engine / trans was dropped into the car.

4. there is a large reduction in exhaust piping from the downpipe into the aftermarket main Cat, and then back into the stock rear exhaust. something like 3" down into 2"...

5. The bov has a BUNCH of washers loading up the RFL BOV spring. probably could use more since its leaking under certain vacuum pressures (like under cruising speeds)...

6. the elbow from the intercooler into the TB has a crazy bend in it, which bothered me, but i couldnt fit the intercooler any other way, unless the Fuse Box was completely relocated out of the engine bay...

7. From the time Brapple rode in the car, I was able to refine the tune and address the initial BOV issues, and the car drove SO much better when mixtape picked it up.

8. MBC is a voodoo branded controller... i got it off their ebay store, and read a lot of stuff on it. for the price and reviews, it seemed like a good option. it works properly, and is setup correct...

9. the original Tial bov was removed, and an adapter was installed for the RFL style bov, as I converted it to recirculate the blown off air back into the intake tract after the MAF. The Tial caused the car to stall constantly, and no matter how i tuned for it, it kept doing it and was becoming dangerous to drive that way. Recirc'ing the air made issues go away, and driving and tuning was easier to manage.

SO... I have always stressed that a much better diaphram type bov would work better than the piston style RFL bov we have on there. We used the best option we had to work with at the time to get it running. and it does run great, just need to get a BOV that wont pull open under normal cruising speeds.

Brapple, you would be surprised how much faster the car got once i loaded up washers in the bov, and adjusted the tune!
Torque steer all over the place!! lol...

Anyway, mixtape should adjust or replace the bov. I feel a recirc bov is still the way to go with this kit (if the MAF could be setup as blow thru, a vta bov would be cool to use), and if he wants the bov "sound", maybe getting a hybrid vta/recirc bov may be the best option... otherwise a good recirc valve will cure the non-boosting issue during cruising speeds.
 
The bov being open during idle and high vacuum conditions is not an issue in recirculation mode as long as it closes and seals when the throttle is opened. I would highly recommend the synapse synchronic diverter valve. Its a piston type so it opens extremely fast but unlike the rfl it actually seals properly. Plus it can used in pull mode like the ssqv.

I think either the boost controller isnt working properly and the wastegate is opening, or the rfl is leaking horribly.
 
i am leaning towards the bov leaking. it works when it wants.

witht the tial bov, the wastegate worked perfect. boosted all the time with no issues.

with this rfl bov, it just doesnt bost when getting on the gas during cruising. isnt sealing fully to allow boost to build properly. it'll get to 1-3 psi, but turbo is working hard under those conditions.

we used the rfl mainly because i had it hanging around the shop and was brand new in the box. didnt have to wait again for new parts, etc.
this build took long enough to get to where it is. overall its working well, just the leaky bov isnt helping boost under cruise.
easy enough fix the the right bov.
 
aboythatskates said:
put it on a dyno for 75 bucks and check the damn conditions while ur simulating driving! vwala!
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Rates for dyno runs are twice that around here.
I know what the car's issues are... I spent plenty of time working on it, diagnosing it, and repairing stuff.

The bov needs adjustment or replacing, then if mixtape has the funds, we know of a dyno tuner in southern CT that can hook him up with a tune
And everything for a good price. Car's issue needs to be addressed before dumping the money into the dyno tune.

Car runs very well on the tune it has now, imo. The bov just isn't allowing a full seal sometimes and it won't build boost...
But when it does, car is fast.
 
My money is still on the wastegate, with the little amount of pictures and info posted. Based on the pictures its not the tune though, its something to do with the setup.

Have you vacuum tested either of the BOV or the wastegate? You can rig up a test to see if the bov is opening at low pressure as well, but my guess is it is its where it is tapped to or the bov/wastegate line setup.

Even Kaizen Tuning, probably most expensive shop in Mass offers 3 pulls for $75. (http://www.kaizentuning.com/tuning) Everywhere charges that. I don't know what you are talking about that shops charge twice that.

If your not going to test the valves correctly, pump up the BOV with some pressure to keep it closed, or remove it completely and go for a drive.
 
2000ZxT said:
updates? Hope you have it all sorted out
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Unfortunately I haven't had much time to troubleshoot the car yet. I've been working extra hours lately to counteract the Christmas shopping :blackeye::help: lol.

Though I did add four quarters to the BOV spring this past weekend. That would make around 8 washers/quarters in total. The problem was still there though. On top of that, I just noticed that the car will stall if I quickly go from WOT, to coasting in neutral. Though I'm not sure if upping the tension to the BOV spring caused that. Normally I just shift to the next gear and cruise. It could possibly have been something I hadn't noticed before doing these test runs.

I'm surprised though, because even if the BOV was stuck open, shouldn't the car stay running with a recirculated setup? My thought is that the tune is adding fuel to compensate where it predicts there to be boost, but without that extra air, it runs rich in high RPM and stalls :shrug:. I'm hoping that the stalling problem will go away once I can get it to boost properly.

My goal is to replace the BOV with a TiAL QR, and see if that helps. I believe the 11psi spring would work best considering my vacuum at idle is 20 in/hg. I think getting a precise spring will be a lot easier than guessing if I need more or less quarters/washers. What do you guys think?
http://www.ebay.com/itm/150954973903

If the problem persists, then I'll focus on the wastegate and the possibility of leaks :blackeye:

Thank you so much everyone. It's almost there :).
 
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