Hey all, I posted a bit ago about getting a new turbo and I did. Got the ZFR 6758 and it's installed. While getting the tune done, the boost PSI would peak at 19 (WAS SET TO 19) and then taper off after 4800 RPM or so down to 18, then to 17, and near/at redline to 16. My tuner tried a few things to fix it and nothing changed, still happened for every pull on the dyno. I was wondering if anyone else has had this problem before. The tuner was telling me that the stock spring for BPV is kinda crappy and weak for the 6758, which is what I'm leaning towards. Those that have the 6758, did you have to change the BPV spring or no? I have also noticed that the BPV flutters when let off at peak boost or any boost for that matter, obviously less flutter for the lower boost.

**I got the turbo a week and a half ago from ZZP and has been on the car since Sunday**

 

Who is your tuner

 

Also post your mods

 

Did you break in the turbo?

 

What wastegate canister does your zft have and what is the pre-load? Also the stock bpv is fine, it doesnt use the spring to hold it closed.

Starting point would be a boost leak, the 6758 has no issue holding 30psi to 7,000rpm here in Denver so it should hold just fine in Utah. Then PM one of the tuners on here about a remote tune, the LNF ecu is a different beast

 

Your tuner should have zero issues with holding 19psi throughout the entire rev range. Even on the medium can, there should be little issues with holding close to 30psi or more by redline. Same thing goes for the bpv, there's zero issues with the system. You either have a mechanical issue, or your tuner stinks.

 

If anything the bpv spring is to tight, to much flutter and crappy sounds , I replaced it with forge. But ya either ur tuner sucks or u got a boost leak or something . Mine holds 28 psi all the way to redline. I got same waste gate canister u have

 

Leak

 

Mods: K&N SRI, Cat-less downpipe, Injen charge pipes, 3 BAR MAP sensors, full 3" exhaust, ZZP Intercooler, ZZP Billet Motor Mount, OTTP Trans Mounts. (Stock injectors) The turbo is the stock 6758 with the wastegate that comes from ZZP, didn't change a thing. Unsure whatever one that is. Tuning place is called FNP Tuned. As far as breaking it in, I didn't boost it before getting tuned.

 

6758 isn't stock. k04 is stock. do a boost leak test, and please, boost that thing to like 25 psi lol 19 is a waste.

 

Its only to 19 since we don't know what's wrong, and it was set to that during the dyno pulls for tuning purposes. Trust me, I'm having it set to 27/28 when I find the problem haha.

 

Pretty sure you tuner has no idea how the LNF ecu functions

 

ya this question should answer what the issue is, has ur tuner tuned a lot of lnfs or is this his first?

 

If your tuner is saying it's the BPV spring causing the boost to drop off I suggest finding a more competent tuner as quickly as possible.

 

He has before which is why it's puzzling me..

 

If remote tune is what I need to do, then it's what I'll do. I'm sure there is nothing wrong with the turbo. The tuner has done a few LNF's before, but not a lot of them. I checked the Tuning Sticky and only found one here in Utah, do any of you guys know of others or would a remote tune be better?

 

Terminator2

 

I'll send him a message and see what we can do. So apparently the tuner is the problem here guys. Not changing anything with the turbo. He thinks it won't make more power above 24 PSI. Definitely going with someone else.

 

Hell the fun doesnt even start until 24psi. Are you sure he knows you have an aftermarket turbo?

 

Yeah I told him its the 6758 but I'm not going back there. He even looked at it and saw it. There's a local shop here that mainly does GM vehicles and who I went to for the stock K04 tune.

 

That's what I'm doing, don't worry on that.

 

Leave and never return. If they don't understand a EFR compressor map they should not be tuning turbo engines.

 

I would go back and ask him to take the tune off and ask for a refund lol. At least a partial refund.

 

Never going back there guys. Thanks for he help/insight.

 

120% tuner problem. One simple table is all that needs to be tweaked and done.