Which one would be better? Ideally I want 400/400. Which I know the 6758 can get on pump. Also is the Z57 a good option at all?

 

The efr is top notch. It's more expensive because it's a ball bearing turbo verses the z54. If you have the money go 6758. If you want even more power potential you can also use the 7163. But it's harder to fit because it's slightly bigger than the 6758.

 

thank you! Yeah makes sense. I’m definitely leaning towards the 6758 just for the nice power band, quick spool and it will make the car a nice and enjoyable DD. I would run the 7163 if I had E available to me. 7163 definitely is appealing but if I’m gonna be on pump 6758 is fine for 400whp.

 

If you want simplicity, 400whp, and long-term reliability... go with the Z54. Journal bearing turbos are great for a handful of reasons, with longevity being at the top of the list. This isn't the 80's/90's anymore; journal bearing turbos have really good spool characteristics these days. And if anything, the slight delay you will experience compared to the EFR will help save your transmission.

I say this as someone that spent almost $2000 on a cutting edge, best-of-the-best turbo about a decade ago... you really don't need all that extra fanciness. Get the Z54 and spend that extra $700+ on supporting mods... or a spare transmission.

I guarantee you that you will not be upset with the Z54.

 

Fair enough. Good explanation. Though sounds like people have had problems with Z54. So I’ll pass. Also talking to my tuner he stated that Z54 is junk. EFR 6758 is probably the best bet. Just will need a boost ramp to spare the trans.

 

If you over spin any turbo its going to die. These turbos that have been dying are likely related to to high of wheel speeds shredding the bearings.

I think the z54 suffered similar fate as the gen1 efr, people just slapping them on and going full send without thinking about the possibility of to high of wheel speed or hitting surge lines

 

Do you think the Z54 can achieve 400whp on pump? I am figuring out which turbo to upgrade to I want around 325-350whp on a conservative tune.

 

I've never seen dyno numbers on it for pump gas. I've seen a dozen or so in the low 400's with various ethanol mixes though. ZZP claims they made 480whp with it on E85.

If you want mid-300's, it'd be perfect IMO. That's what I was considering it for... mid 300whp range.

 

Unreal thank you for your reply! And is there anything to keep in mind to make sure it stays reliable?

 

The Gen 2 LNF is reliable to 450-500WHP on stock bottom end. Maintenance is always a huge part in reliability and also not having a shitty tune. Also make sure it has Oil in the turbo before you fire it up. Trans is a weak part in these cars so look out for that. No full throttling below 3k or even 3500

 

Good to know! I've done pretty well so far for 9 years of ownership haha

 

For those who have the Z54 I am finally going to be installing it in a week or so but have been hesitant due to ppl telling me about the failures happening. Are you guys still running it and how is it holding up?

 

2k+ on the Z54 and no issues so far! It has been 50/50 WOT pulls and highway cruising but I make sure she's been getting used!

Been pulling on a bunch of Type R's, Vettes, and Camaro SS. I'll update some more but it seems I got one of the good Z54s! Fingers crossed, knock on wood!

 

Hey man, that’s good to hear well it is a sub 50lb/min airflow turbo. So it does support quite a bit more than the stock k04.

With my previous cobalt I ended up getting a EFR6758 used with 10k miles and it worked beautifully. They are probably among the best and most reliable turbos. BW Products are definitely top notch. In my most recent car I was running a EFR7163. Also an amazing turbo.

I hesitated to run a Z54 or Z57 because of the reliability issues. Though I’m sure ZZP have revised them since that time and probably are more durable than before. Z54 is just a journal bearing version of the EFR6758 and a inconel turbine wheel.

In another thread I was thinking of running a Modified S257 with a SXE362 compressor wheel.

But I have since shifted that plan and want to run a EFR8370. EFR, Airwerks divisions of BW are absolutely incredible products. I definitely recommend running a BW turbo if you decide to change it up at all. If you are interested in info I don’t mind at all sharing.

 

Oh yeah for sure bro. 7163 or S256 is next. I just had some extra cash around and figured they should have sorted out the issues with the Z54 by now and bit the bullet and so far so good. I plan on running the Z54 while I get all my parts for my head work...let's see if it holds up until then haha but I ok not put 2k+ on it so time will tell..I just wanted to keep ppl in the loop since there wasn't much consistency IMO on info with the Z54

 

don’t get the SX256 it’s outdated and the SXE257 spools quicker and makes more power. The compressor wheel and turbine wheel design is improved over the SX line. EFR7163 imo is the best if you are looking for fast spool and a higher airflow capable turbo. You can hit 500WHP+ on E with the EFR7163. Also it’s bolt on. SXE257 is probably the best if you are looking for bigger power like 550WHP+

 

ah **** damn autocorrect hahah I ment 257. I am just waiting for Black Friday to see what ZZP/OTTP has going on for sale. I wanna go 7163 but I've been seeing some failure post on FB lately so kinda been bouncing back and forth on wth I wanna do. The Z54 has been good to me so far, so let's hope it continues lol

 

EFR7163 is extremely unlikely to fail unless contaminated oil or improper install due to the aluminum core. I have not see ANY posts of EFR7163 failures across many platforms. Unless you are referring to the ZZP 7163 aka Z57 which has had many failures. Ball Bearing turbos are far more durable particularly BW Turbos. EFR is a genuine BW product. ZZP Turbos are knock offs, you get what you pay for. It’s alright if you don’t know man.

 

I’m among the the failed z54s
had about 10k km on it. Basically the shaft was sliding 1/4 inch side to side and Coolant and oil started coming out my exhaust when moving it by hand.
I have the latest revision coming this week. I sorta had the first revised version with my other one. Version 1.5 if you will.
apparently this has a lighter stronger center and revised wastegate. And some “optimizations” over the old. Hopefully she holds up.
It failed on my dyno day afte running mostly trouble free for two years (ther was a bit of smoke later on and occasionally lag feeling near the end. Obvious why now…
so anyway it put down 287whp and was only boosting 16psi
didn’t realize it was underboosting so I was lost why it was so low. Didn’t notice for two more pulls. Ended up getting up to 18 psi and put down 310 whp.
I normally run 26spike to 24-25 at redline.
So I can only guess what I would have made if it hadn’t crapped out.

 

Waste gate rods have been snapping on the 7163. Nowhere near as many instances as the Z series turbos but still weak for a 2k+ turbo. Hop on FB my guy.

I've been working on these cars since 2008 brother, I was one of the first LSJs back in the early 2000s on E85 tuned by Vince.

 

Almost 5k miles on my Z54 with NO issues. Gaping cars left and right. 🙌🤙

 

EFR is the only way to go IMO. as said above you get what you pay for and failures for both have been documented with alot more on one side. Just what ive read as I dont have skin in the game for either.

 

Hopefully it lasts!