Z54 or Z57
 

What are you guys running and how has it been for you? How long have you had it for? Can't decide if I want to spend the extra on the Z57 if I am only looking to add a bit of horsepower + replace my original k04.

Bumpiddybumpbump. I have the same dilemma. For those that know let us know!

Aftershok read the reviews here. It seems like its a bit more of a tight fit but other than that everybody seems very impressed with the added hp and trq. Honestly I say go for it brotha. It will take your car to the next level.

https://zzperformance.com/collection.../zzp-z57-turbo

sweeeeeeeeet:guns:! Thanks Monie5gt for the response. I've done a bit of research. & I think the Z54 is The Waaaaaaaaaay for the power I'm looking for. Kind of want to wait & hear about the reliability. I know they started off with problems but so far it seems that they tightened up all the loose ends. Ya an affordable efr is all I can ask for the price. Like I said though kinda on hold for reliability posts. Ya I read the zzp ecotec turbo descriptions everyday! My car feels stout and reliable right now with no problems @ 180,xxx. I just trying not to make an impulse buy. I'm very good @ those when it comes to boost:lol:.

lol yeah I feel you bro. Its one of those things where you gotta make sure its the right choice and make sure your wallet isn't completely empty afterwards and have to eat KD for months lol. Before I decided to boost my ride I was on te fence because of the cost. But at the same time if you want to do it right you have to get the right parts and most times they are not cheap. Glad I could help at least most people on these forums are really helpful. Great thing about the ecotec platform is its been out for a long time so you can get know how much these engines can handle.

been running my z54 for two seasons now. Haven’t had any issues related to the turbo. Very significant power gains over the k04 and less boost lag than I would have suspected. I’m running 25 psi on 94oct tune. Haven’t made it to the dyno yet but numbers suggest I should be around 380whp.
this turbo does have some lag but what doesn’t compared to the k04.
unless you have power goals over 400whp I wouldnt go z57 and give up the responsiveness.

maybe I miss interpreted what you said but these aren’t efr turbos.

Right on Monie5gt I completely agree with you. I feel super lucky to have the car I do in the shape it's in with this much knowledge/ upgrades for the platform. There's always more mods man:twothumbs. I definitely want this done right the first time & I know now it's z54 time!

Thanks for chiming in slapbetcommissioner! I appreciate the review on the z54 turbo. Would you happen to know what rpm full spool sings @? You didn't misinterpret me I got it wrong. Z54 is not an efr. Thanks for clarifying:r:. These cars sure are allot of fun. I can't wait to upgrade.

Boost seems to start coming on somewhere high 2k rpms. Which isn’t bad at al. But noticeable compared to the stock. Not that I recommend hammering on any turbo car under 4K rpm hard on the driveline. But in a more daily driver way its a little more noticeable not having the low low torque 🤷🏻‍♂️.
I have no experience with the z74 but it must spool slower. Unless you have big power goals down the road just run cheap fun responsive.
if money is no object get the zfr6758 and give up almost no lag with even more power potential.0

awesome im glad to read that you are enjoying it! do you run your cobalt all year round? I am tempted to get the z54 because I don't want that much power for the z57. I just want whichever will be most reliable long term with a conservative tune.

The zfr7163 actually spools faster than the 6758 surprisingly, the 7163 gets the fancier tech for exhaust wheel.

The z57 spools pretty damn quick for what it is. I haven't pushed how quick it can spool as I'm trying to keep my transmission together. It just keeps pulling all the way through 7,000 rpm, I didn't get around the getting the tune completely dialed in before the snow came and winter tires went on so there still some room to gain. I'm sitting at 18-19psi (still need to dial the cams in) and flowing the same air as my KO4+ was at 26-28psi on a dialed in tune. I have no doubt I'll be able to be over 400whp and not have to break 24psi

Wow eh and how long have you been running it for?

Since August, I've put about 4,000 miles on it.

That's good to know! And you will run it at 24psi? Do you have the mods in your sig or do you have more?

My sig is waaayyyy outdated :lol:

I'm running zzp stg2 cams, zzp 78# valve springs,opels, zzp intake, zzp intercooler, zzp hotside, catless dp

I'll probably run it at 24psi in 3rd and 4th gear above 5500 rpm since I rev out to 7000, but only on my summer tune. Assuming nothing bad happens to the engine this spring while turning everything up (still on the stock LNF block with 145k miles), I have another car I can DD if my cobalt goes down so I'm not super worried.

lol I had thought so damn ok you are around the same miles that i have (200k kms which is around 125k miles?) wihich makes me happy to know im not too late adding a bigger turbo to my DD :D

Last question would be your thoughts compared to the stock turbo so far? Since you are running around the same PSI as a GMS1 tune would.

You know how the stock turbo likes to fall on it's face around 5500ish rpms? It doesn't, just straight pull through 7000rpms. Seems way faster with pulling all the way through 7000rpms, the boost build post shift is certainly a little slower. I'd need to dig up some old logs and I can see how long it takes to regain boost after a shift. You def won't regret going larger turbo, you generate less heat and therefore less stress on the engine at lower boost levels.

Unreal thank you so much for your replies! Ya right now my stock turbo is at 22-23 psi so if I can build more power and run it around there 23-24psi that would be awesome. Do you recommend the springs then to be able to run to 7000 rpm?

Oh yeah, you'll probably have valve float otherwise or might break a spring reving that high

Ah thought so! So stock can go around 6500? Would that be still worth the z57 over the z54? not sure if I wanna do anything internally yet to my stock engine which is why I wont push it past what it can handle reliably.

I'd say you could get away with 6500, but I have no idea how long things would last. The valve springs are relatively inexpensive and can be done with the head still installed.

If you're trying to keep the budget tight, I'd get the z54 and the valve springs. If you have a little more leeway, I'd go with the z57 and valve springs (extra US$500)

Are the springs hard to install with the head on?

I guess my main question should have been what is the difference between the two z57 and z54? I am looking for reliability as top priority so if the Z54 can be kept reliable and it just means less power then I am ok with that. If the Z57 is a noticeable improvement and more reliable then I will save up for that! I am currently pleased with how my car is tuned so I know I won't be looking for much power increases. Also dont want to over spend haha

You're going to need a new tune on either of the tubros.

If you have the GM spring compressor tool it's not bad, just connect an airline into the cylinder spark plug hole (make sure all valves are closed) pressurize, push the retainer down, remove locks, let spring extend. Grab next spring place, compress, reinstall locks, gently let retainer lock into the locks. I think the whole process took me about 2-3 hours. I was going slow and making sure the lifters stayed in the same positions (moving cams over from another head).

Yes i will be getting re tuned since I will be installing a bunch of parts at once (new clutch, ic) and also gettin my valves cleaned finally

Not trying to argue as most of my info is outdated. when I got my zfr6758 the 7160 wasn’t even out yet. When guys first started putting 7160 on they all had the same statements about the power curve and that was you don’t need to ramp boost with it as it doesn’t come on as low and hard Unlike the trans killer 6758. Perhaps people have made this quicker with tuning in later years? It doesn’t make sense to me it that it would spool faster but I’m willing to listen in that regard.
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not saying he z57 would be slow or anything but with power goals in mind faster is better for a nice low torque curve is all since peak power isn’t the goal. Biggest thing I noticed with the z54 was exactly what you were saying about making power right to redline. Very nice to hit 6500rpm and feel like there still more room up top with springs and possibly cams.

I don’t run it all year around. Haven’t for 7-8 years now. I e put about 15000km on the current setup. Only issue I’ve had was my throttle body dieing which wasn’t likely turbo related hah. Never removed or cleaned since new. Surprisingly wasn’t even dirty.