Look I'm just gonna get straight to the point. I've been looking forever for these exact numbers, but have been quite unsuccessful. From what I heard these engines are quite impressive, and don't need much work for a big turbo swap. I'm looking to make 450whp on 93 octane (highest local octane). Its not at max goal though, any higher number I'm fine with . So far my mod list is as followed: K&N cold air intake, ZZP intercooler kit w/ upgraded charge piping, MAF relocation, ZZP 50mm BOV, 22psi ZZP pretuned PCM, ZZP 3" catless down pipe, ZZP 3" cat-back exhaust w/ muffler, and a BPS short throw shifter. I'm set-up and ready to go for the ZFR turbo swap, how ever I want to make sure my car will hold up before hand. So my questions are simple, the closest numbers you guys know from testing. I'm looking for max hp/trq numbers on the stock driveline, bottom end, top end, fuel system, and tranny. If possible please answer in this format. Keep in mind this is max recommended hp/trq before upgrading certain parts (i.e. clutch, head, pistons)

1. Stock engine block/assembly (includes pistons, crank, rods, etc.): _____ hp _____ trq
2. Stock engine head assembly (includes cams, valve springs, head, etc.): _____ hp_____ trq
3. Stock fuel system (includes injectors, pump, etc.): _____ hp_____ trq
4. Stock driveline (includes clutch, tranny, axles, etc.): _____ hp _____ trq

I will retune the car and get the proper parts as necessary, I just want to know what people recommend to upgrade to safely push for 450whp goals Keep in mind all of this is being done to a 2009 cobalt ss sedan. Sleeper status? Sorry for all the questioning!

 

400whp/400wtq is the max safe numbers you can run, even at that, the tranny is suspect.
There are people with s256 turbos' and 500whp on stock motor, and tranny only lasted 3k miles....
Pistons are suspect after 400whp too

 

450whp isn't happening with the zfr on 93 unless you go unreasonably aggressive with the tune (WAY above your 22psi canned zzp tuned). I would personally be more worried about the trans though. Ask me how I know.. lol

 

See these are things I'd like to know. People are telling me I can do the zfr and only have to replaced the clutch and that I'll be fine on a good tune. I have all supporting mods so with the zfr I should make a decent amount of power. At least 400whp.

 

I am aware that the pistons are the only unforged part in the block which sickens me. Why have forged cranks, rods, etc but not pistons.

 

lol.... I'm telling you from experience, not guesses. I've tuned plenty of zfr's, including my own car. You won't hit 450whp on 93 octane without a silly aggressive tune or an extremely liberal dyno. Either way, trans is a ticking time bomb no matter how you dice it.

Forged pistons just aren't very realistic in a dd driven production car. Hypereutectic pistons allow for better piston ring sealing, expansion and less oil consumption.

 

I was looking at the p&p head swap with cams arp head studs on top of the turbo swap. I've never heard of tranny issues though, only the clutch. And good info on the pistons, interesting never knew that. Still upsets me though. Think a zfr on a mild tune will make 400whp on 93 octane?

 

And let's just say if I bought the zfr right now and got my car tuned. What else would you recommend me upgrading?

 

You never heard of any trans issues with the LNF? Do some more reading then my friend. Trust me, I actually just found out the hard way myself the other day. 3rd gear goes boom in the F35 trans pretty regularly with turbo upgrades, particularly in the LNF due to the taller final drive gearing that GM decided to use.

What's your idea of a "mild tune"?

 

I wouldn't really blame third gear or the tranny, yes they are weak, but it's also how u drive the car. I have over 100k on my tranny, but I also only go wot @4k or above. A lot of it is ur tune and ramped in boost. Just my two cents

 

K. Let's clarify this.

1. I put down 500whp on the s256et on the stock block. Yet you can blow your motor on the stock turbo. The pistons are good for over 400whp easily. The problem is detonation. The larger your turbo, the more boost you can run and the more power you can get. Also, the higher octane your fuel, the more timing you can run. Both these things dictate how much power you can make. It's a complicated relationship. You can detonate on the stock turbo. Bye bye motor. Detonation does not care that your car has shiny new parts. The stock pistons are hypereutic, and do not take well to knock. Forged pistons let you get away with more, that is all. IMO your stock block will take 470whp all day long, provided there is no detonation, and a few hits of 500whp. People say on 24psi is the limit. That is complete nonsense. On the stock turbo I say no more than 26psi. Road course tunes, I would say 22psi MAX. I say the jury is till out on big turbos. I screw around with my car just to see, and I put 30psi through it at stoich - just to see. Monitor detonation (KR) with an aerofoce interceptor. Some people have spent ten grand with a big company yet didn't have an aeroforce, yet blew something. Detonation kills.

2. The tranny will be the first thing to go. 400wtq will shatter your 3rd gear pack. People run way more than that on the stock turbo and yell they are fine. IMO it's not just the instant torque, it's how long the torque load is held over the power band. That is why a bigger turbo is lethal on a tranny, especially the zfr. I made 380 wtq from 4k all the way to almost 7. Way longer load period than the stock turbo. I have a 4.45 now, and it rips. 4th is way more lively, and the higher revs help a bigger turbo spool by keeping it in the rev range.

3. The fuel system will provide 500whp and 450lb ft on gas ie. race gas. e85 your numbers will decline. I find that every car is different. There are cars that can't handle it, and there are others that can. The fuel system is cam driven, and the higher your revs, the more your fuel system can keep up. ZFRs are hard on the stock fuel sytem.

4. The stock clutch is hit and miss as well. My stock clutch took 434wtq before it failed. Others can't get beyond 360wtq. IMO, upgrade it.

5. Ported heads do very little on the LNF. The ported head has to be designed a certain way to allow proper air delivery as the pistons are bowl shaped. Port the head too much and you lose power. IMO stick with the stock head as ported heads are expensive and go bigger on the turbo.

6. Upgrade your valvesprings with a big turbo, period. The higher you rev, the more power you make generally. If you miss a shift without valvesprings, kiss some stuff goodbye in your head. Fuel cut off should be 7400 as you can't rev higher safely yet because of the cam phasers. Some rev to 8k. I wouldn't.

Before you blow anything - IMO A 5858/5857 or s256et is your best bet for safe 450whp. For 400whp the ZFR/s252et. I'm not a fan of the 5557. Too small. Or the BNR. Why go small and laggy - makes no sense. You get what you pay for. Sell your stock trans for dough or upgrade it before it fails. Having one fail, (mine did), and upgrading it after will cost you way more money. And get a stock fuel cam with fuel loeb from ZZP. (Only 199)

Last but not least - Pick your tuner wisely. 09CobaltSS1, Term2, Cobaltssoverbooster, SSKev, ZZP, Area47, T-Man and Iam Broke are all good (if they all still tune)

Good luck.

 

Better said ^ especially pick ur tuner wisely

 

Thank you! I wanted to push roughly 23-24psi and was mainly interested in zfr due to the easiness of installation and the price. I was going to get stage 1 cams instead of the head and upgrade my valve springs w/ titanium ones. I do however want arp head studs but I'll wait on them incase I ever decide to rebuild the block. I'm gonna do the clutch and flywheel at the same time. Any word on the f40 6 speed swap? How's that tranny? Anyone like the 6 speed? Will it work with my bps shifter?

 

Bump for more info! And opinions!

 

Like everyone says...many LNF's stand the 400whp easily...some are around 500whp...on the engine is mainly the abuse you give it. Tranny is the weak link!...I'm at 420whp...1 year and counting...my combo is a BNR/meth but I don't really abuse my car...only once or twice a month...mainly no dig racing...mostly roll racing...Tranny is next upgrade on list. Also I'm using lsj's LSD (4.05) as it helps the tranny stand to the power. Most of all tune wisely!!

 

I know that Omiotek was running 442whp/450wtq on the 5557 with stock motor and he never had any issues with it.

 

Reaver pretty much nailed it.

Another testimonial of the integrity of the LNF. My friend's LNF with a 5557 on 23 lbs made 430whp for 2 years on an E blend. He got cams and springs and went E85 and 26 lbs and made 476whp all year. He is now on an s259et and going strong. Only thing that happened to him was last year about this time the trans gave out, so he went with the 4.45.

Another friend made 420whp/410tq on the zfr and E47 maxing the fuel system by 5900 rpms. Has a 5857 now and on E30 and 23 lbs. He knows to be ready for the trans to go to lunch though.

 

Emissions believe it on not. Stock pistons only require .0015 wall clearance whereas forged require .003 or more.

 

Many INF owners got new engines because of the foam cast crap block leaking coolant into the oil.

 

LDK + 6spd tranny.

 

I like my engine though I don't wanna swap her.

 

Like infra said im on 476 give or take a little since i swapped to a zzp kit and 259et. My trans randomly went out one day driving lost 3rd and 4th just cruising but i was on over 400HP for over a year or two. As of now ive been running over 400hp for 2 years and still luckily no issues...Well im probably screwed now that i said that haha

 

MORAL OF THE STORY, GET A 4.05 0r 4.45 TRANS AND PISTONS BEFORE THE TURBO UPGRADE. Not a fun way to do things, but saves the heartache later.

 

No. Get the trans. Yes. Run your stock Gen 2 lnf till it blows and replace with Gen 3 LDK. You don't need pistons for 450whp. Save your money.

 

LDK is a direct drop in right? No tuning i mean stock for stock