Corksport turbo as stock replacement
 

Alright, I drove this 3 off the lot at 9:00AM on November 9, 2006. Bought the thing for my wife and developed a love affair with it shortly thereafter (don't tell my MR2). It's been very reliable, never left either of us stranded. Absolutely LOVE this car! With that said, it is starting to have a few minor issues, namely, turbo issues. I've been looking around for a good replacement for the stock turbo that has the oil issues ironed out, found the Corksport turbo. Question is, How will it do as a stock replacement? Anybody here have unbiased feedback on the subject?

Thanks for any feedback.

the corksport turbo is good especially for the price however it has had some problems with boost creeping at higher boost levels so make sure you port the wastegate if you are planning on running higher boost levels.

Some people have chased this problem and have gotten very annoyed with it.

If you are just using it as a stock replacement ive heard nothing but good things personally.

They are on the cheaper side so don't expect it to last as long as a garrett turbo or anything like that but it should give you 50,000 trouble free miles easily.

Get BNR S1. The Corksport (CST4 i'm assuming) is a great option for stock replacement if you plan on adding some power in the future. You will need a tune to safely run the Corksport turbo. But a good stock replacement turbo with the oil problems fixed; BNR S1. You don't even need a tune for it.

The Corksport CST4 turbo doesn't creep at high boost. It creeps at high flow.

Thanks much for the feedback! I'll look into the BNR turbo for sure.

I have the Corksport and it is an awesome turbo. I run an E30 tune and full E85 at times. BUT. The dynamics of the car will change noticeably. There is a noticeable difference is spool up and low end, kick you in the ass feel of the stock ko4. You essentially need to drive at a higher rpm to get some of the zoom zoom back.

The endless power all the way to redline more than makes up for the loss down low but I have serious buyers remorse all the way to 3400 rpm then it’s goooooone and before I can say “shift” I’m bouncing off the rev limiter.

With a stock bottom end, you don't want the kick in the ass spool of a K04.

But with my built bottom end, I can hit 20psi by 3000 with the CS turbo and not worry about bending rods.

Do you have upgraded manifolds ? My tuner was unable to do that even with a full 3” exhaust and intake.

With the stock ko4 I hit 18psi by 2400 and 23psi by 2800 on E85.... That’s a noticeable spool difference. I tried my hardest to bend rods but either the wheels spun Or IF I had enough traction in 4th the clutch would slip. Smells like dead burnt fish crap. I was probably over 400ftlbs at 2500rpm based on people saying the stock clutch is only good for 400 and some Virtual Dyno runs.

I still don’t believe the whole power bends rods with these cars. 1st-4th just spun wheels with to much power. Never did it in it in 5th or 6th. on purpose at least.

Ok, I'm not looking for a ton of power, wouldn't mind a bit more though. Currently I have the Mazdaspeed CAI, actually came on the car when I bought it, and the upgraded HPFP offered through COBB. Not really going to do much, I live in Cali and the idiots here like to suppress anything that deals with cars. Y'know cars are the Devil's toys.

So, I have to ask, who has experience with the recommended DNR turbos?

Looking for comparisons here. Any input?

@jakeypoo, you are not trying hard enough, you can throw rods at stock power levels let alone upgrading stuff. Floor it at 1500 rpm a few times and report back.

@zmmzmm3 I have the now named CST4 and I like it, maybe in the future if I get more retarded I'll replace it with either a bigger CS or something else but for now its doing its job well.

ZMMZMM3 It really depend what you are looking for.

The CS claim stock replacement because it is some kind of bolt on because it house larger wheels on stock frame. But it is a larger turbo than stock and that need supporting mods. If you don't plan for it, you shouldn't get that expecting to run on other factory parts...
This would be a S1 instead.

Dont miss that boost reading is a reading of engine restriction not about power. With larger turbo and open exaust, you make more power at lower boost level....Look at your g/s reading instead...when this rise, you are making more power....

And keep in mind an awd 6 would give more load to rise boost than a spinning 3....just compare the boost rise in 3 vs 4th gears....

If you don't believe bent rods, it is probably because you didn't get it for long enough....You can read about LSPI...This is the problem of all kind of new engines....small turbo and a lot of torque. It may still last but you need low BAT and enough octane or the knock will vent the bloc.

Been there done that. Been doing it since I bought the car. It was fun doing that when I had the stock turbo but now it just lags till the boost starts building. Over 150,000 miles. I did it 10 times during my test drive.

Damn I hope I didn’t just jinks myself.

I still love the Corksport. But I just wish I had known that it would feel so much different. Once I learned to drive over 3000 instead of 2000 I was much happier. But I do miss the down low diesel type torque of the ko4.

The BNR S1 is what you want. It is true plug and play, everything is in the right place, oil lines, water lines, vacuum and boost lines, flanges - everything.

That is because it uses a K04 outer shell, but modified internally for a Garrett GT28 guts. The journals and seals are GT28 size and design.

It requires no tuning change - the flow, both on the impeller and compressor side is identical to the K04.

Ask me how I know, having gone through two K04 replacements before setting on the BNR S1. This solves the problem. They just don't smoke.

BNR makes several stage upgrades. You want the basic S1. The others require tuning and in most cases, upgraded hardware.

Jeff23. I’ve known that name for a long time. I agree with the awd fact you mention. I also agree that LSPI is a pita and will bend rods and blow holes in blocks. But lspi can happen at 263 hp or 500hp. My assumptions and opinions are based virtual dyno graphs and not psi. Probably not the best source. But good enough.

Most importantly I don’t agree that the Corksport is a replacement for the ko4. Its a different beast. I nice one but different.

I still have stock intake and exhaust manifolds. If I can remember tonight, I'll post an old datalog. I believe I was making 20psi by 3000 when the weather was cold. It's harder to do when it warms up.

Just my opinion but these are not the cars you want if you like to lug the engine down and/or have low end torque...

We both agree on that too. Not sure if my sentence was confusing but i was trying to say the same...Someone with a factory car that just want a factory replacement turbo shouldn't buy the CS but a BNR S1

Did you mean BNR turbos? If so, yes. I solved my smoking turbo problems with the BNR S1. K04 on the outside, Garrett GT28 on the inside. Much beefier journals and seals. Identical flow as stock. Plug and play. After two failed smoking K04's I was not going to keep doing the same thing (definition of insanity). If you are satisfied with the potential of the K04 with compatible mods, it will take you up to the limit, about 300-310 whp on pump gas, maybe 320-330 max if you run ethanol blends with the right mods and tune.

In case I forgot to say it, its not cheap, but not more than buying a new K04 from Mazda . . . and it will not smoke.

Sounds like the BNR S1 would be a better choice. I might do as much as a couple of bolt-ons in the future. My main concern is the smoking turbo, California smog program y'know. I have been happy with the car, it's a blast! If anything gets done in the future it'll be a rebuild. I might install an ethanol injection plate/spacer plate after the TB. That would mostly be for a cleaning charge into the intake.

I would say that if you are looking for the same power, and just more reliable then go for the s1. My opinion is your having to break everything down and pull that SoB out of your car. I would say put a bigger turbo, like the CS, thats the one I have, and get a mild tune. I just dont like having to pull the thang off and have to deal with all that trouble. The BNR s1 is like $950, the CST4 is $1000 plus a couple of supporting mods like boost solenoid, bar map that is free with the turbo. Your going to all that trouble of pulling it out, might as well upgrade and be done with it.

Getting what he needs (BNR S1) now will save him so much money later because getting a CST4 will open up a rabbit hole of mods.

$350 for the HPFP internals and $130 boost solenoid, and $200 for E tune. I agree, if money is really tight then might not want to do that. I guess it depends on what you are looking to do in the future.

What he "needs" is a BNR s1. Everything else is cool but would be considered a "want"

You are correct. He said that he would be looking for a bit more power, so my argument was if your getting in there and switching the turbo out, go ahead and do it all while your in there.

Yeah, just a stock replacement. As much fun as it is to mod the engine, I'm getting to the point where I just want to cruise anymore. Hell , I might be the oldest guy on this site, anyone here older than 55? Old and broken, more broken than old though. I'm even thinking of letting go of my '87 MR2 and getting rid of my 4X4 cause I can't handle getting beat like that any more. I've had my fun.

Really! As of late I've enjoyed driving my wife's '97 E36, soft suspension, slushbox, anemic power, HEATED seats, great for a bad back, old fart car. Although my opinion is the E36 is the best looking 3 series BMW has made, it was the worst.

To be honest with ya, if I would have known about the bnr s1 as complete stock upgrade, with no issues, just without the smoking, I probably would have done that. After ripping out two turbos though, I said I wasnt going to do it again, and got in there for hopefully the final time for my car.

Theres something you dont hear everyday. I dont think Ive ever heard anyone say they prefer the looks of the e36. I love e46s, e30s and of course e92 but the e36 never did anything for me.

never been a huge 3 series fan, looks-wise, but the e46 was probably my favorite. Just wish the had sold the F20 in the US. One of my favorite BMWs ever! Great looking, the size of an MS3 with an easy to tune I6, Bi-Turbo, & RWD. :biggthumpup:

Like I said, my opinion. Some people think the AMC pacer is the best looking car out there.....

E36 with some sort of appearance package looks pretty good to me, but my favorite 3 series look is E46.

I like the E36 for it's smoother lines. I think it was the last model before they started looking like the designers used CAD to design the body.

Uh, I'm 69 years old. I bought my '08 Speed 3 new in the Spring of that year. I was 58 years old then! The need for speed has no age limit. At a new car price of under $25,000 it was the greatest performance value on the planet.

I just sold my well-maintained Speed 3 in January to another board member here. I had one vehicle too many and one had to go. I could not maintain the full size Armada SUV for towing my boat, the Volvo XC-90 for the wife, my new Audi Q5 (supercharged variant) and the Mazda. I do all my own wrenching and maintenance.

I hated to see it go, but the Audi is actually quicker in a straight line, even with just a larger bolt on crank pulley, ECU and TCU tune than was the Mazda. And it has all the creature comforts (but at over twice the price). Knocks off mid 12's in the quarter just by pushing the go pedal to the floor, letting it shift and keeping it in its lane. I'm about to increase that pulley ratio and get it retuned and should drop into the high 11's with no other changes. AWD 0-60 is amazing - 4.2 seconds now and probably 3.9 soon.

I do miss the agility of the Mazda, though. The Audi is an AWD midsized SUV, much higher center of gravity, and weighs a very porky 4,400 pounds. I admit to bias, but I do think that Audi has won the styling/beauty contest with BMW in recent years.

I still hang out here, just to try to share what I hopefully learned from 10 years of ownership and the help of some really wise and experienced members here. I'm trying to pay back for that great help over the years.

69? I don't feel so alone now. I've had one Audi in my live, 5 cylinder turbo S4. It was a monster, tuned out to over 600 at the wheels. The offer was too good to keep the car!

I do all my wrenching too. But with all the injuries and abuse my body has endured I'm slower at repairing my car than continental drift. Took 2 weeks to change the timing chain in my 3. Main reason for not doing a lot of mods, and looking for a replacement part that won't need to be worked on sooner than not.

OP, what turbo did you end up getting? How do you like it? It's time to switch out my K04 and I'm leaning towards the CST4 or BNR S1/S2. S2 is disconnected but I still find it online.

Looking for the most affordable Turbo option because I'm getting an AP and full tune along with it.

BNR S3 is a closer match to CST4.
I wouldn't bother with the S1 or S2 if you are going with a custom tune.

Need a turbo requires the least supporting mods possible because I'm doing some work on my home and need to prioritize my $$. Figured S1/S2 with AP+Tune would give me what I want. Just installed hpfp & CS TIP yesterday which is how I noticed my K04 is shot.

I'm nervouse about the CS turbo because of what I have read and I think S3 requires a couple of other mods I dont think I can afford now.

I believe the only "extra" mod for the S3 vs the CST4 is the intake.
Since you "just installed" a CS TIP, you may be able to sell it as almost new and put that towards an intake for the S3. If you would prefer the S3 over the CST4.

I've have put almost 2 years of service on my CST4 and was pushing 26-28PSI for the last 6 months.

What other mods are you thinking of?

With either turbo, the minimalist approach would be adding a 3-port EBCS for better boost control. With a conservative tune you can run the stock downpipe although I do recommend running a test pipe (secondary cat delete).
S3 does have a slightly larger compressor inlet. Aftermarket intakes will fit but it will be a tight squeeze. With the CS TIP you can easily change the coupler.

You would need a tune and a compatible intake but everything else really depend on how far you want to push the new turbo. You could even run a 600hp turbo dialed down to 350 but you would'nt like the useless added lag that came with it.
I think you should consider a BNR-s3/CST4 and just tune it for the mods you have and this way, it will last longer than a tiny one pushed beyond the limits like the k04...