Bottom line up front: Know what you are buying. This turbo will not hold up to motorsport or fast road use. It is made of cheap Chinese components, sometimes in a used BorgWarner housing, sometimes in a cheap Chinese housing.

I have been a customer of Mario’s for a few years now. He is a super nice guy, but he misses some marks on the technical side of things. When I initially contacted him my car was pretty stock. Muffler delete, cat-less downpipe, intake, and an intercooler. Since the car was my daily, we decided stage 2 would be ideal. He sold me Manic Stage 2 with an SPS and took my NM Performance Module in return. He was super helpful and even though USPS lost my DME for a few days, everything went well. Things went so well, that I ordered his downpipe to replace the cheap CNT downpipe I had been using.

A little over a year later, I decided that I wanted more. I had begun tracking the car and found the S turbo just could not perform above 5500 RPM. I reached out to Mario to talk turbos and tunes. He recommend the “43mm Quick Spool” because “all of the track guys like it”. I made it very clear that the turbo would see a lot of track time and that it needs to work. He assured me that it would be fine and that I’d be happy with it. By this time Manic was closing its doors, so he recommended RPM Power. He said that I could retain the SPS and we could load multiple maps to the RPM tune in the same way that Manic had multiple maps. He also recommended ARP connecting rod bolts. This seemed like a no-brainer, so I added those to the order.

This time the DME arrive safely. The turbo swap and rod bolts were straightforward, and he was available via text for any questions I had. There was one issue, however. Despite the fact that I paid for a new turbo, I received a used Borg Warner. I assumed that he installed new components in a used housing, which makes sense except that I paid for a new turbo. I let this go. It didn’t really matter at the time.

The first test run with the turbo had two issues. The turbo was hitting 27 psi, and the map switching function didn’t work. When I switched maps, the car sputtered and died like it wasn’t getting fuel. While the map switching issue is an inconvenience, the over-boost to 27 psi is deadly to my motor. Had I not installed a mechanical boos gauge, I would have never known. My Scanguage was reading 22.5, while the real gauge was showing 27. I have beaten this into the ground on this forum and on Facebook: get a mechanical boost gauge!

Mario’s instructed me to adjust the wastegate until I reached the correct boost. As you can imagine, there was a lot of trial and error here. After the boost was sorted I had to send the DME back to him to correct the “tune”. He replaced the mapping function, so I lost the option. (Did I mention that I paid full price for Manic Stage 2 and then Had to pay full price (stage 1 to 3) for RPM Power? That’s not his fault, Manic did that to themselves, but it still sucked.)

Third times the charm I guess, when I got my DME back everything was great, and it was just in time for a track weekend. Needless to say, the car was like night and day. The 43mm turbo was awesome, had a ton of power and pulled all the way to redline at 6800 RPM. Well, at least on the first day it did. On the second day, I notice the turbo was not hitting 22 psi and it felt and looked like it was spooling slowly. It would max out at around 18 psi, and I had to be above 4000 RPM to get it to spool in a reasonable manner.

When I got home after the track weekend, I reached out to Mario to let him know how happy I was and to get his advice on the boost issue. This would be the first of many times that I would hear him ask “have you checked the diverter valve?” Well, he was right, I had a bad diverter valve. He sent me the updated one and everything was good to go again. For about a week. Then the same slow spool, low boost started again. I followed his advice and adjusted the wastegate. I also checked for boost leaks, because to be honest, that’s what it looked like. I replace the diverter with a new OEM diverter and then a Forge recirculating valve and then another new OEM valve. I replaced every hose clamp with t-bolt clamps. I replaced all of the fittings on my WMI system with compression fittings. I checked and rechecked everything. I spent countless hours wrenching and troubleshooting. He kept telling me to adjust the wastegate to reach the right boost, so I did. And finally, after nearly a year of this, the wastegate stopped sealing. That’s 8000 street miles and six track days.

When I contacted Mario about the failed wastegate, he was really understanding. I reached out to him as a courtesy to give him a heads up. I didn’t expect anything, and he certainly didn’t have to do anything. But he did. He sent me a new turbo as a replacement, and I sent the old one back to him. While waiting for the new turbo to arrive, I noticed something odd about the failed turbo. The wastegate actuator arm was noticeably longer than the arm on my sock turbo. Obviously, the arm was an incorrect part and was probably the source of my frustration.

The replacement turbo arrived in a matter of days; Mario was really quick with that. But there was another red flag. This turbo was brand new, but it had no markings. No casting marks, no data plate, no markings whatsoever. I didn’t really mind, Mario’s a standup guy, right? I went ahead and installed it along with new OEM hollow bolts, washers, studs, and gaskets. The first test drive was magical. 22 psi quickly and the car just pulled hard. I was ready to get back on track and really put it to the test.

About a month later we headed to Roebling Road Raceway. The turbo was great for the first day. By Sunday morning, I knew something was not right. The boost leak symptoms were back. So back to square one. Replace the Forge diverter valve with OEM. Checked for leaks, replaced a few rubber vacuum lines with a silicon tube. Checked the wastegate, no changes. And then I stumbled across a thread where another guy was having the same issues as me.

As it turns out, this is an issue with the turbine housing leaking boost pressure. Apparently, it is common with cheap Chinese turbos. At this point, I decided Mario was my problem. I bought a new OEM JCW turbo and decided to start over. Low and behold, zero boost leaks. Zero issues. It. Just. Works. I had a boost leak, I replaced a turbo and the boost leak is gone. Simple as that. I have taken his replacement turbo apart and it is gnarly. The turbine housing is very rough on the inside, it should be smooth. The “360 bearing” is a gated bearing, and I’m still not certain about the origin of the turbo, but my best guess puts it between eBay and Amazon.

That’s what you get for $1300. A $300 Chinese turbo. Thanks, Mario. I’m now in the process of getting the car re-tuned and buying a different downpipe. I want nothing to do with Mario or RPM.

 

The compressor housing looks like it could be smoother where the impeller sits... but, I’ve not seen the inside of a known quality housing.

Shaft bearings and washers look brand new still.

That turbine housing looks terrible for supposedly being a low mileage housing. Cheap iron casting?

 

Yeah, I should have included the photo with the magnet stuck to it. My issue with the bearings is that it is not a 360 bearing. For what it's worth, a friend showed me photos of his JMTC S42 and it had the same bearing. JMTC advertises this bearing as a 360-degree bearing when it clearly is not. And despite the like-new appearance of the internals, this turbo leaks boost pressure from somewhere.

 

To be fair, it's not really MarioKart, mQubed Motorsport fault.

Looks to me the turbo can be purchased from many places in USA/Canada off the shelves.

Also the price seems lower than many other hybrid turbos from Germany & UK.

Have you looked as the Owen developments turbos as that has pedigree in Motorsports or even the ones from Germany?

 

How is it not his fault? He sold the turbo and represented it as the turbo that he builds. When the first one failed he replaced it with this very inexpensive, poorly assembled turbo that failed a month later.

Owens would be a good choice, but I went with a plain JCW. If it fails I have FCP Euro's lifetime warranty to fall back on. At this point, I'm not chasing horsepower. I am the slowest part of this car, so I'll improve that aspect with more seat time.

 

I have this turbo myself. It was almost certainly rebuilt from a Cooper S turbo, same part number tag as the stock turbo I pulled off my car. The turbine housing is non-magnetic, so probably stock inconel.

When it arrived the bolts holding the compressor housing were loose, and the outlet on the compressor housing was dented slightly. I mentioned the former to Mario and he gave me the torque spec to tighten it myself, I didn't really care. Also had the typical wastegate adjustment issues. Turbo made 12psi max out of the box, had to adjust it and monitor boost to get it up to the proper 22psi. On a Manic Stage 3 tune as well, not RPM.

My turbo hasn't failed, granted my car is a daily driver that sees weekend mountain driving in the warmer weather. But just wanted to share my experience regarding this turbo and Mario.

 

Was that before or after you blew a hole in your block? Did you ever get an answer for why that happened? I think I asked you at the time and you said were using an OBD reader for a boost gauge.
For what it's worth, the first turbo he sent me was a rebuilt Cooper S. After that failed, apparently, he thought a cheap eBay was a suitable replacement for a track car.

 

Before. Installed the turbo Dec 2018/Jan 2019, tuned Jan 19th 2019 (not by Mario), blew up April 14th 2019. Still running DashCommand to monitor and log boost, which admittedly isn't the best way to do it but it's still better than nothing.

I honestly think I was just making too much power for for the stock engine and the rod bolts failed, which is the common weak point on these cars. I was hammering it on TOTD for 4 days straight prior to the engine blowing up. Plus being on a Manic tune with a dumbed down knock sensor (verified by another tuner) probably wasn't helping the situation. But I don't blame it on the the turbo.

 

I still wonder how much boost you were actually pushing, but I guess we'll never know. I hate that happened to you. The issue with Manic suppressing the knock sensor is criminal.

 

That's probably the point, the turbo wasn't suitable for track/race.

Have you checked over your car if it has any problems that can cause problems to the turbo?

Don't people replace many parts after one or two hard days track/race and expecting a cheap turbo to last is probably expecting too much.

I've used the OE JCW for normal daily driving and that lasted ~10 years & ~90K miles before I needed to replace it.

 

Did you blow your engine before or after you've installed the Aquamist?

 

I'm sure I've read this somewhere that this isn't done on the Manic maps.

 

I must have not been clear in the original post. I told Mario how I intended to use the turbo. I told him that the car would be used for track days. Mario assured me that this turbo was made for that and that his track-oriented customers love it. I paid around $1300 USD for it. The components and construction may have been cheap, but the price certainly was not.

Edited to add: This also doesn't address the wastegate issue on the first turbo he sent. Nothing on my car caused it, the turbo was faulty. Period. The wastegate had to continually be adjusted until it could not be adjusted anymore and the wastegate would no longer seal. This was done as per Mario's instructions and the turbo started to fail. Mind you, this turbo was hitting 27 psi with the wastegate actuator set to 151mm. That alone would have cost me a motor had I not been monitoring boost with a mechanical gauge.




I'm sure I read somewhere that it was? He even said his new tuner confirmed that this had been done.

 

Yeah, that doesn't look good. Not sure how long you've used that from new, but my 10 year old OE JCW turbo didn't look that bad when it got replaced.

 

Yes. This is a photo of the first turbo Mario sent me. This is his 43mm. It was "new" when I received it. I put a total of 8000 miles on it. Mostly street miles and six-track days.

The purpose of this thread was to consolidate know issues with Mario, mQuebed Motorsports, and JMTC. A lot of the problems I have encountered are buried in my build thread, I need to migrate the posts over to here.

 

After. Well, I blew it up once on manic Stage 2 with no meth, then more recently with Manic Stage 3 and meth.

Only heard from former Manic dealers that it isn't. But my new tuner confirmed that the knock sensor sensitivity was turned down on my Stage 3 map at least.

 

This whole thread is why I ended up with a Garrett. Had similar issues with people and there supposed good turbos....decided to just go the tried and true route.

 

I'm just so glad I went with Borg Warner's Airwerks turbo, which is a tad bigger than a stock JCW turbo. Inconel housing and superb quality. No wastegate issues, no leaks, holding boost strongly, and it is under manufacturer warranty. As you said, It just works and it cost me way less money. I was really hyped for the JMTC turbo (read as Mario Kart's custom 43mm turbo) and his RPM tune. I went with a custom tune, these RPM tunes are made and developed on a one test car and then flashed to every other car.e (thats what my tuner told me, 25+years of experience).

I dont want to go against Mario, he is a cool and friendly guy, If here or there are people running fine and are happy with RPM's tunes or these cheaply made turbos, good for you! Everybody has a choice.

 

Which Airwerks model?

 

Borg Warner JCW K03-2074D turbo (PN:5303-988-0146)

FCP Euro:
https://www.fcpeuro.com/products/min...er-11657583149

So far it spools quickly and holds boost to 6500 RPM.

I'll have it out at Roebling Road Raceway this weekend so we'll see how it holds up.

 

According to BW's glossy brochure, that is the upgraded version of the JCW turbo. The hot side is the same as previous Mini turbos. The compressor is a 41x51mm wheel. Pretty sure the first iteration used a 40x50mm wheel.

I would expect it to do quite well. I'm running the stock S turbo with an upgraded IC and an RPM stage 2 tune, and can usually maintain close to 21 psi to a little better than 6k. Roads and traffic have gotten in the way of a more complete "test". Car is a 2013 Hatch and is catless

 

Six hours on the track, broken up into 30-minute sessions. The Airweks turbo ran like new the entire weekend. Absolutely zero issues. Spools quickly and holds 22psi to around 6500 RPM. This is the first weekend I've had in quite a while that wasn't spent troubleshooting the turbo. It was really refreshing to just get out there and drive.