How to make Turbonetics ST more reliable?
 

Hey all,

I have purchased an 03 Z w/53k miles. ~5k on the turbonetics kit. Other power mods are 5/16" MD spacer, nismo catback. It is still running the stock TN reflash. It does have an AEM wideband and boost gauge.

So onto my question. I have read and read on here about the TN kit. It seems like everyone on here pretty much hates the kit. Since I already have the kit I am looking for advice on how to increase the reliability. So far I have the following plans...
- TUNE! I'm gonna go with Sound Performance in Chicago to get this thing tuned. I'm looking at using UpRev.
- hook up water lines
- turbo blanket to control heat
- header wrap on down pipe and possibly intake pipe
- use heat wrap on surrounding components
- change wastegate and dump to atmosphere? It has the updated piping and the owner reported no over boosting whatsoever.
- and last but not least, common sense driving.

I realize that with any FI there is risk and I understand that all I can do is minimize those risks. Any advice would be greatly appreciated.

Sell it.





jk
Fab up a bigger diameter custom down pipe and get a good boost controller.
Go to a good shop (ie SP is great) and ask them what they can do for you and what they recommend doing to increase reliability.

I just realized you are running the stock reflash. Upgrade that FIRST. osiris would be a great solution or utec. Again, ask your shop/tuner.

Here's a little bit of flow knowledge for you to soak up (regarding wastegates)
A bigger wastegate is needed for lower boost, and a smaller wastegate can actually hold HIGH boost, better than one that is bigger. (there are many limitations to this statement, and it doesn't always hold true)
Explained: Low boost: more bypassed air, High boost: less bypassed air. A small wastegate can have serious trouble bypassing enough air to hold the pressure you want, while a bigger one can let out just enough, regulating pressure better. If the wastegate isn't big enough, it can't bypass enough air causing boost spikes (although on the case of the TN kit I think it hast more to do with the ruhturded design). Interestingly enough the other side of the coin dictates that too big of a wastegate and you could potentially have trouble keeping pressure up (the wastegate lets air out at such a fast rate that when the wastegates crack open, manifold pressure drops more than needed and in theory causes boost to drop, although this is virtually impossible unless your wastegate isn't properly installed, in which case it doesn't matter the size).

So in short I'm telling you a bigger wastegate isn't necessarily better, even though it feels like it could be. A 38mm is a pretty good size for that t-netics turbo, and a 40 wouldn't really be that much better.

That idea that you can use a small wastegate to hold high boost with NO issues is used by some (*cough* synapse *cough*) companies to convince you their XXmm model is better than brand xxxxx's bigger wastegate. They tell people their 38mm's work on huge hp drag cars when in reality, they barely even need a wastegate; they want maximum possible hot side pressure. In fact, more than a few drag cars don't even run wastegates on the exhaust side, but on the charge pipe.

:stfu::rofl2:

Long story short, a bigger wastegate could/should help, but a better solution is to sell the tn kit (lol).
/rant
Edit:
Also get rid of that tnet turbo, get something garret based. Garret original, precision hks... yada yada... whatever, just be aware that turbonetics have had some bad wheels come out, and you probably won't get them to back up their product as a second owner... And fuel system, upgrade that; add in a fuel return line w/ fpr, 255lph pump etc.
/rant2

Thanks for the response. So from what I gathered from your post I should also look into a fuel return line, fuel pump, possibly larger wastegate, larger down pipe, and of course advice from my tuner.

What about larger fuel injectors?

Can you expand on the reasoning for a larger downpipe? Specifically, how would it improve reliability?

Also, you mention that some TN turbos came with bad wheels. The car has been boosting for 5k miles, wouldn't a defective turbo have gone bad already? Especially if it were a bad wheel?

Add meth injection to keep intake temps down.

Take it from the people who have had this kit before. You already have the updated version of the kit. Keep the kit under 10 psi or just at 400whp or below. The less variables you add to this kit the better. Solid conservative tune is a must.

+1

To increase the reliability, dont push the kit past what it was intended for. Everyone bitches about it bc they want too much. The kit wasnt designed for more than stock block use. But tuned in that range, its perfectly fine.

Larry at SP is a great guy. They dont have Uprev though, so you'd have to have the cable and rom editior yourself and bring it to him.

I had the kit on my old G35 boosted ok the stock block from 62k mikes to 113k miles until I sold it. The tune was on 8psi and around 350whp. I drove the car hard a lot. I had over 180 drag passes (12.2 @ 115mph) and had a lot of fun daily driving it. I had a Utec for tuning, the original oil cooled turbo, an open wastegate. I had no boost spiking, but the turbo would smoke on rare occasions. I'd lose about a quart of oil every 3k miles.

The only problems I had were that I burnt through both AC line and the lower radiator hose. I had both upper/lower AC lines custom made and extended so I could bend them a bit farther from the hot components and had them wrapped in 750 degree fire retardant wrap.

Like others have/will say, if you don't expect the kit to make a lot of HP, it's good for what it is. If you're happy with 350-400whp, make sure you have a good tune, keep up with the oil changes, and a little luck and you will be good to go.

Replace with a BP single kit, and call it a day....

** link below.

Thanks for all the responses. I've decided to go with everything on my original post plus an oil cooler with thermostat. I was also thinking of re-doing the cold side piping to be more like the momentum kit but I think heat wrapping it will be sufficient.

98intrigue,
Good to hear that you were able to run this kit hard for so many miles. It seems like from what some of you mentioned and from what I've read that people were running into problems with this kit when they tried to turn up the boost or if they were victims of the old wastegate piping design.

i agree with not pushing it. Take it to get a professional tune and ask larry what HIS opinion is. Since he's tuning it and deals with these cars he would know what the car needs most. Should be just fine on stock block if you try not to max anything out or go crazy like rich said.

+1 to what everyone has said. I have about 22K miles on my upgraded TN kit. Out the box I say the kit is good for about 430hp and thats it. I bought my kit with bigger downpipe and wastegate. The seals in the oil cooled TN turbos SUCK!!! I'm having to replace my turbo. I'm gonna do a few more things as far as fuel return and bigger injectors. Just want to hit 500hp. As far reliablity its fine, just don't go all crazy on it.

Is Larry the 350z tuner at Sound Performance? The reason I ask is because I have already spoken with Reid a couple of times. Is Reid also a tuner?

larry is the tuner. I'm not sure reid's actual title but he does a lot with customers. He's who i've talked to every time i call them.

I THINK it's reid who works with customers and maybe does some fab work, at least thats the impression I got off supraforums. And larry is definitely the tuner.

But op, just go to the shop you are going to get tuned at, and ask them. Or email larry : XXSUPRAXX@aol.com, while reid's is: ReidatSP@aol.com. Or of course you can call the SP shop: (630) 893-5002.

^I hope that isn't breaking any forum rules^...

So larger injectors is a must for 400whp. I think you should be fine with some drop in 440cc's. I thought you might have already upgraded them with the kit but IDK what the kit includes.

Larger downpipe; the turbonetics kit comes with a tiny downpipe because it has such a weird mount angle and can't fit much more going down the car. As vinny said "you can't **** more than you eat". It just causes problems with holding boost and the smoothness. [Edit: for your power levels. On higher power levels, the DP would restrict flow to the point where the car doesn't make any more power] Bigger downpipe increases the effective 'vaccum' on the other side of the turbo which helps to draw air out of the hotside, thus increasing the efficiency. Flow is all about pressure gradients (drops boosts etc)... Simple physics really. But IDK if the 'improved' pipes solve that issue. I'm willing to bet your down pipe is no larger than 2.75", if even that. Originally the kit came with either a 2" or a 2.5" which is ok up to like 450ish crank hp. More than that you usually want a 3". On a lot of turbo setups you can run a smaller down pipe, because the downpipe is usually very short, but I think that the tnetics one is pretty long.

Yes it is possible that the turbo would have shat it's self already... Some people have them go out really quick some take a while... Your turbo may be fine, esp if it has gone 5k miles. If you notice extra smoke, then its likely that the seals went bad. If it were me and the seals are gone, i'd just buy another turbo. Unless you have been shutting the car off right after pulls, there isn't much reason for seals to just go bad after a few thousand miles. If your turbo does sh*t its self, just get a different one (like I said, a non tnetics). It seems that the compressor blade on turbonetics aren't always fully balanced, or sometimes the manufacturing process leaves flaws causing broken wheels down the road. I never dealt with one personally, but if yours is running fine then don't stress it.
Also I would recommend wrapping all hot pipes or ceramic coating them. Even go as far as a turbo blanket for the hotside. This is a non tnetics specific mod that everyone should do, but it seems that it would help the tnetics the most just because there is soo much hotside piping.

EDIT 2:
The reason why I say just swap out the turbo now is that incase the turbo goes, you'll need a new intercooler, and possibly worse. You don't have to go for a real expensive turbo, you can try out a Master Power turbo, or an entry level Precision turbo. My friend ran a MP turbo in his 1jz supra and it hauled ass, and spooled pretty damn well for a journal bearing, anti surge housing turbo... sounded boss to boot. They run about 600$. Although you would probably have to do a little bit of fabricating to get it to work so again, talk to the shop you are going to work with BEFORE buying ANYTHING. Of course you could do the research your-self, but (no offense) you wouldn't have posted a thread asking these questions....
GL

What does that mean? You have a FI car and you are going to drive it like a woman?

/thread

Resmarted,

One advice SP had was to stay <400whp so I probably won't need the upgraded injectors. Also, I'm happy with the current power levels so I probably won't be upgrading the downpipe. I'll keep an eye out for the smoking you mentioned and will look into a turbo upgrade if there's a problem. I'm already planning on wrapping up all the piping and getting a turbo blanket. I will try to get ahold of Larry directly to see if he has any other advice for me.

Ruthless18x,

No I won't drive it like a girl. I just meant that I will be mindful of the cars limits. Proper warm up/cool down, paying attention to the wideband, oil pressure, oil temp, water temp, etc. A custom tune before pushing the car. Just pure common sense. I've read a lot of stories on here where the blown motor was because of driver stupidity.

lol if you want reliability dont get a turbo blanket or wrap the tubing. doing so will increase your spool but it will also increase how hot the turbo and tubing gets. since this kit has problems from cracking you dont want to further heat it so it can crack easier

It's either hot piping which could crack or hot intake air temps which could blow my motor. Piping/turbo is easier and cheaper to fix than the motor.