Edit: Brand New BigT28 DEAD. See my last post.

[Lord Khan]

Me and a couple friends installed a fp t-28 on a 95gsx, i've done many turbo installs without a problem but about a 1.5months later the turbo started to whistle and developed some shaftplay, the whole time my friend was only running 13psi because he was on stock injectors. my .02 cents

-Damian

Was his ported? Also, did he get any hassle when trying to warranty it?

 

[6damian6]

no his was not ported, and no he had no problems getting it rebuilt under warranty.

-Damian

 

[Lord Khan]

Cool. Thanks for the info man. I REALLY appreciate it. Has his turbo been ok since the rebuild?

 

[6damian6]

Yes, but its only been about 1.5weeks

-Damian

 

[Lord Khan]

I've gotten an email, and their saying that I might have injested something to damage the turbo. They said that if it were installed incorrectly it would have failed almost immediately, so they don't think it is anything like that. They seem like a very good company, and they seem to want to help me out. I feel a bit better now. Thanks again for the info.

 

[BMPDirk]

so whats going on man, did you take care of it yet?

 

[Lord Khan]

I thought I would have to wait for this weekend for my friend to take out the turbo, but he loaded up his truck with his tools this morning and is coming over this evening to take it out. So I will be sending it to the company tomorrow, so they should get it sometime next week, inspect it, and let me know what they are going to do. The guy sounded like they'll probably fix it under warranty, but he said they still have to inspect it just to double-check. I keep you guys posted and let you know what condition the turbo is in once its out.

 

[rarson]

Going 100mph on the highway is not going to run the turbo harder than any other time. When it's making 12-15psi of boost the shaft is spinning at a particular speed regardless of gear.

Shaft speed depends on not only pressure but also airflow. Look at a compressor map. Maybe I'm misunderstanding what you said? But my point is, higher rpms usually result in higher airflow even if the boost is lower, and therefore a much higher shaft speed (for instance, a T25 pushing 12 psi at 7000 is spinning faster than a T25 pushing 15 psi at 3000 rpm).

I for one would have been worried when the car ran a 14. Plenty of people have ran 13's on the T25. Do you have supporting mods?

 

[Lord Khan]

"I for one would have been worried when the car ran a 14. Plenty of people have ran 13's on the T25. Do you have supporting mods?"


I have a GS-T, and I could only run my car at max about 17-18lbs before hitting fuel cut cause fuel is my last mod that I haven't done yet. Not to mention that it was hot and humid that day so their were a lot of turbos running crappy numbers (we were talking about this in the DSM Meet North East forums). For me though, that was a pretty good time as I'm not a very good racer, and I'm still learning how to launch. But yeah, I have everything but fuel, so it will be a while before I can crank up the boost to 21+ lbs and run 13's.

As for my friend taking out the turbo today, looks like he can't do it til Saturday cause he got held up with other affairs. So I'll have to continue to be patient.

 

[JiveMasterT]

"I for one would have been worried when the car ran a 14. Plenty of people have ran 13's on the T25. Do you have supporting mods?"


I have a GS-T, and I could only run my car at max about 17-18lbs before hitting fuel cut cause fuel is my last mod that I haven't done yet. Not to mention that it was hot and humid that day so their were a lot of turbos running crappy numbers (we were talking about this in the DSM Meet North East forums). For me though, that was a pretty good time as I'm not a very good racer, and I'm still learning how to launch. But yeah, I have everything but fuel, so it will be a while before I can crank up the boost to 21+ lbs and run 13's.

As for my friend taking out the turbo today, looks like he can't do it til Saturday cause he got held up with other affairs. So I'll have to continue to be patient.

don't run 17 psi on your car unless you have the supporting fuel mods. the t28 flows more than the t25, especially at the upper rpm ranges. remember, hitting fuel cut is a bad thing. i would have run like 13 psi on it.

 

[Lord Khan]

don't run 17 psi on your car unless you have the supporting fuel mods. the t28 flows more than the t25, especially at the upper rpm ranges. remember, hitting fuel cut is a bad thing. i would have run like 13 psi on it.

Besides melting pistons in severe cases, what kinds of damage can fuel cut cause?

 

[JiveMasterT]

Besides melting pistons in severe cases, what kinds of damage can fuel cut cause?

well, it usually when you hit fuel cut its cause you are pushing in too much air and running lean, so you end up doing tons of damage to things like your spark plugs, cylinders, possible valve damage, etc etc. its not hitting fuel cut that is a bad thing, its the circumstances that lead to fuel cut.

 

[NOSLO2PT0]

well, it usually when you hit fuel cut its cause you are pushing in too much air and running lean, so you end up doing tons of damage to things like your spark plugs, cylinders, possible valve damage, etc etc. its not hitting fuel cut that is a bad thing, its the circumstances that lead to fuel cut.

once again, we have a newb that doesn't understand what fuel cut is or why we get it. So, i'll save you the legwork:

Modern turbo design notwithstanding, it is still very possible for the wastegate on the turbo to malfunction, leading to exactly the ever-faster turbo behavior described above. Recognizing this, the designers of the DSM ECU built a fail-safe limiting mechanism into the DSM ECU modules. And it goes like this:

Should the ECU ever see an intake air mass greater than a certain preset level, it will stop fuel delivery and spark to the engine cylinders. This 'critical mass' depends on air volume, temperature and pressure, as measured by the MAS sensors. The act of the ECU cutting off fuel delivery to the engine is known as the infamous 'fuel cut'.

Why'd they do this?? Well, should the wastegate ever malfunction in such a way as to allow the turbo to spin out of control, the ECU will stop firing the cylinders to save the turbo from exploding. This is not the only method the ECU has to limit the turbo operation, but it is the last and most desperate. The mass air limit at which the ECU will fuel cut was based off of the maximum amount of fuel that the stock fuel pump and injectors could deliver to the engine cylinders.

Unfortunately, those owners who purposefully modify their engines to provide greater power are deliberately forcing more air through their engines in order to produce more power. Recognizing the limitations of the stock fuel delivery system, serious modders usually upgrade the fuel pump and/or injectors in order to provide enough fuel capacity for the hopped-up engine.

However, the fuel cut limit, based on the stock fuel system, is pre-programmed into the ECU and cannot be changed. There is no method by which the ECU can be made aware of the improvements made to the fuel system, so it will blithely cease fuel delivery once the mass air intake reaches a predetermined level regardless of how much fuel capacity is really available. This characteristic of the DSM ECUs, while understandable, has been a source of nearly endless frustration for power-hungry owners.

 

[JiveMasterT]

once again, we have a newb that doesn't understand what fuel cut is or why we get it. So, i'll save you the legwork:

Modern turbo design notwithstanding, it is still very possible for the wastegate on the turbo to malfunction, leading to exactly the ever-faster turbo behavior described above. Recognizing this, the designers of the DSM ECU built a fail-safe limiting mechanism into the DSM ECU modules. And it goes like this:

Should the ECU ever see an intake air mass greater than a certain preset level, it will stop fuel delivery and spark to the engine cylinders. This 'critical mass' depends on air volume, temperature and pressure, as measured by the MAS sensors. The act of the ECU cutting off fuel delivery to the engine is known as the infamous 'fuel cut'.

Why'd they do this?? Well, should the wastegate ever malfunction in such a way as to allow the turbo to spin out of control, the ECU will stop firing the cylinders to save the turbo from exploding. This is not the only method the ECU has to limit the turbo operation, but it is the last and most desperate. The mass air limit at which the ECU will fuel cut was based off of the maximum amount of fuel that the stock fuel pump and injectors could deliver to the engine cylinders.

Unfortunately, those owners who purposefully modify their engines to provide greater power are deliberately forcing more air through their engines in order to produce more power. Recognizing the limitations of the stock fuel delivery system, serious modders usually upgrade the fuel pump and/or injectors in order to provide enough fuel capacity for the hopped-up engine.

However, the fuel cut limit, based on the stock fuel system, is pre-programmed into the ECU and cannot be changed. There is no method by which the ECU can be made aware of the improvements made to the fuel system, so it will blithely cease fuel delivery once the mass air intake reaches a predetermined level regardless of how much fuel capacity is really available. This characteristic of the DSM ECUs, while understandable, has been a source of nearly endless frustration for power-hungry owners.

ho ho, that explains a lot. thanks for that, i had no idea. basically if you are running the stock turbo and getting fuel cut, then thats a bad thing. if you are running an after market type setup and hitting fuel cut and everything is tuned properly, then its just annoying. i got it.

 

[BMPDirk]

Does this happen to alot of you Bigt28 users?? Since April i have heard of four different stories already of people getting the big28 and it blowing shortly after install(1, 2, 3 months)

 

[Lord Khan]

Well, found out whats wrong with the turbo. The EXHAUST FINS ARE ALL CHEWED UP AND BROKEN.

Either my engine spit out something to damage those fins, or they hit the sides of the housing and were destroyed. Also, this damage caused play in the turbo, and oil spilled right out of the exhaust side. The whole exhaust fin assembly is coated in thick oil. I'm sending it to the company on Monday to see if they will repair it under warranty.

 

[NOSLO2PT0]

Do you have an EGT gauge and probe? That's my first guess. If that is the case and it ate the probe, forget about a warranty. Where on the fins are they chewed up? If the damage is solely on the outside of the blades, the damage may have been caused by a bad thrust bearing. If the damage is all over the entire blade, including the inner portions, something went thru the turbo.

 

[Lord Khan]

No, I don't have an EGT guage. Yes, the damage is all around the whole exhaust wheel on the outside of each blade. And they are chewed really bad. Could this have been cause also by the turbo having play in it or strictly by something going through it?


Oil is coating the whole exhaust wheel, as it is just leaking into this portion. The guy from FP said in an email that it sounds like total bearing failure.

 

[psychlow]

It could be that the turbo wasn't properly clearanced/machined/balanced, and once you started running it hard, it ate itself (turbine blades slapping the exhaust housing).

Otherwise, it could be that your engine spit something at it, chewing a few wheels, which would cause it to be mis-balanced and the same thing as above might have happened.

Sure your mechanic didn't leave a nut or a bolt in the exhaust somewhere?

 

[Lord Khan]

It could be that the turbo wasn't properly clearanced/machined/balanced, and once you started running it hard, it ate itself (turbine blades slapping the exhaust housing).

Otherwise, it could be that your engine spit something at it, chewing a few wheels, which would cause it to be mis-balanced and the same thing as above might have happened.

Sure your mechanic didn't leave a nut or a bolt in the exhaust somewhere?

I guess anything is possible. Only thing is that I had ran this thing hard a few other times since installation and it was ok. Just one of those flukes that sometimes happens. It's getting sent back tomorrow, so I'll keep being patient.