how about this turbo?

[86grandnat.]

I found a pt54 turbo for sale near me. I was wondering if these turbo's are a direct replacement from the stock one I have now? How do they work with a stock long block and a stock converter. I have green stripe injectors for now, but will be changing probably next year or so. Any input is greatly appreciated!

 

[mygrain]

Its too big for a stock torque converter. That turbo is comparable to a TE61.

 

[boost86]

If you got that turbo you would have to get a diffrent stall and injectors. But the turbo is very nice just alitle slow on spool up

 

[86grandnat.]

Alright, but would that turbo work for now, cause my stock turbo is junk and I need a new one ASAP! My stock turbo is dumping oil into the exhaust making it smoke really bad! I will upgrade the injectors and converter later, but would that turbo work for now. I just need something to be able to drive the car, cause I don't plan on takin it to the drag strip for a long time. Any more input is greatly appreciated!

 

[Tin Man]

Yes, it will work fine. When I first got my TE-61 I ran it with the stock converter. It really didnt spool that bad, but I wasnt taking it to the track either. On the injectors, just dont turn the boost up too far and monitor it.

 

[86grandnat.]

Alright, so if I were to get that turbo, what would the max. boost I would be able to run with 91 octane. What would also be a good chip to get, cuase I really need to upgrade that as well. I just got the translator and the 3" Impala MAF. Thanks so far!

 

[DonnieShort]

Alright, so if I were to get that turbo, what would the max. boost I would be able to run with 91 octane. What would also be a good chip to get, cuase I really need to upgrade that as well. I just got the translator and the 3" Impala MAF. Thanks so far!

I wouldn't go over 15 psi on 91. As far as a chip, since you've got the Translator get the most out of your set up and get the Extender chip. The best there is IMHO.

 

[TurboDave]

I'll echo what Donnie said, but also add a bit more. Yes the turbo will work, BUT and that's a big BUT, you could be asking for problems, especially if you go WOT.
Remember, even at only 15# of boost that 54 turbo is going to be moving a TON more air than the stock turbo. 15# of boost on a stock turbo is nothing like 15# on a 54!! Remember, boost is really only the air that didn't get into the cylinders (not very technical but that's the idea). All that extra air at 15# is, not maybe, IS going to lean you out terribly with those weeny little green stripes (not really any bigger than stock). And until you get an Extender chip, the problem will be exacerbated once the MAF tops out at 255, trying to deliver fuel for green stripes and hitting it's max at 255MAF, with that 54 pushing more air than your engine ever dreamed of seeing.
Well..... you get the picture. Could get ugly.

The only safe way to do this is with bigger injectors (or don't even think about going WOT until you do), and a much better chip (Extender) that will deliver the fuel needed.
The torque converter can come later, but you'll see why that's important also. Wont hurt, but will just be slowwww spooling.

 

[86grandnat.]

So, with that said, should I just go with my initial plan of getting a gt3255e, which is going to cost more, but is new. I really dont wanna change my stock converter, but I am goin to change my injectors probably next year or soo, most likely go with 50's. I just want my car to run in the 12's in the future and I hear that the gt3255e is more then capable of doing that. This car is only going to be ran at the track maybe once a year and mostly just a cruising/car show car. Any more input is greatly appreciated!

 

[Dan K]

If your goal so only to be in the 12's...what's wrong with the stock turbo?

 

[86grandnat.]

I would just use the stock turbo but the one I have is pretty screwed. Its got a ton of shaft play and its litterally pissing oil into my brand new exhaust. I figured instead of sending it away to get rebuilt I may as well just buy a bigger one. Thanks for the input!

 

[turbopete]

Replacing the turbo

I went with a TA 49 to replace my stock turbo. It should easily get into the 12's with just the minor bolt ons to support the extra power. I like it.

 

[Lee_Burough]

I went with a TA 49 to replace my stock turbo. It should easily get into the 12's with just the minor bolt ons to support the extra power. I like it.

Plus, you can rebuild your stock turbo as a Ta-49....Easy choice

 

[Ormand]

Remember, even at only 15# of boost that 54 turbo is going to be moving a TON more air than the stock turbo

We'll have to disagree on that one, Dave. At X rpm, the engine is only going to take in a fixed volume of air. Pressure doesn't matter, that changes density, but it doesn't affect the displacement of the engine. For a 3.8 liter 4 cycle engine, that amount of air is going to be pretty close to a half gallon, every time the engine turns over.1000 rpm, 500 gallons of air per minute. Now, a bigger turbo will probably be more efficient at some point, and at that point there may be cooler air, thus more weight, but it won't be huge difference. Unless there is a BIG diff in air temp, there won't be much diff in the mass air flow, and no diff in the volume flow. And if the bigger turbo is more efficient, there will be more power out of the engine, at the same boost level. So, you need to be careful, and watch the O2 levels, but it shouldn't make a big diff, IMO.

 

[S2V6RACER]

Looks like you have been corrected Dave.

 

[GS70350]

yea its still going to have about the same amount of cylinder pressure at 15psi with either turbo. The difference in airflow will come from a more efficient compressor that introduces less heat into the system at said 15psi boost and therefore results in a denser charge. However this shouldnt be enough to cause the car to run out of fuel.

Your green stripes will be fine for a year if you can get a good deal on the PT54. Its a pretty big turbo for a stock setup but it will work fine for now. If you ever feel like low 11s, there wont be a need to upgrade later. A stock d5 converter will work fine till you want to upgrade, its just not as easy to blow the tires away since spool up will be slower. On the other hand i find it to be a little safer for most people who drive my car with street tires, since its less likely to end up in a ditch with the tires still gripping the road.

Just keep the boost at stock levels. People have run low 12s on stock injectors, and with a good pump and more pressure they can flow enough to make around 400 hp static.

 

[Blazer406]

We'll have to disagree on that one, Dave.

Me too..... but this is not a bash dave thread....so.....

From an engineering standpoint, boost is only a pressure at the intake manifold caused by the spinning compressor wheel of the turbo. Merely changing to a larger turbo will not move a ton more air than the factory turbo (at the same boost level...with all other aspects of the engine constant). The heads and intake provide a "resistance" to flow thereby directly affecting the boost you see.

If you were to lower this "resistance" ... ie... ported heads....big valves.... bigger cross-section runners.....you would flow more air at the same boost level. But I don't think this was the case.....

In this case, the larger turbo could probably drop inlet air temps some (depending on where the efficiencey of the turbo was) causing some improvement due to the drop in inlet air temperature, but probably not "night-and-day" difference....

......unless you already had massive flowing heads, intake, throttle body,.... ect... and the stock turbo was waaaaayyy out of its intended efficiency range.

just my $0.02

 

[86grandnat.]

So, after all of this, should I go with the 54 or get the gt3255e. The guy is asking 600 canadian for the turbo, and it has 3000 km's on it. Does that sound like a good deal?? Thanks for the help thus far!

 

[GS70350]

Ive seen used turbos of the same sort go for upwards of $500 US consistently. Since im not up on exchange rates at this time you can do the math yourself.

For what its worth since your goal is only to run 12s, a used stock turbo can be purchased off the "Parts for sale" forum for around $100 US. This will surely be a better choice for a 12 second car and the $ you save makes it my pick.

 

[TurboDave]

We'll have to disagree on that one, Dave. At X rpm, the engine is only going to take in a fixed volume of air. Pressure doesn't matter, that changes density, but it doesn't affect the displacement of the engine. For a 3.8 liter 4 cycle engine, that amount of air is going to be pretty close to a half gallon, every time the engine turns over.1000 rpm, 500 gallons of air per minute. Now, a bigger turbo will probably be more efficient at some point, and at that point there may be cooler air, thus more weight, but it won't be huge difference. Unless there is a BIG diff in air temp, there won't be much diff in the mass air flow, and no diff in the volume flow. And if the bigger turbo is more efficient, there will be more power out of the engine, at the same boost level. So, you need to be careful, and watch the O2 levels, but it shouldn't make a big diff, IMO.

I guess we'll just have to agree to disagree. You're statement that "At X rpm, the engine is only going to take in a fixed volume of air" IMHO is totally wrong.
And when you start moving up to bigger turbo's and are able to monitor the amount of air moving into the engine, you'll find out that there certainly can be a lot more air moved through the engine at a given rpm.
Since I'm able to watch (via direct scan) the raw data being produced by the MAF (and not limited to the stock MAF's 255gps upper limit). It's very easy to monitor a specific rpm range at a given boost level and watch the difference in air flow across several different turbos and even different turbine configurations on a given turbo.
Nothing on the inside of my motor has ever been changed. Still all stock. In comparing imperical data files on DS and watching the tremendous differences in air flow from a stock turbo to a TA49 and then to a TE44, then to a PTE44. The bigger turbos are in fact able to force more air into the engine at a given rpm point and boost point.
I always like looking the points about where my car makes the 2-3 shift. It's very consistent and usually always occurs at 5000-5100 rpm so this is a good point in the graph to look at data. The boost and rpm are constants. The only difference being turbos and turbo configs.
If your original statement above were true there certainly would be no need to go to bigger injectors cause the engine just can't move any more air.

Just increasing the efficiency isn't going to account for the need for more injector. Moving more air, and lots of it, will increase the need for fuel to maintain a given air fuel ratio. When I move up to my present turbo configuration TE44 with .85 Precision turbine housing, even the red stripe 40's I had couldn't supply enough fuel to keep up and were being forced to duty cycle levels exceeding 120%. To keep air fuel ratios in the safe zone I had to move up to 50's, and they are being driven to duty cycles in the 87% range, which I consider to be just about perfect.

And I know for a fact I could move even more air through it even before modding the engine. Just need a bigger turbo to prove it ($$$$).

My airflow at this stage is now consitently in the 360gps range at the given point I mentioned above. Significantly more air than was attainable with the smaller turbos.

I've been racing this same car for 19 years, and collecting data for more than 10.