I think this talk about 30% and 33% "more airflow" needs to be clarified which I tried to do in my post #8 here... only 24lbs of boost on GTP38R BB turbo ... https://www.ford-trucks.com/forums/8...ml#post7539899

For a given BP and MAT you get the same MAF airflow into the engine with any turbo including the stock GTP38!

For a given compressor wheel rpm an 88 mm compressor wheel generates more CFM volume airflow into the turbo inlet than you get with a stock 80 mm compressor wheel spinning at that same rpm but if the stock 80 mm compressor wheel spins at a higher rpm it generates the same turbo inlet CFM volume airflow as a turbo with a larger compressor wheel does spinning at a lower rpm and in both cases you get the same BP in the engine's intake manifold and therefore the same MAF airflow into the engine!

Of course if you look at the compressor map for a stock turbo you'll see it has a limit for its maximum compressor wheel rpm and this limits the BP to a maximum of about 28 psi and I know from experience that if it's frequently operated at 25 to 28 psi BP a stock turbo will only last about 50K miles!

On the other hand if occasional bursts of 25 to 28 psi BP is all you need then a stock turbo might last for 75K to 100K or more and you can buy two or three rebuilt stock turbos for the price of a GTP38R!

Also it's increased fuel flow that makes HP and increasing the airflow without the additional fuel flow actually reduces HP because when that extra airflow is compressed the compression stroke pumping loss increases!

 

OK, so make sure you have the fuel to take advantage of whatever turbo you get. Without that, don't bother?

 

There's the crux of the discussion. If you're not planning on injectors, you'll never take that 38r anywhere near the top end. Curtis is running one on stock sticks IIRC, and there's nothing wrong with that. But putting a 1.0 A/R exhaust housing on a stocker and addressing the surge issue with a WW or ported compressor housing will get you a turbo that will last a lifetime on stock injectors...

 

Joe are you positive about that?

These all look the same to me. Even the description on many of them are nearly identical. The one from BD comes with a .84 turbine housing, while most others are selling it with the 1.0.

http://www.puredieselpower.com/catal...roke-p-97.html

http://www.htturbo.com/ford.htm

http://www.gillettdiesel.com/gdsballbusterturbokit.aspx

http://www.gdsdieselparts.com/late_99-03_ps_turbos.htm

The only discrepancy I've noticed is how they size the compressor wheel in their advertisements for some of these turbos. From what I've seen they all use the same compressor housing and the same T-61 compressor wheel.

 

That's what I was going to add into the mix. Now I've never ran all of them like you have, but will be running a modded H2E when I do upgrade. I've never seen any map comparisons either. But I have talked first hand to people that have ran both and deal with both turbos on a regular basis in their business. The only problem with it, IMO, is it's not a drop in and that scares some people away. I've been told the back pressures are better with the modded h2e in comparison to the stock 38R. By putting on 1.15 housing on the 38R it helps. But the 38R still has its limits that are much below the potential of the h2e.

 

Ok, so now I am completely confused... Garrett's BB Turbo shows max PSI of 40.

Are you saying that the new turbo with my existing Tuner and Exhaust will NOT give me any more boost then I have now with a stock turbo?

I have been told that the Smaller housing on the BD (and others) will not help decrease my exhaust gas temps, only helps the turbo spin up sooner.

Right now, I peak my PSI (with the stocker) @ about 25ish (give or take). My turbo starts to come alive @ about 1700-2000 RPM. What difference would I see here by changing turbos?

In my higher tunes, I push TONNES of black smoke (which tells me that I am wasting power, and I assume that more are or a bigger turbo to make more air, will compensate for)

From what I have gathered from the FAR too technical of a conversation, is that the Garrett BB turbo is the way to go for only a few $$ more for the following reasons:

Decreased EGT's as a result of the larger housing
Quicker Spool up as a result of the ball bearings
Longer life as a result of ball bearings
More potential for future mods


Are these assumptions accurate?

 

25PSI... Sounds like you need a BD Adjustable Wastegate to help you build more boost. The extra boost would tax the stock turbo a bit more but your wastegate is likely opening up at 25PSI which is what is causing the black smoke and leaving some power on the table. I would rather build 30-35PSI and tax the turbo a bit than run high EGT's and blow lots of coal.

 

Dave, I'm sorry but I have to disagree with you completely. It is common knowledge that running the stock turbo above 25 psi for an extended period of time causes shortened life due to premature thrust bearing failure.

That is precisely why so many in this thread are recommending a GTP 38R. I know you claim to use a higher quality thrust bearing in your turbos but to suggest someone run over 25 psi on a stocker long term is reckless.

The OP has stated that he plans to go bigger on injectors in the future. An adjustable wastegate on a stock turbo with bigger sticks is asking for turbo failure.

 

Of course you do but am not clear on how are you disagreeing with me? I said it would be harder on the turbo, but if his plans are to replace it, why not run some more boost through it until the injectors get done?

The OP is not running enough now to get 35 PSI and reckless is too strong of a word for 30PSI.

 

The Garrett GTP38R is the turbo all other 7.3L turbos are judged by. I suggest going this route. We have them in stock, ready to ship if you are interested.

 

Wow, well that sold me...

 

I guess the question is: Are you dead set on getting a drop-in turbo? I ask because you know what these 2 options you're looking at cost, but for a few hundred $$$ more, you could get an h2e bolt on kit that has WAY MORE upside potential for future power mods that either of the other 2.

Just my $.02

 

Dave, if you paid attention to the original post: Why in the world would you try to sell him an adjustable wastegate. Is this where customer service has gone?

Can you guys post some actual #s, compressor maps, real world tests? Help the guy make a decision that is going to benefit him towards his power goals and not just line your pockets.

 

12s? On 525 HP? I don't think so... Maybe in a Mustang.

 

Well that's what I'm saying because it takes the heat ENERGY from a lot more fuel to provide the turbine driveshaft HP to turn the compressor wheel hard enough to get that 40 psi boost. That Garrett spec is just telling you how hard you can drive their turbo without blowing it up!

Well the smoke means you're wasting fuel not power and the smoke is partly due to the injector actuation pressure being too low and causing poor fuel atomization and an upgraded HPOP might be the primary fix for that not a new turbo!

The subject of how much HP you can get at a given EGT is complicated and I'll address it later but I've already posted many times about a mod that costs 0$ and takes all of 5 minutes to do and will lower your EGT by at least 100F at WOT!