Another T4 thread

[Big Bore]

I think the 74 turbine that the sxe comes with is what i would do.
It takes a bigger turbine to power a compresor at high boost levels.
When i had my s366 it actually made more peak boost ovrr my 364.5 with same fuel. I contribute that mostly because of the bigger wheel in the turbine. 74 over the 68.
I think with the .83 housing combined with the 63 compresor your going to be more then happy with spool up.
Dont forget, the new style 74 tubine is not the same as the old style, it responds a lot faster.

I had the uncontrollable urge to quote David Lott here. "Boost is a measure of restriction". Meaning, boost pressure is not something you can use to make a linear comparison unless you are comparing the exact same turbo. You can have less boost, and more HP, since you can flow more air for a given boost pressure depending on the turbo.

 

[mattman347]

I talked with Mike at SE and he helped me a lot. It came down to wether i want the 74 or 68 turbine to match up with my 363. Mike there thinks that the 68 will respond better and still flow enough with proper wastegate settings.
That being said i only want 475-500 hp
How do yall feel about the 68 vs 74 turbine with the gated .83 housing?

I would for sure do the larger turbine, lots of customers running it with any spool up issues! It will have more room for all that 7.3L's of displacement too!

 

[Swaan]

I had the uncontrollable urge to quote David Lott here. "Boost is a measure of restriction". Meaning, boost pressure is not something you can use to make a linear comparison unless you are comparing the exact same turbo. You can have less boost, and more HP, since you can flow more air for a given boost pressure depending on the turbo.

Yup your correct.
This also just confirms my theroy of the bigger turbine has more shaft hp to turn the compressor at high pressure ratios.

My s366 had a bigger 74 mm turbine over the 68mm in my 364.5. So it actually had less restriction but still made more boost. Savvy?

 

[Big Bore]

Yup your correct.
This also just confirms my theroy of the bigger turbine has more shaft hp to turn the compressor at high pressure ratios.

My s366 had a bigger 74 mm turbine over the 68mm in my 364.5. So it actually had less restriction but still made more boost. Savvy?

Yea lol, of course. I was simply tossing that out there. Your post was more of an opportunity to do so. It was in response to a couple comments I read this morning over coffee in this and another thread regarding boost numbers. I remember being dismayed that the 38r made lower boost numbers than a stocker. lol

 

[Tsgs69400]

I think the 74 turbine that the sxe comes with is what i would do.
It takes a bigger turbine to power a compresor at high boost levels.
When i had my s366 it actually made more peak boost ovrr my 364.5 with same fuel. I contribute that mostly because of the bigger wheel in the turbine. 74 over the 68.
I think with the .83 housing combined with the 63 compresor your going to be more then happy with spool up.
Dont forget, the new style 74 tubine is not the same as the old style, it responds a lot faster.

I appreciate the help Swaan, especially since you have tried a couple. Mike at SE noted that the 68 turbine is already larger than the factory tp-38 charger that came on these trucks. So i am gaining a step up in flow with the 68. My only concern was , as you say, i am choking it down with the .83 housing which is why i wanted to go with the 74 turbine.
I explained that concern to Mike a SE and he felt that the gated housing had enough bypass volume to handle my 475-500 goals with superior spool.
I still do not know where my egts will be tho on a long hill towing tho.

If i can get the tuning and injectors matched right id like to get this thing to spool up a lot better around 1500 rpm since thats my dead zone right now. Maybe im not able to at all but i wana try haha

 

[Tsgs69400]

Fyi i saw where bw rates the 363sxe at 78lbs/min with the 68 turbine but the 74 turbine i think was at more like 80-82 lbs/min

 

[Swaan]

I understand.

You are correct thou. You can have a turbo flow more cfm at lower boost then another at higher boost.
It really is a bit of a science.. so many factors come into play and the turbine side has as big or bigger effect on things as the compressor side. But yet people still seem to judge a turbo or relate to a specific turbo by its compresor inducer size.
There is a reason people like pius,reed partridge and jose at forced inductions is in business. As there is so much to understand and most people just would rather leave it up to the professionals to figure out. Either way i do find it interesting and have invested a lot $$ trying diffrent combinations. Not only on my 7.3 and 6.0 but on my detroit and cat engines in my class 8 otr trucks.
Turbos are like crack always looking for a better high.

 

[Swaan]

I appreciate the help Swaan, especially since you have tried a couple. Mike at SE noted that the 68 turbine is already larger than the factory tp-38 charger that came on these trucks. So i am gaining a step up in flow with the 68. My only concern was , as you say, i am choking it down with the .83 housing which is why i wanted to go with the 74 turbine.
I explained that concern to Mike a SE and he felt that the gated housing had enough bypass volume to handle my 475-500 goals with superior spool.
I still do not know where my egts will be tho on a long hill towing tho.

If i can get the tuning and injectors matched right id like to get this thing to spool up a lot better around 1500 rpm since thats my dead zone right now. Maybe im not able to at all but i wana try haha

Well mike does have a point . That housing has a gate for each volute so im sure it will bypass enough as to not have back pressure issues. It sure will spool fast that is forsure. I would set the gate for about 38-40 psi and try it.

I think for your goal of 500hp its a tad on the small side but for optimum response and smoke free power under 400 hp it would be a great performer. Im a firm believer if it is a daily driver then spec the charger on the smaller side for drivabillity reasons alone.

Having said that. If it was me id still do the 74 mm turbine. Lol

 

[ja_cain]

The real question for me is, which configuration is going to allow me to tow 10k at any posted speed limit? I'm thinking 350 hp will do this as my buddies lly dmax will do this stock. I'm thinking he 63mm with the gated (smaller ar) setup is the key, but like swaan said, is the better choice a 68 or 74?

Sent from my SM-G930V using Tapatalk

 

[superpsd]

Like was said earlier in this thread tuning is going to have a huge effect on turbo performance. Granted there is a trade off with a smaller unit vs a larger. However tuning is going to be the difference between a hot smokey setup or a clean runner. I would not go to small on a turbine as was stated it may perform well down low but they usually perform poor up top. It's always going to be a balancing act. I could spool my completely stock turbo 1.10 with 200% nozzles no problem. After putting the 369 1.0 in with same tuning it would not spool. Pulled timing and walla now it's spooling up. It's all a balancing act the turbo and tuning. That being said a the .91 housing is likely better for a towing low rpm daily truck. I would like to hear the results if anyone goes with the gated housing on the 74 turbine.

 

[Swaan]

Man. I would of done the .83 gated housing on my 364.5 but i just dont want to deal with building another down pipe off the turbo. I was ready to set my truck on fire after the first episode. The super duty crowd got it easy!! Lol

 

[Big Bore]

I remember my first dp install on an OBS. Sawzall, breaker bar, low profile jack, install dp, drive around listening to it vibrate against firewall, more prying...

 

[Swaan]

Yeah exaclly!! Lol
I dicked around with mine for a whole day. Finally got it so it was not rubbing on anything. Im afraid if i have to build another to accommodate this new housing people might be sacrificed in the process. Faaaak i hate those obs downpipes.

 

[Tsgs69400]

Thanks again guys, im glad we are all on the same page.
I spoke with Matt at Itate and he agreed with me/us on the 74 with the .83 should spool fine. Swaan, i feel the same way about these turbo combinations as you, you can go crazy looking at numbers and ratios all day but the truth is that each engine is different and will respond differently.
While we talk about the 7.3 im still thinking in the backgound about how completely different my approach will be when choosing a turbo for my dt360. Totally different displacement, thus different sizing.
That said, since nobody has tried it yet but we all agree that the .83 gated 74 should be quick and support a broader range of power, i think ill order one up from SE this next week and see what happens.
I do not know how soon i will get it on tho with work so busy. However, i will be sure to share my findings when i can.
Now i need to decide if i have time to build my t4 kit or not. Hmm

 

[Swaan]

Thats great!! Lookin forward to how it works. Im willing to bet its gonna be a game changer.
Let us know how the install goes . I just hope that wg canister is in a good spot so not to interfere with anything. You never know till you try.

 

[Tsgs69400]

The real question for me is, which configuration is going to allow me to tow 10k at any posted speed limit? I'm thinking 350 hp will do this as my buddies lly dmax will do this stock. I'm thinking he 63mm with the gated (smaller ar) setup is the key, but like swaan said, is the better choice a 68 or 74?

Sent from my SM-G930V using Tapatalk

Cain, ill have to see how my temps do towing my gooseneck after the swap.
I am around 350 or so now and it tows nice with the d66 as long as i stay above 1800rpm, then she heats up, tho its controllable. Tuning is key. What hurts me is my 3.55 gears and 33" tires. Leaves a big dead zone between 58 and 70 mph. Temps are better above 70 until the hills.

 

[Tsgs69400]

Thats great!! Lookin forward to how it works. Im willing to bet its gonna be a game changer.
Let us know how the install goes . I just hope that wg canister is in a good spot so not to interfere with anything. You never know till you try.

I hope yall dont loose interest by the time i get it in. Haha ive been workin 6 days and 10-12 hrs plus on call. Maybe ill splurge and just buy the kit and leave my patience all for the downpipe. I thought i may try an ovaled 3.5" pipe with just the right bends.
Something like this... but idk.. haha
http://www.spintechmufflers.com/oval-tubing/oval-elbows/vertical-oval-elbows/cat_46.html

 

[superpsd]

I doubt most would lose interest. Honestly many have put down 600hp thru a 3" downpipe. I went 3.5" off the turbine and then necked down to 3" and 4" after the squeeze. The old Mormon flange that fits the TP38 is the reducer. Boost comes on fast. More tweaking to the tune will make the difference as well.

 

[Big Bore]

Dang

 

[gnxtc2]

If you wanna do some surgery....... 3" to 4"

The new metal was covered with Dynamat.

Billy T.
[email protected]