Turbo talk

[ISPKI]

I used the formula I already gave you and used algebra to move the equation around so that instead of finding max cfm you are finding max boost.

Here’s the mental math I did, using the numbers you came up with.

So we have 400cfm max from an na engine, that is with with 14 psi of atmospheric pressure.

So if 14 psi=400 cfm then 1 psi is ~30 cfm.

So if we have 500cfm and we divide that by 30, well that’s ~17 psi

Which is less than 4 psi of boost... not even taking ve into affect.

Volumetric efficiency is what, 70%ish with an intercooler?

 

[Thewespaul]

Yep around there, and I hope you don’t take this as shutting down your idea, really it’s the opposite. It’s just not a simple task picking a turbo out, and if there was a simple solution for big power with our engines someone would have done it by now.

 

[ISPKI]

Thanks for the breakdown btw.

So a turbo for this truck would need what, 620ish cfm airflow to make any decent gains? Or run a pair of smaller turbos, that way you would get very high flow with lower pressure?

How would running twin 500cfm turbos in parallel work on these engines? you would have a combined 1000cfm and they would spool extremely fast I would assume

 

[ISPKI]

Yep around there, and I hope you don’t take this as shutting down your idea, really it’s the opposite. It’s just not a simple task picking a turbo out, and if there was a simple solution for big power with our engines someone would have done it by now.

Not at all! It's a learning experience for myself and hopefully for anyone else on here looking for the same questions and answers. I just really like to have these types of conversations because, well, there just aren't alot of people near me who do this with old IDI motors.

 

[Thewespaul]

2 500 cfm turbos spools the same as one 1000 cfm turbo. It’s the piping and layout that makes the difference. In some vehicles two small turbos fit better with less piping than a big turbo. In our trucks a big turbo fits better with less piping than with twins

 

[79jasper]

You could do a vgt. Lol

Sent from my SM-G892A using Tapatalk

 

[ISPKI]

You could do a vgt. Lol

Sent from my SM-G892A using Tapatalk

Just looked those up, what kind of benefits with they provide over a standard vein turbo?

 

[ISPKI]

I've seen a few HX35s for sale neat me, searched around but can't seem to find air flow values, I've seen 60mm/76mm sizes so I would estimate it to be over 700cfm but not by much.

 

[79jasper]

HX35 is also slightly small. Members here have done it, search around.
Again, that's from a 5.9L engine that actually has a lower rpm range.
Over on the GM side, some are doing the HE351VE. Which is from the 6.7 Cummins.

Sent from my SM-G892A using Tapatalk

 

[snicklas]

Just looked those up, what kind of benefits with they provide over a standard vein turbo?

With a a VGT (Variable Geometry Turbo) there Is a set of veins in the exhaust side of the turbo. The PCM (or some type of stand alone controller) moves the veins. So, at low load, or low speed conditions, the veins are more closed, making the exhaust side of the turbo act like a small housing turbo. As load or speeds increase, the veins open up, allowing more exhaust to escape, while keeping the balance to load as efficient as possible. The 6.0 PSD, the 6.7 Cummins, I think one of the Duramax engines,and some larger engines have a VGT. Basically it is a variable sized exhaust housing.

Here are a couple videos explaining VGT’s

xc_hide_links_from_guests_guests_error_hide_media

xc_hide_links_from_guests_guests_error_hide_media

This last one is longer, it was made by Diesel Tech Ron, who was a Ford Dealership mechanic and worked on all the diesels. This shows disassembly of a 6.0 VGT and how it works.

xc_hide_links_from_guests_guests_error_hide_media

Ron’s videos, along with the ones from FordTechMakuloco, who is a member here and next door, are very good resources. Makuloco, has videos on all Ford vehicles, Ron’s were mainly diesels. I have learned a lot from both of their videos. They are both on YouTube, as DieselTechRon and FordTechMakuloco. Unfortunately, a couple years go, Ron was killed in an automobile crash.... so there videos on the channel about that also.....

Hopefully theses help explain a VGT and some of the advantages and disadvantages..... big thing with a VGT is don’t idle a lot, and you need to not baby them.... make the veins move. On my 6.0 I make sure to be heavy on the throttle every few days........

 

[79jasper]

Also the 6.4 PSD, and 6.7 PSD have vgt.
All Duramax have them, far as I know.

Sent from my SM-G892A using Tapatalk

 

[pelky350]

The Vgt has been done before with a video on YouTube but he had a manual controller for it to move the veins, if someone spent enough time they could maybe figure something out? That would be the most ideal turbo and plentiful for cheap used. Maybe actuate the veins using the boost somehow slowing turbo speeds once boost is achieved. like a waste gate with no waste just actuate the veins with one. it makes sense to me sorta but probably not anyone else lol

 

[79jasper]

That can and has been done.
Or you can get a aftermarket standalone controller. Or make your own from a arduino. I can direct to both.

Sent from my SM-G892A using Tapatalk

 

[Thewespaul]

Not all dmax had Vgt, but they are amazing performing turbos. If you had an electrical engineer and computer programming friend you might be able to make it work well on our trucks otherwise it’s a waste

 

[Runningaford]

The member that installed the VGT Turbo -

xc_hide_links_from_guests_guests_error_hide_media

The turbo is manually controlled via a toggle switch in the cab.