Sooo i have this 1964 galaxie with a 390. I ended up with a cast vs 7875 turbo. I have done some preliminary measuring and I think I have a plan. Help me here if any of this is incorrect as this is my first turbo build.
Single mounted on pass side . 2.25 hot side to turbo . 50mm wastegate. Cold side 3" tubing to ic and into the TB. Holley terminator x max processor controlling fuel with e85 capability and 4r70w trans. Holley 340 retrofit intank fuel pump with -8feed . I know there are a million details to attend to also. Hopefully I can get the headers fabbed and start making sence of what's in my head..

 

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Sounds good

 

Love a Galaxy. More pics.

 

Sounds like a good build.

 

Thanks for the responses.. i have a lot to learn and am glad to be here.
Its far from perfect but I will see this thru 100%. I have an apt with redistrip in a couple months(3month out for apt) to strip a better frame for this car and then that will get a ridetech coil over system. The 4r70w will go in when the chassis is being prepared and the current engine is moved over. My goal is to drive this from the Midwest to cruising the coast next fall.... I will be working on header fab very soon so I can get the turbo mounted.
After the above pic I think I will remain the cold side outlet down rather than out into the inner fender.

 

From experience, that is about half the turbo you need, on the exhaust side.

Had a customer who could only get 575hp out of his, was pretty pissed after the money he spent building the motor.

He didn't want to do a bunch of fab work to fit a new turbo, so I worked a few tricks and he picked up 200hp. All I touched was the hot side. Yes those 7875s are cheap, but that doesn't make it the right pick for 390cu/in.

 

With a single turbo 281 C.I. a 75 hotside impeller will take you to 1k hp.

 

Less displacement means you need more boost to move the same amount of air.

That makes the corrected exhaust flow less so it aligns with what the hot side will flow.

 

If you could explain what “That makes the corrected exhaust flow less so it aligns with what the hot side will flow.” means in retard language for me I could understand what you mean.

 

I see what you mean @bbi_turbos but the thing is you wanna find that sweet spot where you can get the power output you want without loosing instant spooling based on turbo size alone.

 

The higher the boost, the smaller the exhaust flow becomes.

 

Only total power output ability is limited to turbo hotside sizing. Power dosent come directly from ability to flow, it instead comes from putting packets of pressurized air into the combustion efficiently based on the users wants to achieve.

 

Total power output, efficiency, cruising efficiency/ boost, is all affected by the hot side.

Having too small of a hotside creates higher backpressure in the exhaust manifold, which fights the boost that's trying to come in. lowering the engines potential for flowing air, which is power.

How good, really, is "instant spool" when you pick up 200hp, and power also throughout the whole range, from some tweaks on the hot side? People get waaaay to wrapped up in the "instant spool" and then end up fighting wastegate control and other issues.

Fact is, the turbine side is MORE important to size than the compressor side, but its also a lot more complicated than the boost side of equations.

 

How much power are you hoping to make? I have an eBay 7875 on a stock 5.0 SBF. Stock fuel system with flexfuel aeromotive 340 and stock lines and rails. I assume the -8feed will stretch the pump but my fuel pressure was dropping with straight pump E. I did Southeast Street and Yeet last week and blended the E down to E50ish and that seems to help the fuel pressure. I did run into boost creep but I have one poorly placed 44mm gate.

Looks forward to seeing your build!

 

Honestly the 390 is only a 9:1 compression engine with a mild camshaft. If it made 575 i would be over the moon. This car will have ac, 4r70w and will get driven. Im not so much interested in racing the dyno here. If it makes 8-10psi and is dependable and makes 450...im very happy.

 

is a milf camshaft better than a mild camshaft lol?Why not run a manual trans like a toploader, TKX ?It would make it a real fun street car especially with a responsive turbo .

 

S475 would even be on the small side but would work. I went with an s480 on a 395w. You have an adapter to bolt up the 4r onto an FE?

 

The 340 pump might be maxed out with E. Terminator X can monitor fuel pressure I would suggest you get a sensor. If you don't already have the 340 the next size up. Check out the chart from Real Street.

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