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Discussion Starter #1 (Edited)
My car currently has a single 340 LPH fuel pump and 42# injectors. Planning on better cylinder heads and a bit more boost. What power levels do those components support?
 

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Well, 42# injectors need a calculated 211.76 LPH to be supported, so you're well covered there.

You're a good builder, so, on a good build, they should support 500hp. (538 calc)

That number is probably +- 50%, depending on Engine, building ability, etc.; I'd probably not be that good. :)

I just happen to have a freshly rebuilt set of 60's, btw... :grin2: EDIT: I'm a DA, they're 42's.
 

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42# injectors will safely support about 500hp at the crank in a supercharged application. Given that you are making 375 to the wheels, presumably through an automatic and IRS, you are probably somewhere north of 450 at the crank right now, so I would say an injector upgrade is a necessity if you are doing heads and more boost. The pump itself will probably be OK, depending on a number of factors. In theory, that pump will support close to 700hp at the crank, but if it has to crank out a higher pressure against boost, that number goes down. If it has to push through stock fuel lines and rails, that number goes down. If you are running factory fuel pump wiring, which is undersized for the 340 pump, then the pump will not see the full 14v, and so the flow and therefore the amount of power it can support goes down. Even if you have all these things working against you, it will probably still support 550+ at the crank, so unless you are looking for more than an extra 100hp, you are fine.
 

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Discussion Starter #5
Thanks guys! Taking the next step with my powertrain is a complicated (and expensive) decision, so I appreciate your input.

A little more background info:
* Yes, my car has a built 4R70W and IRS.
* My estimate is that the power loss is 18-20%, so current crankshaft horsepower is 457-469.
* The "better cylinder heads" I'm looking at are the TFS Race 195 units.
* The "bit more boost" I'm contemplating is an increase from 11 psi to 14 psi.
* Another definite upgrade will be from non-intercooled SVO (water/meth injected) to intercooled supercharger (maybe TVS).

My initial thought was that, to be worth the effort and cost, I need RWHP to increase to at least 525, which would be 640-655 at the crank. Based on your comments, that would require 60# injectors and a Boost-A-Pump at minimum. Maybe larger diameter fuel lines and bigger gauge fuel pump wiring. Changing from my NPI heads to the TFS units has got to be worth 50-75 HP, and getting the IAT down into a reasonable range to accommodate more timing is probably worth another 25 or more. Add in a more efficient S/C design, and the 150 RWHP increase is definitely doable. In fact, the new combination might generate significantly more than that, but it would likely run into more limitations.

Any other thoughts or recommendations are welcome!
 

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Thanks guys! Taking the next step with my powertrain is a complicated (and expensive) decision, so I appreciate your input.

A little more background info:
* Yes, my car has a built 4R70W and IRS.
* My estimate is that the power loss is 18-20%, so current crankshaft horsepower is 457-469.
* The "better cylinder heads" I'm looking at are the TFS Race 195 units.
* The "bit more boost" I'm contemplating is an increase from 11 psi to 14 psi.
* Another definite upgrade will be from non-intercooled SVO (water/meth injected) to intercooled supercharger (maybe TVS).

My initial thought was that, to be worth the effort and cost, I need RWHP to increase to at least 525, which would be 640-655 at the crank. Based on your comments, that would require 60# injectors and a Boost-A-Pump at minimum. Maybe larger diameter fuel lines and bigger gauge fuel pump wiring. Changing from my NPI heads to the TFS units has got to be worth 50-75 HP, and getting the IAT down into a reasonable range to accommodate more timing is probably worth another 25 or more. Add in a more efficient S/C design, and the 150 RWHP increase is definitely doable. In fact, the new combination might generate significantly more than that, but it would likely run into more limitations.

Any other thoughts or recommendations are welcome!
Nice. Any reason why you'd go with a TVS and not a Vortech/centrifugal, I think it's easier to keep IATs down with those too since the air gets compressed a while before it gets to the engine, and probably easier to do an intercooler setup with too. Dunno.

Also how is your engine built up like? Just wondering what you got under there that can take 600+ hp.
 

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Discussion Starter #7
Fair questions. I like having a Roots-type supercharger because of the instant torque. I know a centrifugal is better for maximum power, but would require an air-to-air intercooler and piping which are bigger than the air-to-water intercooler and hoses used by most Roots-type units. The TVS is a relatively compact, highly efficient design which is used by OEMs; that tells me it is pretty durable.

My engine has forged pistons and rods. The crankshaft is cast, so it is the "weak link". I've read a few places that the cast crank is not an issue unless engine speed reaches 7000 RPM. My current setup has the rev limiter set at 6500 RPM, and that would not change. But, I am considering changing to a forged crankshaft for extra safety margin. Have also thought about putting in a stroker crank if I make that change (which would increase the displacement from 5.0 to 5.3L), but either approach adds a lot more cost and would require paying somebody to assemble the short block for me. I'm comfortable pulling the motor, replacing heads, cams, blower, etc, but setting up clearances in a bottom end is something I'd prefer a professional to do.

Another consideration in all of this is how much power the rest of the car can support and/or survive. We've already touched on the fuel system limitations. My transmission, driveshaft, differential and half-shafts can all handle about 600 HP, but going much past that might be asking for failures.

Lots of decisions to make!
 
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