Author Topic: 87 4x4 6.0/6l90 swap  (Read 360 times)

Offline jobobcat18

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Re: 87 4x4 6.0/6l90 swap
« Reply #15 on: May 15, 2018, 04:08:37 PM »
What size is the pump outlet?  Probably -6 AN, which is 3/8".  The Pollack valve has 3/8" Feed.  Most sites will tell you that -6 AN is capable of supporting up to 500 hp.

Your 340 lph pump only flows 340 lph at freeflow (0 psi).  It doesn't flow that at 60 psi.  Plus your injectors will only flow so much.
I'm new to fuel systems so please excuse if what I say is incorrect. My goal is to push the engine to about 510-520 hp. Which i believe it can be done with a tune, electric fans, headers, cai, texas speed vvt stage 1 cam, and new injectors possibly. I'm wanting to keep the dual tank so I was looking at the Pollack valve. I have read that the 255 lph pump wouldn't supply enough for over 500. So I was thinking about a 340 lph pump. Do you think my goals here are achievable with the valve or should I go single tank?

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Offline ehjorten

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Re: 87 4x4 6.0/6l90 swap
« Reply #16 on: May 16, 2018, 10:50:17 AM »
Well...the 2016 Chevrolet Express Van with the Gen IV 6.0 L96 made 342 HP @ 5,400 RPM SAE & 373 lb.-ft of torque @ 4,400 RPM SAE.  It has I think 50 lb/hr flow rated injectors at 58 psi.  That high flow of injectors is for the E85 of the flex fuel programming.  So...the injectors can support a lot of HP, but what is realistic in your vehicle?  You say you think you can make 510-520 HP?

Well...naturally aspirated engines are most efficient in the 0.4 to 0.5 BSFC.  That is 0.4 to 0.5 lb/hp/hr.  If you are making 520 HP then at 0.4 BSFC you need 208 lbs of gasoline.  208 lb of gasoline divided by 8 injectors is 26 lb/hr.  With an injector duty cycle of 80% that equals 32.5 lb/hr injector rating.  At 0.5 BSFC that is a 40.6 lb/hr injector.

Gasoline density is about 6.073 lb/gal, so you need somewhere between 34 and 43 gallons/hr to support 520 HP.  That equates to between 129 to 163 lph, so I don't see where you would need the 340 lph pump, but you have to look at the volume provided at pressure.  Pumps are rated at free flow, so you need to look at the flow curve.  A typical Walbro 255 pump flows about 189 lph at 60 psi and 12 Vdc.  That same pump flows about 227 lph at 60 psi and 13.5 Vdc.

Now, forced induction is less efficient than naturally aspirated.  The BSFC can be up to around 0.75.  That means to make the same 520 HP in an engine that is turbo'ed or supercharged, you would need 390 lbs of gasoline!

My guess is that you are going to be fine with the 3/8" fuel line.  That is the size of the feeds on the Pollack valve.
« Last Edit: May 16, 2018, 10:57:58 AM by ehjorten »
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline jobobcat18

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Re: 87 4x4 6.0/6l90 swap
« Reply #17 on: May 16, 2018, 11:29:12 AM »
Nice write up my friend. The 510-520 rating I'm estimating is for sure flywheel power. I know the van engine is rated less than the truck's 360. However I could not find a mechanical difference between the engines and I also seen where a boxed tune would give the truck l96 40 hp. That's where I got the number from. This is my first rodeo for anything like this, gotta start somewhere I suppose.

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Offline jobobcat18

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Re: 87 4x4 6.0/6l90 swap
« Reply #18 on: May 16, 2018, 11:34:41 AM »
Another question. Would it be better to run the filter/regulator before or after the valve? I dont mind buying 2 of them if it would be a better option.

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Offline ehjorten

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Re: 87 4x4 6.0/6l90 swap
« Reply #19 on: May 16, 2018, 01:01:34 PM »
Run it after the valve.
-Erik-
1991 V3500 - Gen V TBI 454, 4L80E, NP205, 14 bolt FF, D60, 8" Lift on 35s
1977 K20 Silverado - 350, THM350, NP203, 14 bolt FF, D44, Stock Lift on 31s
1969 Chevelle Malibu Sport Coupe - EFI350, THM350
1968 Chevrolet Step-side Pickup - 300HP L6

Offline jobobcat18

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Re: 87 4x4 6.0/6l90 swap
« Reply #20 on: May 16, 2018, 01:49:37 PM »
Run it after the valve.
Gotcha. I appreciate the help on that.

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