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Thread: Air flow, turbos, fuel and more?????s

  1. #1
    Join Date
    Mar 2004
    Posts
    115

    Default Air flow, turbos, fuel and more?????s

    Hi guys, As some of you know I have blown up the board with questions. Sorry for wearing eveyone out. I am in the middle of my build on my 6.5 and I am looking for as much info as I can get. I build turbo charged V-6s-v-8s for a living so forced induction is not new to me. I am looking to make 250-300 at the tire with my 6.5TD. Forget the mechanical limitations of the block crank etc. Lets focus on making the power. Opinions welcome.

    For a gas engine for every pound per minute of air you can make 10HP. So if your turbo flows 20 ppm you can make 200HP. I know this is over simplified but its the basics.

    Does the same rule apply to Diesel fuel?

    Looking at the maximum air requirement of a 6.5 with 15psi of manifold pressure

    1500rpm/19ppm
    2000rpm/26ppm
    2500rpm/32ppm
    3000rpm/40ppm
    3500rpm/46ppm

    This also aSSumes you can get the air in and out of the engine.
    I see no way you can do this with any of the GM turbos GM-8 etc. Not even close. I know you see 15 psi on your gauge but there is no way that turbo is moving that flow rate of air. I have also seen the back pressure on the GM turbos is crazy hi. Much over 8 psi. is 2 to 1. and then some. I am thinking that I should use a turbo that will meet the air requirements 15 psi manifold pressure. I am thinking a turbo in the 40ppm range. Thats enough air to make 400HP will easily supply more than enough air at a reasonable boost pressure with a minimum back pressure. Jim, JK, RJ any thoughts?

    Now how do we get the fuel to make this power with the DS4 pump and marine hi pop injectors? I do plan on having Kennedy burn a chip for the truck. I just hate to wear those guys out with questions till I figure out how to attack this monster.
    It was posted earlier that the DS4 can be turned up to 91mm . (I am assuming this is done with a chip)

    Approximately How much power can be made at that setting?
    How much would that be in Pounds Per Hour of fuel ?
    At what approximate Air fuel ratio is diesel performance optimal?
    Lonnie Diers Extreme Automatics
    1994 Chev 2500HD 532,119 miles 21,300 GCW towing machine.
    Original engine, injectors, replaced head gasket 1 injection pump, 3 turbos

    Ready to install ( was ready now changing to 18.1 pistons)
    New engine 4 bolt splayed steel caps
    Lightly ported heads
    Polished intake port matched
    HX35W Turbo
    Intercooler (very efficient tube fin design)
    Marine Injectors hi pop
    Cooling upgrades
    3" DP
    4"exhaust
    remote mount PMD cooler
    Fresh air intake (in the making)
    Gears ???? have not decided looks like 3.42
    250HP at the wheels or bust (maybe both)

  2. #2
    Join Date
    Mar 2004
    Posts
    115

    Default

    Ok Guys your not helping me much. I do know I need to get out more. I am going to move forward with my turbo Idea. Maybe Kennedy can reply to this question. How much HP can the DS4 supply fuel for? Does the pump need to be modified or can it all be done with a chip?
    Lonnie Diers Extreme Automatics
    1994 Chev 2500HD 532,119 miles 21,300 GCW towing machine.
    Original engine, injectors, replaced head gasket 1 injection pump, 3 turbos

    Ready to install ( was ready now changing to 18.1 pistons)
    New engine 4 bolt splayed steel caps
    Lightly ported heads
    Polished intake port matched
    HX35W Turbo
    Intercooler (very efficient tube fin design)
    Marine Injectors hi pop
    Cooling upgrades
    3" DP
    4"exhaust
    remote mount PMD cooler
    Fresh air intake (in the making)
    Gears ???? have not decided looks like 3.42
    250HP at the wheels or bust (maybe both)

  3. #3
    Join Date
    Sep 2001
    Location
    Lubbock TX, USA
    Posts
    4,194

    Default

    Finding which turbo works well for your application is going to be the key.

    Here is what I've found that works and I'm guessing get's pretty close to 300 flywheel horsepower.

    The chips on the market can call for max fuel from the DS4 which can put down (if a very healthy pump that is) approximatly 80cc's of fuel at the MOST.

    Which is enough, barely.

    You're right, the GM-x turbo isn't going to get close.

    Another key, this setup HAS to be used with a CHARGE AIR COOLER (aka intercooler).

    J

  4. #4
    Join Date
    Dec 2003
    Location
    SC
    Posts
    939

    Default

    Don't get frustrated you ask techie questions. Seems some have built close to 275 maybe almost 300 hp at crank 6.5 drivable and working trucks.
    Getting 250 + at wheels is the next step up and few do it mostly a little at a time. After the 250hp at crank mark money spent and hp developed is like hot boats and race cars the cost goes up exponentially with hp/speed increase. And you have to start making some trade offs low end loss and drivability etc. Again few do it.

    I am no expert but have read like John says around 80 mm^3 (81-84?) max for a DS pump. I think Westers garage modifies a DS pump for a bit more (maybe thats the 91 you posted). I think they configure a different cam ring or something internal. Read Pennsilar turns up a DB pump for thier hot rod 6.5's. One guy even mounted (2) DB pumps on a tractor for more fuel. I have read Heath's legendary 500hp 6.2 used a different IP entirely something off a medium duty truck.

    Just some suggestions for you to get the last 5-15 hp possible out of a DS IP 6.5. Timing gears, feeding the beast mod, FluidDamper balancer.

    Is this going to be a race motor, street truck, sleeper, or work truck?
    97 5spd K2500 Ext Cab short Bed ~160K miles.
    TM, 3" downpipe & 4" exhaust, remote FSD, remote oilfilter, Gauges: EGT, Boost, Fuel Pressure, B&W Gooseneck Turnover ball, Prodigy Brake Controller. Hi-Temp Hydraulic Oil Cooler Lines.

  5. #5
    Join Date
    Feb 2000
    Location
    Montana
    Posts
    11,382

    Default

    Quote Originally Posted by quickv6 View Post
    Hi guys, As some of you know I have blown up the board with questions. Sorry for wearing eveyone out. I am in the middle of my build on my 6.5 and I am looking for as much info as I can get. I build turbo charged V-6s-v-8s for a living so forced induction is not new to me. I am looking to make 250-300 at the tire with my 6.5TD. Forget the mechanical limitations of the block crank etc. Lets focus on making the power. Opinions welcome.

    For a gas engine for every pound per minute of air you can make 10HP. So if your turbo flows 20 ppm you can make 200HP. I know this is over simplified but its the basics.

    Does the same rule apply to Diesel fuel?

    Looking at the maximum air requirement of a 6.5 with 15psi of manifold pressure

    1500rpm/19ppm
    2000rpm/26ppm
    2500rpm/32ppm
    3000rpm/40ppm
    3500rpm/46ppm

    This also aSSumes you can get the air in and out of the engine.
    I see no way you can do this with any of the GM turbos GM-8 etc. Not even close. I know you see 15 psi on your gauge but there is no way that turbo is moving that flow rate of air. I have also seen the back pressure on the GM turbos is crazy hi. Much over 8 psi. is 2 to 1. and then some. I am thinking that I should use a turbo that will meet the air requirements 15 psi manifold pressure. I am thinking a turbo in the 40ppm range. Thats enough air to make 400HP will easily supply more than enough air at a reasonable boost pressure with a minimum back pressure. Jim, JK, RJ any thoughts?

    Now how do we get the fuel to make this power with the DS4 pump and marine hi pop injectors? I do plan on having Kennedy burn a chip for the truck. I just hate to wear those guys out with questions till I figure out how to attack this monster.
    It was posted earlier that the DS4 can be turned up to 91mm . (I am assuming this is done with a chip)

    Approximately How much power can be made at that setting?
    How much would that be in Pounds Per Hour of fuel ?
    At what approximate Air fuel ratio is diesel performance optimal?
    Your HX35 should be a big step forward, but an efficient 20 psi is where you should be going. This is a pressure ratio of 2.4, which is in the vicinity of 55 lb/min air flow at 3000-rpm. A 70% efficient compressor at 20-psi or more and at 55 lb/min will be a part of the equation to get you close to 300 FW. I don't know if the HX35 is the best choice for this combination, but it is a big step up from the GM series of turbochargers, when making power at higher rpms is important.

    x% exhaust opacity at rated power is what determines the fuel-rate you need. Shoot for 20%... You should be able to get close to 300 FWHP with the stock DS and the right programming (and the right engine build). Just such a turbo/engine combination is discussed in the upcoming article on turbochargers.

    Jim
    Last edited by More Power; 10-24-2007 at 17:38. Reason: typo

  6. #6
    Join Date
    Mar 2004
    Posts
    115

    Default

    I talked to JK today on the phone about the fuel pump. Thanks for your time John. He has convinced me that the DS4 will handle to job and I will buy my chip from him. I am really not sure what my plans are for the truck. It has been a work horse for me since 1999 and I have logged 300,000 of the now 468,000 miles on the truck. Believe it or not she still looks like a 50,000 mile truck. I guess I am looking for a hot rod truck that will pull my open trailer and enclosed to a few races a year. So hot rod/semi work truck.

    I know the HX35 is a little small for what i am looking for. I was thinking something in the 55ppm range. I am going to start with the HX35 and look for something else. I build intercoolers so I am looking at a very efficient air to air or maybe a liquid cooler with a heat exchanger. I like the liquid cause I can mount it anywhere and do not need air flow. The exchanger can fit in front of the grill.

    I am looking at the Phazer Gear drive and now own a fluid damper. I started this project 2 years ago finished engine and opted to sell the truck and buy new. After putting engine and old K2500 up for sale no one wanted to pay anything for a 460,000 chevy 6.5 no matter how nice the truck is. A 50K duramax is not going to happen. So I decided to go back to the original plan. I ma looking forward to the Turbo article to give some more Ideas to wear you guys out over.
    Lonnie Diers Extreme Automatics
    1994 Chev 2500HD 532,119 miles 21,300 GCW towing machine.
    Original engine, injectors, replaced head gasket 1 injection pump, 3 turbos

    Ready to install ( was ready now changing to 18.1 pistons)
    New engine 4 bolt splayed steel caps
    Lightly ported heads
    Polished intake port matched
    HX35W Turbo
    Intercooler (very efficient tube fin design)
    Marine Injectors hi pop
    Cooling upgrades
    3" DP
    4"exhaust
    remote mount PMD cooler
    Fresh air intake (in the making)
    Gears ???? have not decided looks like 3.42
    250HP at the wheels or bust (maybe both)

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