tyoneal

Hello:

I have a '97 K2500 'Burb. 7.4 Vortec wore out and wanted to replace it with a Procharged, HO 502 Bottom end. (502 has 8.75 CR, and 112 LSA Cam) Brodix "Race Rite" Oval Port Aluminum Heads. (119 combustion chamber) D-1 Procharger with intercooler. Banks Performance Headers with high flow cats and mufflers. 65 pound injectors. 4L80e rebuilt for 1000 hp. 4.10 Differential. LS7 MAF sensor.

Stock EFI flows about 640 CFM (Stock Power 290hp/410tq) and I need to make enough airflow for 750 fwhp / 900 fwtq.

Questions:

1) I need a EFI induction system that will still work with the gauges, 4x4, and transmission electronics (4l80e).

What do I need to buy to get all this to work properly?

I have heard that the ECU #0411 is the best upgrade, and a newer PCM (Don't have any numbers yet) for the best tune.

Truck trys to make power but craps out at 3800 rpms.

2) Where is the best place to get this information if no one here has done something like this?

I am really behind the eight ball on this and I just need the correct combination of these parts to be on my way.

Please give me a hand if you can.

Thanks,

Ty O'Neal

Vortec350ss

iTrader: (20)

Wow sounds like it'll be a hell of a build.

I cant answer your questions specifically, but I know others will be able to.

The few things I would like to know more about... will the D1 be able to feed the 502 the way you want it to? Seems like a lot of cubes for that blower. Also, will the 65# Injectors be enough? How much boost are you hoping to make? How high do you think it will rev?

I would imagine this thing will be a monster!

tim wellington

this just my opinion i would call f.a.st . change intake to 4500 flange and run a flying toilet bowl type buteerflies and 65lb injectors are not enough unless u running two per cylinder .i knew a guy with similar set up if i remember right he made 1250 rwhp .he had a2water intercooler

tyoneal

Vortec350ss:

Thanks for reading my post.

My wife and I use this truck for everything and travel all over the country in it as well as using it to pull my tractor from place to place. On road trips we often spontaneously take off on roads that look fun and challenging.

I'm pleased you are certain I'm finally in the right place, I think my intensions were right but I trusted some advise that was lacking in accuracy.

It has the stock Throttle Body with upgraded injectors. When my 7.4 crapped out, the HO 502 was supposed to be a replacement engine. I was having difficulty pulling my trailer as it is very large, plus at altitude it was just a dog.

When my 7.4 went south I wanted to make sure the replacement had a forged bottom end, had low compression (8.75:1) and a cam with a LSA of 112 or higher

When I spoke with Procharger they mentioned that 65 pound injectors would be plenty, and the cam was good. With the intercooler the engine runs cool and without detonation at 9 psi.

The D-1 was suppose to be able to handle this engine fine especially since it won't be running at WOT very much if at all for any extended time.

The cam is set to work great from idle to 5500 RPM's. Just that amount should make good power, be dependable, and easy to live with.

I'm really just in a position to finishing it off in exactly the right way. Currently peak power is at 3800 rpm's at 305 rwhp and rwtq @ 4200 rpm's and 398 pound feet.

Not steller numbers by any stretch, but when these items are corrected the rear wheel numbers should show 550 - 600 rwhp, and 700 - 750 rwtq.

The truck is heavy, and the wheels are 32 inches high and I think this will be an excellent upgrade IF I can get the correct information to finish.

BTW: I live in Frisco, Texas just north of Dallas 20 miles. If people know of some great suppliers or tuners near me, that would be terrific.

Thanks again.

Ty O'Neal
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Vortec350ss

iTrader: (20)

With those RPMs in mind the D1 will be just fine! You will have to pulley down pretty aggressively though!

There are a lot of good tuners in your area. I'm anxious to hear what others with experience in this arena will come back with.

James B.

iTrader: (1)

I am going to assume the Procharger includes an FMU to increase fuel pressure, and probably a boost-a-pump electronic fuel pump voltage multiplier of some sort...

Let's start with the tuning. Your factory PCM only goes up to 1.0L per cylinder. That can be compensated for by artificially inflating the VE number in the main and backup tables. (These PCM are tuned differently than the later generations.) It's also got no option for a 2-BAR MAP sensor, but even than can be compensated for by artificially manipulating VE. With the 1-BAR sensor the PCM will only ever see 105kpa and the job of supplying the increased fuel falls to the MAF and the FMU adding fuel pressure. It's not an optimal scenario. I would also be willing to bet that you're maxing out your MAF sensor. I did that with a 383 and 10psi on my Tahoe. There are a couple options for that - you can split the intake symmetrically and run twin MAF sensors, one will be a dummy and one measures air, then int he tables you have to half the values. Or, you can omit the MAF. Your PCM can run that way with the MAF in a failed state, however that would have to be done in conjunction with the 2-BAR MAP sensor I mentioned so the PCM knows it's getting more air into the motor. (Running a 2-bar MAP also allows you to remove the FMU)

Guys here call the generation PCM you have the "Black Box". Getting it to run what you got is possible but a kludge at best. I happen to know this first-hand because I am the only one I know of here who has run one with a 2-BAR MAP. I can also tell you it is so difficult it tested the limits of my tuning ability. For this reason I recommend against trying.

The best solution is to retrofit your harness to a 411 PCM. These will accept the Gen-III engine MAF sensors which have a higher frequency range, and thus measuring range, than the GMT400 Vortec stuff. There are also custom OS mods for that PCM that allow you to properly run a 2-BAR MAP sensor with no tricks.

You've got two paths to choose from when converting to a 411 PCM.
- You can start with the Express Van calibration which support the distributor, the 1x reluctor on the distributor, and the 4 reluctor on the crank.
- OR you can install LS-type coil per plug distibutorless ignition in conjunction with an L21 reluctor ring (24x) for the crank. When doing this you need to either be able to reprogram the firing sequence and bank assignment in the PCM, or swap the cam to a Gen-VII (aka Vortec 8.1) BBC cam.

Your setup has potential. I am very familiar with that bottom end and those exact head. The problem is in the EFI.

tyoneal

Tim:

Thankks for the post.

I spoke with FAST and they had a syatem that would really make the engine breath, however I am concerned with the other items that run off of the computer. Specifically the gauges, 4x4, and the transmission. 4L80e.

That seem to be the rub on alll of the more popular systems. They just don't know which if any will work with their computers so they all say I need to speak with people who have already done this type of swap.

I know I can't be the first one doing this in a 1997 Truck, I just haven't found the people who have.

I'd be tickled pink with 600 rwhp, the truck would feel like it weighs 1500 pounds, at least until I need to turn. or stop.

Does anyone know if I am trying to do to much?

If things are tuned properly and I'm able to get a good complete burn in the engine, pipes and cats, shouldn't it have a fairly clean exhaust?

Thanks again for you help, I'm going to check out the items you recommend. I may very well have missed them, or not properly worded my question to the Tech help.

I appreciate your time.

Ty

tyoneal

===========================
I am as well.

The tuner has done many cars for a number of years, however he said that he hadn't done one like this with a truck and a stock throttle body even though the injector were 3X as big as stock AND 9 psi was pumped. The TB could only pass 640 cfm, with the needs of just the 502 requiring 850 cfm N/A. (this was the recommended carburetor size) I didn't know the stock TB was so lame until I really did the research.

Live and learn. This is my first blown application so my learning curve is almost vertical right now.

Thanks for posting and I will keep things updated especially with the new information I learn here.

Ty

tyoneal

James:

Your information sounds really interesting. Here is what I know that I'm working with in more detail. I will confirm as soon as I pull all everything together.

Dyno Tuner: HP Tuner (?) maybe.

GMPP HO 502ci Crate Forged bottom end

Brodex Heads Aluminum BBC "race rite" 26*

Bank's Engineering 7.4 BBC "Tourque Tubes" w/ High flow Cats

D1 Procharger Supercharger

I'm thinking thse are the injectors:
Fast 60# injectors #306008

8-pack of 60 LB/Hr High Impedance/Long Injectors Fuelairspark.com

Walbro 465

Remove fuel tank, old fuel pump
Modify tank for walbro 465 high flow pump
Walbro 465 LPH DCSS Twin Turbine High Pressure Fuel Pump (E85 Compatible)

PCM (Remanufactured)2001 Chevy Express 5.7L 4L80E

MAF Sensor (GM LS7)
Silicon Reducer, 4.00" to 3.5", 45 Degree Bend Shipping (for both couplers)
MAF Housing Fabrication
MAF Adapter
============================
Analysis and recommendations:

Exhaust Fabrication For Cat-Back Including two flowmaster mufflers all the way to rear of truck

Single plane intake, 1100CFM Carburetor, Long tube headers. Suburban from the factory makes 180rwhp. The Suburban still has the factory induction, throttle body, intake, Short tube headers.
To reach potential of motor and blower there will need to be some major changes
.New stand alone computer, harness. This will more than likely cause issues with 4x4 controls that are controlled with factory computer.
Might need bigger injectors?
Complete new induction to be fabricated. .Long tube headers
Larger blower piping
Larger intercooler
More fuel system
Estimated Horse Power with these changes will be 480-520RWHP

I will need to research what you wrote to make sure I understand it all. I'm very happy you chimed in. Can you tell me more about your tahoe? It's very cool you have already gone through all this.

Thanks again for you post.

Ty

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James B.

iTrader: (1)

I wouldn't let the transfer case compromise the goals here. The autotrac case is doesn't have the greatest torque handling abilities any way. There is always the option of swapping it out to a manual case. If you do decide to go with an aftermarket harness be sure transmission tailshaft sensor is feeding the PCM and not the one in the case, otherwise it will cause havoc in 4lo. The VSS in the transfer case supplies the instrument cluster and the ABS.

The last boosted motor I've had was a GMPP HT383 shortblock with Edelbrock e-tec 200 heads, 1.6:1 roller rockers, 114LSA cam, and a marine intake with 63# Siemens injectors. It also had long tube headers and true-dual 3" exhaust with metallic cats. The transmission was a 4L80-E with a Gear Vendors overdrive andd 4.56:1 gears in a custom 10.5" rear with Eaton Posi. Boost came from a 2.3L Whipple overdriven to 10psi with a huge air-to-water intercooler.
As for the EFI, I ran this with the stock 1999 PCM (96-97 are the first generation and 98-2000 are the second generation of the "block box") It had an LT1 knock module installed in it. The transmission was controlled by a stand-alone TCI TCU left over from the days before we had the ability to tune these PCMs with TunerCATs. I had the IAT sensor moved to a bung after the intercooler. No MAF. No Whipple electronics or auxiliary injectors. A 2-BAR MAP sensor was used. Fuel pressure was regulated to 3 BAR instead of GM's usual 4 BAR using an Aeromotive regulator. The reason for this is that the factory pump can actually move a greater volume of fuel at the lower pressure. The injectors were Siemens 63#. Stock throttle body, 72mm.
I had to toss the MAF early on because it was being maxed out at full power past about 4500 RPM. Getting the 2-BAR MAP to work was the trickiest. Basically, I went into every table that referenced kPA and manipulated the data. So, for example I'd start at 15 kPa, and then copy the values from the 20 kPa column into it. Then into the 20 I would copy the 30kPa values, and then into the 25 copy 40's values, and so on until I was putting 105kPa's values in the 55kPa column. The rest of the table from 60 on had to be fabricated loosely based on the curve established by the existing values.

Here's that voltage table:


The hardest thing was getting it to idle. There 2-BAR MAP has half the resolution than a 1-BAR does and the slower processor int he black box PCM has a tough time making rapid adjustments. Once off idle though it ran perfectly. The timing was tuned for 91 octane.

Here's the engine bay:





And here's how it ran:
http://bertok.us/pics/0-120.mpg

This was on drag radials trying to figure how hot they needed to get to stick. (Answer=VERY, I did eventually get those tires to work and have photos with the front wheels in the air.)
http://bertok.us/pics/DR-Launch.mpg

After the 383 broke the snout off the crank from the blower torque I put a 454 into it. Drove it that way until replacing it with the 98 Suburban I drive now. I have a 3.3L Whipple and another intercooler for the Suburban's 502, but I haven't began the fab of that system yet. I will be running that with the factory PCM at first, with the possibility of a 411 and 2-BAR custom OS and coil per plug ignition later. I have smog to consider here and need to retain the ability to entirely swap back the Suburban's OEM 454 every two years. That was something that became impossible with the Tahoe.