tyoneal

Hello:

I picked up a HO 502 from GMPP rated at 450/550. The 454 on my 1997 Burb went south on me and I needed to replace the engine. I do a lot of hauling so I wanted to make sure I would have more than enough.

Weight of Truck 7500 pounds. (guessing, as it has heavy bumper and 32 inch Tires)
Transmission is a 4L80e built for 1000 hp.
Differencial is a 14 bolt with 4.10 Gears

I bought the GMPP HO 502 and wa sgoing to run a D-1 Intercooled Procharger on it for some great improvement. Below are the specs of the New Engine:

Block (P/N 19170540): Cast-iron with 4-bolt main caps
Crankshaft (P/N 10183723): Forged steel
Connecting Rods (P/N 19170198): Forged steel, shot peened
Pistons (P/N 12533507): Forged aluminum
Camshaft Type (P/N 24502611): Hydraulic roller
Camshaft Lift (in): .510 intake / .540 exhaust
Camshaft Duration Part Number: 12568778
Engine Type: Chevy Big-Block V-8
Displacement (cu in): 502
Bore x Stroke (in): 4.470 x 4.000
Cam: Lift .510 intake / .540 exhaust
Duration (@.050 in): 211° intake / 230° exhaust
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Removed and replaced with Brodix race rite heads (See below)
Cylinder Heads (P/N 12562920): Iron rectangular port; 118cc chambers
Valve Size (in): 2.190 intake / 1.880 exhaust
--------------------------------------------------------------------------------
Compression Ratio: 8.75:1
Rocker Arms (P/N 12523976): Stamped steel
Rocker Arm Ratio: 1.7:1
Water Pump (P/N 19168606): Cast-iron, long-style
Flexplate (P/N 10185034): 14"
Recommended Fuel: 92 octane
Ignition Timing: Base 8° BTDC, 30° Total
Maximum Recommended rpm: 5,500
Balanced: External
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It was said to be a replacement engine for my Truck so I expected I could used the Bank's Torque Tube Headers I had along with the EFI. I upgraded the stock EFI to 65 psi injectors and found out that it would only hook up to OVAL port heads. I picked up a pair of Brodix Oval Port Aluminum Heads.

http://www.brodix.com/heads/big-bloc...block-series26

Competition Valve Job
• Intake Valves:
2.250 x 5.218 o.a.l. – BR 81040
2.190 x 5.230 o.a.l. – BR 70019
• Exhaust Valves:
1.880 x 5.394 o.a.l. – BR 81038
• Valve Springs:
1.550 Hydraulic Roller Valve Spring – BT 120121,
140 lb Closed, 400 lb Open,
1.950 Installed Height,
.600 Maximum Lift
1.550 Roller Valve Spring – GA 1000,
240 lb Closed, 550 lb Open,
1.950 Installed Height,
.700 Maximum Lift
1.640 Roller Valve Spring – MA 221424,
250 lb Closed, 745 lb Open,
2.050 Installed Height,
.800 Maximum Lift (Spring Upgrade)
• Retainers:
1.550 10° Steel – CC 752
1.625 10° Titanium – MA 23640
• Valve Locks:
10° Jumbo – CC 611
• Rocker Studs:
7/16 – BR 716L, AR RRS-4I
• Guide Plates:
3/8 – CC 4806
• Valve Seals:
11/32 – US VS529V

The Distributer required updating and a proper MSD was added.
WITH 9 psi of Boost

Max rwhp @ 4250 rpm's = 307.18
Max rwtq @ 3800 rpm's = 397.36

The figures decline from there to 214 rwhp and rwtq @ 5300 rpm's.

I do believe this really sucks. Where have I gone wrong? I run this on and off road all the time and I was wanting some real grunt. I figured a Drive Train Parasidic Loss of 30% which should still support a rwhp of 519 hp, and rwtq of 635 pound feet.

Any help you can offer would be really helpful. I called Procharger and they thought it was suffereing from belt slip, however things were re-checked and that doesn't seem to be the case, plus the boost stayed constant at 9 psi through the pull, I was told.

It is running Large Duels, but maybe the header are to small? I couldn't find the specs on them as Banks no longer makes them, but Banls from my experience usually does their homework and things are well engineered as a rule.

I thought maybe the EFI was too restrictive, but I still can't figure how power would continue to drop if the boost was constant and the A/F remained balanced?

I REALLY NEED SOME SOUND HELP. I USED THIS TRUCK TO PULL MY TRACTOR AND TO TAKE MY WIFE AND I ON GREAT ROAD TRIPS. I have to make this thing perform correctly.

The tune was done by a Procharger Dealer.

I hope this is enough information to start getting some hard answers.

Thank you in advance for any help you can offer.

Ty O'Neal

uxojerry

I would have expected those hp/tq numbers from your engine with no boost. The race rites should have put your gross to 500+. Something is definitely wrong. I would have expected 500rwhp from your set up.

tyoneal

Jerry:

Thanks for the post.

I believe I have found what the issue is.

I am needing to find a EFI induction system that can move enough air so the injectors can put enough fuel into the engine to make the power.

I thing I need to make sure of is when another ECly
you is used to run the EFI, I don't want to have any problems with the gauge cluster not working correctly, nor the programming for the transmission or 4wd.

Does this seem to be a reasonable view of the problems and issues?

Whoever has any ideas they can share especially from personal experience, I would really appreciate hearing from them.

Jerry, thank you again for posting. I do agree with you on your thoughts.

Ty
=====================

uxojerry

I would recommend running the truck down to a modern day tuning shop. I would guess they can get the efi and D1 working together. Another option is to contact 427hotrod. He did a 555 twin turbo with efi and could probably steer you in the right direction.

You have a really nice set up and it ought to be making big numbers. It could be the 9psi reading is artificially high due to the efi. Is this a ramjet efi? You could try a smaller pulley and see if your hp goes up.

Your set up could be running an F2, lol. A cheap solution is to ditch the efi and go with a blow thru carb set up. This allows you to ditch the intercooler as your boost numbers will be low enough for blow thru cooling effects.

tyoneal

Jerry:

Thanks for the additional information, I'll will give 427hotrod a shout.

If I can't find a suitable EFI system, the Blow through Carb you mentioned, would be a great idea. Do you have any idea if someone who has Free Flow Cats on their car, the headers have a EGR set up, and a very accurate induction system is propely tuned, would there be much of a chance that this truck could pass a sniffer test for the annual inspection?

Since the cam is not crazy with overlapp, and the cat are in a good place to get nice and hot I was hoping that it might pass the sniff test.

Anythoughts?

Thanks again for the tip and help. I really do enjoy hanging with like minded people about such cool things as engines and cars/trucks.

Take care,

Ty

uxojerry

The Edlebrock pro-flow would be a nice edition to your engine and provide the modern efi programming you need.

jcb5565

With that many Cubic Inches and only 8.5x1 compression your supper charger may not be able to move enough air. I would check with Procharger and see if that super charger is correct for you.

tyoneal

Thanks for the advice. I followed up with Procharger and they said given my truck won't be running at wot all the time, it should be plenty for the times it is to the floor. He mention that when you spin the SC to fast they get to hot, so unless I see the temp start rising it should be fine without having to spend the money for a "F" series.

I am re-dueing the exhaust as it is wicked loud. Once I get that taken care of then I'll look to getting a Edelbrock "Pro Flow" system.

Then at lomg last can I be finished with this ongoing project. Has have other projects I would rather be messing with.

Are there other thoughts you have in mind that could make things easier?

Ty

tyoneal

Which Pro-Flow system do you think would be the best for my truck?

Ty

uxojerry

The proflow xt is the one Im looking at. There are several software choices so make sure you get one that accommodate FI. There aren't many bbc's using the proflow, but a lot of LS guys are happy with it.

I had a nasty BBC 477 built and am thinking about the proflow xt in case I want FI later.

I honestly think you should take your vehicle to a new tuner and see if they can identify why your not making power. It could be something very simple. I would think the set up you have should work for your goals.

Other than a low dyno reading, how does the truck feel under boost? Is it possible you are getting low numbers due to the auto trans, heavy weight, etc?