Marine Intake is on and running.

[Fast355]

http://www.youtube.com/watch?v=N2qH75oYnyMBasically

Starting a new thread with a question from the last post of another.


That intake looks great. Mine was painted Mercruiser red all over. Good luck with your retrofit.

If you are planning on using the stock injectors, I had a set flowed and they came out at 25 lb/hr at 43.5 psi. Comes out to 28.9 lb/hr at 58 psi (4BAR) which is the pressure the marine regulator outputs with with the vaccuum reference unplugged. Plugged in pressure comes down to around 52psi.

peace
Hog

Hog are you sure that those injectors come in all Marine intakes. I picked up so much airflow through the MAF its retarded my timing to 22° at WOT but thats not the biggest issue. Even using your flow value I am running 10:1 air/fuel ratio at WOT and my long term fuel trims are around -15%. Either I was tuning around a massive vacuum leak before or now have larger injectors than your intake came with. Fuel pressure rises to 60 psi with the KOEO.

[Hog]

Not 100% sure. #280 150 081 is what my intake came with. They are the same as about 8-10 marine intakes that a buddy had at one time.

Your KOEO sounds about right. The injector report I am staring at for the injectors is 25 lb/hr at a 43.5 psi.

Hmm.

peace
Hog

[Fast355]

Not 100% sure. #280 150 081 is what my intake came with. They are the same as about 8-10 marine intakes that a buddy had at one time.

Your KOEO sounds about right. The injector report I am staring at for the injectors is 25 lb/hr at a 43.5 psi.

Hmm.

peace
Hog

My intake came off of a 6.2 MPI so perhaps that is the difference. It was also returnless initially.

[Hog]

I'm getting the same p/n on the injectors across the 5.0/5.7/377/6.2 on the cross ram L31 look aike marine intakes.

here is the list


350 MAG MPI ALPHA/BRAVO


350 MAG MPI ALPHA/BRAVO EC


350 MAG MPI HORIZON ALPHA/BRAVO


350 MAG MPI HORIZON ALPHA/BRAVO EC


350 MAG MPI HORIZON MIE


350 MAG MPI MIE


350 MAG MPI SKI


377 MAG MPI BRAVO


377 MAG MPI BRAVO EC


4.3L MPI ALPHA/BRAVO


4.3L MPI ALPHA/BRAVO EC


5.0L MPI ALPHA/BRAVO


5.0L MPI ALPHA/BRAVO EC


5.7L MPI HORIZON MIE


5.7L MPI MIE


5.7L MPI MIE EC


5.7L MPI SKI


5.7L MPI TOWSPORT WITH GEN III


5.7L SKI EC


6.2L MPI HORIZON MIE


6.2L MPI MIE


6.2L MPI MIE EC


MX 6.2L MPI BRAVO


MX 6.2L MPI HORIZON BRAVO


MX 6.2L MPI HORIZON MIE


MX 6.2L MPI MIE

p/n 879312003 is the common injector. Same regulator is listed as well.

peace
Hog

[Hog]

You are using the injectors in your pictures correct? EV6/USCAR connectors.
Like these?
http://i1202.photobucket.com/albums/bb373/Paul_Schermerhorn/iamf.jpg (http://s1202.photobucket.com/user/Paul_Schermerhorn/media/iamf.jpg.html)

Only way to know for sure is next time you pull one out, take note of the part number;0-280 150 081 are 25 lb/hr@ 43.5 or 28.9lb/hr@58psi or 29.4 lb/hr@60psi.

Which t-body did you use? A Vortec truck, or marine T-body. If you use a truck T-body a gasket must be used. I 1st installed it incorrectly and had a massive vaccuum leak.

Are you using the marine IAT/MAP combo sensor?

peace
Hog

[Fast355]

You are using the injectors in your pictures correct? EV6/USCAR connectors.
Like these?
http://i1202.photobucket.com/albums/bb373/Paul_Schermerhorn/iamf.jpg (http://s1202.photobucket.com/user/Paul_Schermerhorn/media/iamf.jpg.html)

Only way to know for sure is next time you pull one out, take note of the part number;0-280 150 081 are 25 lb/hr@ 43.5 or 28.9lb/hr@58psi or 29.4 lb/hr@60psi.

Which t-body did you use? A Vortec truck, or marine T-body. If you use a truck T-body a gasket must be used. I 1st installed it incorrectly and had a massive vaccuum leak.

Are you using the marine IAT/MAP combo sensor?

peace
Hog

Yea the ones I am running are EV6/USCAR but they have a red band at the bottem, unlike the ones I have seen on the marine setups. I guess I need to pull the dog house and get some numbers soon.

I am running a CFM Tech bored truck throttle body with a 454 Vortec Gasket.

I am running the marine IAT/MAP sensor since I got a connector with my intake. The MAP seems to read perfectly.

[Fast355]

I found out that someone switched the injectors for a set of 03-08 5.7 Hemi injectors. No need for injectors that are rated at ~28 lb/hr in my engine. I swapped them for a set of 2006 4.7 flex fuel injectors I had kicking around that flow ~24 lb/hr @ 43.5 psi. I messed around with the tune a little today and the engine wraps up and goes now once it gets up on cam. Really needs the headers and exhaust now, but its running GREAT.

[Fast355]

Has a lean stumble on take-off around 2,000 rpm that shows up exactly at the stall speed.
Also get alot of knock retard on the WOT 2nd gear torque converter lockup at about 60 mph.
Runs pretty well otherwise.

http://www.youtube.com/watch?v=x7wo0EjjNNU

[Fast355]

I found the lean spot it was the PE fuel delay being set at 2,000 rpm. I guess the PCM could not react quickly enough to keep it from leaning out at the stall speed. I lowered the delay to 1,000 rpm and the lean spot vanished.

I also turned off the 2nd gear WOT lockup and had to lower the timing in a few cells around 4,000-4,600 rpm. Also turned the catalyst overheat code back on and am using it for a unique reason now. The 350 likes 28* of timing and 13.4:1 air/fuel ratio on the initial hit and I am using the catalyst overheat to richen the mixture back up to 10.7:1 in steps. Then using the AFR timing compensation table to retard the timing progressively as the mixture richens. This eliminated the WOT knock retard I was seeing without requiring me to run a richer AFR to start with. At prolonged WOT I am very close to stock timing values and nearly a full point leaner on the air/fuel ratio!! That is how conservative the factory tune really was.


http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=5655&stc=1&d=1382157937


http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=5656&stc=1&d=1382157937

Also should mention these timing/fuel values will likely not work out well running the stock, high heat range platinum tip plugs and stock thermostat temperatures. I am running a 170*F thermostat and run cooler heat range copper R42LTS spark plugs in my Vortec head engines. Also run 93 octane gasoline that seems to have very little ethanol in it.

Its looking like this tank is on track to take me about 450 miles or about 16 mpg. Not bad for a fullsize conversion Express with a 4L80E driving around the congested Dallas Fort Worth area.

[Fast355]

Hit up a Dynojet today. It was 46*F outside when I hit the dyno. The 4L80E in 2nd gear definately takes some extra HP to spin compared to the locked 4L60E in 3rd. It was done in 2nd because I did not feel like testing my luck with the cut down, balanced, stock GM driveshaft spinning 6,000 rpm. Last dyno was nearly 300 RWHP/350 RWTQ on a Mustang dyno. The Marine intake is definately making more HP than the original intake.

Run 1 was an unlocked converter
Run 2 was the converter commanded locked with HP Tuners.

On Run 1 the fan clutch started coupling at 5,000 rpm and roared the fan pretty hard up top. Although if it were not for the underdrive crank pulley, I think it would have take a heavier HP toll.

I am not certain how much more the 4L80E is taking, but I do now that a 4L60E and 8.5" 10-bolt takes about 15-18% of the power with a locked converter. I would think the 4L80E and GM 9.5" 14-bolt take a little more, maybe as much as 20-25%. At 20% that is 405 HP to the flywheel turning a mechanical fan with stock single cat LT1 F-car exhaust manifolds. If its 25% that is 430 HP at the flywheel! Wonder how it would look with a slightly bigger cam, better heads, and my doug throley Tri-Ys.

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=5659&stc=1&d=1382203907

[Fast355]

Here is a screenshot of a steady cruise at 75 mph on the highway on flat land.

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=5661&stc=1&d=1382207400

[EagleMark]

Well it's not struggling pushing that big heavy brick at 75 and to get 16 MPG there I'd say job well done! :thumbsup:

What's a marine intake worth? With injectors, rails and TB? Or easier question should I pay $300 for one? What to look for as far as defects ETC...

[Fast355]

What's a marine intake worth? With injectors, rails and TB? Or easier question should I pay $300 for one? What to look for as far as defects ETC...

Sounds like a fair deal. Just look for corrosion and cracking.

[Fast355]

Well it's not struggling pushing that big heavy brick at 75 and to get 16 MPG there I'd say job well done! :thumbsup:.

I am not stopping there though Mark. I picked up some Dorman replacement fans for a 2008 5.3 Tahoe and 3 relays to create the OE style pcm contolled dual fan setup. I have also never been a fan of the stock airbox setup and will be installing an 85mm 5 pin 5.3 maf I have hanging around and either a 3" or 4" custom cai setup. I am pulling down to 93 kpa at 5,300 presently. I feel the changes will put some extra power into it.

I have had a set of LS1 fans on this but the OE 130 amp alternator could not handle the idle draw. The 220a replacement should be able to handle the 40-50 amps of the Tahoe fans on high just fine.

[JeepsAndGuns]

I am just curious because I have seen yall talk about this "marine" intake in a couple threads. What makes this intake different/better/more sought after? I know very little about chevy engines/intakes.

[Fast355]

I am just curious because I have seen yall talk about this "marine" intake in a couple threads. What makes this intake different/better/more sought after? I know very little about chevy engines/intakes.

I borrowed a few pictures around the net a will let them speak for themself. The Marine intake uses external injectors that can be upgraded. The spider type sits in the plenum of the intake and is limited in flow. My mildly cammed engine was close to maxing out the stock injectors at 85% DC. Then notice how much less trash the air has to flow around in the marine intake without the spider in the way.

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=5666&stc=1&d=1382280304

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=5667&stc=1&d=1382280304

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=5668&stc=1&d=1382280304

[lwrs10]

I am just curious because I have seen yall talk about this "marine" intake in a couple threads. What makes this intake different/better/more sought after? I know very little about chevy engines/intakes.


The stock Vortec 5.7 has the injectors under the upper plenum. People call them the poppit or spider style injectors. Not only are they not upgradeable, they create a pretty big restriction in airflow. they are right in the intake runner paths on a few runners.

The marine one is open on the inside, since it uses normal style injectors mounted on the outside with normal fuel rails.

[JeepsAndGuns]

Oh wow, I see now. No wonder you and other people wanted that intake. I have never seen the inside of the stock intakes, and I must say, that is not the best design I have seen.

[1project2many]

Vortec heads were actually used in Marine applications before the trucks. The first application I'm aware of is around '92 IIRC. Although many people want the truck style intake to keep the engine looking stock-ish and minimize the amount of changes to the truck, there are other marine intakes that can be found.


http://home.metrocast.net/~shannen/efistuff/S10/MarineIntake1.JPG
http://home.metrocast.net/~shannen/efistuff/S10/MarineIntake3.JPG

http://home.metrocast.net/~shannen/pics/Mpfi3.jpg
http://home.metrocast.net/~shannen/pics/Mpfi4.jpg

I picked these up years ago but there are other options today right out of aftermarket manufacturer's catalogs. Good thing, too. Anything that looks like a marine manifold usually fetches top dollar these days.

[Fast355]

Got the Tahoe fans all wired up to discover I had a bad relay and a wrong relay. I will be picking up a better set of relays today. Already swapped in the massive 34" x 18" x 2 3/16"core radiator into place to match the fans. Everything is soldered, heatshrunk and fused. I will throw the loom on it once I get the relays swapped. Somehow I obtained a SPST relay with dual outputs rather than a SPDT with switched outputs. As soon as it activated for high fan it would short power to ground and blow the fuse.

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=5673&stc=1&d=1382361467

[lwrs10]

Vortec heads were actually used in Marine applications before the trucks. The first application I'm aware of is around '92 IIRC. Although many people want the truck style intake to keep the engine looking stock-ish and minimize the amount of changes to the truck, there are other marine intakes that can be found.


http://home.metrocast.net/~shannen/efistuff/S10/MarineIntake1.JPG
http://home.metrocast.net/~shannen/efistuff/S10/MarineIntake3.JPG




I picked these up years ago but there are other options today right out of aftermarket manufacturer's catalogs. Good thing, too. Anything that looks like a marine manifold usually fetches top dollar these days.


That is the intake I am running!

http://i.imgur.com/eGUxTaUl.jpg

[Fast355]

http://www.youtube.com/watch?v=hdzYKsGIpC4

Fan wiring is loomed and fans installed. Still cannot get the PCM to activate the fans with the a/c but altered settings on the low speed for the present time to run anytime the engine is warmer than 30°F and less than 40 mph. I will add in a dioded circuit to the compressor relay or run my old method of an auxiliary fan control on the pcm and temp switch in the head for high speed.

The voltage does not even quiver with my 220a alternator although I do need to tweak the idle air volume for the fans some.

[lwrs10]

you either have to activate the AC fan control in raw hex in the system segment(best way), or swap in a camaro system segment. None of these can you do in HP tuners.

[EagleMark]

Lots of options in EFI Live and looks the same in TunerCat? Or am I missing something?

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=5680&stc=1&d=1382498860

[Fast355]

Lots of options in EFI Live and looks the same in TunerCat? Or am I missing something?

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=5680&stc=1&d=1382498860

I can control low speed just fine. High speed just clicks the relays. Considering just hooking back up the temperature switch in the head.

[Fast355]

I can control low speed just fine. High speed just clicks the relays. Considering just hooking back up the temperature switch in the head.

Cylinder head mounted fan switch method is now being used and the setup is cooling well. I have only heard high fans activate once after a stopping in traffic right after a taking a heavy beating at prolonged WOT!

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=5745&stc=1&d=1383507230

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=5746&stc=1&d=1383507230

[brian617]

What year 4L80e are you using Fast?

[Fast355]

What year 4L80e are you using Fast?

2002

[Fast355]

Someone got ambitious and datalogged after adding 2° of timing across the board under load and 2° more in the heavy load, lowest rpm area. Still massaging a lean spot caused by the intake but this thing pulls harder now than ever. The only time I am seeing any knock retard is at the lowest speed the converter stays locked in overdrive while aggressively opening the throttle. No timing was added in the trouble area but I am considering adding a little more burst knock back in and around that area to prevent it from doing it. I have also considered slightly raising the lockup mph to keep the engine from seeing that load.

[Fast355]

I raised the TCC lockup to 60 mph and the lockup induced lugging and spark knock is no more. I am able to run a 13.4:1 air/fuel ratio and 28* total timing from 3,500 rpm though 5,500 rpm in 1st and 2nd gear. I found through testing the CCOT logic is actually very accurate. I have the EGT limit set to start brining in the CCOT at about 1,400* and have the AFR timing compensation map setup to pull up to 8* of timing as the CCOT air/fuel ratios increase. The maximum enrichement is set for 1,650*F estimated EGT and the actual EGTs run about 1,600 on prolonged WOT and actually start to drop as the air/fuel mixture richens to its maximum of 10.8:1 at about 85 mph. With the timing retard I am not seeing knock going into 3rd gear either. So basically its working as intended now.

Also managed to get a piece of 3.5" aluminum tubing mandral bent in the shape of my PVC intake and wrapped with a heat insulator. We tig welded on a couple of aluminum tabs to hold the intake on the fan shroud. I am seeing 98 KPA on a 101 KPA baro reading now and spikes over 250 gms/sec airflow.

Someone is also well over 300 RWHP now with his L31/4L80E/9.5" 14-bolt driveline. This person also gained 40 ft/lbs of torque at 1000 rpm at the wheels by adjusting the timing map in that area using a locked 3rd gear pull on a dyno. Talk about a throttle response boost. Someone drifted his Express around a 90* right hand corner afterwords without intending to.

[EagleMark]

Someone is also well over 300 RWHP now with his L31/4L80E/9.5" 14-bolt driveline. This person also gained 40 ft/lbs of torque at 1000 rpm at the wheels by adjusting the timing map in that area using a locked 3rd gear pull on a dyno. Talk about a throttle response boost. Someone drifted his Express around a 90* right hand corner afterwords without intending to.
Dam! Who might this someone be? Can you get him over here to tell us how? :thumbsup:

I like the toque curve, thius would explain the express van drifting?

[Fast355]

Dam! Who might this someone be? Can you get him over here to tell us how? :thumbsup:

I like the torque curve, this would explain the express van drifting?

The little 4x4 comp cam and marine intake are likely the biggest part of the equation. Followed by lots of little stuff to the setup and tuning.

I have a crazy aggressive timing curve that works well for this setup. Running no less than 10° @ 1000 rpm except during burst knock retard, 24° by 2,800 and 30° total by 4,600. I can't wait to see how it reacts to the tri-ys! I have seen milder engines gain 20 hp and 30-40 ft/lbs at the crank from a simple set of long tubes. That and it needs 4.10s badly so much so that I wish I had gone with a smaller, lighter, higher STR 2,800 rpm converter.

[Hog]

Nice package there Fast, you've got LS1 power from the GEN !E Vortec, plus its running through the HD drivetrain, better than LS1 power!

That lean spot you're speaking of, was it a lean bog when cold? I myself had some decent lean bogging upon throttle application after the swap. AT least 3 other guys I know have had the same issue, exageratted when cold, not as bad when engine is warmed up.
There are no "throttle stomp" or "pump shit" in the blackbox PCM, IIRC I did some major VE tuning as a work around.

Do you think that the stock L31 intake manifold are major obstacles to making power on the L31?

Cant wait to see after the Thorleys are installed.

Someone asked about prices, I paid around $600 for mine, it came with brand new parts to assemble the USCAR connectors, colour coded wires, wiring diagram, all gaskets for instal, marine t-body, marine IAT/MAP sensor, cleaned and flowed marine injactyors(25 lb/hr@43.5psi), machined for Vortec bypass, a couple new brass waternecks, new pig iron quick connect heater connector, it was a very good kit.
My retrofit was done for under $1000 including tuning. IO cant remember if my Tunercats OBD2 tuning system was in that $1000 or not. I paid $330 for it during a group discount.

Good work man, that torque curve is flat, tough to pic a stall speed with that flatline. Good problem to have.

peace
Hog

[Fast355]

Nice package there Fast, you've got LS1 power from the GEN !E Vortec, plus its running through the HD drivetrain, better than LS1 power!

That lean spot you're speaking of, was it a lean bog when cold? I myself had some decent lean bogging upon throttle application after the swap. AT least 3 other guys I know have had the same issue, exageratted when cold, not as bad when engine is warmed up.
There are no "throttle stomp" or "pump shit" in the blackbox PCM, IIRC I did some major VE tuning as a work around.

Do you think that the stock L31 intake manifold are major obstacles to making power on the L31?

Cant wait to see after the Thorleys are installed.

Someone asked about prices, I paid around $600 for mine, it came with brand new parts to assemble the USCAR connectors, colour coded wires, wiring diagram, all gaskets for instal, marine t-body, marine IAT/MAP sensor, cleaned and flowed marine injactyors(25 lb/hr@43.5psi), machined for Vortec bypass, a couple new brass waternecks, new pig iron quick connect heater connector, it was a very good kit.
My retrofit was done for under $1000 including tuning. IO cant remember if my Tunercats OBD2 tuning system was in that $1000 or not. I paid $330 for it during a group discount.

Good work man, that torque curve is flat, tough to pic a stall speed with that flatline. Good problem to have.

peace
Hog

I was able to tweak on the end of injection timing and accelerationenrichment tables to make the lean spot vanish with a cold engine. The latest lean spot was due to the CAI leaning out the tune slightly. Added between 1% and 5% to the MAF table via datalogging amd its now just about perfect. In this cool weather it likes spinning the 255s on it. I think the factory intake, throttle body and intake ducting are all major restrictions to power once a decent cam and exhaust is installed.

[PJG1173]

Fast,
which comp 4x4 cam are you using the 260, 270 or 280? with the 280 cam I can't get more than 24*@3200 without knock on my TBI converted vortec 355.

[Fast355]

Fast,
which comp 4x4 cam are you using the 260, 270 or 280? with the 280 cam I can't get more than 24*@3200 without knock on my TBI converted vortec 355.

Its the 258/262 grind, but I had it ground on a 110° lsa.

[PJG1173]

did a one degree reduction in LSA make a difference? if its the one I'm thinking the out of the box one has 111*

[Fast355]

did a one degree reduction in LSA make a difference? if its the one I'm thinking the out of the box one has 111*

No idea, never ran the 111* LSA version of the cam. After running a very similar flat tappet grind in my 305 in my Vette I just felt the engine would like the 110* LSA more than it would a 112 or 111*. Its also still ground 4* advance on a 106* ICL. Not to mention the idle sounds beefier with the tighter LSA cams.

[1project2many]

There are no "throttle stomp" or "pump shit" in the blackbox PCM, IIRC I did some major VE tuning as a work around.

If you read through the manual for (IIRC) the Accel DFI unit they discuss a mode where AE fueling is done as an automatic calculation rather than a programmed table. They lay the equation out, too. I realize most people have decided the black box is worthless but I'd look at the disassembly to locate AE routines and see if fuel delivery is calculated the same way.

[Hog]

Hey Fast355, I know I have asked you before, but I cant remember the answer and I cant find the post but, with your dyno tuning, what is the marine intake worth power/torquewise on its own. When I did my swap I notice more torque and more power, but that was simply from doing acceleration tests, less power falloff aove 5000rpm etc. So CSFI for cross ram marine intake with appropriate PCM tuning, what increases did you see?
Thanks, I have a guy that wants to do teh swap, but is undecided. He will only be using a xe270hr cam with a 112lsa and wants to know if teh intake swap is really worth it or no.

Thanks man.

peace
Hog

[Fast355]

Hey Fast355, I know I have asked you before, but I cant remember the answer and I cant find the post but, with your dyno tuning, what is the marine intake worth power/torquewise on its own. When I did my swap I notice more torque and more power, but that was simply from doing acceleration tests, less power falloff aove 5000rpm etc. So CSFI for cross ram marine intake with appropriate PCM tuning, what increases did you see?
Thanks, I have a guy that wants to do teh swap, but is undecided. He will only be using a xe270hr cam with a 112lsa and wants to know if teh intake swap is really worth it or no.

Thanks man.

peace
Hog


Wish I knew what the intake alone made for power. I gained 35 RWHP at peak and closer to 50 RWHP toward redline with the marine intake, e-fans, and my custom mandrel bent 3.5" CAI setup however that was including the additional loss of the 4L80E over the 4L60E. The 80E is probably eating a minimum of 6-8% more power than the 60E.

[Hog]

Wish I knew what the intake alone made for power. I gained 35 RWHP at peak and closer to 50 RWHP toward redline with the marine intake, e-fans, and my custom mandrel bent 3.5" CAI setup however that was including the additional loss of the 4L80E over the 4L60E. The 80E is probably eating a minimum of 6-8% more power than the 60E.
Thanks man, appreciate it.

peace
Hog

[Fast355]

Thanks man, appreciate it.

peace
Hog

I logged into my youtube account today and ran across a video. Its a stock 2003 Express 5.3/4L60E and what looks to be 3.73s based on the shift speeds. It made my lack of gear very apparant. I need to get my 4.10s and Tri-ys installed. It would be very close 0-60 with me gaining an edge as my top-end hp took over. I alwayd wondered what my Express would have been like with 3.73s and the 60e. 30-90 wouldn't be an issue though.

http://www.youtube.com/watch?v=WNOm2otMTA4

http://www.youtube.com/watch?v=I7aYqJ71HyA

[Roadknee]

When you consider the stock Vortec 350 is some 255 hp at 4,400 at the flywheel this is a very impressive build. It's making over 255 at the wheels at 4,400 and some 320 hp peak.

For what it's worth, the 4L80E and 14 bolt probably won't show a drastic reduction on the chassis dyno compared to the 4L60E an 10 bolt rear. The acceleration rates on a chassis dyno are relatively low so the additional hp required to accelerate the higher mass is relatively low as well. As acceleration rates grow, the difference between the two would become more apparent. Even so, I recall a HP TV episode where they compared a Mopar drag car at the track with a 8-3/4" rear and a Dana 60. The D60 is a much larger and heavier unit, but the 1/4 mile time was basically unchanged.

I have a header design program called Pipemax that also does a pretty good job of estimating torque and hp given some basic engine parameters. It predicts 255 hp and 340 ft-lbs for the stock vortec assuming 95% peak VE, which I think is about right for these motors. Your motor peaks on the chassis dyno at around 5,600, and would peak a few hundred rpm higher on an engine dyno. The exhaust manifolds are the real bottleneck and are likely limiting VE to something under 100%. Assuming a 5,800 rpm engine hp peak and 98% VE, Pipemax predicts 380 peak hp and 380 peak ft-lbs. Your headers might increase VE to 102%, which is what my AFR headed 383 with equal length tuned headers makes. Pipemax predicts 400 peak hp and 400 ft-lbs. Pipemax also recommends intake and exhaust valve lift of 0.564" intake and 0.540" exhaust (preferred) and 0.500" intake and exhaust (minimum) to prevent choke. Depending on your valve lift, you can potentially find some gains there as well.

[Fast355]

When you consider the stock Vortec 350 is some 255 hp at 4,400 at the flywheel this is a very impressive build. It's making over 255 at the wheels at 4,400 and some 320 hp peak.

For what it's worth, the 4L80E and 14 bolt probably won't show a drastic reduction on the chassis dyno compared to the 4L60E an 10 bolt rear. The acceleration rates on a chassis dyno are relatively low so the additional hp required to accelerate the higher mass is relatively low as well. As acceleration rates grow, the difference between the two would become more apparent. Even so, I recall a HP TV episode where they compared a Mopar drag car at the track with a 8-3/4" rear and a Dana 60. The D60 is a much larger and heavier unit, but the 1/4 mile time was basically unchanged.

I have a header design program called Pipemax that also does a pretty good job of estimating torque and hp given some basic engine parameters. It predicts 255 hp and 340 ft-lbs for the stock vortec assuming 95% peak VE, which I think is about right for these motors. Your motor peaks on the chassis dyno at around 5,600, and would peak a few hundred rpm higher on an engine dyno. The exhaust manifolds are the real bottleneck and are likely limiting VE to something under 100%. Assuming a 5,800 rpm engine hp peak and 98% VE, Pipemax predicts 380 peak hp and 380 peak ft-lbs. Your headers might increase VE to 102%, which is what my AFR headed 383 with equal length tuned headers makes. Pipemax predicts 400 peak hp and 400 ft-lbs. Pipemax also recommends intake and exhaust valve lift of 0.564" intake and 0.540" exhaust (preferred) and 0.500" intake and exhaust (minimum) to prevent choke. Depending on your valve lift, you can potentially find some gains there as well.

I think like the LT1 the 5.7 Vortec is a bit underrated. If it were on an emgine dyno without the restrictive stock cats and muffler and accessories especially that mechanical fan, I bet it would put down 280 hp and 360 ft/lbs. I bet the loss through a 4L85E and 14-bolt is still quite a bit more due to the fact the 85E uses straight cut gears and has a gear style pump that eats more hp than the 4L60E style pump. The 14-bolt also has bigger gears and more internal friction.

I am about to change this setup up some. I am building a 355 for my boat out of a TBI block and will be robbing the stock vortecs off the Express and the current cam. In its place will be Edelbrock Etec 170 heads and a custom grind 270/276 @ .006, 215/220 @ .050, .501/.510" lift, 114 lsa cam ground on a 110 icl. I will be installing the doug thorley tri-ys at the same time. I bet it becomes a monster!!

I found some interesting LT1 dyno information that is imo similar to our old*5.7 vortec once the factory intake is trashed. The only real difference is the reverse cooling, 1 point higher compression, and slightly shorter intake runners. Looking at what the LT1 is capable of making through the manifolds partially explains why my L31 runs as well as it does. I put down 280 rwhp on a Mustang Dyno with the stock gm 142 LT4 cam, 1:6:1 roller rockers, stock vortec intake manifold while spinning the clutch fan. I put down roughly the same hp with the current cam but gained 50 rwtq down lower in the rpm band. A friend of mine just dyno'd his Titan same day on both the Mustang dyno and the Dynojet and saw nearly an 11% increase in rwhp on the dynojet with similar torque numbers on both. Which means the dynojet I put down 330 rwhp on would have read about 309 rwhp prior to the 4L80E, 14-bolt, marine intake, 3.5" CAI and e-fans. Given that kbowledge I feel that I am losing a substantial amount more hp through the driveline. The biggest loss at the moment is overall gearing. 1st gear is a pooch compared to a 4L60E with more stall speed. It takes me until 30-35 mph to rise above 3,000 rpm. It actually suprised me yesterday evening driving in ~30°F weather I kept breaking tires loose at stoplights and stop signs. Kind of a shock considering I am running a stock torque converter and only 3.73 gears with 255/70r15 tires.

http://www.gmhightechperformance.com/tech/lt1_engine/ghtp_1304_dyno_testing_7_popular_lt1_engine_modifi cations/

http://www.gmhightechperformance.com/tech/lt1_engine/1311_dyno_testing_new_mods_for_the_lt1_motor_part_ 2/

[Roadknee]

That's a pretty cool article. I remember when the vortec heads first became popular a 350 with the Hot cam dual plane high rise, good carb and headers would make an easy 410 HP, just like test 4 in the article you linked.

I agree you're building a monster there. I tuned a 406 SB with Etec 170 heads, a Stealthram and a very mild 219/227 at 0.050" hydraulic roller. Based on lb/hr fuel used and 0.50 bsfc it was making 450 HP. I think your changes will bump the power peak 400-500 rpm and add 40-50 flywheel hp over your current combo. Install 1.6 intake rockers if you can. It will make a difference.

[Fast355]

That's a pretty cool article. I remember when the vortec heads first became popular a 350 with the Hot cam dual plane high rise, good carb and headers would make an easy 410 HP, just like test 4 in the article you linked.

I agree you're building a monster there. I tuned a 406 SB with Etec 170 heads, a Stealthram and a very mild 219/227 at 0.050" hydraulic roller. Based on lb/hr fuel used and 0.50 bsfc it was making 450 HP. I think your changes will bump the power peak 400-500 rpm and add 40-50 flywheel hp over your current combo. Install 1.6 intake rockers if you can. It will make a difference.

One of the first articles I remember on the Vortec heads had to be the one by Hotrod magazine. They literally pulled a junkard 350 from some 70s junker, opened it up, tossed a comp xe268 in it, put 083 tpi heads on it and made 320 hp. They pulled the 083s off and tossed on a set of vortecs. Gained like 55 hp from a head swap. Then they tossed a victor intake and holley on it and came in a touch under 400 hp. It was a dirt cheap~ 400 hp.

[97Z71]

Can anyone give me some info on where to get the marine intake manifold that comes with injectors, fuel rails and the injector harness??Thanks in advance

[1project2many]

They're getting fewer and farther between these days. Watch Ebay and Craigslist, ask around at marinas for boats going to salvage, and just be patient.

There are aftermarket automotive manifolds that will work in many applications.

[97Z71]

I found one in Michigan. But it's just a bare intake. No fuel rails, injectors or harness. That's the main thing I'd like to find is the harness

[Fast355]

I found one in Michigan. But it's just a bare intake. No fuel rails, injectors or harness. That's the main thing I'd like to find is the harness

The Marine harness is not going to help you much if you are swapping over a L31 truck. Its easiest to raid the matching connectors as pigtails in the salvage yard, cut the connector off and solder on the longer pigtails.

[ZQ8 Blazer]

Hey Fast355. Delete some of your pm's. I have one to send you. Thanks.

[Fast355]

Hey Fast355. Delete some of your pm's. I have one to send you. Thanks.

Deleted some old junk, never realized I was out of space.