Marine Intake is on and running.

[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?

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?

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...modifications/

http://www.gmhightechperformance.com..._motor_part_2/