454 vortech power and torque numbers and AFR

[John Cunningham]

Probably has the same delayed PE that the later LQ4 6.0s and 8.1s do.

Explains why the 454 I towed with years ago felt gutless compared to the way my L31 ran when it had the milled 906s with 2.02/1.60 valves, 395 cam, marine intake and thorley tri-ys. I did 303 tq @ 3,400 (290@ 2,900 where the pull started) and 230 hp @ 4,400 with bad valve springs. Swapped the springs and retainers to LS6/Comp787 and put down 310 tq @ 3,200 and 257 hp @ 4,800. Those were locked converter 2nd gear pulls through a 4L85E and GM 9.5" 14-bolt.

On a different note you have atleast 25% drivetrain loss. That puts the HP at 266 and TQ at 386. Far closer to the 290/410 rating than 240/340.

The fuel pump wiring being undersized and creating high resistance is a known issue and often the pumps have seen better days because of this (low fuel pressure is the result). The MAFs get dirty and under report airflow. Also the factory injectors tend to give issues. Factor in a distributor drive gear that likes to wear and possible tired ignition parts and that only means you can make drastic improvements without diving too deep into the engine.

Hypertech's dyno testing of a stock 2000 C3500 454 gave 215 hp @ 4,250 and 320 tq @ 2,000.

torque alot lower..I guess it fell in range

 

[John Cunningham]

I think it's higher on the trucks.

probably

 

[L31MaxExpress]

On my Express van I had low fuel pressure a few years ago and I installed a new Delphi pump with the updated connector on the housing and installed a Racetronix Hotwire Kit. It made a noticeable difference in the way the engine ran and I had to go back in and mess with the tune to lean it back out from years of compensating for low fuel pressure in the tuning.

 

[John Cunningham]

Click upload a file down by the post reply button, let it upload, click full image and it should show up.

Ill try in a bit

 

[454cid]

...I installed a new Delphi pump with the updated connector on the housing and installed a Racetronix Hotwire Kit...

My latest pump has the upgraded connector. When I changed the pump in 07-ish, I assumed I already had the updated connector since my truck was a 99. This past summer, I discovered the updated connector was a flat-four. I decided to do the upgrade.

How does the Racetronix Hotwire Kit work... is it basically heavier wire and a relay activated by the stock harness?

 

[L31MaxExpress]

My latest pump has the upgraded connector. When I changed the pump in 07-ish, I assumed I already had the updated connector since my truck was a 99. This past summer, I discovered the updated connector was a flat-four. I decided to do the upgrade.

How does the Racetronix Hotwire Kit work... is it basically heavier wire and a relay activated by the stock harness?

10 gauge wire for both power and ground activated by a relay and the fuel pump is fed directly from the alternator output stud. They make several different versions depending on the OE harness and fuel pump type you are using. You probably could not duplicate the quality of the harness for the same $.

 

[L31MaxExpress]

From what I remember this is the harness I used. I updated the harness on the fuel tank to use the newer GM connector that came with the pump and this harness plugged right in. The tank is right under the middle of the van on the driverside. I was able to route the positive feed wire all the way from the tank to the fire wall inside the OEM convulted wiring loom for the engine harness with the included harness length. I was also able to mount that fuse housing in a place under the hood and out of the way and easily accesible. Since that is meant for an SUV and I used it on a Van I will say your result may vary but it worked out well for me.

https://www.racetronix.biz/product.asp?ic=fpwh-022

I had the regulator on the stock spider set at 70 psi and with the OEM wiring when the pump got hot it would only crank out 66-68 psi and fell to about 62 at full throttle and higher rpm. After the new OE pump and wiring upgrade it would hold 70 psi endlessly. The WOT air/fuel mixture richened up a whole point. The stock 23 lb/hr spider running at 62 psi was marginal at best over 5,500 rpm on that setup. I was able to decrease my duty cycle at 6,000 rpm by over 10% after the upgrade.

 

[John Cunningham]

With a sniffer after the cat and warmed up the operator says the engine is anywhere from .1 to .5 richer at the engine...so 15.1 would be about 14.5 at the engine...really lean

Wow, weird. I never would have guessed. FWIW though the tailpipe wideband tends to read lean, dynoing through an unlocked converter artificially imcreases torque. Did the dyno operator use bidirectional controls to hold the truck in gear with comverter locked? What gear did you dyno in? Got a graph?

He said it was probably no richer than 14.5 at the engine...Tailpipe sniffers with everything warmed and under load will read leaner than the engine really is. He did use bidirectional controls but it kept kicking down so he said he rolled into in slow in 3rd gear and he was comfortable with that...he said at the most it would off by only 5-7 ft pounds of torque. Low stall converter helps with this.

 

[John Cunningham]

Probably has the same delayed PE that the later LQ4 6.0s and 8.1s do.

Explains why the 454 I towed with years ago felt gutless compared to the way my L31 ran when it had the milled 906s with 2.02/1.60 valves, 395 cam, marine intake and thorley tri-ys. I did 303 tq @ 3,400 (290@ 2,900 where the pull started) and 230 hp @ 4,400 with bad valve springs. Swapped the springs and retainers to LS6/Comp787 and put down 310 tq @ 3,200 and 257 hp @ 4,800. Those were locked converter 2nd gear pulls through a 4L85E and GM 9.5" 14-bolt.

On a different note you have atleast 25% drivetrain loss. That puts the HP at 266 and TQ at 386. Far closer to the 290/410 rating than 240/340.

The fuel pump wiring being undersized and creating high resistance is a known issue and often the pumps have seen better days because of this (low fuel pressure is the result). The MAFs get dirty and under report airflow. Also the factory injectors tend to give issues. Factor in a distributor drive gear that likes to wear and possible tired ignition parts and that only means you can make drastic improvements without diving too deep into the engine.

Hypertech's dyno testing of a stock 2000 C3500 454 gave 215 hp @ 4,250 and 320 tq @ 2,000.

regarding the delayed PE : his reply: I dont think so TPS 100 over rides the delay table

 

[L31MaxExpress]

With a sniffer after the cat and warmed up the operator says the engine is anywhere from .1 to .5 richer at the engine...so 15.1 would be about 14.5 at the engine...really lean


He said it was probably no richer than 14.5 at the engine...Tailpipe sniffers with everything warmed and under load will read leaner than the engine really is. He did use bidirectional controls but it kept kicking down so he said he rolled into in slow in 3rd gear and he was comfortable with that...he said at the most it would off by only 5-7 ft pounds of torque. Low stall converter helps with this.

regarding the delayed PE : his reply: I dont think so TPS 100 over rides the delay table

It usually does not overide the delay. It either has to reach the RPM value programmed to bypass the delay which is often set really high or go longer than the delay period is set to get into PE even with the throttle open 100%. I would drop the enable RPM down around 1,000 rpm and set the delay to Zero. Then alter the PE ramp to atleast 1.0. I like the PE to come in the instant the throttle is open. My Express van comes in at 50% throttle and 600 rpm.