Advice needed on post '96 454 tuning

"MasterMario - Keeper of the V8s" (mastermario)
08/14/2017 at 17:11 • Filed to: Advice

So I recently bought a truck with a Vortec 454

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A couple things that have been done to the truck are the cats were removed and the EGR valve was blocked off. I have the cats, the PO gave them to me with the truck. Now, the truck has no tune on it, it’s running stock software. What I’m trying to decide is if I want to unblock the EGR valve (probably will) and re-install the cats (probably not).

So anyone familiar with tuning these engines, what should be my plan here? My internet research leads me to conflicting views and it’s hard to find anything authoritative on this. Should I leave things as they are and take it to a tuning shop? Should I just unblock the EGR valve and run stock software? Should I also reinstall the cats?

Thanks in advance

DISCUSSION (17)

Jcarr > MasterMario - Keeper of the V8s
08/14/2017 at 17:19

LS swa—oh.

crowmolly > MasterMario - Keeper of the V8s
08/14/2017 at 17:29

I’d do headers and an exhaust, followed by a tune. I think torque management is enabled for your year. With high flow cats if you can swing it.

Kiltedpadre > MasterMario - Keeper of the V8s
08/14/2017 at 17:29

Are you just looking for mods in terms of software and exhaust, or are you interested in digging further into the motor? The main weakness of that motor that I have heard of is the heads. The intake ports are smaller than what older BBC used, and the combustion chamber has a ridge that was somehow supposed to help with emissions. A good set of upgraded heads is a good upgrade, or at least having the original heads ported and polished will go a long way.

Takuro Spirit > Jcarr
08/14/2017 at 17:38

Nah, I would keep it Vortec

Kinja'd!!!

Die-Trying > MasterMario - Keeper of the V8s
08/14/2017 at 18:00

i would base what you wanted to do to it, on how you were planning to use it. i seem to recall having seen somewhere that you were going to be towing 8000+ lb boats with it on a regular basis.

if it were just a cruise around town truck, where mileage was the main concern, just put the cats and egr back on, and call it a day.

if you were after something with a more grunt, find some long tube headers, put the egr, and 02 bungs back on (so that the computer knows what its doing). and have someone try to put a tune on it, to get as much out of it, while making sure it isnt getting lean......

Nibbles > MasterMario - Keeper of the V8s
08/14/2017 at 18:33

Yes to cats. High flows are just fine and greatly reduce your environmental impact (if that is a thing to you).

crowmolly > Nibbles
08/14/2017 at 18:42

Car won’t have a smell, either.

Sweet Trav > Takuro Spirit
08/14/2017 at 18:46

8.1l is not a traditional big block.

Sweet Trav > MasterMario - Keeper of the V8s
08/14/2017 at 18:48

Depends on what you’re looking to do.

Hooking the EGR and cats back up will make the stock tune happy.

If you’re looking to tow, I’d put a set of long tube headers on there. These big blocks have tiny itty bitty baby cams and the exhaust manifolds strangle the hell out of these trucks, but the rest of the exhaust isn’t too restrictive.

The downside being pre-obd2 tuning will be hard.

I’m guessing you have the MPFI version not the throttle body injection motor?

MasterMario - Keeper of the V8s > Nibbles
08/14/2017 at 19:09

I think eventually I’ll do cats. I just didn’t want to deal with having someone cut up and weld the exhaust back together

MasterMario - Keeper of the V8s > Sweet Trav
08/14/2017 at 19:11

Right now I’m not planning on any major work. Just trying to figure out if it be easier to have it tuned as is or go back to stock

MasterMario - Keeper of the V8s > Die-Trying
08/14/2017 at 19:20

Just trying to figure out what’s best. Not planning any work really right now. I’m thinking going back to stock for now is best

Die-Trying > MasterMario - Keeper of the V8s
08/14/2017 at 19:33

those had a good bit of pull to them stock....... and if i recall correctly, they got around 13 mpg on a GOOD day.......

gmporschenut also a fan of hondas > MasterMario - Keeper of the V8s
08/14/2017 at 20:24

Super clean find

Are you going to be towing that boat across state lines, in/through a state that requires original emission equipment to be installed?

I would just run the cats. The amount of HP gain imo is negligable. Its a 454, I can’t imagine it hunting for more torque when cruising.

I would be more concerned with engine/tranny cooling

http://trailers.com/tow-capacity/1995_Chevrolet_GMC_K3500_Pickup_(4WD) _1376.html

Tristan > Sweet Trav
08/14/2017 at 20:27

It is OBD2, though.

Tristan > MasterMario - Keeper of the V8s
08/14/2017 at 20:29

Do a Google Search for 0411 ECM swap. I bought the ECM from a junkyard for $12 and had it tuned by Black Bear Performance for $250. It’s a great mod and the tow/haul mode is nice to have.

Sweet Trav > MasterMario - Keeper of the V8s
08/14/2017 at 21:18

i would return it to stock, and maybe find some headers that will work with the factory exhaust / cats