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Anyone added significant horsepower to their 4.3?

Donstar

By Donstar
in Engines & Drivetrain

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DONWT15 Enthusiast

DONWT15

Posted
Posted
24 minutes ago, TXGREEK said:

 


Hmmmmm, and yet here you are and you’ve proven my point. You just can’t contain yourself can you. They let you and a couple of your buddies out of the looney home for good behavior?



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Don't be an ass. They aren't the only "old guys" on here.

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TXGREEK Senior Enthusiast

TXGREEK

Posted
Posted
Don't be an ass. They aren't the only "old guys" on here.


Im old too, thought I unfollowed this discussion.


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TXGREEK Senior Enthusiast

TXGREEK

Posted
Posted
Don't be an ass. They aren't the only "old guys" on here.


Looney home, not retirement home.


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Donstar Senior Enthusiast

Donstar

Posted
  • Author
Posted
6 hours ago, DONWT15 said:

Donstar,

I think overall the only option to gain some power is to boost it. With the high compression and fuel systems in these Gen V engines you wouldn't be able to use a lot of boost like the Fords do. It would probably be impractical financially and shorten the reliability. I have not done this to any of these engines, but I did put a centrifugal super charger on a mid 90's 350.

Made good power but the upkeep was a pain.

Just my opinion, but your thread looking at the 2018's with the NHT package is probably the best way to go.

One old guy to another.

   

Yes, I suspect there would be more information readily available if there were practical ways to add  significant boost to these engines.  I was  interested in finding out what others may be doing with their 4.3 but the topic sure found one member quite excited that I even asked.  I agree that the NHT option is the answer for me and I am waiting for the right one.  I came very close a couple of weeks ago but even the right price couldn't win me over!  I don't need to "settle" for a truck that I don't enjoy as much as, or more than, my current truck.  If it looks like a trailer upgrade is imminent before finding a truck, I'll buy a '19.

2017_whitez71 Enthusiast

2017_whitez71

Posted
Posted

Wow this got out of hand fast.  It's amazing how one person, who has nothing to contribute, can ruin a good conversation.  @Donstar in my opinion, I think you will be better off to trade your truck for max tow.  I think that the 4.3 is an excellent engine, I have had 3 myself, but I am afraid if you start doing major modifications to it you will lose reliability. As far as simple horsepower mods to the 4.3 go I did run e85, cold air intake and a tune on my 14 and it really responded well.  However I know you said that you don't have e85 available to you.  Best of luck with your decision.

WHITESSTOWPIG Enthusiast

WHITESSTOWPIG

Posted
Posted

Forums can be such a silly and insecure place these days.The vast majority will buy the 5.3 then spend all day posting threads nut swinging the 6.2 trying to match its performance but anytime someone takes interest in other than a V8 all of the sheriffs come out of the woodwork.This time next year the half the trucks will have 4 cylinders in them and the whole thing will be just as funny to watch

KARNUT Senior Enthusiast

KARNUT

Posted
Posted
Forums can be such a silly and insecure place these days.The vast majority will buy the 5.3 then spend all day posting threads nut swinging the 6.2 trying to match its performance but anytime someone takes interest in other than a V8 all of the sheriffs come out of the woodwork.This time next year the half the trucks will have 4 cylinders in them and the whole thing will be just as funny to watch

If GM would offer the 6.2 in more models the problem would be solved in most cases. Imagine one in an single cab. It’s just a 2500$ upgrade. The problem is you have to buy an SLT to get it. It becomes a 10K upgrade or more. It sends people to Ram or Ford. I was real happy with my truck with the 5.3, I would have paid 2500$ for the 6.2 upgrade but not the 10K more for the SLT on top of that. Then they turn around and give the E-85 to boost the 5.3 but not the 6.2. Maybe they’ll figure it out before they loose their number two status for good to Ram.


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  • 1 year later...
Maxime Fortier New Member

Maxime Fortier

Posted
Posted
On 8/16/2018 at 10:13 AM, WHITESSTOWPIG said:

I have done a few mods to mine and it feels at least as quick as all the 5.3 loaners I have driven since then.Stock for stock the 5.3 honestly barely felt like an upgrade so that isnt really saying much.Truth is there anything " significant " that can be done to an already high strung naturally aspirated engine while keeping it suitable for truck use.A few guys have tried boosting them but there just wasnt enough fuel to make much power with them.Here are some non-intrusive things I have tried which had a positive effect on the 4.3 in case you catch the mod bug

 

E85 gas

JET maf

Range AFM

Overkill  TB

K&N intake

Gutted 3rd cat

Muffler delete

 

Which tb did you use ?

Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted

How about a logic walk? You get four choices to make more power. Spin it harder. Make it bigger. Boost it. Spray it. The last two come with a heat penalty that will butt the factory gap rings up hard enough to pull the tops off pistons if you lay in it long enough. The cure would be open up the ring gaps then you get yourself to the second wall. Fuel octane limit. That limit is closer than one might think. Even with 94 (RM)/2 E-0 fuel mine has a trace of KR under moderate loads like empty pulling a long 7% grade in high gear. That pretty much limits 'adders' to the top 1/3 of the rpm range past peak torque rpm. Medium sized turbo or low pressure centrifugal supercharger? Small spray kicking in late?  All three of those could be done without ring mods IF it is just a short burst toy. IF you want more sustained pulling power those rings gaps will need attention. 

 

Problems making these newer motors larger. Darn little room. You can't bore it large enough to make a difference and the cylinder walls are too short to add much stroke. 

 

Spin it harder is an option. You will loose AFM. You will loose some bottom end grunt. You will loose some cruise mpg. You will have to pioneer a profile and find a grinder to work with. Still it CAN be done. 

 

Then there is the non-power adder grunt adder. Gear what you have to work the ground like a bigger motor. 

 

IF I had the inclination, time and money I believe I would open the gaps. Increase cooling capacity. Add a centrifugal supercharger with a 5 psi pully at 5200 rpm and gear it 3.73 or 4.10. You could tow with that. Could be some fun too, eh? 

 

When people put down a V6 they show their ignorance. They show it in their argument. They argue 6 cylinder vs 8 cylinder but what they are really saying is small displacement vs large displacement. A large 6 pot Caterpillar Diesel will out pull anything in the GM line up. Has noting to do with cylinder count.

 

I'm very happy with the 4.3's power density just as she is. Every once in awhile I get a itch that I have to scratch and I can tell you that I can break any legal speed limit in my area with room to spare in the length of the on ramps. When 80 mph is no longer fast enough to safely merge I'll just quit driving.  I can safely merge at 55 mph so my license in safe enough. 

 

 

WHITESSTOWPIG Enthusiast

WHITESSTOWPIG

Posted
Posted
8 hours ago, Maxime Fortier said:

Which tb did you use ?

Its the 80mm throttle body retrofit Overkill Motorsports sells for the LFX 3.6 engine.Its basically the stock unit from a 5.3 with an adapter spacer but it will feel more responsive on the 4.3 because the built in throttle delay is less sensitive.Another thing I added was a catch can from Elite Engineering.Here is a photo so you can see how the throttle body and catch can look.

dasda.thumb.jpg.bf32c1491f5c5dc16294a4ab7708c98f.jpg

WHITESSTOWPIG Enthusiast

WHITESSTOWPIG

Posted
Posted
1 hour ago, Grumpy Bear said:

How about a logic walk? You get four choices to make more power. Spin it harder. Make it bigger. Boost it. Spray it. The last two come with a heat penalty that will butt the factory gap rings up hard enough to pull the tops off pistons if you lay in it long enough. The cure would be open up the ring gaps then you get yourself to the second wall. Fuel octane limit. That limit is closer than one might think. Even with 94 (RM)/2 E-0 fuel mine has a trace of KR under moderate loads like empty pulling a long 7% grade in high gear. That pretty much limits 'adders' to the top 1/3 of the rpm range past peak torque rpm. Medium sized turbo or low pressure centrifugal supercharger? Small spray kicking in late?  All three of those could be done without ring mods IF it is just a short burst toy. IF you want more sustained pulling power those rings gaps will need attention. 

 

Problems making these newer motors larger. Darn little room. You can't bore it large enough to make a difference and the cylinder walls are too short to add much stroke. 

 

Spin it harder is an option. You will loose AFM. You will loose some bottom end grunt. You will loose some cruise mpg. You will have to pioneer a profile and find a grinder to work with. Still it CAN be done. 

 

Then there is the non-power adder grunt adder. Gear what you have to work the ground like a bigger motor. 

 

IF I had the inclination, time and money I believe I would open the gaps. Increase cooling capacity. Add a centrifugal supercharger with a 5 psi pully at 5200 rpm and gear it 3.73 or 4.10. You could tow with that. Could be some fun too, eh? 

 

When people put down a V6 they show their ignorance. They show it in their argument. They argue 6 cylinder vs 8 cylinder but what they are really saying is small displacement vs large displacement. A large 6 pot Caterpillar Diesel will out pull anything in the GM line up. Has noting to do with cylinder count.

 

I'm very happy with the 4.3's power density just as she is. Every once in awhile I get a itch that I have to scratch and I can tell you that I can break any legal speed limit in my area with room to spare in the length of the on ramps. When 80 mph is no longer fast enough to safely merge I'll just quit driving.  I can safely merge at 55 mph so my license in safe enough. 

 

 

GM has the best NA V6 there is for a pickup truck.However GM also has lowest power NA V8 there is for a pickup truck in one of the most popular platforms.Naturally when most guys who have never driven one firsthand hear the word V6 then wont want to imagine having an even smaller motor than they already have.I can certainly respect that way of thinking but its just one way of thinking.Personally for me in every truck ive driven neither engine turned these trucks into hot rods and I would happy go either way honestly especially in a Regular Cab.If I had to get a double cab I would go V8 just so I could get the 8speed transmission which really wakes the engine up alot.

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