Please help with 4.3L HP increase?

[TomBrady80]

2 hours ago, Donstar said:

 

I bought my Defenders because of my past experience with the LTX MS2/LTX MS series of tires.  I read that the Defenders were an improved version.  When I first replaced my factory Bridgestones with the Defenders, there wasn't the "wow" factor like my previous switches but I simply attributed this to the fact that the Bridgestone was also a smooth running tire. Maybe Defenders are a rougher tire than the MS2's.   I have found them a great all year round tire and very good in the snow.   Another type of Michelin may be the answer and I notice they still offer the LTX MS2 in the 275/55/20 size.  I would suggest giving Michelin a call and explain your concerns.  They could possibly make your call worthwhile and give you a coupon or something to help you with a new purchase. You could also check at your place of purchase.  My son-in-law swears by Pirelli tires on 20's for his Navigator but not a fair comparison as I do not know first hand how it handled without Pirelli's.  Tire technology has improved to a point where I believe light truck tires with an aspect ratio of 55 on a 275 width can meet the expectations of truck owners with smaller rim sizes.    Many of us recall thinking 16" rims were big on a 1/2 ton and I believe now 20's are the new norm.

Thanks! And yeah I remember when 18s were considered a bigger rim and upgrade and if anyone had a 20” then that was big news lol! Now most have 18” or 20”. They just look so much smaller and I guess over time I’ve grown to see those as normal too. I’m sure with the smaller rim back on my ride would be better, but it sure looks better now. The vibration still has me puzzled at 70mph though?

[WHITESSTOWPIG]

I have driven every engine in every cab configuration numerous times and the 4.3 is a fine little motor even when compared to a 5.3.Box stock they are putting down 255whp on gas and 270whp on E85 which is what bolt on previous gen 5.3's use to put down.When speaking on the newest gen Ecotec 5.3's for me it was a crap shoot when purchasing because they honestly felt similar even when better gearing was put on the V8.The 6.2 however really feels like a different beast all together.The biggest thing with the V8 is the sound being more desirable and the aftermarket support being of course much greater.That being said here are some bolt ons I have on my RCSB 4.3 errand truck which seem to be working well

 

E85 gas

JET maf

Range AFM

Overkill  TB

K&N intake

Gutted 3rd cat

Muffler delete

Edited June 24, 2018 by WHITESSTOWPIG

[TomBrady80]

21 hours ago, DONWT15 said:

That is a really good looking tire and wheel set up in your picture.

More sidewall would help the harsh ride some people experience. The vibration you have at 70 mph, if you didn't have it before, is likely the tires or wheel balance issues.

Thanks! I love the rims I got for it but it’s got to be the tires that’s causing the vibration at that speed. It’s pretty smooth until I hit 70mph.... I just got some used tires with the new rims until I got the leveling kit installed so that way the new tires wouldn’t rub. 

[TomBrady80]

3 hours ago, WHITESSTOWPIG said:

I have driven every engine in every cab configuration numerous times and the 4.3 is a fine little motor even when compared to a 5.3.Box stock they are putting down 255whp on gas and 270whp on E85 which is what bolt on previous gen 5.3's use to put down.When speaking on the newest gen Ecotec 5.3's for me it was a crap shoot when purchasing because they honestly felt similar even when better gearing was put on the V8.The 6.2 however really feels like a different beast all together.The biggest thing with the V8 is the sound being more desirable and the aftermarket support being of course much greater.That being said here are some bolt ons I have on my RCSB 4.3 errand truck which seem to be working well

 

E85 gas

JET maf

Range AFM

Overkill  TB

K&N intake

Gutted 3rd cat

Muffler delete

Thanks! I also came across this too....

[TomBrady80]

What about this? 

[WHITESSTOWPIG]

A tuner is going to show the biggest gain in the form of better shift points but overall horsepower will be less of a gain than if you just ran E85.IMO the benefits of having an active warranty outweigh the increases of a tuner which is why I did not bother with one and just stuck to simple bolt ons.If these trucks where forced induction ofcourse it would be alot more tempting because the gains would be much more aggressive.

Edited June 25, 2018 by WHITESSTOWPIG

[TomBrady80]

11 hours ago, WHITESSTOWPIG said:

A tuner is going to show the biggest gain in the form of better shift points but overall horsepower will be less of a gain than if you just ran E85.IMO the benefits of having an active warranty outweigh the increases of a tuner which is why I did not bother with one and just stuck to simple bolt ons.If these trucks where forced induction ofcourse it would be alot more tempting because the gains would be much more aggressive.

Thanks. I didn’t think about warranty being voided.... Will getting someone to tune it for E85 mess with the warranty? I’m still unsure what all an E85 tune does.

[WHITESSTOWPIG]

30 minutes ago, TomBrady80 said:

Thanks. I didn’t think about warranty being voided.... Will getting someone to tune it for E85 mess with the warranty? I’m still unsure what all an E85 tune does.

One of the advantages of the 4.3 is they all come standard with the ability to run E85 if I am not mistaken.If you look at the sticker inside of your gas door it will indicate if the truck is E85 compatible or not.Not all gas stations carry the fuel but E85 compatible trucks can run on any mix between gas and E85 allowing it to be added to a tank at any given time.As the E85 content in the gas gets higher the vehicles computer is going to make the tuning progressively more aggressive 

[TomBrady80]

10 hours ago, WHITESSTOWPIG said:

One of the advantages of the 4.3 is they all come standard with the ability to run E85 if I am not mistaken.If you look at the sticker inside of your gas door it will indicate if the truck is E85 compatible or not.Not all gas stations carry the fuel but E85 compatible trucks can run on any mix between gas and E85 allowing it to be added to a tank at any given time.As the E85 content in the gas gets higher the vehicles computer is going to make the tuning progressively more aggressive 

Oh okay. Sorry for the ignorance, but all I have to do is use the E85 ethanol? It’s alrwady got the yellow cap and ready for it, but when I here people talk about tuning to the E85, I was thinking they meant some kind of additional mods needed to happen besides just filling up the tank with E85. I never used the E85 before but it’s definitely equipped to handle it. Thanks 

[WHITESSTOWPIG]

28 minutes ago, TomBrady80 said:

Oh okay. Sorry for the ignorance, but all I have to do is use the E85 ethanol? It’s alrwady got the yellow cap and ready for it, but when I here people talk about tuning to the E85, I was thinking they meant some kind of additional mods needed to happen besides just filling up the tank with E85. I never used the E85 before but it’s definitely equipped to handle it. Thanks 

E85 is optional on the 5.3 and is not available equipment for the 6.2 so alot of trucks out there do need to be retrofitted as well as tuned for E85 usage.The 4.3 however is mainly a fleet engine so they usually come standard with this capability and do not need anything additional to take advantage of E85 fuel.I am sure further gains can be realized even when tuning a truck already using E85 just as they can on gasoline but 10hp and some better shift points is not worth dumping a warranty over IMO

[KARNUT]

It one really amazing performance option that GM did with the E-85 tune. It’s baffling how little it’s appreciated. Twenty five HP by adding fuel, E-85. You could build a single cab 6-8 cylinder, E-85 equip, gear, tune 12s would be easy and not expensive. If I wasn’t so happy with my old truck I’d do it myself. It wouldn’t be the first time.


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[TXGREEK]

Oh okay. Sorry for the ignorance, but all I have to do is use the E85 ethanol? It’s alrwady got the yellow cap and ready for it, but when I here people talk about tuning to the E85, I was thinking they meant some kind of additional mods needed to happen besides just filling up the tank with E85. I never used the E85 before but it’s definitely equipped to handle it. Thanks 

 

E85 may give you a bit more HP if you even notice it but it caused my 14 5.3 issues back then. The one thing that’s [emoji817]% is that you won’t get near the mpgs that you’d normally get with regular gas. Give it a try, try super and worse case would be trade it in or just keep it.

 

 

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[TXGREEK]

I would definitely bring this to the attention of my sales outlet and/or to Michelin. I buy my Michelins from Costco and they are good with customer satisfaction.  I once found a tire weight in my driveway where I normally park my truck.  Costco pulled all four wheels and re-balanced them to make sure it wasn't one of theirs and to make sure I was a satisfied customer.  With your experience with the Michelin brand I am confident your complaint will be taken seriously. You have nothing to lose and may gain a considerably good deal on a great set of new tires!

Had a couple hours to kill, tossed the defenders and installed the new Michelin Premier LTX. Going on a short 3 hour road trip in the hills in a couple weeks, I’ll let you know how well they ride but so far so good.
FYI: I was warned that they may wear out quicker than their 60K advertised.









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[Jb84]

Hi Donstar. Is that a 2wd with the 3.23 rear end?