Upgrade engine

[daiglesteve1965]

I was wondering if I could upgrade my 93 6.5 engine.to a newer engine that has less trouble and will bolt up to trans.thanks

 

[SuicidalTherapy]

Just about any 454....

 

[Will L.]

Options for a worth owning 6.5:
If you can do that (acceptable by local dmv and emissions folks)
Rip off the ds4 and get a db2 = loose all the electronic engine nonsense
Get balanced flow waterpump with better fan clutch and fan for cooling
Proper turbo instead of the gm mity-mite with 4” exhaust all the way back.

There is other stuff to make it a more secure rig too. Powermaster 9052 starter to spin it like it should. And AC Delco 60G plugs to make it start like it should.

 

[Will L.]

Although 454 is a good option - if you go gas, then I would deal with the electronics and get a 6.0 LS. More power, better mpg, longer life than the 454.
But seriously look into the full cost before doing it. Many people get part way in and get buried. Then everything gets sold for a few hundred bucks.

Way better off to sell the diesel- which is higher demand- and buy a factory gasser.

 

[jrsavoie]

I hear all this talk about more dependable gassers.
I never experienced that.
I had issues withe every gasser I ever had.
I had issues with the 6.5's also.
But I considered them maintenance issues, given the miles run

 

[Stoney]

For all I bitch about my 6.5, honestly engine wise it's been seriously dependable.. I haven't really put much into the engine itself except basic maintenance stuff.. sensors, harmonic balancer, little stuff like that.. upgraded water pump.. considering it has 320,000 on it and still runs like a beast I can't complain... Now if we want to talk about chassis parts..THEN I will bitch up a storm..the whole front end design is crap. Starting with the coil springs not being heavy enough for the weight of a 6.5. maybe different on a I-beam front end but on independent front suspension it's a joke...

 

[Will L.]

Duramax bolts up. It will destroy the transmission unless you tune it way down, but the engine will be ok. The 01-05 gm vans had dmax tuned way down with the 4l80e. Idk if a manual trans would live behind it.

You really need to give more info. Like what trans, whatvpower are you trying to do,
What issues are you trying to avoid. How much money are you willing to spend. 2wd/4wd.

See, get a 2001 dmax engine but it will need all new injectors at this point. Probably has 200,000 miles on it. That is not gonna be more reliable- definitely will cost more in the end to do the conversion and refresh the engine. Hummer owners drop in dmax fairly frequently. By the time the entire job is done- they are happy with a cost of $70,000 if everything works properly. Why? Because there is a couple dozen people that cheaped out at $40,000 and sold the pile of non working parts. There is a guy on the hummer forum just a couple days ago looking at buying one for about $50k that is “mostly complete” when a finished dmax converted hummer sells for $100,000- so what does that say? Granted there is more to modify in a hummer than a pickup. But i have never heard of a guy getting a duramax into any truck that is a conversion 100% completed for under $15,000. That is if he does all the work himself, cut/weld/ electronics. Lowest price ai have heard of a shop doing the labor for one- NOT COUNTING PARTS- was $20,000 into a square body where there is far more room to do everything.

If you are trying to save money- walk us through the issues and we can help.
If you have $20,000 and you want to wisely invest it so you can get 250,000 trouble free miles let us know and we can walk you through the options.

 

[SuicidalTherapy]

Although 454 is a good option - if you go gas, then I would deal with the electronics and get a 6.0 LS. More power, better mpg, longer life than the 454.

I never said it was the best option . Though there are plenty of factory EFI 454s and 496s out there too. The Vortec 8100 puts down better numbers than the 6.0 out of the box, though it's going to be guzzling considerably more gas doing it.

Would the Dmax even fit in the engine bay though? Thought I had read somewhere that they're too tall to fit the GMT400 trucks due to the lower hood compared to the factory Dmax trucks. I never really looked into it though, as I never planned on going bigger with this truck.. just planned on going straight into a medium or heavy duty chassis.

 

[Will L.]

I never said it was the best option . Though there are plenty of factory EFI 454s and 496s out there too. The Vortec 8100 puts down better numbers than the 6.0 out of the box, though it's going to be guzzling considerably more gas doing it.

Would the Dmax even fit in the engine bay though? Thought I had read somewhere that they're too tall to fit the GMT400 trucks due to the lower hood compared to the factory Dmax trucks. I never really looked into it though, as I never planned on going bigger with this truck.. just planned on going straight into a medium or heavy duty chassis.

Right- there is dozens of options. But @daiglesteve1965 needs to share more details to his situation and desired outcome.

I had a neighbor about 5 minutes from my house that before I caught him stealing from me, I helped finish his dmax gmt400 build. But his is on 40” tires so his body lift helped fit everything under his hood no problem. I never measured if it would have fit without the body lift- can’t remember the clearance. It was a beautiful truck until one day he came out to a marshmallow roast. Wonder what happened- hmm. On a side note- really smart to have full coverage on any rig that you put tens of thousands into. Live and learn.

 

[daiglesteve1965]

Options for a worth owning 6.5:
If you can do that (acceptable by local dmv and emissions folks)
Rip off the ds4 and get a db2 = loose all the electronic engine nonsense
Get balanced flow waterpump with better fan clutch and fan for cooling
Proper turbo instead of the gm mity-mite with 4” exhaust all the way back.

There is other stuff to make it a more secure rig too. Powermaster 9052 starter to spin it like it should. And AC Delco 60G plugs to make it start like it should.

What turbo would you recommend.dont want to spend a ton.

 

[SuicidalTherapy]

A bigger turbo isn't going to do jack all for you without the ability to flow more fuel as well, the factory injection pumps on these things are close to maxed out already, and the factory turbo flows more air than the pump can handle already.

Sure, throw a bigger turbo on it, along with a worked over pump. Oh, don't forget bigger injectors too. Now you've got a 250HP motor that has cost you a few grand, and running on the edge of ventilating the block.

Look around...there's a reason why there aren't a ton of highly modified 6.2/6.5 motors out there, and those that are required the owners to open their wallets wide. The people that recommend this stuff are the same ones that think EFI is garbage and a carb makes a motor more powerful and more reliable....because they can fix it with a screwdriver..while ignoring the millions of EFI cars that routinely go 200K+ miles without ever taking a tool to the motor.

 

[Will L.]

The turbo choice has to fit what you are doing with it. The factory one is simply too small. In a suburban it definitely is too small trying to move that weight.

Hx35/40 hybrid is a great move. Hx40 is good if you don’t need all the torque from the stop sign. @Big T could tell you his call on the ATT in a suburban. But the ATT is better on ds4 than db2 because no waste gate means harder to spool up, but sure breathes easier down the hiway- especially when loaded.

When it comes to more fuel- that depends what you are doing.
I know several people that went to a hx35 and 4” exhaust, nothing else- quite happy with the change. The gm turbo which is prized by many 2.2 honda owners for being a great fit for them- is simply too restrictive.

The banks sidewinder was a tiny bit bigger than any of the gm options that gm came out with after the fact. And it was all about faster 0-40 mph pulling a trailer and having nothing else changed. Banks saved the platform, and was focused on an affordable upgrade for the natural aspirated anchor.


Big boy ip, turbo, injectors, etc- yeah really good power can come. But most don’t go into 6.5 for that. They just buy a cummins or dmax.

 

[Big T]

The turbo choice has to fit what you are doing with it. The factory one is simply too small. In a suburban it definitely is too small trying to move that weight.

Hx35/40 hybrid is a great move. Hx40 is good if you don’t need all the torque from the stop sign. @Big T could tell you his call on the ATT in a suburban. But the ATT is better on ds4 than db2 because no waste gate means harder to spool up, but sure breathes easier down the hiway- especially when loaded.

When it comes to more fuel- that depends what you are doing.
I know several people that went to a hx35 and 4” exhaust, nothing else- quite happy with the change. The gm turbo which is prized by many 2.2 honda owners for being a great fit for them- is simply too restrictive.

The banks sidewinder was a tiny bit bigger than any of the gm options that gm came out with after the fact. And it was all about faster 0-40 mph pulling a trailer and having nothing else changed. Banks saved the platform, and was focused on an affordable upgrade for the natural aspirated anchor.


Big boy ip, turbo, injectors, etc- yeah really good power can come. But most don’t go into 6.5 for that. They just buy a cummins or dmax.

Is it the GM4 or GM8 turbo that the Honda rice rodders want?

 

[Will L.]

Is it the GM4 or GM8 turbo that the Honda rice rodders want?

Yup. Well, it used to be. The availability of turbos now has greatly improved so idk if they still want them or not. But 10 years back- they were scouring junkyards and would here the 6.5 and come up to leave their number with ya incase you decided to get a proper turbo. The 2.2 shifting at 6,000 rpm had the turbo screamin is like a 6.5 at 2,000 rpm.
Figure out the cummins I6 has kore natural torque because it is an inline 6, then being 5.9 liter and shifting at way lower rpm than we do... and they run a bigger hx35-
These turbos are just strained and choking.

 

[WarWagon]

A bigger turbo isn't going to do jack all for you without the ability to flow more fuel as well, the factory injection pumps on these things are close to maxed out already, and the factory turbo flows more air than the pump can handle already.

Sure, throw a bigger turbo on it, along with a worked over pump. Oh, don't forget bigger injectors too. Now you've got a 250HP motor that has cost you a few grand, and running on the edge of ventilating the block.

Look around...there's a reason why there aren't a ton of highly modified 6.2/6.5 motors out there, and those that are required the owners to open their wallets wide. The people that recommend this stuff are the same ones that think EFI is garbage and a carb makes a motor more powerful and more reliable....because they can fix it with a screwdriver..while ignoring the millions of EFI cars that routinely go 200K+ miles without ever taking a tool to the motor.

No need for more fuel with a better turbo.

It's because words can't describe how bad the OEM turbo is. It's simply done at 2200 RPM with the waste gate open and backpressure through the roof. More RPM is fighting the turbo and you can feel it. The backpressure does a good job of keeping heat in the engine that the cooling system with a locked up, power robbing, and screaming cooling fan has to deal with.

Bluntly the factory turbo doesn't flow worth a damn. No it sure as hell can't flow enough air for what a stock pump can put out. Not even enough for a smaller plunger 6.2 pump.

More fuel would be nice, but, a 1/4 turn on the fuel screw in the DB2 pump the OP has is enough for even the huge towing turbo's. That wakes it up unloaded with the stock garbage turbo as well.

No need for injectors either.

More or less better lift pump to keep the IP from starving for fuel and fuel as lube (as they bypass return a lot of fuel to the tank), better turbo, and exhaust. If the fender snorkel restriction is still in place it needs to be gone. These minor changes will outrun the mediocre gutless 454 of the day.

Backpressure... I have posted nearly the same dyno numbers with a huge towing turbo, the discontinued ATT, and a HX40II. The ATT was at ~14 PSI and the HX40II was at 24 PSI. The smoke was impressive as well as the audience running for their lives when the turbo to intake hose blew at 24 PSI. My 6.2 didn't come in last for numbers that day. Again more PSI in the intake is useless if the backpressure to make it is extreme.

 

[Husker6.5]

If you're staying diesel and want to bolt to your existing transmission, grab a Cummins 4B out of an old UPS/FedEx delivery truck based off of the P-30 chassis. They already have the bell housing adapter plate on them to bolt them to a Chevy/GM transmission (they were in front of a TH400 in the delivery trucks), are 100% mechanical with a P7000-based in-line injection pump so it is easy to modify for increased power using all the same parts as its 6BT big brother and is really happy running with your GM-X turbo on it. Plus, being 2 cylinders shorter and about ⅓ lighter than a 6BT, it is much, much easier to put under the hood!

 

[Stoney]

@Husker6.5 you just made my day.. I've been wondering if a 4bt could be put in my truck. We (brothers and I ) have 3 of them in the bone yard . I don't know alot about 4bt's but I know there pretty reliable... always figured if I blow up the 6.5 I didn't really want to put another one in... Would rather have something with a little bit more power.

 

[ak diesel driver]

Unless it's a new one, they have a balance shaft, they have a ton of vibration at idle.

 

[blumpkin]

I,d like to add ,.. put a decent set of big oval heads on a truck 454 (496 better, 502 more better) with small chambers and milled a little for good quench adding some compression, add a 110 lsa cam,. a decent dual plane intake and a 750 vacuum carb, of course a decent set of stepped headers,with lengthened collectors and you will have a pretty reliable torque monster,.. swapping gas into a 6.5 hole, the trans shifting will need to be addressed, same with swapping in the cummins. My diesel days are on hold due to the price of fuel here in canada,. ( 9.25 cdn for us sized gallon @ 17 mpg thats 54c a mile.--ish)

 

[daiglesteve1965]

A bigger turbo isn't going to do jack all for you without the ability to flow more fuel as well, the factory injection pumps on these things are close to maxed out already, and the factory turbo flows more air than the pump can handle already.

Sure, throw a bigger turbo on it, along with a worked over pump. Oh, don't forget bigger injectors too. Now you've got a 250HP motor that has cost you a few grand, and running on the edge of ventilating the block.

Look around...there's a reason why there aren't a ton of highly modified 6.2/6.5 motors out there, and those that are required the owners to open their wallets wide. The people that recommend this stuff are the same ones that think EFI is garbage and a carb makes a motor more powerful and more reliable....because they can fix it with a screwdriver..while ignoring the millions of EFI cars that routinely go 200K+ miles without ever taking a tool to the motor.

Thanks ! New to diesels.jist looking to do the things I need to for better mpg.having block and heads done next week.so just looking to improve what I can.will be daily driver..I'm looking for dependable and best mpg I can get.tjanks again