GMx turbo upgrades for towing heavy, worth it?

[red]

Yes there are better turbos out there, not the focus of this thread.

Considering upgrading the stock GM turbo on my 95 3500hd for some better performance while keeping it on a budget. The truck is used to tow heavy, between 15k-26k combined weight. Curious if the turbo master and wicked wheel modifications are worth it for this application, or are they aimed at empty truck/playing around and of no benefit for tow rigs?

Pic just because, lighter load at around 15k pounds.

 

[Rockabillyrat]

I personally wouldn't waste time making upgrades to a GMx turbo. The boost to drive pressure ratios is 2:1. I know you want to only discuss GMx upgrades... But a more efficient turbo is really the best way to go about it.

 

[MrMarty51]

I dont know all that much about the turbos, whats good, whats not but, I will say, Your light load is probably heavier than anything I`ll tow. LOL
I`ve been thinking on the Wicked Wheel too. Just to give it a try. Maybe I will be able to hear that unit.
I think the WW will be My next purchase, seeing as how I`m getting some of the more important items out of the way. Fluid Dampener, Leroys pump & harness relay kit, 4" Diamond Eye with the diamond eye cross over, a few other items I can think that I`ve installed.

 

[red]

I personally wouldn't waste time making upgrades to a GMx turbo. The boost to drive pressure ratios is 2:1. I know you want to only discuss GMx upgrades... But a more efficient turbo is really the best way to go about it.

Agreed there are far better turbos out there which are worth the cost, just looking at $300 vs $800+ (add in studs with new head gaskets, ........). Many threads discussing the better turbos, just want this thread to focus on the GMx turbos for whether that $300 is worth it for a towing application.

I dont know all that much about the turbos, whats good, whats not but, I will say, Your light load is probably heavier than anything I`ll tow. LOL

Haha it's always been that way for me and the reason I bought the hd. Go from empty, to usually 18k-23k combined weight hahaha. Actually heavier in that pic, forgot the roughly 2500 lbs in fuel.

 

[Rockabillyrat]

Ok, well my opinion on a GMx turbo is that any upgrade is a waste of time. Might as well flush $300 down the toilet if you buy a WW.

 

[ak diesel driver]

Might do twins about the only way a gmx is good for anything with the 6.5

 

[Will L.]

The problem with 300 vs 800 is dollar spent per what you gain.
Wicked wheel works. But so does just cranking up boost pressure via turbo master. It will do a little better than stock, but not enough if you will tow at freeway speed.

Your comment of “ (add in studs with new head gaskets, ........)” I think warrants a response: Using a larger turbo that moves more air with less pressure LESSENS the requirement of headstuds- it doesn’t increase the need. That wicked wheel helps by allowing you to get more boost pressure (and getting closer to max cylinder pressure) without holding as much egt. So turbomaster adds power at downfall of more boost, more cylinder pressure, more egt, more ect. Adding the wicked wheel to this only slightly lowers the negative effects a couple percent, so you can easily add a hair more throttle pedal and offset the gains easily.

I relate to this situation because my hummer with it’s gearing, me having it weigh 10,000, and the aerodynamics of a block wall stock yet mine’s even worse since I built my roof taller than stock and the overbuilt rack on top. Then my hoodscoop helps the cooling but also is more air drag. I looked hard at the wicked wheel, but the couple guys that l helped do theirs- just not worth it. I am 99% going to end up with cko holset because of cost.
If WarWagon hasn’t sold his ATT yet - you ought to really consider it. I would do it and the torque converter that he already proved as a winner- except I still need the very low rpm boost coming in for my off-roading. I need to give up some freeway mpg and have a crazy pricey radiator to deal with the extra heat I will have because I need a wastegate to make that happen.

To ak diesel driver’s point- I had twin gm4 before. Seriously considered it for the hummer but it won't fit well under the hood - but if you have a second gm turbo laying around they fit fairly easy in a pickup. The twins do spool slower than the single.

if you could get a wicked wheel for $100 or less- then maybe it would pay off if you drive it a lot.

 

[Twisted Steel Performance]

Contrary to popular belief a charge air cooler will help cool the air a gm turbo is pushing , all be it not as good as another snail but it would help cool the charge...

 

[Will L.]

Contrary to popular belief a charge air cooler will help cool the air a gm turbo is pushing , all be it not as good as another snail but it would help cool the charge...

I agree. Hummers run gm6 or gm7 and when they add a cac it helps. There is a about 150 rpm lag more, but worth it.

who would think a cac wont help a gm x turbo?
I know a couple people did a cac on the ATT and didn’t get good results, but that’s because boost (turbine compression) is so low. But if it were done here or Phoenix- it might in the summer.

 

[red]

The problem with 300 vs 800 is dollar spent per what you gain.
Wicked wheel works. But so does just cranking up boost pressure via turbo master. It will do a little better than stock, but not enough if you will tow at freeway speed.

Your comment of “ (add in studs with new head gaskets, ........)” I think warrants a response: Using a larger turbo that moves more air with less pressure LESSENS the requirement of headstuds- it doesn’t increase the need. That wicked wheel helps by allowing you to get more boost pressure (and getting closer to max cylinder pressure) without holding as much egt. So turbomaster adds power at downfall of more boost, more cylinder pressure, more egt, more ect. Adding the wicked wheel to this only slightly lowers the negative effects a couple percent, so you can easily add a hair more throttle pedal and offset the gains easily.

I relate to this situation because my hummer with it’s gearing, me having it weigh 10,000, and the aerodynamics of a block wall stock yet mine’s even worse since I built my roof taller than stock and the overbuilt rack on top. Then my hoodscoop helps the cooling but also is more air drag. I looked hard at the wicked wheel, but the couple guys that l helped do theirs- just not worth it. I am 99% going to end up with cko holset because of cost.
If WarWagon hasn’t sold his ATT yet - you ought to really consider it. I would do it and the torque converter that he already proved as a winner- except I still need the very low rpm boost coming in for my off-roading. I need to give up some freeway mpg and have a crazy pricey radiator to deal with the extra heat I will have because I need a wastegate to make that happen.

To ak diesel driver’s point- I had twin gm4 before. Seriously considered it for the hummer but it won't fit well under the hood - but if you have a second gm turbo laying around they fit fairly easy in a pickup. The twins do spool slower than the single.

if you could get a wicked wheel for $100 or less- then maybe it would pay off if you drive it a lot.

Freeway speeds with my 3500hd is 60mph, 2450rpm roughly. Those 5.13 gears with overdrive have it gear bound almost as bad as the 82 crew cab with no overdrive hahaha. For a stock 6.5 it pulls those weights quite well.

The truck is currently the daily driver.



Was hoping the responses with both the wicked wheel and the turbo master would be along the line of "Yea it's no aftermarket turbo but makes it reasonable for cheap". Looking like that's a negative haha.

 

[MrMarty51]

Was hoping the responses with both the wicked wheel and the turbo master would be along the line of "Yea it's no aftermarket turbo but makes it reasonable for cheap". Looking like that's a negative haha.

Yeah, that's the answer I too was hoping for, on the WW.

 

[Chewy1576]

I have drank the CAC kool aid, I am a firm beliver that a CAC will help a forced induction application in longevity and performance in all situations. The question becomes is it viable/possible/cost effective? There are applications where some form of CAC simply aren't worth the undertaking to do, but that doesn't mean the application wouldn't benefit from having one.

 

[Chewy1576]

Freeway speeds with my 3500hd is 60mph, 2450rpm roughly. Those 5.13 gears with overdrive have it gear bound almost as bad as the 82 crew cab with no overdrive hahaha. For a stock 6.5 it pulls those weights quite well.

The truck is currently the daily driver.



Was hoping the responses with both the wicked wheel and the turbo master would be along the line of "Yea it's no aftermarket turbo but makes it reasonable for cheap". Looking like that's a negative haha.

There is nothing that can be done about the GM-X turbos impact on drive pressure. The turbine housing geometry is fixed, and shoving more boost pressure in the intake side only compounds the issue.

 

[red]

I have drank the CAC kool aid, I am a firm beliver that a CAC will help a forced induction application in longevity and performance in all situations. The question becomes is it viable/possible/cost effective? There are applications where some form of CAC simply aren't worth the undertaking to do, but that doesn't mean the application wouldn't benefit from having one.

Agreed coolers work well. Parts/labor to build the system and doing the mods to the GM turbo (or setting up for twins) would be similar to the cost of a single better turbo, which is essentially bolt on nowadays. My 82 gets the wilder mods, the 3500hd is about cheap/reliable towrig so I won't be going with cooler or twin GM turbos on it. The new wheel and turbo master I'll consider since they are cheap and simple but according to others it's not worth the cost.

 

[WarWagon]

@red Winding up the Asthma Attack GMx turbos to "work" are just that. Then the heat they keep in the engine locks in the cooling fan and it's game over. The drive pressure over 2200 RPM is fighting the engine so hard in so many ways it's not funny.

My ATT paid for itself in fuel savings: something a modded GMX will NOT get you. Going from 7.5 MPG (Can a 454 actually burn more fuel?!) to 10.4 MPG on a 550 mile weekday delivery route with the 6.5TD. And I gained over 20 MPH on a specific long grade by sending the GMx where it belongs: the scrap metal pile. I tried the turbomaster and gained MPG, but, same miserable MPG.

I am "old school" as some different turbo's have shown up for the 6.5's since people got "Woke" to the fact the GMx is a problem without a cure. Don't misunderstand as I am referring to the time a decade ago and what it took to get people "Woke"... Scorched flame suits and all.

There is risk of swapping turbo wheels out - bad casting or done wrong and the turbo blows, well, the engine eats the debris. One more reason to not mess with a GMx.

The GMx is boosting from the starter spinning RPM the engine till it rolls over and makes the engine play dead above 2200 RPM.

An ATT IS Dead until around 2000 RPM then hang on as it's a freight train till redline.

I had the same ballpark dyno power at 15 PSI on the ATT as I did with a HX40II at 24 PSI. Thus the need for head studs is less as it's the same boost as a GMx but less backpressure.

The Yank gets the ATT into the spool up RPM from a stoplight till you are at whatever speed you want to go then locks up. Once the TCC locks up you don't even know it's a higher stall converter.

With your lower gearing you likely don't need to do a stall converter with a an ATT. Just be clear getting going from a stop to 2K rpm without a stall is the trade off esp. with the AC on and fan locked in.

I still have an ATT "kit" and the Yank Converter for sale at half the cost of new. Frugal not cheap. Some used ARP head studs could go with em... I even have a local scrapyard you can drop off the GMx at so you are not dragging that boat anchor around...

Seriously, even if you use another turbo, ANY other turbo, don't waste your time on a GMx.
.

 

[Paveltolz]

If you want to try an upgraded GMx as a loaner then I'll have the one on my wrecked Burb back in about a month. Bolt it on and run it a while and see what you think. It's the Heath Hurricane 7 which has his version of a wicked wheel, bearings, and hot side wheel mods.

ATT would work with your loads and gearing. Not so much with a light K1500 running pretty much empty though. Bottom line in all this is does the turbo do what you want it to do at the price point and, if any, risks to the motor?

 

[red]

@red Winding up the Asthma Attack GMx turbos to "work" are just that. Then the heat they keep in the engine locks in the cooling fan and it's game over. The drive pressure over 2200 RPM is fighting the engine so hard in so many ways it's not funny.

My ATT paid for itself in fuel savings: something a modded GMX will NOT get you. Going from 7.5 MPG (Can a 454 actually burn more fuel?!) to 10.4 MPG on a 550 mile weekday delivery route with the 6.5TD. And I gained over 20 MPH on a specific long grade by sending the GMx where it belongs: the scrap metal pile. I tried the turbomaster and gained MPG, but, same miserable MPG.

I am "old school" as some different turbo's have shown up for the 6.5's since people got "Woke" to the fact the GMx is a problem without a cure. Don't misunderstand as I am referring to the time a decade ago and what it took to get people "Woke"... Scorched flame suits and all.

There is risk of swapping turbo wheels out - bad casting or done wrong and the turbo blows, well, the engine eats the debris. One more reason to not mess with a GMx.

The GMx is boosting from the starter spinning RPM the engine till it rolls over and makes the engine play dead above 2200 RPM.

An ATT IS Dead until around 2000 RPM then hang on as it's a freight train till redline.

I had the same ballpark dyno power at 15 PSI on the ATT as I did with a HX40II at 24 PSI. Thus the need for head studs is less as it's the same boost as a GMx but less backpressure.

The Yank gets the ATT into the spool up RPM from a stoplight till you are at whatever speed you want to go then locks up. Once the TCC locks up you don't even know it's a higher stall converter.

With your lower gearing you likely don't need to do a stall converter with a an ATT. Just be clear getting going from a stop to 2K rpm without a stall is the trade off esp. with the AC on and fan locked in.

I still have an ATT "kit" and the Yank Converter for sale at half the cost of new. Frugal not cheap. Some used ARP head studs could go with em... I even have a local scrapyard you can drop off the GMx at so you are not dragging that boat anchor around...

Seriously, even if you use another turbo, ANY other turbo, don't waste your time on a GMx.
.

No arguement that the ATT, hx35/40, super 54/60, all are far better turbos than the GMx.

Torque coverter doesn't do my 3500hd any good, nv4500hd trans.

 

[Rockabillyrat]

If your towing with a manual transmission it helps to run a smaller a/r on the turbine housing to help it spool. You will have to spool that turbo 5 times as you shift. A auto drops less RPM between shits so it can keep a larger a/r turbo spooled throughout up shifting.

If I was in your shoes I would get a hx35 off a cummins. The 12cm turbine will spool nicely with a manual transmission. They are cheap and easy to find. And you can upgrade them later if desired with different wheels or housing sizes.

 

[red]

If your towing with a manual transmission it helps to run a smaller a/r on the turbine housing to help it spool. You will have to spool that turbo 5 times as you shift. A auto drops less RPM between shits so it can keep a larger a/r turbo spooled throughout up shifting.

If I was in your shoes I would get a hx35 off a cummins. The 12cm turbine will spool nicely with a manual transmission. They are cheap and easy to find. And you can upgrade them later if desired with different wheels or housing sizes.

I remember that being the preference when new turbos were first being tested, HX40 and ATT needed 2000+rpm which is an issue with the nv4500. Curious how the new super 54 compares.

 

[Rockabillyrat]

The s54 is a hx35. It's just not an off the shelf turbo. He uses a combination of genuine holset parts to build a turbo to better fit the 6.5.

The 12cm is a little small for the 6.5. And the s54 uses a larger a/r turbine housing because of that. But with a manual trans and heavy towing. A slightly tight turbine housing will help with low end spooling. Either turbo should be great for a 6.5 used for towing. I personally have not ran a s54 so I cant comment on how it does with a nv4500. But the hx35 off the cummins does a great job for a cheap off the shelf upgrade.