What would be a good turbo to replace the GM-4 turbo? I am looking at a A-Team turbo. Id also like to know whats the max boost I should run. I hear 12-15 is the max and stock is 7-8. Id like to know a few things that will improve performance. The few things I have is a 4" Exhaust and Air pod filter and also a 80hp 160ft/lbs chip from SSdiesel Supply. I have gauges just not hooked up yet. Id like to know a few things I can do to get the most out of it. Just let me know what you know and thanks for all the help.
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6.5L Turbo
- Thread starter 907
- Start date
ak diesel driver
6.5 driver
Where you at?
Max boost before a GM turbo chokes and becomes a heater is 14 PSI. Other turbo's can give you more boost without choking. Head studs are a good idea at higher boost.
What do you intend to do with the truck? DD or heavy loads towing? What performance do you want to improve? 1/4 mile, long haul, MPG?
What do you intend to do with the truck? DD or heavy loads towing? What performance do you want to improve? 1/4 mile, long haul, MPG?
Turbine Doc
Just Another Diesel Guy
Welcome to the site & first post.
Umm your choice of SS Diesel for reprogram....claims made on the output advertised have been found to be less than advertised. Be that as it may it is better than what came from the general in way of programming.
With a GM-4 we are going to assume you have an earlier model 6.5 as WW said we kind of need to know your plans how to work the vehicle and your budget as a boneyard GM-8 from later model 6.5 will give some improvement over your GM-4.
Umm your choice of SS Diesel for reprogram....claims made on the output advertised have been found to be less than advertised. Be that as it may it is better than what came from the general in way of programming.
With a GM-4 we are going to assume you have an earlier model 6.5 as WW said we kind of need to know your plans how to work the vehicle and your budget as a boneyard GM-8 from later model 6.5 will give some improvement over your GM-4.
I am looking at making it more for a 1/4 mile. I don't pull very many loads other then a 4 wheeler. As for budget don't really matter just list some things and ill work on getting them. I hear the GM-8 spools faster but it will choke as the ATT will take longer to spool but won't choke.
buddy
Active Member
If worried about 1/4 mile, I would look for a T3 turbo with a 14cm^2 exhaust housing. That would not choke like a GM turbo, but spool fast enough off the line. There are some new knockoff HX40s that way, or a used HX35 you could get for like $300-$400. I recommend the HX40 though because it has larger wheels (get the 76mm turbine specifically). The GM turbo is like a 10cm^2 housing, tiny anyway so it chokes. And some better intake, like the penninsular upper that has a 3" inlet, or just a piece of aluminum plate with a 3" pipe coming out of it.
If money wasn't an obstacle I would have the exhaust manifolds extrude honed, which is a cheaper and easier alternative to custom header work. Honing would end up like $800 with shipping though, more than the turbo.
Attached is my list of stuff, which isnt 100% complete, but stuff I would do with a 6.5 to improve performance. The only stuff I intend to add is common maintenance stuff like energy suspension motor mounts. There are no missing links in there as far as a key ingredient to performance, except for maybe a camshaft grind, but remains to be proven and a whole other discussion and not necessary to hit 300hp and outdo some more modern beasts.
If money wasn't an obstacle I would have the exhaust manifolds extrude honed, which is a cheaper and easier alternative to custom header work. Honing would end up like $800 with shipping though, more than the turbo.
Attached is my list of stuff, which isnt 100% complete, but stuff I would do with a 6.5 to improve performance. The only stuff I intend to add is common maintenance stuff like energy suspension motor mounts. There are no missing links in there as far as a key ingredient to performance, except for maybe a camshaft grind, but remains to be proven and a whole other discussion and not necessary to hit 300hp and outdo some more modern beasts.
Turbine Doc
Just Another Diesel Guy
Pretty much everything applicable to performance applies to tow rigs, my setup in my signature allows me to pull short infrequent trips to 200 miles up to 18K# loads when moving my backhoe. The engine & trans is not my weak link, it is my K1500 frame & single rear wheel for me to recommend pulling that weight far & often.
I'm partial to ATT for towing, it is what that turbo was really purposed for, that said it does as you stated a much better job on top end than GM-X so in a "leg race" the ATT is fairly performance minded as well and keep the boost levels to the intended boost operating limits of the engine.
I beefed up my trans clutch pack, shift programming/TCC lock which afik SSD tune does not address, cooling and fluid capacity, B&M towing shift body/porting in the trans, as well as upgrading brakes-tires-rims-suspension.
For 1/4 mile where you have to make as much speed in that distance with shortest time as you can ATT probably not best choice for that application, but you make a trade off in power in top in power for quickness off line or put on extra engine stress with higher boost on stock compression. To make use of some of the higher boost pressure capable turbos out there, without putting undue stress on rest of the engine, consensus recommendation is to lower compression level.
When you get a moment can you go to the tool bar at top of the forum look for the tab labeled Forum Actions, then the drop down to Edit profile, then to left middle is the edit signature which allows you to add in vehicle information, which is handy to know at a glance when advising folks on 6.5 stuff.
I'm partial to ATT for towing, it is what that turbo was really purposed for, that said it does as you stated a much better job on top end than GM-X so in a "leg race" the ATT is fairly performance minded as well and keep the boost levels to the intended boost operating limits of the engine.
I beefed up my trans clutch pack, shift programming/TCC lock which afik SSD tune does not address, cooling and fluid capacity, B&M towing shift body/porting in the trans, as well as upgrading brakes-tires-rims-suspension.
For 1/4 mile where you have to make as much speed in that distance with shortest time as you can ATT probably not best choice for that application, but you make a trade off in power in top in power for quickness off line or put on extra engine stress with higher boost on stock compression. To make use of some of the higher boost pressure capable turbos out there, without putting undue stress on rest of the engine, consensus recommendation is to lower compression level.
When you get a moment can you go to the tool bar at top of the forum look for the tab labeled Forum Actions, then the drop down to Edit profile, then to left middle is the edit signature which allows you to add in vehicle information, which is handy to know at a glance when advising folks on 6.5 stuff.
Last edited:
buddy
Active Member
Depending on the year of vehicle there are different recommended mods in cooling and air box.
Turbine Doc
Just Another Diesel Guy
Yup and sort of why I was looking for a sig update so we could make a more accurate recommendation recommendation and keep track of mods as he progresses in the quest for power