I have talked to many of you already and everyone has been helpful. rather than clutter up everyone elses turbo post i figured i would start my own! ok so i want a little more boost in my 6.5 ( after i fix my injector problem ) i dont hot rod it all the time but would like to occasionally. what turbo is right for me? i love the turbo whine noise and extra power 24/7 i know this is NOT going to be a cummins but i would like to to be a very respectable 6.5! TIA.
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Dumb turbo questions thread.
- Thread starter 6chevy9
- Start date
Woody35
Active Member
A team turbo is an obvious choice lots of people are going to say. no turbo whistle though. go read the replacement turbo thread for more info. sit and get something to drink becasue its going to be a few hours. hx-35 or the other holset turbos of the same series are a good fit but they need to be wastegated. turbos are pretty uncharted waters in the 6.5 world. not a huge number of people running anything but stock
NVW
Well-Known Member
GM put on a small turbo to spool up quick. Great for emissions and snappy response but when you load the truck or get up in high RPM the turbo becomes an exhaust restriction.
The ATT: you are going to a bigger turbo that will not spool as quick but has a better top end simply because it is a bigger turbo. Top end is where the turbo has a high engine load and lots of exhaust heat to work with like trailer towing.
The housing design and lack of waste gate make it flow better than a GM X. Again at the trade off of the low RPM or ¼ mile times.
A Turbo Master that gets 14 PSI tops out of your GM 3 or 4 will really wake your truck up. Factory is 6 PSI tops on my 1993. Follow it with a DB2 conversion ½ turn high or computer tune for your computerized 94 and you get the best you can on stock parts.
Then get ready to spend money.
The ATT: you are going to a bigger turbo that will not spool as quick but has a better top end simply because it is a bigger turbo. Top end is where the turbo has a high engine load and lots of exhaust heat to work with like trailer towing.
The housing design and lack of waste gate make it flow better than a GM X. Again at the trade off of the low RPM or ¼ mile times.
A Turbo Master that gets 14 PSI tops out of your GM 3 or 4 will really wake your truck up. Factory is 6 PSI tops on my 1993. Follow it with a DB2 conversion ½ turn high or computer tune for your computerized 94 and you get the best you can on stock parts.
Then get ready to spend money.
mine already runs 18 psi mashed to the floor. im still unsure of what turbo it is. and the truck has basically all of the bolt on parts plus ecm chip ect ect ect. i was told 18 psi is not a safe number off a gmx turbo? so that concerned me. it spools pretty fast and stays at 18 till i let out of the throttle. i belive it spools around 2000 rpm or so. the truck does not move untill 1600-1700 rpms, ( i think it may have a stall converter? ) not sure. im not really sure which direction to take with this truck to be honest.
Slim Shady
DEATH BEFORE DISHONOR
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Everybody has different driving habits. The ATT turbo does not have lag at the lower rpm. It is not like the gm turbos at the lower rpm though.
If you plan on racing your truck or consider getting from zero to sixty your goal you will want a quick spooling turbo like the gm factory turbo. If you want a turbo that will be good for most daily driving and hauling then a larger turbo is in your future. I would suggest asking the different owners what they think of their turbos, Ask the guys with the Holset turbos and the owners of the ATT Turbo. Getting information from an actual owner is the best. In the end it will be your choice. They all have good points and their compromises.
If you plan on racing your truck or consider getting from zero to sixty your goal you will want a quick spooling turbo like the gm factory turbo. If you want a turbo that will be good for most daily driving and hauling then a larger turbo is in your future. I would suggest asking the different owners what they think of their turbos, Ask the guys with the Holset turbos and the owners of the ATT Turbo. Getting information from an actual owner is the best. In the end it will be your choice. They all have good points and their compromises.
yeah i hear ya there. well i like to take off fast every now and then but not often. i will be using this as a DD here shortly and also for long trips towing my 97 to the dunes. i would like to have the off the line power and speed. i would also like to be able to hear that turbo scream, thats what i love about turboed vehicals what can i say. mpg isnt totally important ( i would sacrafice it a bit for the power ) reliability is a must. i had an HX-35 on my dodge and loved it. so i thought it may be a good turbo. but at the same time i relize completly that the 6.5 is no where near a cummins so i dont know how it would handle something like that. money really isnt an issue ( in a few months when i build my bank back up atleast ) i know those are big shoes to fill for a turbo but i think it can be done.
Turbine Doc
Just Another Diesel Guy
Stock Cummins is hard pressed to keep up with a tweaked 6.5, our problem with the 6.5 where we max out with it is just above where the performance minded Cummins guy starts building for power.
With the right program behind the ATT you won't feel any lag worth mentioning, mine is a daily driver and a tow rig, I've been here getting on/off the NY toll roads for the last month, thus far I've had sufficient acceleration to manage getting moving for any & all traffic, surprised a few with ability to put the truck into a "hole" in the traffic pattern.
With the right program behind the ATT you won't feel any lag worth mentioning, mine is a daily driver and a tow rig, I've been here getting on/off the NY toll roads for the last month, thus far I've had sufficient acceleration to manage getting moving for any & all traffic, surprised a few with ability to put the truck into a "hole" in the traffic pattern.
Well thank you for the input! as of right now my pretty respectable 6.5 is no match for my old near stock cummins 
but that could change alot after fixing my injector problem. does anyone have a video of there ATT turboed 6.5? i would like to see and hear one most certainly before i bought it.
but that could change alot after fixing my injector problem. does anyone have a video of there ATT turboed 6.5? i would like to see and hear one most certainly before i bought it.
I had a h1c Holset on my 6.5 and then on the 6.2,it had a nice turbo whistle at idle and a decent whistle between shifts,and pretty loud whine when spooled,it was not waste gated. I would think a Schwitzer S300 with a 10 blade turbine and correct sized wheels and exhaust housing would be great, I am going to try a Schwitzer off of a Cat 3116,but don't know if it is a S300 since Cat has there own part numbers. My pro 52 Holset lights at 2000 rpms on the 6.2,has a nice whistle,but its pretty big,and makes a lot of boost , I don't know what it would do with normal fueling.
:nono: Wrong engine and age for that expectation esp while hot rodding it. Sure you can get 400K out of the block if it doesn't crack but there will be a trail of parts behind it... Age has a lot to do with reliability going downhill as parts fail due to age alone. Good news is that the parts are cheap and the 6.5 design is stupid simple.
So get used to it needing TLC often or get rid of it for something more modern and reliable. You have a 15+ year old truck. Electronics expected/design lifetime is around 10 years. Set your expectations of the 6.5 accordingly.
Over 14 PSI the GM turbo is out of it's efficiency range and is just a big intake air heater - restricting the exhaust and heating up the intake air more than the PSI boost is worth. make sure the WG isn't wired shut and adjust the Turbo Master, hopefully equipped, to go 14 PSI max with a trailer, full load, behind it. Unloaded gives you lower boost.
And from your sig: get the intake back into the fender. Nothing kills power faster than hot air in the intake. Esp on a Non intercooled Turbo! Look up the HP derating tables by temperature for a shocking amount...
635
New Member
Well thank you for the input! as of right now my pretty respectable 6.5 is no match for my old near stock cummins
There was a big difference between the A team turbo and my sort of stock GM-8. The A turbo made my engine pull a lot harder than with the GM-8.
6.2 turbo, i like what i am hearing. any info on where i can read more about these? or get one for that matter? warwagon, why does everyone keeps saying i need this and that? my engine and most of the electoronics have around 600 MILES! what more could need replacement? it has cheap injectors and that is my only problem. nothing more period! the motor trans most of the electrical was all done at one time and together has around 600 miles give or take a few. i relizes there are other little things to break, im talking about the turbo and engine reliability. EX not blowing the heads off, not needing head gaskets every 4 miles. those are the reliability questions im talking about. im sorry for going off a little bit about this, but everyone keeps telling me to replace this and that when everything is literally brand new or replaced. had the truck been all original i totally agree with you about reliability.
These are all pretty much Cummins oriented turbos,my GM1 turbo made 28 psi,the Schwitzer S300 and S400 are the latest and greatest for the Cummins,and there's several versions of each one,I'd tend to think a properly built S300 would be awesome,but it might make to much boost for you,also they cost alot,this is why I get used turbo's on ebay. The h1c is just and older version of the hx35.
Matt Bachand
Depends on the 6.5
Another great ATT feature is its the closest thing possible to plug n play. No custom fabricating, and the kit gives you everything you need to toss it in in a planned Saturday.
I know I'm going to benefit greatly because I'm always heavy.
It sounds like that long hill of a highway onramp is a perfect job for ATT. I have alot of those around here!
I know I'm going to benefit greatly because I'm always heavy.
It sounds like that long hill of a highway onramp is a perfect job for ATT. I have alot of those around here!
tanman_2006
Just a farm kid...
The reason we tell you all these thing you can do is because you say you want the most out of it. No doubt there have been some major improvement s over stock but there is still the next level to reach. Its a never ending process. GMx turbos are obsolete. We give you ideas when and if you decide to do them is up to you.
i was just talking about the whole reliability thing. sorry i blew my top a lil there guys! i know its not going to be as reliable as a brand new truck, but you can see the 97 in my sig ( im an obvious OBS for life kind of guy ) i know the trucks inside and out, the 6.5 not even kind of. its totally new to me but i know the lower end and trans are solid. the turbo and injectors are about all i want to change as of right now from what little i know about this motor. if i do everything i find within reason of doing and still dont feel the power i would like, ill sell the motor, trans, and bolt ons to do a cummins swap. but like i said im going to try to be different here.
NVW
Well-Known Member
http://www.youtube.com/watch?v=rRFIhBSaWsM
The truck runs better now, that was in winter, cold difs, winter fuel.
The truck runs better now, that was in winter, cold difs, winter fuel.