Which particular part number would you suggest for my application? Thanks
First, a DS4 tune is specific to your VIN and added options "it's not one size fits all."
Big HOLSET/CKO HX40 turbochargers are now confirmed as a decent upgrade on the GM/AMG 6.2/6.5 diesel platform, the HX SUPER 40 & CKO w/850 cfm available can feed a potential 450 hp +- build, I say potential because of the lower efficiency of the IDI diesel design over a DI diesel must be considered.
While other factors like intake, head & exhaust flow fit into the equation for the ultimate build those are more a personal choice as opposed to being commonly done or even practical for those who do not have deep pockets or the skillset to do it themselves.
BIG AIR the denser the better is required for best results “so open air filters or air boxes are a NO, NO.” As I have found out using a BIG HX40 requires a full 4” intake & a full Marmon or other 4” exhaust from the turbine back no if’s but’s about it anything smaller becomes a restriction to be avoided.
BIG AIR is achieved via a bigger turbo, a belt driven supercharger or blower and compound combinations thereof, the objective being the most air at the lowest boost level tuned to the max rpm range of your GM/AMG 6.2/6.5 build. Quick Spool Valves (QSV), variable vain turbines, compound charging etc. are all considerations. Want instant acceleration then a blower or compound turbos are the ticket. Depending on how deep your pockets are or your level of skillsets will be the deciding factor in your final decision.
As for the stories about a big turbo not spooling or making boost until 2k rpm “my HX40W 18 cm2 CKO starts making boost @ 1.0K/1.2K from there boost up to 2.9 pressure ratio is instant,
2.9 pressure ratio equates to 42.50 +- psi actual.”
BIG AIR increases volumetric efficiency (VE) and that number increases with increased rpm I posted a chart relating to this in the 6.5 performance forum. I will say normally a 400 ci can flow 850+- cfm at a safe 3.5k rpm based upon how much BIG AIR you supply to increase VE but again keep in mind the loss of efficiency w/IDI diesel design so a % equal to the loss of IDI efficiency of rpm increase over the 3.5k for air being delivered is required.
An air box or canister having more than 850 cfm is critical (most are about half that) dual air boxes where space is tight might be the way to go for some, keep in mind the higher cfm flow capacity the better. Understandably, all the mods in the world will choke when the air filter can’t flow the required cfm for the build. Big canisters are costly but can be had on the cheap via military surplus, there are aftermarket spun aluminum canisters used off road and sandy environments that can be fit to the GMT400 by removing and relocating one of the batteries.
Obviously, larger diameter exhaust is required the biggest downpipe available aftermarket for the GMT400 platform is 3”, a straight 3” exhaust pipe can flow 747 cfm minus frictional losses in bends/radius it can become a restriction at upper rpm levels when running any BIG AIR turbocharger, supercharger or blower.
Charge Air Cooling (CAC) aka: intercooling (IC) is a must, it is achieved in a few different ways air to air which must be installed in front of cooling stack to be most efficient and the cooling stack should be ducted and sealed all the way to the radiator and IMO also applies to any H1 too so the cooling fan can pull air through them. Any CAC/IC mounted under the chassis between the frame rails is OK for minor mods but only works while airflow is flowing across them and really needs puller fans that turn on at slower speeds or stop-go-idle situations to make them more efficient. Next is water to air which can be sized and placed anywhere there is space to do so.
High pressure water injection 1.0k is another option using fogger nozzles directly into intake or sprayed on outside of CAC/IC, triggering can be done a few ways. Fact is 1.0k water injection can be used to prevent detonation in gasser turbo or blown applications so-much-so that ignition timing can be safely advanced instead of the commonly used retarding yielding big power numbers over what you already thought were great numbers. The war effort WW-2 applied this to aircraft and entities like RSR racing have been using high pressure water injection with their builds for a long, long time.
It is of the utmost importance to understand increased air density can make up ‘too a point’ for lesser cfm flow however big cfm w/massive air density is best. Insulating all intake runners, air box aka: filter box, turbine and down pipe are critical too.
EXCESSIVE HEAT which is well known to be the enemy of any engine and especially the GM 6.5 diesel platform. Another consideration revolves around upping the boost on any IHI/GMX turbocharger which not only superheats the air-charge it brings EGT/ECT/IAT to critical levels which IMO has more to do with cracking blocks and heads than any other factor “The GM/AMG 6.2/6.5 diesel can take the heat as long as a properly sized turbocharger, proper fueling and a good cooling system along with aux oil cooler is used.” Yes! There is an ongoing debate as to how much heat is OK? Consider, the HMMWV max engine coolant temp was listed (not sure if it still is) at 250dge f. then consider the military has very deep pockets to replace anything at any given time while GM has a listed lower max cooling system operating temperature. IMO the best coolant to use on a modified GM/AMG 6.2/6.5 is “waterless” my reasoning revolves around preventing steaming, cavitation and safer higher operating temps in general. Waterless coolant along with a programmable fan clutch is perhaps the best route.
PURE SYNTHETIC oils and lubricants because of their ability to operate at higher temps without breaking down are hands down best protection against the heat breakdown suffered by DINO based oils and lubes at lower temps.
There are other strings about my use of waterless coolant and the reasoning behind it as well as others views for and against which can be found on this site I urge you to read them.
Fueling is another story in itself, IMO a DS4 simply can’t supply the fuel needed when running BIG AIR there are rumored higher flow DS4 pumps being marketed however how much fuel can be delivered is a mystery best left to those who don’t know any better, however if not going for the bigger HP levels the DS4 will provide the best fuel control under all conditions.
I favor the custom built DB2 w/documented fuel delivery for a good reliable build like n8in8or is running w/o what I like calling the guessing game DS4 tuning for a BIG turbo it can’t possibly feed enough fuel too.
