HX40 = Fuel Economy Killer in town?

[Vaughn MacKenzie]

I may be on the verge of pulling the trigger on an HX40 (that is, unless I come to my senses on the $$ and get cold feet #ad
)

I am wondering if the HX40 users on this forum could comment on the fuel economy they're seeing running around town/city driving, compared to their stock turbo. My fear is, running a big turbo and continually doing stop/go driving, mileage might suffer. What do you guys think? Please post your signature or post your BOMB setup, and please keep posts to actual experience instead of speculation/opinion.

Thanks guys.

Vaughn
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'01 2500, QC SB 2wd, ETH/DEE, 3. 54lsd, RV injectors upgrading to DD3s in the near future

 

[Chad Sheets]

Well, I dont have any HX40, however I do have a wealth of diesel knowledge that you might be able to apply here.

We understand the spool up part of it... bigger turbo, slower spool up. This isn't always true however. If you have all the other engine mods in place necessary to spool that beast up, and have a combustion chamber with the volumetric efficiency to handle all the fuel/boost mods, then you dont loose any spool up time as compared to the stock turbo with stock fuel mods.

Imaginary example. You take a stock truck and figure out it takes X amount of time for the turbo to get to 50,000rpm from a stand still. Just for fun lets say it takes 1. 0 second to do this. Now you add fueling boxes and injectors along with some other goodies. Now the desired 50,000 rpm turbo speed is achieved in 0. 5 seconds.

Now if you put the larger turbo on, one would think it would be a slower spool up. In reality by doing this you have brought the 50,000 rpm spool up time back to 1. 0 seconds just like in stock form.

This example is just that, an example for simplicity. I have seen some engines with larger turbos added in testing areas that get high CSFC (calculated specific fuel consumption). Replace them with some smaller turbos and everything jumps back into the parameters.

Think of the kid in high school we all remember who had that inline 6 Nova and put a big 4 barrel Holley on it thinking it would make his ride fast. You dont want to be that kid, unless you have done all the necessary engine improvements to handle the extra 2 barrels, if ya know what I mean. Hope this helps some. I think your truck would handle it pretty good with the DDIII's and perhaps a big fueling box as well.
Otherwise it might be a little to much in your current form.
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Always ready to help!
2000 2500 Red Sport quad cab, 4x4, K&N, DDI's, straight piped, boost, pyro and fuel pressure gages, Hot Power Edge, EZ box, mean looking set of 33. 5" tires, Snap On diamond tool box, Marine Corps window sticker, Semper Fi!

1972 340 Cuda'. Original tripple Black, 340 car w/air. Good clean car, super stock springs, Weld Prostars, shaker hood, strong 340 with a 727/4000 stahl, 4. 56... . Bombs away!
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[This message has been edited by Chad Sheets (edited 02-01-2001). ]

 

[Vaughn MacKenzie]

Chad, I plan to get the turbo competition prepped by Majestic Turbo. I think with the pinwheel/turbine lightening the turbo will work well with DD3s only. In fact, it may not be that bad with RV injectors and boost module. When driving HVAC's truck last summer running the DD3s only (turned all the boxes and gas off) I thought his HX40 spooled up more willingly than my HX35 12cm. Unfortunately that is the only experience I have with the turbo firsthand.

Not long ago someone posted a graph of all the Holset turbocharger models and what HP range they were practical for. As I recall the HX40 had a much wider HP range than the HX35. The HX40 started around 300hp as I recall. I don't think I'm far from that now. Stock I dynoed at 245 with a green motor, but feel that may be 10-15hp optimistic. But even figuring a conservative 230hp and adding 45hp for RV injectors that puts me at 275 easily. With the competition prep I think the turbo will do OK but be a bit doggy with the RVs.

I am going to expect a possible . 5 to 1 mpg loss in stop/go driving; if mileage holds I consider it a bonus.

Vaughn

[This message has been edited by Vaughn MacKenzie (edited 02-01-2001). ]

 

[WeirCummin]

Vaughn
If you can hold off a short time maybe I'll have an answer to your concerns. I picked up my Majestic HX40 yesterday and as soon as my down pipe arrives from Stan's it will be installed. I Dyno'd Wednesday with a fellow BOMBER in Austin. My HX35/14cm2 didn't seem to be a limiting factor on the dnyo but I'm not sure. It is on the road due to EGT's. The Max
power with RV275's EZ and PE on level 3 was 334. 3HP. I am unable to run on the street with both boxes due to clutch slippage but didn't have a problem on the Dyno. Talking with the crew at Majestic, it is thier feeling that with the work that they have done to the HX40, there should be less lag and better driveability than my current HX35 It will be interesting to see what HP increase there is with the 40 as sportbike has suggested.

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Y2K(BD. 11. 18. 99)PW7A BE2L34,(A4OP=ETC/DDX),DMDP w/DSA,AHJ,Autometer Pyro& 50#Boost,STD. PE&EZ,275RV injectors Psychotty,14cm2,Wlkr#21468

 

[kevin1]

hey Vaughn I know of a guy here in calif that does the balancing on turbos he builds the turbos for our pull tractors he has them pretty much perfectly balanced he has forgotten more about turbos then most people will ever know, I put both Nowell and Adam in touch with him to get them the right turbo set up for their application, also check out my sig the reason fuel economy goes down is you can't keep your foot out of it

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2001. 5 ETH/DEE DD3's EZ HX40 machined out for more flow, Custom 4" exhaust turbo back staight pipe with 5" chrome tip in front of rear tires,spa's, mcleod clutch, fuel lines,mag hytech rear end cover,more to come

 

[Mopar-muscle]

vaughn , good topic , i am leaning towards the bigger turbo also . heres a heads up , don't forget hvac has a TST reflashed ECM in his truck also .

weircummin , are you sure your clutch wasn't slipping ? i would have expected a bit more, 20 maybe 30 HP out of your combo .

 

[Vaughn MacKenzie]

Bill, glad to hear you'll be at Rob's. Spec-ing out a truck that is BOMBed like I'm planning before plunking down $$ is a good thing #ad


WeirCummins, keep us posted on your HX40 install and impressions.

Vaughn

 

[_Bill]

Vaughn, I did not notice a decrease in fuel milage or loss of spool up. My truck has been averaging about 18-18. 5 mpg around town. I am going to try and make it to NW Bomb party on the 17th if you want to check out my set up then (DD III's, HX 40, boost module, 4"exhaust).

 

[JR2]

I do not seem to be able to find much info on the HX40, any one have a rough cost estimate on one. I know I would need a new downpipe, but how much is the turbo. Thanks...

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John D. Rathert Jr.
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01 2500 SLT+ QC LWB 4x4 Auto 3. 54 rear end, Forrest Green Sport with all options avail. DC Nerf Bars, DC Grill Gard, DC mud flaps, Line-X bed liner, Leer 160XL Topper, Power Edge, EZ Edge, SPA Boost/EGT Gauge on pillar mount, DDT's torque converter - valve body combo, 275 RV injectors, Diesel Dynamics 4" Exhaust and a KN RE0880 where the air box use to be.
New turbo (HX40), SS fuel lines and bigger injectors in planning stages... .

See My Truck

Dads truck: 98. 5 3500 SLT QC LWB 4x4
Brother Truck: 92 W250 SLT CC LWB 4x4 (Dads old truck)

See 5 Diesels and a Gasser
Winter fun: 2000 Skidoo Summit 700
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[kevin1]

the turbo is right around 800 bones

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2001. 5 ETH/DEE DD3's EZ HX40 machined out for more flow, Custom 4" exhaust turbo back staight pipe with 5" chrome tip in front of rear tires,spa's, mcleod clutch, fuel lines,mag hytech rear end cover,more to come

 

[Ted Jannetty]

Vaughn, You are far from ready for an HX 40 given your listed mods.
The mileage may or may not change much but the throttle response, and acceleration will suffer.

Unless you dicide to bite the bullet and build a race truck I suggest you save your money for other things.



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Ted Jannetty, Owner President, Jannetty Racing Enterprises, Inc.
97 3500 4x4 club cab 5spd. RED, JRE custom power kit, JRE 4" exhaust
JRE 1/2 inch fuel system, Bosch 300 hp injectors, Prime loc,
Cummins chrome kit, US Gear 20% over drive, 3. 54 posi, Autometer
Ultralite 50lb. boost, and Pyrometer, BD exhaust brake.
Horton fan clutch

99 Ski-Doo 800 Formula III Pipes, reeds, studs and clutching 172 hp
99 Honda Forman 450 ES jet kit, pipe, lift kit, 27" Mud Runners
2001 Ski-Doo MXZ 800 X stock for now 140 hp
2000 TransAm Ram Air WS6 Flowmaster, K&N, Granatelli Mass air meter, LS1 Lid 370 hp
1973 Camaro Rally Sport Street Strip 850+ HP

 

[Arcticat]

Mopar, I thought a little low too but he does have a standard PE rather than our hot edition. 190stock + 80PE + 40RV275 + 25EZ(peak) sounds about right. I am thinking about that turbo too, to go with DDIII's and a PE Comp...

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'00 2500 reg cab LB 4x4, 5spd, LSD, Hot Poweredge, 275 injectors, Warn HS9500I winch, Trans4mer grille guard/winchmount, TracRack, Line-X OTR, G-tech, Loadsaver, and a bunch of other crap I don't technically "need" Name a factory option-I don't have it!

 

[Vaughn MacKenzie]

Joe. . . no, I don't think the HX40 will cut it with my current mods. It will go along with a set of Stage III injectors. I heard Holset may raise the price of the HX40 so thought I might grab one incase that happens.

Since I started this thread, I have gotten 3 or 4 emails from guys running DD3s and no box (except boost module) and have been pleased with the drivability with the HX40.

If I wanted to go with best "bang for the buck" a 16cm housing on the stock turbo would probably be a good way to go. I am giving that some thought as well.

Vaughn

 

[Chad Sheets]

I like the sounds of that as well.

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Always ready to help!
2000 2500 Red Sport quad cab, 4x4, K&N, DDI's, straight piped, boost, pyro and fuel pressure gages, Hot Power Edge, EZ box, mean looking set of 33. 5" tires, Snap On diamond tool box, Marine Corps window sticker, Semper Fi!

1972 340 Cuda'. Original tripple Black, 340 car w/air. Good clean car, super stock springs, Weld Prostars, shaker hood, strong 340 with a 727/4000 stahl, 4. 56... . Bombs away!
NRA Life Member
My Diesel Page

 

[Bart Timothy]

Be careful in comparing BOMBed ETCs and ETHs as they are 2 entirely different animals in the results. There are several owners of ETHs with DD3s and HX40 running around who have reported no loss of throttle response if extra fueling is added at the low end. In theory it you would think it would be injectors and driving habits which would affect fuel economy more than the turbo. In going to DD3s from 275s my ETH milage went down a mile or two.

One big hidden cost of going to the HX40 is a new down pipe and clamp. I decided to build my own down pipe, but ended up paying almost as much for the parts to convert my old down pipe as a new one would have been. The little 3" SS section of pipe which connects to the back of the turbo is anywhere from $48 to $51 from Cummins (anybody know where to get one cheaper?). The clamp is $18 to $20, and a 4" x 12" 45 deg bend section is $20. Then everything has to be cut and welded together

 

[OO]

I made my own downpipe also. You can save some money on the clamp and flanged pipe by welding either the elbow or a short piece of pipe directly to the flange.
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I made my downpipe with a 4" 45 and a 18" length of 4" flex pipe.
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