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Just upgraded to hx35, not happy


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So here's the deal. Truck is an 02 with a built auto, 120k miles and edge comp with tapped wire, stock injectors. After tons and tons of reading I decided that upgrading to an hx35 would be better for the truck and just make the truck better overall but I honestly don't know how to feel about it now that I'm doneThe truck makes way more heat on the egt's. Like everywhere but way up high in the rpm range. With the stock injectors and pinned I can only just barely touch 1250 unloaded but this was impossible with my hy. and whereas my hy made a max boost of maybe 20 the hx makes about 37 max psi.whats going on here? I get more heat, less spool up down low. Higher cruising egt's and lower crusing boost pressure just running unloaded down the highway and the only improvement I can see is when I'm pushing it hard but even that is next to nothing (more air but doesn't feel any different, same max temp), certainly not worth the cost.Any thoughts here guys, should I just put the hy back on and be done with it? Currently I'm not hauling or towing so its just unloaded highway driving but it feel less responsive but with similar mileage and higher cruising temps? No boost leaks anywherethanks for your help guys

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I did the same swap on my 01 and I did notice the slower spooling and less bottom end. But I never had my EGT hooked up with the HY to compare. What are you running your Comp box set at? If I pin mine on a decent hill on 3 or higher it will crank the EGTs to 1200+ in a hurry but I have RV275 injectors. With the smaller turbo my truck would almost break the tires loose on the 1-2 shift stock. It won't do that now, but it pulls harder up top.

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The hx is going to spool slower on the low end than the hx due to the exhaust housing size. The hy is smaller than the hx and spools quicker. Your boost pressure is determined by the waste gate. Stock it should open around 20 psi. Mine will make 33 or 34, but I have an aftermarket waste gate that opens at the higher pressure. You will make more power with more pressure, but I believe 35psi is about the max effective pressure for the hx. Above that you can loose power and make more heat like you are seeing.There are some much more knowledgeable folks here that will be able to explain this much better. I am sure they will be speaking up soon. Do you have any other mods on your truck? If you would fill out your signature with any mods you have it will help with solutions.

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That because of a few different things happening. 1. Yes. The exhaust housing is bigger the bigger the housing the the slower the spool up. 2. You've went beyond the the turbos ability. When you start getting drive pressure above the boost pressure you over the choke point of the turbo you need to turn down the boost elbow to limit the wastegate at 35 PSI.Now Remember I've got.* Stock 3" Exhaust Straight piped* Stock HX35W turbo* +50HP injectors* Edge Comp Tapped and set to 5x3Absolutely no problems towing my 31' Jayco trailer at all. Very controllable for EGT's and climb a 6-7% grade in 5th gear @ 60 MPH for 70-80% of the grade wasn't till I hit 1,200*F I back out and grabbed 4Th and still held 55-57 MPH the rest of the way.

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As others have said you need to back the boost down, 33-35 is the absolute most you want to see and probably better in the 33-35 range. The HX still has a fairly small small compressor wheel, and more than 35 psi is just starting to push hot air. Also as stated the HX has a larger turbine housing, which means slower to spool in this case. It shouldn't be much but it will be there. This is also the reason for the higher cruise EGT's, you have less boost at cruise. Unless they are a lot hotter that's not a big deal.

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the only improvement I can see is when I'm pushing it hard but even that is next to nothing (more air but doesn't feel any different, same max temp), certainly not worth the cost.

You have 17psi more boost yet the same max EGT....and the same power. Something is very wrong with that picture. That would be like me going up a steep hill at 70mph with the trailer at 20psi and you're saying you can do it at 3psi and get the same power and EGT :think:

Now I am not trying to criticize or anything but you can clearly see something is way off. The boost might be a little high but eh, not exactly 50psi like some of these guys are ignorantly running on an hx. Something is just way out of whack. Did you change anything else?

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Most likely before you were gated .... and when you hit 20psi the gate opened and you hit a wall (performance and fuel wise) ..... all the turbine hot air was allowed out ...... but not building boost eitherNow your able to push the MAP and the gate doesn't open till late ......... but your out of the MAP range now ...try adjusting the actuator or the boost elbow so that the gate opens around 25psi - not 35pis ..... you can test this with compressed air ...... then redrive and let us know.

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My 2000 4x4 Ram with auto came with the HX35 turbo. It had the 12cm2 exhaust housing. I run a 4" exhaust (turbo back) and the ZXT+ chip. There was no lag in this setup at all.I think the HY turbo comes with a 9cm2 exhaust housing.I lost the oil seal on my HX35 so I replaced the turbo with an HX35/40 hybrid with a 14cm2 exhaust housing. This setup produced a small lag when you accelerated hard from a stop but it pulled much harder than than the HX35 when passing.I then installed RV275 injectors and the lag completely disappeared. In fact for the first time ever I was able to spins the tires (with positrack rear end) from a dead stop in a non-boosted launch.This setup worked very well for my truck. So well in fact, that every time some drives my truck they ask me if I am interested in selling it.:think:So it is not really clear to me why an HX35 in an '02 would produce lag while an HX35 in an '00 does not.Could it be installed in an larger exhaust housing than a 12cm2?

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My 2000 4x4 Ram with auto came with the HX35 turbo. It had the 12cm2 exhaust housing. I run a 4" exhaust (turbo back) and the ZXT+ chip. There was no lag in this setup at all. I think the HY turbo comes with a 9cm2 exhaust housing. I lost the oil seal on my HX35 so I replaced the turbo with an HX35/40 hybrid with a 14cm2 exhaust housing. This setup produced a small lag when you accelerated hard from a stop but it pulled much harder than than the HX35 when passing. I then installed RV275 injectors and the lag completely disappeared. In fact for the first time ever I was able to spins the tires (with positrack rear end) from a dead stop in a non-boosted launch. This setup worked very well for my truck. So well in fact, that every time some drives my truck they ask me if I am interested in selling it.:think: So it is not really clear to me why an HX35 in an '02 would produce lag while an HX35 in an '00 does not. Could it be installed in an larger exhaust housing than a 12cm2?

Are you gated? What boost numbers do you see? Have youdynoed?
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No dyno runs. I am gated and I see about 30-32.I can't burn the tires off but I can leave a two stripped patch when I take off in a hurry.Never was able to do that on a good day with the stock HX35 with the ZXT+ and 4" exhaust.

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No dyno runs. I am gated and I see about 30-32. I can't burn the tires off but I can leave a two stripped patch when I take off in a hurry. Never was able to do that on a good day with the stock HX35 with the ZXT+ and 4" exhaust.

Good thought about the larger exhaust housing ...... could be modified ....... but then technically the EGT should be lower in the top end ... but hard to say without knowing if the turbine side was modified. Boost leaks could push EGT up - but he's hitting good boost on stock injectors ....... When you gate opens at ~32 ...... do you lose power .... almost like defuel limit ? I ran a s-hx40 on RV275's and +75hp ....... the lag wasn't really that bad ....
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No dyno runs. I am gated and I see about 30-32. I can't burn the tires off but I can leave a two stripped patch when I take off in a hurry. Never was able to do that on a good day with the stock HX35 with the ZXT+ and 4" exhaust.

I can break the tires loose in 2nd or 3rd gear on dry pavement. :burnout: On wet pavement I can break loose in 4th gear as well. :burnout2: HX35W turbo is a good turbo as long as you tune around it.
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What are your plans with the truck? If you plan on leaving it in stock form, it was most likely not worth the swap. Cummins spends lots of time and money in R&D. They engineered the truck with the HY simply swapping out one component will make a negligable difference if any. Now if you were to throw a tuner and a set of injectors on (added timing and fuel) now you will be benefiting from the larger housing.

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That because of a few different things happening. 1. Yes. The exhaust housing is bigger the bigger the housing the the slower the spool up. 2. You've went beyond the the turbos ability. When you start getting drive pressure above the boost pressure you over the choke point of the turbo you need to turn down the boost elbow to limit the wastegate at 35 PSI. Now Remember I've got. * Stock 3" Exhaust Straight piped * Stock HX35W turbo * +50HP injectors * Edge Comp Tapped and set to 5x3 Absolutely no problems towing my 31' Jayco trailer at all. Very controllable for EGT's and climb a 6-7% grade in 5th gear @ 60 MPH for 70-80% of the grade wasn't till I hit 1,200*F I back out and grabbed 4Th and still held 55-57 MPH the rest of the way.

Sorry for the delayed reply but I'm back Tuner lives on 5x5 (edge comp with tapped wire) truck is not modded heavy at all. BHAF the comp box 285 wheels, spooge tube mod, high idle and mpg fooler and thats about it. QCSB Now I"m obviously not driving it at 35 psi very often, just when I floor it up a little grade to get it to max out out can I see those pressures and temps. This turbo is a real holset though with no wastegate, I plan to put one on eventually but honestly with the truck pinned at only making ~35psi I have other worries at the moment, I know nothing is in danger there my big problem is I honeslty don't feel like it is hardly any different than the hy was. It builds boost slower and later which I can see due to the bigger exhaust housing and my temps are hotter all the time I'm running empty. and way hotter going up a canyon. The only time I feel like this turbo is giving me more is when I'm really rapped out and its boosting really heavy but otherwise its giving me the feeling that the truck isn't pushing it into its effective range or something. It feels stronger up top but I'm running very little of my time up there now that I've changed jobs and don't haul much anymore running down the highway with the old hy I could see under 600* egt numbers and running 4-7psi of boost. Now i'm more like 750 egt and 0 psi of boost. Both at 65, no change except the turbo. Is this something that I should have expected? Mileage hasn't really changed to be honest which is only confusing me more:think:. Still getting ~20 mpg, better on longer drives but I want more (i can get 23 for a trip according to my scangauge if the truck is already warmed up when I set off)
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Are you sure its an HX35? I put a series 60 detroit turbo on mine once and the symptoms are identical to yours. That turbo was huge though so it was 10x worse than yours but your symptoms are still pretty similar. It did nothing unless I floored it and it would finally spool up to a mere 15psi. If you have something bigger than an HX35 (but smaller than the series 60 detroit haha) then I can see it causing all your problems. An HY to HX is not anywhere near as drastic as you are saying so thats why I am wondering. I mean wastegated or not, the spool up times aren't that different, not enough to cause huge egt issues. I am sure they sell the HX35 without wastegates but that is also something that makes me curious. So you might double check the numbers, otherwise, ignore this. Could also be worn out so it isn't spooling worth a crap. I am going to say you could get to 45psi nonwastegated if it was an HX35 on 5x5 but if its got a lot of coking on the shaft then its harder to turn and obviously results in less boost. :2cents:

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Are you sure its an HX35? I put a series 60 detroit turbo on mine once and the symptoms are identical to yours. That turbo was huge though so it was 10x worse than yours but your symptoms are still pretty similar. It did nothing unless I floored it and it would finally spool up to a mere 15psi. If you have something bigger than an HX35 (but smaller than the series 60 detroit haha) then I can see it causing all your problems. An HY to HX is not anywhere near as drastic as you are saying so thats why I am wondering. I mean wastegated or not, the spool up times aren't that different, not enough to cause huge egt issues. I am sure they sell the HX35 without wastegates but that is also something that makes me curious. So you might double check the numbers, otherwise, ignore this. Could also be worn out so it isn't spooling worth a crap. I am going to say you could get to 45psi nonwastegated if it was an HX35 on 5x5 but if its got a lot of coking on the shaft then its harder to turn and obviously results in less boost. :2cents:

I'm really really sure thats what it is, I have the wastegate but no line connecting to the cold side to activate it. I'll upload some picture so you guys can help me see it here. The guy said it was freshly rebuilt, it sure feels tight and looks clean these are the only comparison pics I have from off the truck. The nasty old one is the hy http://imgur.com/a/JZbfS please keep the feeback coming guys, maybe I'm overly fussy but honestly, I expected more
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Yeah I think you are good with it being an HX35. I want to know more about what you see Boost/EGTwise at say 70mph on levelish ground. I have about as light of truck as it gets and 2wd low riding as well and see uh I think 5-7psi at 70. Been so long since I've driven it. But yeah you shouldn't be any lower than that is why I'm saying.. Otherwise I would be looking for leaks or turning the turbo shaft after the truck is warm to see how good it turns, check for side to side play etc. Something just seems like that turbo isn't dishing out what it's supposed to.

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