Engine/Transmission (1998.5 - 2002) PDR HX35/14cm - my review

[Mactruck]

This is a review of my new PDR HX35. I purchased this used w/ appx 6800 miles on it. It came with a 14cm housing on it that had a Banks Big head wastegate actuator on it rated to 43 psi. This turbo replaced a stock HY35 w/ 9cm housing on it.

I installed the turbo 2 days before I left for a 1000 mile trek. I took it from CT to Assateague National seashore in Maryland, then across MD to West Virginia, then home. I was able to put it through it's paces from coastal type driving to mountain type terrain. (hey, it aint the rockies but it worked )



Initiallly I was astonished at the turbo's kick in the pants ability. Once the boost kicks in it just wants to run. Even my girlfriend stated when she tried it "The truck just wants to go FAST" The lag is present but liveable from a standstill. I expected a little lag going between my old and the new turbo's. I however have not been able to get the psi's over 35psi. I know PSI is not as important as airflow but this was a bit perplexing. I though on a quick jump I could at least get it higher. This may be because of the amount of air needed to fill the 14cm housing. This would result in lower boost psi's while flowing more air than my HY.

While driving this turbo cools well. This is especially in between 2000 and 2400 rpm. At these rpms the turbo performed flawlessly giving me the quick boost needed to pass whomever I wished when I needed to.

The problem I have now encountered is that because I have a 3. 54 gear ratio as well as 295 size tires, The turbo does not cool as well and is darn near a dog below 1900 RPMs. This is not the fault of the turbo. The problem is I can't build the boost needed because my RPM's are too low. Sometimes cruising at 60 w/ boost at 2-4 psi I would punch it to pass someone and my EGT would hit 1300 (comp on 2) and climb untill the rpm's and boost was built up. This was not a problem with the Hy35 where the only thing that suffered was the high end boost and cooling.



I wonder if I made a mistake. I feel the only solutions would be to:

A) change my Gearing to a 3. 73 or 4. 10.

B) Get smaller tires (Not a chance )

C) Change to a 12cm housing and just keep a close eye on egt's when comp is on 3 and above.

B) I have a Boost leak. I have no previous numbers to back this up.



Like I said this is not a problem with my rpm's being up, the HX sings like a dream, but in OD I have to be going over 75 to 80 MPH to get it to run well. When I was coming home yesterday I did just that but my luck will run out eventually. I really do not want a ticket. :{



Any help would be appreciated..... Maybe it's just a simple boost leak? I am checking though...

 

[Diesel Freak]

How can I say this?



Welcome to MY world!



a tight Torque Convertor can do this to you. While I have a 6speed, I know exactly what you are going through. When you have a single turbo, you have to give up something to gain it somewhere else... . If you want more mid to top end ... . you will lose on the bottom end when going to a higher flow turbo... it is exagerated even more with a tight convertor.



The HY is a rocket off the bottom, but it is a little small for anything above 2500 RPM, and 25 PSI in stock trim.

 

[Snow man]

Mac truck, I put the 14 cm housing on my hx35. I noticed the same things you did right away. I definetely has more power,once under boost,but it comes at a cost. If iwere you,id go to a 12cm housing,it will make a big difference in spool up. My truck now spools at 1600RPM,it used to spool at 1350 with the 12cm housing. I have the 4,10's so it isnt that big a problem,and i intend to keep the 14 for now,but if had any less power,id stay with the 12. My EGTS are down about 100 degrees,with this housing,peak boost used to be 40psi with the 12 housing,now its 35-36 psi,so i think your boost pressure is fine. Your tall tires,and 3. 54's are going to deliver crisp response with any big turbo,we have to give something up to get something in this case. BTW is your t case seal still leak free?,

 

[Jim Fulmer]

Mac Truck, we have talked about this on the board a few times with a tight unlocked converter. Mine in Lockup at 2000+ is fine but below that(say 1800) you have a little lag, one would think T/Q would take over and it will once you get the boost to 30+, now in unlock at 1900 hammer it and it goes like an ape from 2 psi to 36 in an instant, Ok 2 seconds!



Jim



The plus side is at 1500 or below, mash the throttle half way until boost builds and it will clean out the cars

 

[Big White Beast]

I made more boost with the HY.........

Even with the HY EGT's were never really a problem. After the HX/14 the mid range power was enhanced but low end was terrible. Switched to a 12 housing and low end perked up and mid range seems to lose a little. DD2's and an EZ give me around 32 lbs. of boost max. With the warmer weather I think it's helping more.



Sometimes I'm glad I don't have a comp box. It seems your set up can be fine on one setting and crappy on another. These engines definitely need to be balanced. If you set up everything for top power you'll suffer at low end. I got the cake why can't I eat it too???



Garrett

 

[Sky]

I am glad you posted your findings because I have had people telling me for months now that I need to swap out turbos. My biggest issue is I dont want that low end lag. I have 33" tires and the 3. 54's also, I have to do 62mph to just be at 1500rpm in OD. I hate driveing the RPm's that low.



Anyway my egts are always in check so I see no reason to swap turbos. However my turbo has turned quiet yellow. I dont really know what I am loseing on top end though is the problem. Its not like I drive super fast all the time anyway. I would rather have the low end to beat up on punk kids that think there cars are fast from light to light



Mike

 

[Big White Beast]

SKY.......

With the comp and DD2's you probably would gain nicely in the mid range. The HX/12 is similar to the HY in spool up but doubt it would help much with EGT's. The 14 wasn't really bad but my truck weighs so much I notice it more than most. Too bad you can't find someone to swap out with for the day. That would make the decision a lot easier before you dropped the big bucks.



Garrett

 

[RADdodge]

I have Piers HX35 with 14cm housing and I didn't see much difference in lag or spooling from the HY35. I started with the Edge EZ and a 4" exhaust (with the PDR Turbo) and felt little difference in lag and a moderate increase in performance. When I added the DTT mods, DDIII's, and a PE Comp box (I generally set the Comp at 2/1), I feel about a 1 second or so lag before it really kicks in, but it's still noticeably stronger in the bottom end than it ever was before. To me, the power makes the difference more noticeable. When the Comp is set at 5/5, I just don't care at that moment. Life is good in Cummins land! And taking long steep grades loaded down and watching all those under powered vehicles slide away in your rear view mirror while motoring on in cruise control is particularly rewarding. A couple years ago I was ignorant of all this, now, as Jimi said, "Are you experienced?" Well I am. " The TDR is a great place in virtual space. There are pioneers here among us. I'm not one, but I sure have benefited. Thanks!!!

 

[Steve Campbell]

My take home message...

from reading the various reviews and opinions of the PDR-35 is that if you do not have an EGT problem now, go with the 12. Doing so will increase boost, enhance the "driveability", and reduce EGT as a bonus. If EGT is a problem, then go with the 14cm or bite the bullet and step up to the PDR-HX-40.



Is this what others are "hearing" in these various posts, or did I miss something? Perhaps Piers will step in here and do a bit of advertizing!!!

 

[Mactruck]

I feel off the line that this is still a great turbo. From a dead stop you can still blow those little rice burners off the road. This is because the rpm's for WOT are perfect for the HX to shine. The problem is with a 14cm housing, cruising is what suffers. Maintaining that 1800 - 1900 rpm is a little bit of a struggle (65 mph). She wants to go to 2100 rpm (80 mph) If the darn overdrive wasn't a . 69 ratio this would be a good setup.



I think my next option is to switch to a 12cm housing. It's the most cost effective and will allow me to keep my egt's in check a little better than my HY could. I couldn't even use my comp in 4 & 5 with the HY. The egt's would shoot through the roof.



I'm glad this is being covered. Too my memory, in all my TDR reading, this hasn't been really reviewed this way. The HX35 / 14cm has problems for those that are undergeared. It also shows that there are certain limitations to a larger turbo and housing. This is not a bad reflection on PDR's turbo, just that in some instances a larger housing will not work as well.



This would be solved with 4. 10's (for me) That is the biggest mistake I have made. :{ Anyone have a set?

 

[Sky]

Hmmm, see its tough to make decisions here some times when you get conflicting reports. It would be dissapointing to lay out the cash and not be happy with the new turbo. I just need to drive a truck like mine to compare I guess to be more sure.



I dont have a problem with egts on level 4 and 5. I gets hotter but not out of control unless I really lay into it for awhile.

 

[Mactruck]

Sky,

IMHO you would run into the same problem as me. So if you get a new turbo, I would get the 12cm housing. JM2Cents.



My other problem is that I need to get a 4" exhaust. That will be done appx. this month. I was planning on getting it first but this used PDR came up and I had to grab it.



Plus my girl, she's a diesel chick but she keeps saying my truck is too damn loud! ooh well I guess I now have permission to get the 4" exhaust. :-laf

 

[Sky]

Originally posted by Mactruck

Sky,



Plus my girl, she's a diesel chick but she keeps saying my truck is too damn loud! ooh well I guess I now have permission to get the 4" exhaust. :-laf

If she thinks your truck is loud now wait until you put on the 4". And I think you should go straight piped too. It sounds very cool. You should at least try it for a week to see what your missing out on. Oo.



I was just looking at your truck pics and see you do have it straight piped Sweeeeeeeeeeeeet!



I still want the DO bumper that thing is so bad A$$.

 

[Mactruck]

It's straightpiped now - thats the problem I need to put a muffler back on it and I said the only way to is to get the 4". Thanks for the Positive comments of the DO.

It's my "Get the Heck out of my way!" bumper. Oo.

 

[dmistal]

Mactruck,I didn't realize our trucks were so different. I feel bad that its not working as good as you thought it would. Do you have a 12cm housing to swap to? If not ,I have a brand new one I'll send to you,once installed and your set,return the 14cm to me. Just let me know. David

 

[Koa Man]

I have the PDR HX35/14 also, and have found no additional lag in comparison to the stock HX35/12. Spool up (in my case) was much quicker. Boost increased from 34 to 40. EGTs went down about 100*. I need further reduction in EGTs because of my almost daily towing in mountains and will be going to a HX40/16. Biggest difference in the elimination of take off lag for me was changing transmissions.

 

[ToolManTimTaylor]

Anyone have a set?

Ahem ... . Sets (4x4 there kevo)

Good eval kev ++

I am revampin' big whitey (keeping the ddIII's , Blue chip , Van Aken , Volant , exhaust , High ram) Swapping out ( 93% converter in favor of 89 , PDR hx 35 for ..... twins and maybe a bumpstick , and billet shafts) *Snif* *Snif* whats that i smell ... ..... O. T until november?



Reason is tight converter and lotsa fuel + smallish turbo = easy~Bake~Cummins~Oven by fisher price



o. k SO LET'S SAY EVEN WITH A 16cM2 HOUSING to drop my egt's I will wait a week for boost to build cause of my use of such a tight converter (which back when I was bank's powered and lightly injected worked out quite well) and when i do build it, it's hot boost anyways which does nothing for egt's reguardless. I love the pdr on the hightway as 4:11's put her right in "insta~boost" mode at any given moment. I need to be juust a wee bit more smoke savy arround town *Cough* [size=0Twins[/size] *Cough* and maybee pick up a few horseys along the way.



I agree 4:11's + Pdr =funfactor9

 

[jlccc]

swap 12cm turbine housing for 14cm

Does someone close to the Salt Lake City area have a 14cm housing that they are willing to swap for a 12cm? I need the cooling at the top end, not the boost at the low end. Low end lag isn't a problem for me. Won't a 14cm housing offer an improvement in this respect over the 12cm?

 

[Big White Beast]

I'm still up in the air.........

Between the 14 and 12. EGT's are relatively the same.



After I installed the PDR35 I had a friend riding with me on the freeway and puched it to get around a car. He was quite impressed with my 60-90 excelleration.



JLCCC I can't believe you have that much of a heat problem with 275's and an EZ. I have DD2's and I've never seen over 1200° and that's with a 5½ ton truck as a daily driver. Unless altitude has that much effect. Salt Lake is up there isn't it??



Garrett

 

[jlccc]

Re: I'm still up in the air.........

Originally posted by Big White Beast

JLCCC I can't believe you have that much of a heat problem with 275's and an EZ. I have DD2's and I've never seen over 1200° and that's with a 5* ton truck as a daily driver. Unless altitude has that much effect. Salt Lake is up there isn't it??

Salt Lake is about 4500 ft, depending on what part of the valley/benches you are in. I can easily reach 1400F towing a 5000 lb TT with a 700 lb four wheeler in the bed. I've just installed a 4" exhaust so I'll have to see how much that helps before I decide to try the 14cm housing.



Note also that I'm running the ETH and my opinion is that they definitely run a bit hotter than the ETC due to the higher compression.