Engine/Transmission (1998.5 - 2002) New turbo, got ?'s

[mediccummin]

I have had my new PDR Hx35/14 now for a short time, and got some things I'm wondering about. First off I'm running VA, DD2's, AFE and 4" exhaust, I live at sea level. My stock turbo was a Hy 35/9. Now I was under the impression that with the bigger turbo I would see less smoke at bottom end and lower egt's, so far that has been far from the case.



The power feels about the same, with a little more noticeable turbo lag at bottom end but not much, you can tell it is sucking much more air, allot louder in the cab, at mid and high range seems a little more responsive.



With the stock hy I had to really get on it to create smoke at take off. With the new Hx I get smoke on every take off whether I try to or not???



My EGT with Hy at 75mph, 65' temp out side, 12lbs boost was around 750. With the new Hx same speed and temp, I only have 8lbs boost and 850-900 on the EGT's. That is an increase of 100-150. I thought I would see a decrease of that much. What gives here.



On the grade, same temp out side, same speed up hill, with Hy I saw 1000 max, cruising, 24ibs boost, Now with Hx I see 1200, 16 lbs boost. My max boost with the Hy was 34lbs with the new turbo they said they set it at starting to open at 28lbs, I cant even get it to 28, it stops around 26.



Would my boost rise a little slower with this turbo??? I sure it would but was wondering by how much. It holds boost well so I don't think I have a leak, and would it run lower than the Hy?



Will some more miles on the turbo make any difference? I did put some miles to break it in before these results, and I really have not got on it much yet want to give it some time. Any input would be great thanks... ... ...

 

[Oil Burner]

I would say that a real test would be under load where the HY would fall flat and the HX35/14 still has room to build. I know I cannot even think about hitting my max boost numbers unless I have a decent load dragging behind me. Empty runs just don't compare. Also, your smoke on takeoff and slight lag off of the line sound right in line. You increased your exhaust housing side from 9 to 14 cm. That is a decent step. Your turbo will then spool a bit slower and give a little more smoke (due to lack of boost). I think the full advantage of that nice PDR35 would be under load as in towing up a grade under WOT. In that situation, the hx35 should really shine. zipping around town under light throttle with no load, I would actually rather have the smaller turbo and housing. it would be more responsive. You will really appreciate the hx35 when you load it down.

just my . 02.

-Jason

 

[Bob Wagner]

exactly as stated above, try a 12cm housing and see the change

 

[Hohn]

Jason, right on.



The larger housing will net higher AVERAGE EGT (and lower avg boost), BUT will have lower PEAK egt (even if peak boost is lower).



The advantage to the larger housing is that you have freer flow on the top end. Unfortunately, you much sacrifice spool up to get it.



If you REALLY worked that engine (tow heavy) you would note that your peak EGT would be lower, and the EGTs would rise faster initially, but much slower as you approached peak EGT.



The PDR35 with a 14 or 16 cm housing is optimized for towing with a lower hp (read: near stock) truck.



Even with a VA and 2s, you are within the range of a PDR40 with the 16cm housing. Or, for a cheaper option, try the dodgezilla 35/40 hybrid.



Justin

 

[KLockliear]

#1 - with a given amount of HP, a bigger turbo will always be laggier off the bottom (which means more smoke if driven the same), but should provide more top end EGT compensation.



#2 - test your wastegate setup. The easiest thing to do is get a brake line clamp and clamp off the hose going to the actuator. Go out for a quick test ride and got WOT and see how high the boost gets. If it gets to 40psi, back off immediately. If it gets above the 26psi you see now, the wastegate is opening prematurely. If it still makes 26psi, you only have enough power to make 26psi with that turbo setup and that is all you will see.



Cruise EGT with a bigger turbo will usually go up some. Bigger wheels mean less boost at a given engine RPM, which means more EGT. WOT EGT should be down if the turbo is sized properly for your power level.



Keep looking for the boost leak otherwise, especially at the O-ring at the outlet of the turbo.

 

[mediccummin]

Thanks all

For the input so far. I also forgot to mention I added the Pacbrake at the same time, I did-check to make sure it is functioning properly. It is opening all the way up. Thanks for the help you guys confirmed my thoughts on the way the new turbo acts. Just wanted to make sure I was thinking clearly and did not have any problems. I will take your suggestion Keith and give it a try tom. I just got done installing the DDUFM and now have the P1693 code any help on that would be great. I notice some difference in the box compared to my VA but don't really want to get on it to much until my transmission comes. It actually smokes less with the DDUFM even on smoke5. I'll give it all some time and check things out, so far I'm happy, can't wait for the transmission. Later and thanks again.

 

[jrandol]

I did a turbo upgrade a few weeks ago myself medicummin but it was the 40/35 hybrid. At first I was very dissapointed in it but I did play it easy for the first 500 miles to break it in right. I think I have about 1300 miles on it now and I am much more pleased. There must be some sort of break in period on these. They are really tight when new. My egt's have decreased much more now that the turbo has a few miles on it. So maybe try turning a few thousands miles on it and see if that helps your situation any before trying different housings.



Jeff