Engine/Transmission (1998.5 - 2002) Let's talk hybrid turbo.

[BDaugherty]

I've been looking at this turbo:

DodgeZilla Turbo City Diesel - Diesel Performance

It's a hx 35/40 hybrid. I haven't called for details, but it says " largest hx40 compressor wheel available". This would be for my '01 HO6spd with jammer 2's and Edge JWA. I'm looking for spoolup near stock, but with a little more airflow and boost not over 40 psi. I can hit 36 psi now, but I'm thinking that it's mostly hot air. When I use the "hot" level 6, it really doesn't pick up noticeable power over level 4 or 5, it just smokes more. I'm thinking more air would really help clear it up on top end. I don't expect to add any more fuel than what I have now. I'm just looking for a little more cooling on top end, but I don't want to sacrfice towing or daily driving. Also, with this turbo I could save some coin by finding a used exhaust housing and not having to change my exhaust. That brings me to another question. Should I look for a 12 or 14 cm exhaust housing? I was thinking 14, but to tell the truth, I don't know what I have now. I won't be making this purchase anytime soon, but I'm one of those guys who likes to do a lot of research and takes so much time to save up money and make a decision that by the time I'm ready to buy, I really feel good and have all the details on hand.

I'm just looking for opinions here. Who has run this or a similar turbo? Would you do it again? What were the ups and downs of that setup? Thanks in advance for any and all comments and advice.

 

[darkhorse]

I'm running the Dodgezilla & am very happy with it. You most likely have a 12 cm housing, as that is the stock size. I have a 14. My manifold & housing have been port matched as well, which aids spool. I don't notice any difference from stock spool.

 

[Hammer]

High tech Turbo also has the HX35/40 hybrids in many different variations to suit your needs... ... Andy

 

[BDaugherty]

Darkhorse, is your 14cm housing wastegated? I'm assuming it is. How long have you had the dodgezilla and where did you get it? Would you do it again? Thanks for both of the responses so far.

 

[darkhorse]

Yes it's wastegated. I've been running it for 2 or 3 years now. I got it from Rip & yes I'd do it again. I have a Banks Break & didn't want a turbo that wouldn't support it.

 

[PC12Driver]

I'm just looking for a little more cooling on top end, but I don't want to sacrfice towing or daily driving.

That's pretty much impossible with a single turbo. If you're gonna add to the top, you have to take away from the bottom, period. Bigger, more aggressive compressors will move the powerband up, as well as larger exhaust housings. Your stock turbo has either a 54mm or 56mm compressor wheel (I don't remember off hand) and the Dodgezilla uses a 62mm. That's a huge jump, and the powerband will reflect that.



I ran one for a couple of years. The only good thing about it was that I could keep my turbo mounted exhaust brake. However, I now run a HTB2/12 and my exhaust brake is sitting on the shelf. The drivability and the efficiency of the new turbo kick the DZ's butt so hard that I don't feel bad about the deletion of the exhaust brake.



With a trailer on below 2,000 rpm with the DZ/14, egts were uncontrollable and it smoked like a coal train with any throttle. 2,100 and above, the turbo woke up and cooled okay. With the 12cm housing it was slightly better, but since others had reported surging from the big wheel (and my wastegate was tied closed since the DZ uses exhaust housing mounted wastegate actuators, not the compressor mounted like on my truck) I didn't really push it. Without the trailer in tow it was an okay turbo, still smokey and laggy down low, but if I shifted to keep the rpms up in the very narrow powerband it was okay. At 450hp, egts wound up in the 1450-1500* range at the end of a solo speed blast (for comparison, the HTB2/12 doesn't break 1300*). Not much better than stock for the $.



You say you're happy with your fueling - what are your egts now? If you're not far away from safe, start with small steps (maybe an HTT 60mm hybrid like Hammer suggested, or a PDR 35 with a 59mm). Those would let you keep your exhaust system and probably even your exhaust housing (the DZ would not). Or what I would HIGHLY recommend, jump ship from Holset and try one of the Schwitzer variants. A HTBG/12 (57mm) or BD Super B (a 57mm with a 14cm housing) would give you a wider powerband than a Holset of comparable (or slightly larger) size and cool pretty well on top, too.

 

[darkhorse]

I'm don't know why, but my experience is not at all like PC12Driver. Maybe his disabled wastegate is a big part of it. Mine has the turbine mounted actuator with a Banks Big Head.

 

[PC12Driver]

The disabled wastegate was only on the 12cm housing, not the 14 that I ran with most of the time. In normal ops, the wastegate was set at 40psi. Either way, a fixed-closed wastegate wouldn't have anything to do with the bottom end responsiveness.



It's a big wheel, no special mods. A turbo simply transfers energy from exhaust to the intake - it cannot create energy. Physics dictates that big wheels take more energy to turn (aerodynamic drag + inertia), so there has to be some additional lag. The energy coming out of the exhaust doesn't change in the low rpm range with partial throttle, so there's nothing there to offset the increased drag. You cannot have the responsiveness in a DZ/14 that you would in a stock 35/12, and to indicate otherwise is misleading.

 

[jkidd]

I have run 35/40, S300 57/65 and S300 62/65/12 (the 12cm Exhaust housing on an s300 is about as big as an HX35/40/14)

The S300 turbos are quite nice and can be had for less than $1000. Lag is not much different, power on the upper RPM is noticeably different.

 

[darkhorse]

PC, yes in theory you are correct. In practice, I found no perceptible difference in spool up. That is not misleading. Mine spools almost instantaneously.

 

[Forrest Nearing]

the HX series stuff is outdated... get an S300 based turbo and enjoy

 

[PC12Driver]

PC, yes in theory you are correct. In practice, I found no perceptible difference in spool up. That is not misleading. Mine spools almost instantaneously.

I'm not referring to mashing the pedal to the floor for a high speed blast; with enough fueling, any turbo can spool like stock. It's the partial throttle, less than 2k rpm where the DZ falls on its face.



What do you get when you try to accelerate to pass someone from a speed of 50-55 mph in sixth with the DZ and a trailer in tow? How about longer hills below 55 mph in sixth with the trailer in tow? Ever tow at high elevations?



Then there's this thread from a couple years back where another member compared the DZ with a PDR35 and showed that the smaller PDR turbo would outflow the DZ up to about 30 psi and why the DZ feels laggy (post 14, but the whole thread is good from a turbo selection standpoint).



I dunno, I just don't get how you can say a DZ feels like stock. And if you do think it feels like stock, then you wouldn't believe what an S300-based charger would feel like with your mods!

 

[BDaugherty]

Really great info/opionions in here. Thanks to PC12Driver for mentioning compressor wheel sizes. It really helps to put things in perspetive.

As for my fueling, on level 6x5 on a solo acceleration run, I'm hitting about 1425* or so in the top of 5th and above about 2300RPM in 6th. On level 5, EGTs are much better due to the natural defueling of the ECM at higher RPMs. I guess the PDR 35 may be a really good option for me. I'm really just looking for a little more and I sure don't want to go too far and wind up with something that doesn't tow or daily drive well.

 

[PC12Driver]

Have you thought about a cam? It's like going up a size in a turbo without the side effects. A little better cooling, improved bottom end, better mpg (only a little - but it may help make the sale to the other half), and they're cheaper than most turbos.

 

[darkhorse]

What do you get when you try to accelerate to pass someone from a speed of 50-55 mph in sixth with the DZ and a trailer in tow? How about longer hills below 55 mph in sixth with the trailer in tow? Ever tow at high elevations?



I get a short puff of smoke when I roll into the throttle. No I don't tow in the mountains.



I dunno, I just don't get how you can say a DZ feels like stock. And if you do think it feels like stock, then you wouldn't believe what an S300-based charger would feel like with your mods![/QUOTE]



I have no doubt the S300's out perform my DZ but I had the exhaust housing so the cost was less & I get to keep my exhaust brake which is important to me. The porting I did may account for something too. When I ordered it, Rip told me to expect higher cruse egt's but that just didn't happen. I should also say that adding the street cam made a noticeable improvement in spool for less $$'s than a turbo change.



The smaller pin wheel on a PDR or HTT hybred might be a better choice for BDaugherty In any case, the porting is a good idea. I found the instructions on North West Bombers.

 

[darkhorse]

Have you thought about a cam? It's like going up a size in a turbo without the side effects. A little better cooling, improved bottom end, better mpg (only a little - but it may help make the sale to the other half), and they're cheaper than most turbos.

Good call PC. I hadn't seen this post when I sent my last one.

 

[AClayton]

I had a B-1 and shared many of PC's issues and went to my mechanic and discussed with him. If you want the best of both worlds,you simply cannot beat the BD Towing twins. I spent a lot of money on them,but I can say with confidence that you will have a big smile on your face after the 1st test drive. I used to be able to easily exceed the 1250* limit and now I have to seriously try hard to get it to climb into the 850* range. I got my towing low speed performance back and retained my 1800rpm and above cooling. My old B-1 would cruise with trailer at about 900 to 1000*..... slight hill,go to 1250 almost instantly unless I downshifted to compensate. Boost while towing at cruise rpm would stay at about 3 to 5... . now it's 10 to 15... . same truck but added twins... no added mods.



It will probably be cheaper in the long run to bite the bullet and just get twins... . factoring buying 2 different turbos like I did and not being satisfied. I may have improved mpg also but that may be from the weather warming here on the east coast though.





Alan

 

[BDaugherty]

I have to agree on the twins. However, I just can't see putting that kind of $$ into this truck. Before I spend several thousand dollars, I need a HPCR and 4 real doors. I'm thinking the cam that was mentioned would be good bang for the buck. Beyond that, maybe a slightly larger HX35. Thanks for all the suggestions.