Attention: TDR Forum Junkies Basically I feel like I have been shooting in the dark in response to swapping turbos on the 4BTs. The turbo bolt patterns and style between the 4 cyls and 6 cyls are interchangable so all Dodge turbos work on 4BTs.
I am in search of the best answer for all around mild increased performance for a Cummins 4BT that will be daily driven. I am looking for an answer that is similar to "Put a 16cm2 non-wastegated housing on a Gen 1 12 valve instead of the stock 18. 5cm2" - but for a 4BT.
This is my second 4BT. The first time, my stock H1C with 16cm2 non wastegated housing finally died. I bought another H1C off a guy on TDR that was rebuilt and in great shape for only $150. When it showed up, it was actually a WH1C, the rare 1994 model that is basically a H1C but with the larger compression turbine of the HX35 style design, so basically it is a HX35 but called a WH1C. I removed the wastegated 12cm2 housing and used a non wastegated 12cm2 housing because the wastegated model would not fit on the 4BT, interfered with the block. The non wastegated housing worked great though. Peak boost was about 20 lbs, upto 25 psi if really trying to get high boost pressures. In all it seemed like this turbo was a very good fit with the 4BT, noticeably more power and better efficiency. I feel like it was still opened up though and decent for highway driving and EGTs were never an issue.
Now, I have been hearing that the HY35s are a good candidate for the 4BTs, and I need a new turbo, so I bought one. They are basically a HX35 with some small differences as far as I can tell, but with a 9cm2 single port housing, wastegated to open just before 20 psi. Good low end power and boost quickly. I have not got the truck running yet so I am still shooting blindly. Because these are "popular" on TDR and among the 4BT enthusiasts, I have been assuming that maybe ramming as much air in there in this application is a good thing.
But along these lines one might assume that a 12cm2 wastegated housing is best for an early 12 valve 6BT. But I have been reading and according to dodge-ram.org's turbo faq, seems like 16cm2 non wastegated is the best housing for a 12 valve, not too tight for highway driving.
So I am wondering if perhaps it is better to use the stock turbo or perhaps the HY35 with a non wastegated 12cm2 or 14cm2 housing instead of the 9cm2 wastegated housing?
____________________
Also, I do not know much about turbo mapping. I know a lot of gasoline and rice rocket guys are good at it and can read them. I am wondering if people have turbo mapped Cummins 4BTs and if there are good conclusions from it on which turbo to use?
I am in search of the best answer for all around mild increased performance for a Cummins 4BT that will be daily driven. I am looking for an answer that is similar to "Put a 16cm2 non-wastegated housing on a Gen 1 12 valve instead of the stock 18. 5cm2" - but for a 4BT.
This is my second 4BT. The first time, my stock H1C with 16cm2 non wastegated housing finally died. I bought another H1C off a guy on TDR that was rebuilt and in great shape for only $150. When it showed up, it was actually a WH1C, the rare 1994 model that is basically a H1C but with the larger compression turbine of the HX35 style design, so basically it is a HX35 but called a WH1C. I removed the wastegated 12cm2 housing and used a non wastegated 12cm2 housing because the wastegated model would not fit on the 4BT, interfered with the block. The non wastegated housing worked great though. Peak boost was about 20 lbs, upto 25 psi if really trying to get high boost pressures. In all it seemed like this turbo was a very good fit with the 4BT, noticeably more power and better efficiency. I feel like it was still opened up though and decent for highway driving and EGTs were never an issue.
Now, I have been hearing that the HY35s are a good candidate for the 4BTs, and I need a new turbo, so I bought one. They are basically a HX35 with some small differences as far as I can tell, but with a 9cm2 single port housing, wastegated to open just before 20 psi. Good low end power and boost quickly. I have not got the truck running yet so I am still shooting blindly. Because these are "popular" on TDR and among the 4BT enthusiasts, I have been assuming that maybe ramming as much air in there in this application is a good thing.
But along these lines one might assume that a 12cm2 wastegated housing is best for an early 12 valve 6BT. But I have been reading and according to dodge-ram.org's turbo faq, seems like 16cm2 non wastegated is the best housing for a 12 valve, not too tight for highway driving.
So I am wondering if perhaps it is better to use the stock turbo or perhaps the HY35 with a non wastegated 12cm2 or 14cm2 housing instead of the 9cm2 wastegated housing?
____________________
Also, I do not know much about turbo mapping. I know a lot of gasoline and rice rocket guys are good at it and can read them. I am wondering if people have turbo mapped Cummins 4BTs and if there are good conclusions from it on which turbo to use?
Last edited:
