Cummins 4BT & Diesel Conversions Forums banner

1 - 20 of 41 Posts

·
Registered
Joined
·
174 Posts
Discussion Starter #1
I finally got the automatic in my truck 4r100. Wow its aesome i never thought a 300 hp 4BT could be this streetable! The only issue im having is major turbo surge when the covertor locks up at mid to heavy throttle. I never go my compounds on yet i think im going to try those and see if that helps. Otherwise i may try a bigger single i could spool it like nothing with the auto trans
 

·
Registered
Joined
·
2,790 Posts
Did u try a factory hx35 before the ten blade cartridge? If so did it help going to the 10 blade? If so with spool or flow?
 

·
Premium Member
Joined
·
2,974 Posts
Bigger turbo is going to surge worse.
 

·
Registered
Joined
·
174 Posts
Discussion Starter #4
When i was runnng the manual i had a stock hx35w from a school bus. Then i went to the 24v hx35w with the 10 blade. Seemed like it spooled the same but flowed better, cooler egts, but less boost while cruising. Total boost wet from 45 to 50. It did tend to surge more under light acceleration but not like it does now with the auto with the tc lockdd up. What should i try to stop that? Will the compound turbos help? According to diesel power they had no surge with there compound set up on a 12v. Also the 10 blade made the exhaust wicked loud, sounds great!!
 

·
Registered
Joined
·
2,790 Posts
The 24v turbo with the ten blade turbine did it have a 54mm inducer compressor wheel?
 

·
Registered
Joined
·
174 Posts
Discussion Starter #6
I dont know for sure, it was smaller than the school bus one and its off a 98 24v if that helps
 

·
Super Moderator
Joined
·
8,668 Posts
The only way you'll stop a HX35 from surging on a 4Bt is to fit a bigger exhaust housing so it boosts less. A setup that works perfectly on a 6BT is 50% too large for a 4BT.

You need to go compound and fit a smaller primary turbo to avoid surge.
 

·
Registered
Joined
·
2,790 Posts
Thanks polaris , I think it is the same one I have. I didn't look at the turbine blades before installing and didn't know that the turbine was different from earlier models. I have read that the hx35 on the 24v flowed better but most said it was the 7 blade designed compressor wheel. I guess its from both.
 

·
Registered
Joined
·
63 Posts
Just hang a bigger turbo under the hx35 and surge will completely go away. You will be fine.

For example guys with 6bt surge when runnin a bw 6265 14. Then they hang a s475 under it and voila, perfect driveability with power up top.
 

·
Registered
Joined
·
174 Posts
Discussion Starter #12
Well i started working on the compuonds tonight. Hope it does something cool and im doe with t before the weekend is kver. Im hanging a none gated hx55 on it.
 

·
Registered
Joined
·
1,753 Posts
I don't think that's gonna help the surge issue... lol

-Chris
 

·
Registered
Joined
·
174 Posts
Discussion Starter #15
The surge is completly gone! I dont know total boost, more than 60 lol egts only hit 1400 now instead of 1800!
 

·
Registered
Joined
·
2,790 Posts
What about spool? Feel like more power?
 

·
Registered
Joined
·
63 Posts
Oops. I must have nailed it! Sorry dougal.
The pressure after the turbine of the secondary (small turbo) is much higher, as it is now drive pressure for the larger turbo. It does cause small turbo to spool a little slower, moving the surge line down in rpm, but also large turbo is movin more air in at same time, so percieved spool and boost rate isabout the same, if not faster.
 

·
Registered
Joined
·
174 Posts
Discussion Starter #18
Spool seems about the same kinda hard to tell it doesent hit like a single it is extreamly smooth. Its very quiet, almost too quiet, no whistle and it sounds like i have a muffler on it now. Egts only hit 1400, use t hit 1800.
 

·
Super Moderator
Joined
·
8,668 Posts
Sounds like you've just delayed spool until surge disappeared. How many psi do you have at 1500rpm?

1800F is never a good idea. Even 1400F with compounds is asking for trouble.
 

·
Registered
Joined
·
1,753 Posts
I would have thought the hx55 would sing pretty good once lit.....

How is power output?

Pics of the new setup?
-Chris
 
1 - 20 of 41 Posts
Top