Engine/Transmission (1994 - 1998) Tubo housing size

[LHartman]

The old man and I got into a discussion about turbo housing sizes. He has a 97 CTD auto and pushing around 430 hp. I'm in the pre-bombing stages of things and he told me to go to a smaller turbo housing = faster spool up and more snort. I began to disagree with him, but I don't have all the facts as yet. I was told to go to a 14 or 16 housing. My target hp is around 400.



Now the old man and I love to debate on our trucks, so I need to get all my information correct.

 

[Got Smoke?]

If I'm thinking correctly you should have a HX35 turbo with a 12cm exhaust housing(just like my truck). Going to a 14cm or 16cm would be increasing your exh. housing size.



The early 1st Gen's came with like 21cm or so exhaust housings that you could downsize to and pickup the increased spool up your old man is talking about.



However on our trucks the bigger exhaust housing are used to help control EGT issue's when in the process of BOMBing.

 

[LHartman]

Didn't his come with the same size housing as mine stock? You are correct on my turbo, but I assume both are the same. Or was there a change from his year to my year?

 

[Hammer]

A 97 has a HX35/12 housing for a turbo. If he is at 430 hp he is at the upper limit of the 35 efficency wise. IF he was to install a 14 or 16 cm exhaust it will slow down spool up somewhat but lower egt's and allow of a faster exhaust cool down. You last TDR magazine Joe D explains what you loose/gain in the different housings.



To go to a smaller exhaust housing to allow faster spoolup on a modified or heavily fueled truck is asking for problems. The performance you may gain is going to raise egt's and may cause failures related to it. Your truck with a HX35 and the use of a 14 or 16 exhaust housing is quite capable of the performance you seek,however,remember that you are near the limits of the 35 for efficency and once past that all it does is heat the air instead of having good usable air.



Hope that you find what you seek and read Joe's article it is informative and will load you with ammo for a deep discussion with the other gentleman and have hard copy to show him... ... Andy

 

[LHartman]

I KNEW I read that somewhere! Thanks for reminding me. I'll give him my copy to the magazine. Perhaps I can talk him into subscribing while I'm at it.



Thanks guys,



Loren

 

[Snow man]

Lhartman,you want to get a bigger turbo at 400hp. If you run the stocker,top end wil suffer,not to mention the smoke will never clean up WOT. worst of all will be the 1600-1700 EGTS that will kill your engien slowly. Go with ah HX40 or a KSB1 ,and get another 25-30hp,nice top end pull, and EGTs that are manageable.

 

[wsmalley]

I agree with Snow Man, once you hit about 400-wheel, switch to a bigger turbo. Don't bother too much with bigger housings on the -35, they are really not worth the increased lag. EGT control = right foot. Just hold what you got until you get to 350-400 and go straight to the -40 or comparable turbo.