Can a person port a 9.8 hotside to a 10.5 or larger?

 

nobody knows?

 

For the prices eveyone is selling the 10.5 for...it's just not worth the time.
I sure someone has one laying on the garage floor corner somewhere...

 

guess it could be done---find a machine shop with a lathe and someway to secure the housing... depending on how thick the material is will determine how much you can port...I dont know if the turbine wheels are the same for the 9.8 and 10.5..so thats a consideration..

 

Well, from what I can gather, the turbine wheels are the same just the wastegate housing is larger. I have found 3 types of hotsides for the Evo; 9.8 dual flapper, 10.5 dual flapper, 10.5 single flapper. Now I know that the 10.5 single is the real deal, but I can not find anything about the 10.5 dual flapper.

I am in need of a 10.5 (which I think I have found) but if you can port the 9.8 to the 10.5, then I would prefer using my new 9.8 housing I have in the shop.

 

No, the 10.5 aspect is not related to the wastegate ports.

The dual and single flapper 10.5s perform the same, so that's not an issue.

 

i'm just gonna say it...... with thwe money spent to port that much, why not just get a 10.5 hotside?

 

Because I have a brand new turbo, complete with hotside, but it is a 9.8 hotside. What does the 10.5 have to do with? I am very curious of this.

 

u could sell the new turbo and buy a hotside, or sell jus your 9.8 and buy a 10.5 for not much more

 

You guys are missing the question. I want to know what is the difference in the 9.8 and the 10.5. What was changed to make it larger?

 

Sorry, but the 9.8 hsg. cannot be ported to 10.5 hsg. specs. They are different castings. The 9.8 is physically smaller than the 10.5 hsg. This difference in the external dimensions of the castings is carried over internally resulting in dissimilar scroll configurations.

The 9.8, as well as the 10.5 number denotes the A/R ratio of each housing. The A=area of the scroll cross section, while the R= the radius measured from the shaft centerline to the centerline of the scroll cross section.

Thus, in this case, the A/R of the smaller hsg is 9.8 sq cm, whereas the A/R of the larger hsg is 10.5 sq cm. The 9.8 housing's internal convolute has a tighter radius than that of the 10.5 hsg. This results in the flow of exhaust gases entering the wheel inside the "tighter" 9.8 hsg being more tangential, promoting quicker spool but at the cost of reduced high end flow and higher EGT's. In contrast, the flow entering the blades inside the "looser" 10.5 scroll, is more radial , and thus slower, but encounters less backpressure, resulting in higher horsepower.

Having said this, you could still port the 9.8 housing with the aim of improving spoolup characteristics and easing flow out through the wastegate bypass port which would reduce any tendency toward boost creep. However, ultimately, no amount of porting would change the relative length of the radius between the shaft centerline and the centerline of the scroll cross section. So, in the end you would still have at best a ported 9.8 sq. cm. turbine housing, not a 10.5 sq cm housing.

Anybody, please feel free to correct the above amateurish explanation.

 

That is what I was looking for. That is wonderful to know. Thank you! Does anyone know how much loss of spool time one would get from switching to a 10.5?

 

https://www.evolutionm.net/forums/sh...t=10.5+hotside

hey man here is a cheap one

 

I think that the 10.5 is the way to go. You gain about 10-15 WHP and significantly lower EGT's at the expense of a slight loss in spoolup. If you're gonna change turbine housings, then you might as well upgrade the O2 housing at the same time.

 

Very minimal. We're talking 1 to 2 hundred RPM's.