So I think that I am at the point where I want to upgrade my Eaton to a twin screw but it seems that no one is offering a twin screw kit for the X100 any longer. I am considering just going at it myself, I have enough know-how and a home machine shop, enough to fabricate parts but I am hoping that someone on the forum with TS experience can help me out. In exchange for this groups help I will document the project for the next guy after me. I am looking at the Kenne Bell 2.6H blower. This will offer plenty of volume for my 4.0 and plenty if I ever end up with a 4.2. My first question is what needs to be don’t to mount the blower upside down so it discharges up? I posted the question to Kenne Bell CS but haven’t heard back. My concern is oiling. Second, how are the blowers actually mounted to the Motor. I can fab a bracket using the original Eaton mounting points easy enough but not sure if the Kenne Bell has any mounting provisions on the top or am I incorporating into the end plates? Anyone with a TS kit willing to snap a few pics and even possibly measure the nose length so I can make sure I get the right length?

Appreciate any insight those that have gone before me can share.

Mjs128,

You need to contact Avos as he has built a number of Twin-Screw S/C Units and has sold several to XKR Owners here in the States. His XKR produces over 700HP with his Twin-Screw Unit...Maybe someone reading this will have his contact address...

Mjs128,

You need to contact Avos, as he has built a number of Twin-Screw S/C Units and has sold several to XKR Owners here in the States. His XKR produces over 700HP with his Twin-Screw Unit...Maybe someone reading this will have his contact address...

Billy Clyde in Houston

I’m bookmarking this thread. It has potential.

There is an active build thread at the X308 forum. Here at X100 forum not much seems to happen nowadays in this way

Thread at X308 forum

I am also interested in getting a modern Twin screw SC for my Xkr 4.0, but I'm not ready for that yet. The coming winter will be focussed in the rear end of the chassi and just a mild tuning of the SC with the 10% smaller upper pulley, together with rebuild of the Eaton unit and new belt

I too will keep an eye on this thread. All the information to do it yourself has been posted in this forum. Your first challenge will be getting your hands on a 2.6L KB twin screw. Used to be that KB sold directly to consumers. 2 years ago I tried to purchase one directly from them and they said I had to purchase from one of their approved vendors. The price the vendor I called was a lot higher than I expected and way more expensive than the price sheet I had . It took another year plus before I purchased a used one off of E-bay.

Your 2nd challenge will be to determine the snout length and machine / assemble the snout.
3rd challenge will be designing the elbow that goes between the SC inlet and the Throttle body.
(This 2 items alone were worth purchasing the kit from AVOS.) - He spent endless hours designing these parts and getting them right.

Let's see how motivated you are to actually accomplish this project.
I still pan to put a KB on one of my STRs, but lack the time and motivation these days to actually finish this project.

Quick update here, Tijoe was right, getting my hands on a Kenne Bell is easier said than done (though admittedly I didn't reach out to Kenne Bell about buying a new one). I was finally able to get my hands on a really nice second hand KB 2.8L from a Mustang breaker. Not sure he knew what he had his hands on so if I abandon the project I can still recover my $$! I also have a 4.0 and a 4.2 engine sitting in my shop for mocking this up and ultimately parts for a rebuild.

My next question is more for the experts among us, having a set of both AJ27 and AJ33 heads, which one is ideal for a 4.2L engine? My gut would tell me the newer heads are better but I read a lot of post from Count Iblis about how the design of that head went sideways during development. Considering that I have no plans for any porting just a simple rebuild should I go with the older 4.0L? I need to sort that out as it determines what intercooler I use. I have the intercoolers form a 4.0 but no lower manifold and the lower manifold from a 4.2 but no intercoolers so either way I am hunting for parts!

Appreciate all the input folks can share. Next up is to figure out how to mount the blower to the block since this thing was designed to be mounted facing down and the outlet plate was the mounting device. Love a challenge!

Before you worry too much about what to do about the heads, first determine what you plan to do about the throttle body inlet elbow. Either you have to spend endless hours designing one, then machining it or having it machined, or have a chat with AVOS and see if he has any available that he can sell you. Then you have to figure out the length of the SC pulley screw shaft and machine a new shaft housing and shaft. Another item that AVOS figured out and could help with. If you install it from scratch, this will be a very time consuming process and perhaps expensive process!

Do you plan on putting the KB on a 4.0 or 4.2 engine? If your engine is going to be basically stock, then best to start with a complete 4.2 engine. Many small engine improvements on the 4.2 over the 4.0.
If you have both heads available to look at, you should have observed that the 4.0 heads have the valve inlet ports are symmetrically spaced to the combustion chambers. The 4.2 heads have the inlet ports located at an angle to each cylinder. This was supposed to induce more swirl in the cylinder. (Search and read Count's explanation.)
The 4.0 heads have a round shape in the combustion chamber, and the 4.2 heads have squish pads. (Search on postings I made that show images of the cylinder head shapes.

Noting the differences in the shape of the combustion chamber, you will need to match the shape of the piston to the cylinder head. Therefore don't put 4.2 heads on the 4.0 unless you plan to put in new pistons. Visa-Versa for 4.0 heads on a 4.2 engine.
Also note that the inlet manifolds are matched for the 4.0 or 4.2 head designs. You can't just swap those parts.

In conclusion, If you have a 4.0 XKR and the engine is fresh with the timing tensioner upgrades, you can just use the stock configuration. If your engine is a tired 4.0, just plan on putting in a complete 4.2 engine. Don't try to mix and match 4.0 and 4.2 engine parts.

Tijoe, you pretty much spelled out all the issues in my head to work through. I know this is not a weekend project thus why I am starting with an engine on a stand and playing out the details while I keep my car in tact and drivable. Great point about the intake and snout, I reached our to AVOS once via email in the PM section but I didn't follow up. For the intake I was going to machine the flanges and build the rest out of sheet metal. I was planning to angle the throttle body to the side instead of the top like the AVOS kits. I did as much research as I could on his kits, no sense in reinventing the wheel, he did the work and perfected the process I just missed my window to buy one and be done. Once I start mocking everything up I can see how much front to back wiggle room I have and then see what my snout options are. I'd like to avoid custom machining something if at all possible but no idea until I start to fit things up. Right now I just have parts in boxes.

Regarding the heads and 4.0 vs 4.2, I have one of each engine sitting on a shelf. My plan is to go with the 4.2 block but I grabbed a 4.0 cheap so I have proper front covers, sumps, etc, everything needed per the AVOS 4.0 to 4.2 conversion. I read all the posts regarding the heads from Count, but a lot of the science you mentioned above is beyond me (why I'm not porting or modifying the heads). If the 4.2 head woks, terrific I'll go all 4.2; if the 4.0 heads on a 4.2 block are better I'll go that route. I have intakes from both so not a big deal I just want to figure the best parts before I start moving forward. If memory serves the bore is the same between the AJ27 and 33 so I can swap pistons when I re-ring. Again, I have not opened either engine to confirm compatibility between pistons/rods/ring lands etc. Thus if the decision os 4.2 heads then I move forward with 4.2 lower intake, intercoolers, etc.

I really appreciate the input, I know what my limits are!

@Mjs128
1st of all good to hear you like a challenge, although its not rocket science of course, the reward if it works out would be great.
There has gone a lot of time (and I mean a lot) and testing into getting the final version of the kits I made, its not something I would want to give away, especially as I may do something with it again in the future (small chances, but who knows) .

There are so many pictures already out there of my kit and descriptions, you will have a good head start on your project.