As you insult people and make false claims I'm not sure who will want to help you.

 

My 2 cents worth: The Eaton M112 set up on the 4.2 Jaguars are a very limited design.
Doubt if you can get even 10% power increase porting and opening up the intakes. I have a ported Stiegemeier on my STR and it added perhaps 15hp. Stiegemeier has been porting M112s for years. You should contact him and see what he says.

Don't know why you are attacking Avos. He is one of the most neutral and truthful members on the forum who shares his findings and knowledge. If I had decided to go the route of putting on a KB supercharger, I would have purchased one of his kits. It was a deal!

 

Let me save you a BUNCH of Trouble. Porting of this later model M112 just does not give any noticeable gains. This is based off of years of dealing with these Eaton SC's. Most gains will be in using the largest Throttle body you can use (I had mine ported to 83mm) and upgrading the intake tube and mass airflow size. The Earlier 4.0 Eaton m112 did indeed get good gains from porting. The later model m112 however is pretty much maximized with its design.


So the list


1) Port match inlet elbow to SC inlet. There may be gains in creating a new inlet out of sheetmetal with more volume. Money better spent there.
2) Largest TB possible. I couldn't find anything so I had mine punched to 83mm. Idealy a 90mm MAF would be great.
3)Increase intake diameter . The round portion is easy enough to do. The tb to that section now to easy. Id want at least an interior diameter of 3" , preferably 3.5" (approximately 90mm). I actually used oval pipe in that upper section that transitioned to round.
4) MAF. If your tuner can actually tune this car properly It be nice to upgrade the MAF to a 90mm unit as well . I'd love to use a slot type MAF however I have no way of tuning my car so I have the abaco 85mm MAF which the transfer function only can be adjusted.


The BEST thing you can do for this Eaton is reduce restrictions going in. Its not a compressor. It does not compress air it moves it. Any restriction before the sc inlet will reduce power and potential boost.


The one thing you can however do to your SC that will help increase power s to rebuild and recoat the rotor pack. Unsure who does that in Italy but there are several places here in the US...They also generally deal with porting EATONS and wil likely tell you porting this one does little to nothing....Money best spent elsewhere. When I got the twin screw for my xjr I installed my later model eaton on my 2001 xkr. It was totally rebuilt with coated rotors, all ARP hardware and the turned down supercharger snout for the smaller stainless pulley.


Me I have nothing to sell just about 20 years dealing with Eatons


Oh and I'm sure porting the heads would be wonderful as would ceramic coating the exhaust manifolds while your at it

 

Oh just in case..


Jaguar Superchargers - Eaton Supercharger Rebuild Services brought to you by The High Speed Lab for superior customer care, from Embree Specialty Machine with 20+ years Eaton Supercharger remanufacturing experience.


They extensively modified an Eaton m90 back in the day for me..I mean extensively modified. I had them do a quite a bit of stuff for me..BAck in 2003 or so


Magnum Powers: Makers of Fine Superchargers


Charles at MAgnum powers recently rebuilt my rotor pack and recoated it. That's whats currently in my xkr

 

I had Stieg do a set of heads for me back in the day with welded up exhaust ports for my v6. Steig, High speed lab, Magnum power..They all started with playing with m90's of the thunderbird SC's

 

I had PSE Superchargers rebuild an Eaton M112 I bought on Ebay.

They replaced the rotors with some out of a later model car because of slightly better "gearing". They added a 10% pulley and put in new bearings as well as some porting.

Shortly after installing it the rear bearings went!

Then I screwed up the installation and managed to get a paper towel sucked into the SC inlet jamming the rotors.

I then rebuilt the whole thing myself. Should have done that at the get go and with a 6% pulley not the 10%.

Quite tempted to use my original SC with a 6% pulley and do my own porting.

What PSE did in the way of porting was certainly not worth what they charged by a long shot but it would be easy to do myself.

I believe I get excellent power/torque in the mid range which is what I am mostly interested in.

 

thanks for the appropriate response to my request in the tread!

porting of the engine heads is already planned. the TB is already on its way back from MaxBore.

2 are the questions:

Where can I find abacus 85mm MAF? I looked for it but I can not find it. I think the only alternative is Pro-M racing 90mm

I was thinking of closing The two oval slots on the output plate as indicated in this link:

https://www.jaguarforums.com/forum/s...e2/#post445135

what do you think about it?

many many thanks !!!

 

Ok folks. For what it is worth in the pics I am showing here you can see the "porting" that was done "professionally" on my M112 Gen 5.

If you look carefully you can see it is not evenly done. I could do a better job myself.

Supposedly it is for a gain of 10-15hp. I personally do not believe that it is anywhere close.

I was told that this porting is all that is "worth" doing by an expert. I believe him but his tech did not exactly do a great job. I am not naming names
however this expert is very well known in the racing world.

 

All I can see from the photos pears to be some grinding on the narrow vee and possibly some very rough radiusing on the long lands of the Vee is this it?

 

Correct.

I had forgotten about the radiusing on the long lands of the Vee.

 

 

The only reputable ECU tuner on MY 2005 and earlier Jaguar cars is Cambo in this forum.

All others stopped a while ago and only offer tunes on MY 2006 and onwards.

With the X350 MY 2006 saw significant electronic changes to the ECU as well as VVT on the SC.

 

Hi,

What twin-screw kit are you referring to in your signature mods? I'm in the process of rebuilding and modifying an AJ27S and looking at twin screws from KB. Would have PM'd you, but seems you've turned that off. Do PM me please .. after all, we don't want to offend the sensibilities of others now, do we?

 

Haven't turned off my PM, that should just work.

I have the KB 2.6LH, where the H stands for High compression, and it means it compresses inside the unit already to 14.7 PSI, which makes it more efficient the normal twin screws which have about 6 psi.

 

Has anyone tried to rebuild their M112 with rotors from a M122? I have seen a Jaguar Eaton used on a BMW V8 in the UK, and the seller of the adapter plate used M122 rotors in his Jaguar Eaton (from an XJR) and claims to have made about 50hp more than using the standard M112.

Would the longer rotors themselves account for an increase in displacement of the supercharger? I understand the M112 is 1.8l in displacement and the M122 around 2.1l, so would it be worth doing this? I have also seen KB twin screw units where the cases are the same dimension, but the length of the interior rotors changes its displacement.

M122 rotors being used in a M112 case is also a common modification on SVT Cobras, where people take the M122 rotors out of GT500 superchargers and fit them straight into their M112 cases using a spacer and modified drive.

Would it be worth trying this, or would it be better to try and retro-fit the whole M122 to the AJV8? Used M122s can be had for £500 now so only a fraction of the price of a used KB for example.

 

I’ll chime in again about the Eaton M112 Roots blowers in general on the 4.2 engines.

Several years ago I researched ALL the superchargers available on the market at the time to see what I could possibly put on my engine build. My conclusion was that the KB twin screw was and is the only viable option if you are building up a higher HP engine, unless you want to do a bunch of custom design work.
1. The Eaton roots blowers date back many years and the design is basically a positive displacement air pump. Very little air compression. As a result, as you spin them faster to get more compression, they become less efficient and have a high exit air temperature.
2. They were a good approach for the auto industry because they could add a decent amount of power and still meet noise, gas mileage and smog standards.
3. Jaguar selected first the M90s and later the M112 because these blowers were a small package that could be fitted into the block’s valley. But the whole design approach was a compromise.
4. 90 or 180 degree restrictive inlet elbow into the blower. Small plenum area out of the blower into the cooling cores where overheated compressed air is still too hot after it passes through the cooling cores.
5. Very little room to generate any more power out of the system.
6. Twin screws and now Eatons TVS superchargers are closer to being compressors than air pumps. You start out with a much more efficient supercharger design. This lets you overcome many of the deficiencies of the inlet and intercoolers, so that lower temperature compressed air actually makes it into the cylinders.

I personally didn’t think it worth the money to try to do much to the existing M112 design. Over several years I purchased several other OEM superchargers and tried to fit them to the 4.2 block. All of them had to sit up higher, leading to a hole in the hood.

The main problem with fitting other supercharger assemblies onto the 4.2 block is where they located the thermostat. Right up front in the middle of the valley.
Because of this, the KB twin screws are the only blowers that be fitted. A double win! It fits and it is a much better blower than the M112. (I looked at Whipple twin screws - A lot of work. )

Comments on porting heads:
When you get some time, search on head porting in the forum. Many morsels of information posted. There were big changes between the 4.0 heads and the 4.2 heads. The ports on the 4.2 heads are spaced differently so that they enter the chamber at an angle. More Swirl created versus tumble in the cylinders. (Per the Count) On N/A engines this had a big effect, but as far as I can tell, on supercharged versions it doesn’t make that much of a difference. On the other hand, a while back, I posed images of different head dome shapes, and the shape you can machine to can help get you a little more HP.

 

Years ago we installed m112 rotors in an m90 case with a spacer. Never made any noticeable power increase for what its worth. We also modified jaguar m112's to use with little to no power increase...added a 1.7 liter AR..Wallah..More power. We have also tried a variety of whipples and autorotors of various sizes. There were even some who drilled the rotor lobes for weight reduction (unsure how that worked out) and one guy actually made a rotor pack using graphite rotors (Unsure how that worked.)

I personally always wondered if a twin screw or TVS type rotor pack could be created for use in the factory case. Unsure if the inlet and
outlet would be optimized for that but that would be a pretty cool experiment.

 

Look at this Jaguar Brochure :
https://www.jaguarforums.com/forum/x...62/#post444610

Jaguar obviously played with some ideas, but to be able to have a rotor pack with the internal compression, you also need a different intake setup for the right airflow path, and that would just not have fitted with the intake elbow/bypass/throttle setup design.

Spend your money as you whish, if you want cost effective and true power there is only one way (or slide in a different engine), if money has less meaning then of course you wil gain some power here and there by porting/cams etc but the ride wil be more expensive and have less power then....

That's just my experience so far.

 

[QUOTE=I personally always wondered if a twin screw or TVS type rotor pack could be created for use in the factory case. Unsure if the inlet and
outlet would be optimized for that but that would be a pretty cool experiment.[/QUOTE]

Reads like a KB twin screw with an adapter plate and custom inlet housing.
Seems like an easier route than trying to make a new housing that fits different rotors.

Have you looked at the Jaguar 5.0 Eaton TVS? It is a front fed supercharger. No 90 degree inlet duct on the back side of the engine. There has been a lot of speculation on how much more power the Jag's TVS supercharger can put out.

 

Thanks for the gems of knowledge. I actually previously had a small "Autorotor" twin screw supercharger on my STR and am aware of the benefits of the TS design over the Eaton single lobe design. However, despite the extra power I gained using the 1.7 AR, in the end it was too noisy and didn't offer enough extra power so I decided to look for other options. I feel the m112 is more refined than the 1.7 and offers decent power for what it is. I think what's really holding the Eaton on the STR back is the intake/TB/inlet design due to that very sharp bend behind the charger. If a custom intake could me made using a larger 90mm MAF and enclosed air filter I think decent gains could be had. The Eaton M112 pullied and ported makes over 500rwhp on SVT Cobras and has pushed some of the X150 4.2 XKRs over 500hp still on stock pullies so it can't be completely useless.

Obviously the KB/Whipples etc are inherently better being true compressors and if my budget allowed I'd probably go for a 2.1 KB in the future. The M122 doesn't look so much bigger than the m112 though so I wonder if it would fit? Even if I could gain 40-50hp over a M112 on the same pulley ratio I'd be delighted as it would represent very good value against a KB bang for buck. Plus if the larger rorors could be made to fit the m112 case it would save further machining costs of an adapter plate etc.

I've looked at measurements and the TVS1900 from the AJ133s is definitely too large to fit in between the chargecoolers on the STR. Another cheap supercharger are the 2.1 IHI unit of the m113k AMG engines, which are also true twin screws. They look quite narrow too but I believe they have an integrated intercooler which would probably make it too much work for a budget upgrade.