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InfamousSVT
04-13-2006, 12:35 AM
Directly from Stiegemeier:

Stiegemeier's Recommendation with our ported blower -A 2# Lower is Fine- But never use a 4# Lower it causes excessive heat build up and power loss, also rotor flex and case rub can follow.

To put it in easier to read terms, they don't want you running over 16psi with a ported blower or....rotor flex and case rub will occur :eek: :(

That sucks

spincobra03
04-13-2006, 05:38 AM
so I guess getting a port with my 6 lb lower is out of the question??

InfamousSVT
04-13-2006, 11:03 AM
No you can have a 6lb lower, but after talking with Bob at Stiegemeier what he was trying to say is keep the boost around 16psi. Which ever pulley combo you decide to go with just get it high enough to go to 16psi and no higher. If you spin it any faster than that the above will occur, which is due to the lack of efficiency the Eaton has compared to the Whipple or Kenne Bell.
Some people haven't had any problems and some have. Some people are using nitrous for the cooling effect which can keep the temps in check.

blk04cobra1
04-13-2006, 04:55 PM
good find, it seems the Steggy crew has been doing some extensive research :thumbsup:

Linn@Amazon
04-13-2006, 06:29 PM
we have not seen this issue with any of our over 16# boost cars with our ported blowers..our porting is designed so that only enough material was removed so as not to damage the structural integrity of the case..the data we have of the AR porting shows high torque #s.

scrmngdave
04-14-2006, 11:09 PM
Directly from Stiegemeier:

To put it in easier to read terms, they don't want you running over 16psi with a ported blower or....rotor flex and case rub will occur :eek: :(

That sucks

Dude, where do you get this stuff from? I have been all over steigs website, I have called and talked to Bob, I have even read the instructions and warnings that came with my ported blower and don't see that statement. What I do see is that they recommend 16psi but no higher than 17psi for max bolt on power. There are some crazy guys (Nitrous Pete and Jim D'Amore) running 19+lbs of boost on the Eatons(definately good way to grenade it!), but rotor flex and case rub occur on ALL Eatons, stock, ported, Lightening and Cobras. I would definately suggest to anyone that has questions on this go directly to the source whether it be stiegemeier or Amazon or LFP. Get the facts, not just heresay on a forum.:thumbsup:

Linn@Amazon
04-15-2006, 02:25 PM
he is referring to this thread

http://www.svtperformance.com/forums/showthread.php?t=276399

scrmngdave
04-16-2006, 01:45 AM
he is referring to this thread

http://www.svtperformance.com/forums/showthread.php?t=276399

Linn, thanks for the link. Thats what should have been posted to start with instead of a general statement that could cause alot worry and confusion. After reading the link, I believe the general consensus would be is run what works for you!?!?:thumbsup:

ausie
04-16-2006, 12:09 PM
Think of it this way, metal expands as it heats up in all directions. Since the blower sits on top of the engine block it is exposed to a considerable amount of heat in addition to the heat energy from the compression of air. The higher the pressure of the air the more heat is generated. Not only do thermodynamics come into play, so do the mechanics of the assembly of the blower. There is a maximum speed at which the rotors can be spun and that also will increase discharge temperatures from internal friction of the moving parts along with bearing failure or worn gears, etc.... Once you push a component beyond the scope of its design do not expect it to last very long.

There is nothing wrong with porting the Eaton, just do not expect to go beyond the recommended boost levels from the experts recommendations. If you want more boost you would be better off with a KB or Whipple having a larger displacement. I wonder if there is a way to get the Ford GT blower since it compares to the larger displacement units from KB and Whipple even though it is an Eaton with a lysholm twin screw rotor assembly.

Linn@Amazon
04-16-2006, 06:55 PM
The issue is present when to much material is removed from the case..this risks the structural intergrity of the case causing a dangerous degree of flex when hot that can cause the rotors to touch. We realized this and for that reason our design removes a safe amount.We have many Amazon ported cars running higher than 16 lbs of boost with no issues what so ever..and continue to see very nice results.. with no drop in TQ #s.

spincobra03
04-16-2006, 10:46 PM
pushing the product

InfamousSVT
04-17-2006, 02:25 AM
Dude, where do you get this stuff from? ..... I would definately suggest to anyone that has questions on this go directly to the source whether it be stiegemeier or Amazon or LFP. Get the facts, not just heresay on a forum.:thumbsup:
What you said man ;)

Linn@Amazon
04-17-2006, 01:17 PM
pushing the productis that comment directed at me?since you posted right after I did..I will assume that it is..you were referring to pushing the product past its limits..right? and not insinuating that I am pushing an Amazon product

ausie
04-18-2006, 07:00 AM
What are the benefits of a ported blower anyway? Sure the restrictions are removed to some degree but the limitations get in the way like the displacement and type of blower that is being ported. Since all forms of compression produce heat adding more boost just compounds the issue even farther. I would highly doubt that you will be able to get more boost from an eaton as you can with a whipple or KB or other type of forced induction since they are sized for the application of more power. I basically remember that pressure, volume and heat energy have a major part in the thermodynamic relationship. The 2.2L, 2.4L (KB) and the 2.3L (Wipple) would have an advantage over the 1.9L Eaton in more ways than one except in cost. The only disadvantage of the cost is that you already own the Eaton. At least Ford gave us the M112 instead of the M90. Perhaps methanol injection would help reduce the heat to some degree by lowering the intake temperature. I would agree there may be some benefit to porting the Eaton but that will not overcome its limitations. I am still happy with my 8lbs of boost although having more would help at the track to get lower ET's. A larger displacement blower at the same boost level would pack more air into the fixed space of the lower plenum than a smaller displacement blower. It is simply flow rate per unit volume. I read somewhere why Ford dropped the maximum RPM but do not remember if it was due to the small blower or the grinds on the cams.

I am sure there is alot that can be said on porting the Eaton, but like anything in this world it has its limitations.

Linn@Amazon
04-18-2006, 01:51 PM
the ported Eaton came to be when the KBs were not readily available and the Whipple was not available at all.. It was a step that made the Eaton more efficient by removing material that was restrictive. they were attractive to guys who didnt have the funds for an aftermarket blower and all the supporting mods ... they have been developed over the years but I guess like anything else that is modified we are starting to see the limitations of some of the porting designs..you also didnt have to do any supporting mods but as the porting designs evolved that didnt always hold true and we started to see that some cars approaching 500hp had to have MAF and fuel upgrades..one or the other and sometimes both..


more and more guys are going directly to the aftermarket blowers and now the turbo set ups..but porting the Eaton is still a nice HP upgrade for anyone on a limited modding budget..

scrmngdave
04-20-2006, 01:09 PM
I looked at purchasing a whipple before I had my Eaton ported and weighed the pro's and con's of each. You must remember that the Eaton is a solid, 90k mile or more blower. No-one has run the Kenne Bell or the Whipple superchargers that long to really say what the life span is, most combinations change every year or two. Another thing is that it's not a fair comparison between the Eaton and the positive displacement blowers because of the way they work. The Eaton compresses air in the lower intake not the case of the blower as the positive displacement blowers do. So while the Kenne Bell and Whipple blowers offer much greater power at the same level of boost, the Eaton offers long life and decent power with a little porting. It's all up to the individual, I just chose to fine tune the stock stuff rather than just throwing a bunch of parts at it. Lynn is exactly right on the porting too, as long as the port is done correctly, case integrity does not become an issue.:thumbsup:

Linn@Amazon
04-21-2006, 01:55 PM
I love the sound of the screaming roots blowers but I have always been partial to turbo set ups...we are seeing more and more Cobra guys going that route now that there are some good choices...

ausie
04-22-2006, 11:15 AM
I looked at purchasing a whipple before I had my Eaton ported and weighed the pro's and con's of each. You must remember that the Eaton is a solid, 90k mile or more blower. No-one has run the Kenne Bell or the Whipple superchargers that long to really say what the life span is, most combinations change every year or two. Another thing is that it's not a fair comparison between the Eaton and the positive displacement blowers because of the way they work. The Eaton compresses air in the lower intake not the case of the blower as the positive displacement blowers do. So while the Kenne Bell and Whipple blowers offer much greater power at the same level of boost, the Eaton offers long life and decent power with a little porting. It's all up to the individual, I just chose to fine tune the stock stuff rather than just throwing a bunch of parts at it. Lynn is exactly right on the porting too, as long as the port is done correctly, case integrity does not become an issue.:thumbsup:
I would agree that the roots and twin screw compressors are not the same since each has a different method of compressing air. This may hold true to the conventional roots type blowers, however since the Eaton M112 is a modified roots type (having a 60degree helix rotation in the rotors) reduces pressure variations. The main difference of the twin screw and modified roots is that the twin screw rotor is actually shaped like a cone verses the uniform cylindrical rotor that the roots type uses. The connical shape of the rotor is what allows for air compression between the rotors since the overall area decreases as the air moves forward toward the discharge port. Our 03/04 Cobra uses a 4th generation modified roots supercharger and I wonder how much different that would be to the 5th generation M112 which finds its home in Jaguars and other vehicles. I was able to find some info on the gen 5 eatons but that is as much as I could muster up. After a bit of research, it appears that much of the difference between the generations seems to be linked to the porting (input and output) as well as some slight changes to the rotor design. It seems like magnisun is the only resource for eaton's and the information is rather limited. Eaton used to have some good information on their superchargers but now seems defunct. Here is a link to the gen 5 Eaton. Has some interesting information.
http://www.tomhenryracing.com/technical/blower.htm