Ariel.Club Forum

wow, after going to Motor4Toys and seeing the 2 Atom's there I really don't know if there is enough space for an S/C. One side has the frame on bottom and suspension on top and the other side has a catch-can and exhaust in the way. Without cutting the heck out of the engine cover I don't see any reasonable place to install a centrifugal supercharger. And it would have to be a Rotrex because there is no way an old school Powerdyne, vortech, ATI unit would fit in the limited space available. Short of some major replacement of engine parts and cutting of the engine cover I just don't see the space. In my opinion it may be easier to install a turbo or swap out the engine for a LNF rather than strapping a centrifugal S/C to it.
Mind you there is no doubt I could do a S/C install, but it would be very cost prohibitive.

:pop: :pop: :tu: :tu: :tu: :pop: :pop:

this is gonna be fun  8)

I dont know if they did it or I did it.  I ripped it out of the box with a lot of excitement so it was probably me.  Nothing a radiator comb wont fix though. 

Looks familiar! I have a good idea where you can shove that thing and with a few other bit's & pieces, get enough HP to scare you shitless.  :o
You have taken the first step to the DARK SIDE my son!  :angel:

:pop:  :tu:

New intercooler showed up today from TTS :)
[img width=450 height=600]http://bolus.shackspace.com/atom/turbo/Turbo1.jpg[/img]
[img width=450 height=600]http://bolus.shackspace.com/atom/turbo/Turbo2.jpg[/img]

"Did you ever wonder; once you have a given bit of information, what do you do with it?"

If you're smart,you remember it for future use... ;)

Thank you scdyne! That was a great explanation of the various types and lubrication methods of bearings that we take soooo forgranted (until they fail). :tu:
Did you ever wonder; once you have a given bit of information, what do you do with it? :laugh:

This is a very good question that really gets to the point when talking about the differences between centrifugal superchargers, eBay turbos and brand name Turbos.
First of all there are a few different types of bearings and in our case there are fluid bearings and ball bearings. There are also a few different types of drives from direct, on a turbo, to gears or cog and belt, for most centrifugal superchargers, and planetary drive for the Rotrex supercharger. Each of these bearing systems are designed to reduce heat and friction (which are complementary to each other) by taking advantage of oil viscosity. Additionally some higher end turbo's also use water to help cool the bearing housing to help maintain proper oil temperature and viscosity.

http://auto.howstuffworks.com/turbo.htm - This is a good generalization of turbochargers and link to ball bearings.

When all is said and done the primary limiting factor for impeller speed is the bearing design.

[b]Fluid bearings[/b] are nothing more than a housing that contains an oil layer between a hardened steel shaft and brass babbitted housing. Oil viscosity directly separates the two materials from coming in contact and once viscosity breaks down due to heat, contaminates, or impeller shock failure soon fallows. Generally impeller speeds run around 120,000 RPM with these systems, but can go higher with high precision hardware, water cooling, and the right oil. (READ: brand name Garrett, Turbonetics, etc- NOT OBX and other Chinese made knock-offs) Precision hardware, exacting tolerances and proprietary aerospace grade treatments are the KEY to a quality Turbocharger.


[b]Precision Ball Bearings[/b] use high quality hardened balls housed in their own hardened casings (inner/outer). Some use internal lubrication (Powerdyne Superchargers) and others use provided oil. The inner race is pressed to the impeller and the outer race is pressed to the main housing with only the ball bearings coming in contact with the housing at a single ball point - that is in fact separated by the oil. Loads in all directions are controlled by the bearing design and oil viscosity producing less friction. This along with lower mass impeller shafts, composite impeller materials and better cooling impellers can reach speeds of 300,000 rpm. Generally with most turbo's impeller speeds are around 200,000 rpm, but as pointed out other systems exceed 500K RPM.
Side note - Dental tools use ceramic ball bearings with 'ceramic balls', which can withstand temperatures of 250 deg C static (cleaning) and 100 deg C during operation. I think they are water lubricated or internally lubricated with special bearing grease.

In the case of Centrifugal Superchargers the limits are not always the bearings (many Powerdyne owners will disagree-incorrectly) it's the fact that the transmission needed to get from engine RPM to impeller RPM would need to be very large for impeller speeds beyond 60,000 RPM. Most S/C's are designed for voulme instead of pressure to over come the lack of impeller speeds and as a result are less efficient. Vortech, Paxton and Procharger all use normal high speed precision metal ball bearings with any number of oil sources, and in extreme cases use ceramic. Powerdyne being a dry blower uses internally lubricated bearings that tend to blow out due more to heat than impeller speeds- however they are limited to around 50,000 rpm because they are internally lubricated. Ceramic upgrades, special cooling of the housing and proper system design on Powerdyne blowers have achieved much higher impeller speeds and efficiency, but nothing close to that of a Turbo.

Rotrex trumped them all with a planetary drive transmission that can achieve turbo impeller speeds. They too use ball bearings, but the whole transmission is a friction drive system that resides on a thin layer of oil. In this case it's the friction that drives the system and can multiply crank rpm's as much as 12 times. Combined with external pulleys 120,000 rpm impeller speeds are possible.

more later.. I have to eat breakfast..

I have a question of those "in the know". a 250K turbine asks a great deal of the bearings. My dental high speed turbines turn between ~300K- 500K rpms and require turbine replacement fairly often due to bearing failures. Of course, they are heat/steam sterilized several times daily so that is not an apple to apple comparison. Does anyone have any ideas as to the useful life of the bearings and are they easy to replace? Also, how are thet lubricated and are they prone to coking like a typical turbo bearing is? BTW, Happy Thanksgiving to all my Atom friends! :tu:

If I ever get my hands on a second hand GT-40 drivetrain.... I'd just ruin an Atom! ;D

[quote="Gage"]
[quote="CalScot"]
I for one am dropping out of the discussions on this Atom HP thing completely. [/quote]

Just for the record,  I think that would be a crime CalScot.  You are one of the Pioneers in the Atom community.
[/quote]
Gage, don't take that too literally. Some post's are done with a few more glasses of wine than other's :P I was more frustrated with my own self for losiing my objectivity and starting to rant, at which point it's time for a break.

[quote="Benem"]
I have the Rotrax system fitted on a very modified Atom mk1 / 2  Honda K20 engine.  The work for the rotrax was carried out by [url=http://www.tracktive.co.uk]www.tracktive.co.uk[/url] a very experienced group of people and who also carry out this set up in grass track racing.

My set up is differant to calscots which may add to the discussions in the positioning of the aftercooler.  I have a bespoke radiator mounted in front of the standard engine one this feeds to a bespoke charge cooler in the rear pumped by an electrical water pump (always on).  Air is fed through the chargecooler from the rotrax.

It's set at about 320-330 bhp but a lot more can be achieved with a differant pulley and map - (hydra ECU is fitted)

I've added a heat shield between the exhaust and the inlet pipe that comes across the rear of the engine and the cooled air temperature during the height of summer on a track didn't go much above 40 degrees.  At present with the ambient cooler temparatures i haven't seen it go above 12 degrees and it is so very quick ;D.

The configuration of the air intake hasn't been changed at all in fact i love the roar and whine through it with the spitting of air back through it on overun, it sounds very differant and turns heads in the street!

So far a part from a few bracket changes the system has proved to be reliable with now 5000 miles covered since the modification, i don't know what increaseing the bhp will do to the engine but i will be adding about 30-40bhp in the spring to see ;D

[/quote]

For the record, I believe Benem is the true poineer of the Rotrex on a Honda Atom. I was researching the Rotrex when Bruce led/linked me to Benem. Benem was very helpfull and provided me photo's, info and the link to Tracktive. I called Tracktive and researched the Hydra ECU. It all led in a roundabout referal to TTS, who made my kit. I am not so sure I would have the Rotrex on my Atom if it were not for Benem's experience and his willingness to help and provide the details.

The main difference between Benems and mine is the Intercooler design. As he pointed out he has a liquid to air system, as in the Ecotec, (but his actually works) and mine is air to air. Benems ECU is a Hydra ECU. Much much better than the MBE unit and probably on par with the Hondata on several levels and ahead on some. What Is very comforting is that he has some 5K miles on the S/C system and no problems.

It is interesting that both intercooling systems work. My initial efforts were focused on simply replicating as much of Benems design as possible. Why reinvent the wheel? But then when you start looking at the heat transfer needs of a 350HP forced induction system and a 450HP system and add in that my average summer ambient temps are around 95f in summer, with 115+f on summer track days in the desert,(all our tracks are in the hottest part of CA) the disparity becomes an engineering challenge. I looked at all sorts of cooling ideas. From a redesign of the whole front of the car to get bigger coolers, to adding a big pump and piping the entire underside of the tub with finned and vented coolant tubing, but even the most inventive looked like the summer track days were going to be beer drinking days' as opposed to driving because each "calculated" effective heat transfer solution came with to much other baggage. TTS performace (Richard Albans) looked at all the stuff I was worried about and came up with the design I have now. Air to air, very short/low volume piping, best possible airflow on intercooler position and the biggest intercooler we could build for the space. Was this the best solution? I have no idea. I ended up trusting & just going with it. It made sense at the time to me (and I was sober). I have just over 700mls on mine and it's now in for the desperately needed ECU and some engine stuff to keep it in one piece. When I complete the "project", I will have added an external oil cooler for the engine and a water injection system for really hot days as a saftey backup. Some of this is trial and error and as much of an art form as it is objective science.

It does make for two really fast Atoms though ;D

I have the Rotrax system fitted on a very modified Atom mk1 / 2  Honda K20 engine.  The work for the rotrax was carried out by [url=http://www.tracktive.co.uk]www.tracktive.co.uk[/url] a very experienced group of people and who also carry out this set up in grass track racing.

My set up is differant to calscots which may add to the discussions in the positioning of the aftercooler.  I have a bespoke radiator mounted in front of the standard engine one this feeds to a bespoke charge cooler in the rear pumped by an electrical water pump (always on).  Air is fed through the chargecooler from the rotrax.

It's set at about 320-330 bhp but a lot more can be achieved with a differant pulley and map - (hydra ECU is fitted)

I've added a heat shield between the exhaust and the inlet pipe that comes across the rear of the engine and the cooled air temperature during the height of summer on a track didn't go much above 40 degrees.  At present with the ambient cooler temparatures i haven't seen it go above 12 degrees and it is so very quick ;D.

The configuration of the air intake hasn't been changed at all in fact i love the roar and whine through it with the spitting of air back through it on overun, it sounds very differant and turns heads in the street!

So far a part from a few bracket changes the system has proved to be reliable with now 5000 miles covered since the modification, i don't know what increaseing the bhp will do to the engine but i will be adding about 30-40bhp in the spring to see ;D

[quote="CalScot"]
I for one am dropping out of the discussions on this Atom HP thing completely. [/quote]

Just for the record,  I think that would be a crime CalScot.  You are one of the Pioneers in the Atom community.