skc supercharger build
#53
rev it up
Thread Starter
The tune seems good with steady afr through the rev range. i will add octane booster and 2 stroke for track days for extra insurance.
With the surge in torque so early in the rev range i may not need more power.
#55
rev it up
Thread Starter
I should get to drive it tomorrow.
#57
Registered
iTrader: (3)
This is great man--I know you will enjoy the driving. Thanks for sharing all this with us.
You have to forgive me--I always think about things--sometimes too much. But, in looking at the dyno graph--it seems that you have some flow restriction /lost boost pressure after about 6k rpm?
I know you are just getting it going--so the fine tuning is not there yet? But, believe me there is more power in there without the need for a different pulley. Get that done 1st before you start upping the boost?
WELCOME TO THE CLUB
You have to forgive me--I always think about things--sometimes too much. But, in looking at the dyno graph--it seems that you have some flow restriction /lost boost pressure after about 6k rpm?
I know you are just getting it going--so the fine tuning is not there yet? But, believe me there is more power in there without the need for a different pulley. Get that done 1st before you start upping the boost?
WELCOME TO THE CLUB
#59
rev it up
Thread Starter
This is great man--I know you will enjoy the driving. Thanks for sharing all this with us.
You have to forgive me--I always think about things--sometimes too much. But, in looking at the dyno graph--it seems that you have some flow restriction /lost boost pressure after about 6k rpm?
I know you are just getting it going--so the fine tuning is not there yet? But, believe me there is more power in there without the need for a different pulley. Get that done 1st before you start upping the boost?
WELCOME TO THE CLUB
You have to forgive me--I always think about things--sometimes too much. But, in looking at the dyno graph--it seems that you have some flow restriction /lost boost pressure after about 6k rpm?
I know you are just getting it going--so the fine tuning is not there yet? But, believe me there is more power in there without the need for a different pulley. Get that done 1st before you start upping the boost?
WELCOME TO THE CLUB
We have hit a bit of a hiccup with our idle. It seems to idle fine while standing however when driving and slowing down the idle drops too low and wants to stall. Looking to ways to control this issue.
#61
rev it up
Thread Starter
#66
rev it up
Thread Starter
Oil leak near the gear housing. It appears the O ring has given way causing an oil leak at the back of the supercharger unit. In the process of pulling every thing out to have a look.
Will try new O ring and lots of sealer and try again.
We think this is a new oil leak issue and unrelated to the original issue.
This is part of the joy of being a pioneer as this is the first time this kit has been pushed to its limits, albeit on a dyno.
Will try new O ring and lots of sealer and try again.
We think this is a new oil leak issue and unrelated to the original issue.
This is part of the joy of being a pioneer as this is the first time this kit has been pushed to its limits, albeit on a dyno.
#67
rev it up
Thread Starter
I understand you can mechanically control this process so the rev does not drop as quickly as it does now.
#70
Lucky #33
iTrader: (4)
Do you have a kit as well Atl8? I am trying to get all the US Hymee kit guys together in an open discussion. Please shoot me a PM.
Ok well this is what Hymee has to say about the oil seal failure. Please bare with the long post.
I do not believe I have in my position these bungs with my kit, Nor have I checked to see if my SC unit is sealed with fluid already in. I wish I had pics of it fully installed this way or updated instructions. There was also a Huge change in in the line department.
the fist pic is of the updated parts box I have, the second of the updated line layout - oil set up that has also changed. I dont remember the oil to be used but if you PM me I will dig it up.
I still have questions on what the proper fill line should be, change intervals and how to check the fluid.
Ok well this is what Hymee has to say about the oil seal failure. Please bare with the long post.
the initial kits developed an oil leak which I have previously advised. The most suitable engineering fixes have been applied to all of these kits, however there is still a report of some leaking in one of the kits.
Following these issues, we have done a thorough analysis of the cause of failure, and have finally made a decision to rectify the situation. The problem relates back to a design decision we took when we opted to use engine oil to lubricate the internal gears/timing mechanism of the compressor. This seemed “valid” at the time, as it is one of the acceptable ways to provide the lubrication, as recommended by the compressor manufacturer. Subsequent testing indicated this was OK, as I have outlined before. As it turns out, this decision was crucial. It is now evident that the choice was bad due to the following factors:
Viscosity of the oil. The viscosity of the RX-8 engine oil can vary from one user to the other, but generally the RX-8 uses a lower viscosity of “most” engines, so the lubrication we are using is not ideal.
Heat of the oil. The oil temperature of the oil returning to from the oil cooler / filter system is rather hotter on a rotary engine – as is a well documented fact. If this is added to the extra heat introduced during the compression of air, we are getting elevated temperatures. This temperature has resulted in one case of a seal failing and replacing with a Viton seal (higher head range) has seemed to fix the problem.
Volume of oil. It would appear that way too much oil is being bled off the main oil pressure feed into the supercharger, and this is exacerbated by the next point.
Design of the oil return to the sump. This design had the oil returning to the sump through an open cage bearing, very “similar” to a ball bearing turbo lubrication system. The high RPM of the bearing combined with the fact of reasonably low pressure (compared to a turbo lubrication system) prevented the adequate passage of oil from the compressor to the return line and on to the sump.
Prior to the gear driven setup, we always used a “sealed” system for providing lubrication to the compressor. This is the other method recommended by the manufacturer. This proved effective (albeit a simpler drive), and proved itself over some very “highly stressed” dyno tuning session, the most vigorous being the engine dyno sessions extracting the 340 & 360 HP figures. A sealed system is what is used on the transmission and differential of all (or vast majority of?) vehicles.
So – the solution is fairly obvious – leave the engine lubrication system alone (apart from the remote mounted oil cooler – no problems), and use a sealed lubrication system for the compressor filled with a controlled oil. The oil will be provided to you to, or at the least specified so you can procure a small amount of your own. It might be problematic to send oil… Future compressors will pre-filled and sealed prior to shipping.
The other part of the solution is very, very simple. The braided line the feeds the oil will be replaced with two simple bungs (1/8 NPT bungs) to seal the fittings, and the return cover at the end of the blower will be replaced with a cap, sealed by the existing o-ring arrangement.
Following these issues, we have done a thorough analysis of the cause of failure, and have finally made a decision to rectify the situation. The problem relates back to a design decision we took when we opted to use engine oil to lubricate the internal gears/timing mechanism of the compressor. This seemed “valid” at the time, as it is one of the acceptable ways to provide the lubrication, as recommended by the compressor manufacturer. Subsequent testing indicated this was OK, as I have outlined before. As it turns out, this decision was crucial. It is now evident that the choice was bad due to the following factors:
Viscosity of the oil. The viscosity of the RX-8 engine oil can vary from one user to the other, but generally the RX-8 uses a lower viscosity of “most” engines, so the lubrication we are using is not ideal.
Heat of the oil. The oil temperature of the oil returning to from the oil cooler / filter system is rather hotter on a rotary engine – as is a well documented fact. If this is added to the extra heat introduced during the compression of air, we are getting elevated temperatures. This temperature has resulted in one case of a seal failing and replacing with a Viton seal (higher head range) has seemed to fix the problem.
Volume of oil. It would appear that way too much oil is being bled off the main oil pressure feed into the supercharger, and this is exacerbated by the next point.
Design of the oil return to the sump. This design had the oil returning to the sump through an open cage bearing, very “similar” to a ball bearing turbo lubrication system. The high RPM of the bearing combined with the fact of reasonably low pressure (compared to a turbo lubrication system) prevented the adequate passage of oil from the compressor to the return line and on to the sump.
Prior to the gear driven setup, we always used a “sealed” system for providing lubrication to the compressor. This is the other method recommended by the manufacturer. This proved effective (albeit a simpler drive), and proved itself over some very “highly stressed” dyno tuning session, the most vigorous being the engine dyno sessions extracting the 340 & 360 HP figures. A sealed system is what is used on the transmission and differential of all (or vast majority of?) vehicles.
So – the solution is fairly obvious – leave the engine lubrication system alone (apart from the remote mounted oil cooler – no problems), and use a sealed lubrication system for the compressor filled with a controlled oil. The oil will be provided to you to, or at the least specified so you can procure a small amount of your own. It might be problematic to send oil… Future compressors will pre-filled and sealed prior to shipping.
The other part of the solution is very, very simple. The braided line the feeds the oil will be replaced with two simple bungs (1/8 NPT bungs) to seal the fittings, and the return cover at the end of the blower will be replaced with a cap, sealed by the existing o-ring arrangement.
the fist pic is of the updated parts box I have, the second of the updated line layout - oil set up that has also changed. I dont remember the oil to be used but if you PM me I will dig it up.
I still have questions on what the proper fill line should be, change intervals and how to check the fluid.
#71
what was the actual fix? rasing all the idle maps to above the std idle or just changing the slope of the idle fall rate?
#73
Registered
iTrader: (3)
1200 with a/c on--that helps.
Do yall vent the sc drive gear case?
The reason I ask is when Pettit 1st install a few units--the s/c would leak oil after a lot of high speed running. Pressure was building inside gear drive case and that was causing the seals to blow. A simple vent cured that problem. Of course we have the self lubricated type? I dont know if yalls set up address's that pressure build up or not?
Do yall vent the sc drive gear case?
The reason I ask is when Pettit 1st install a few units--the s/c would leak oil after a lot of high speed running. Pressure was building inside gear drive case and that was causing the seals to blow. A simple vent cured that problem. Of course we have the self lubricated type? I dont know if yalls set up address's that pressure build up or not?
#74
Lucky #33
iTrader: (4)
I would say the fix dose not allow for ventilation of the case. I think the cap he was referring to in the email is not the same as the one in the pic. I think It will take me putting the unit on and figuring stuff out as I go to get a good assessment of anything else I may or may not need.
I can try and shoot Mark or Sprintex a email. I thought some SC units push excess pressure or oil back into the intake tract....
I can try and shoot Mark or Sprintex a email. I thought some SC units push excess pressure or oil back into the intake tract....
Last edited by hoss -05; 07-23-2011 at 10:27 AM.
#75
Registered
iTrader: (3)
Yep you can get pressure build up in that case--thats one reason we lower the oil level just a little when we go on track.
But, like you say--you have to see what you have and how it is going to work out 1st. There may be something already build into the kit to handle it.
But, like you say--you have to see what you have and how it is going to work out 1st. There may be something already build into the kit to handle it.