After several weeks trial I have moved the intake back to its position behind the bumper. Fortunately, the larger filter I purchased fits so I now have the benefit of a better flowing filter.

The immediate improvement was that the cold start idle issue and the hesitation around 4000rpm has been resolved.

So it is back to blissful supercharged motoring again

 

Need to find a permanent solution for an alternative bypass system. The Hymee, system is quite complicated and difficult to alter as it has a complex plumbing system. While it is running a lot better the throttle response and the idle issues needs resolving to really enjoy this brilliant system.

I feel that a new system will have to piggy back off the current setup to work and maintain the aesthetics.

I have also developed a new oil leak around the rear case, this is quite likely be around the layshaft area. It is not too bad at the moment.

 

For idle ................what is the tuning system you have in place ?

With throttle response , do you feel the DV is bypassing air initially to dull the response ?

 

The HKS system does not offer idle tuning control. Therefore it relies on the factory computer to control idle.

The mechanical piston in the DV seems to catch and it not a smooth operation. I have tried various ways to smooth it out and change springs however, it seems to work ok for a while then plays up again.

I can only assume that if the DV operation is delayed when applying throttle then it will cause loss of power and cause hesitation.

 

So during my time in Afghanistan I have been thinking about this a lot. I am thinking about welding the bypass to the dogbone, then routing the exhaust to the current bypass valve area. Just need my machinist to cut the current bypass "chamber" and weld and endcap in there on the boosted side; then cut a new "ring" where it used to connect to what I can only describe as the dogbone connector area.

 

Ok, so what type of DV are you going with after deleting the current system. Can the Pettit system be incorporated.

 

I think any adjustable recirc blow off would work. Or a procharger setup.

As far as I know the pettit system is a blower mounted setup that couldnt be converted to our setup

 

ive been using the turbosmart kompact series dual port bpv for my S/C setup, cant fault it.

However i have blocked the atmo part completely.

 

The Hymee system has been designed with the piston physically blocking off the airflow in the air diversion chamber machined into the housing that holds everything together.

If we remote mount the piston then this will impact on the operation of the bypass mechanism due to the Hymee design?

 

Dont really know the design of the hymee well, but if basic principle applies, it has a specific air source.

Bypass valve under boost closes and stops air going through, when under vacuum opens and allows air through.

If you were to modify this specific air inlet with a correct size hose nipple, and a silicon hose/coupler attached to the BPV it should function exactly the same? This will allow for the use of most BPV/Blow Off Valves, if you are finding the hymee design to be lacking.

Without actually seeing the design of the area its hard to comment on how hard this will be, but in any case scenario you will prob need to remove the supercharger to wield specific areas, if it is a central housed unit, you may need to concern yourself with whether removing the built in bypass valve will impact the seal around that area, also whether wielding will alter the housing around that area and what effects it can have.

 

basically the BPV is part of a Vacuum distribution block and tied into the intake post SC

 

Thanks for the photo. Does the vacuum post integrated into the boost generated by the supercharger of is it a separate chamber?

 

Hey, I need clarification on this post i am not sure i understand what you are asking.

 

its tied into the intake side post SC so it works just like a regular vacuum distribution block

 

Sorry, What I am trying to clarify is that if the vacuum post is an isolated chamber. To me it looks like that the vacuum chamber extends into the throttle body. Therefore, remote mounting a BPV may not work.

 

Developed an exhaust leak caused by a worn gasket. I asked the mechanic to check the condition of the cat and we found that it had collapsed and the brick was sitting at an angle causing an obvious restriction. The car was running very quiet and was start to lack power so it I am glad we got that sorted.

As soon as I started the car I noticed that the exhaust sounded louder and a big jump in power. On the way home I dragged a Holden HSV with a LS3 engine off the lights without too much effort and I backed off after 50m and then he went roaring past bemused to see an RX8 taking off so fast.

 

the Vacuum chamber is connected to the intake at the dogbone but its is not tied into the "blower" itself...and you are correct the remote BPV will not work with this set up (I am sure it "could" but its not feasible)

Good to hear about your exhaust leak and cat situation...its like free bolt on power....HAHAHA

 

Thanks for the clarification. I believe that a solution can be found and it probably involves modifying the kit and new plumbing for the throttle body.

Alternatively, if the BPV can be precision built and machined for a smoother operation then we may end up resolving the inconsistency in performance and response.

 

true, if you plugged all the holes on the vacuum distribution block then you could essentially do a remote BPV buy welding/tapping in a separate port. If will be interested to see if someone tries this (ie: go for it...ha)

 

Replaced cat so goes a lot better now. It had collapsed and was restricting exhaust flow. Car sounds a lot louder now. New magnaflow should last longer...I hope.

I seem to have resolved boost an vacuum leaks. However, the bypass valve is still causing issues when driving in traffic and at start up.

When I come to a stop at the lights the car will sometimes stall while idling. This seems to happen as the vacuum gauge moves towards zero. I have tried the stiffer spring and it has not helped with the problem.

 

Does this only happens when you let off the throttle abruptly? On the SC (Pettit) RX-8 I drove, the owner was having similar issues but you could keep it from stalling if you let off the gas slowly.

 

The stalling on deceleration is still an issue for me. However, I am also getting engine cut out on the odd occasion while idling at the lights.

It starts with the idle fluctuating this is mirrored by the boost/vacuum fluctuation and as vacuum gets close to zero it sometimes stalls. If I give the throttle a light tap then it settles down.

I assume this issue is somehow related to the bypass valve.

While driving the car in normal traffic it behaves perfectly and the performance during hard launches is amazing.

 

Post from page one - still relevant ... me thinks .



Except for the protuner part ........ I wouldn't use that anymore .

 

Don't really understand how this works . If the HKS takes over fuel and spark , how does it give control back for idle ?

Or is the HKS just a piggyback ?

 

Yes it is a piggy back system. It is called the HKS Fcon IS, they now have a new system that has access to more features. I the basic system that I have has limited control however, it can do the basics such as timing, spark, etc.

Idle control is left to the stock computer.

The tuner has done a good job as the car is still running however, the system limitations and supercharger hardware issues have left me with a car that is somewhat lacking.