probably--- I just have been toying around the idea on modifing the pettit uim/lim mount. I want to delete the vdi entirely and add some velocity stacks to the primary and ssv runners. This caught my eye.

 

Cat still in good condition however there was a slight leak from the joint seal with extractor.

Also found maf had oil film on the sensors, got these cleaned with a carby cleaner. Car runs a lot better however the hesitation still persists. Next step is to try new coils.

 

good choice--may as well upgrade them?

 

Might check the alternator output first

 

lol--been reading my posts?

 

It is a valid point that you have raised in the other thread and it is yet another variable that we need to consider when fault finding.

 

you don't really want velocity stacks inside an FI plenum, well Denny does anyway ...

 

Where does you bypass valve enter the intake ?

 

why not Mark? air flow is air flow. Boost can influence intake manifold air flow but to rely on boost to overcome inherent flaws in the design is not the best way. Throttle response, equal air flow to all runners is very important and I do think there is room for improvement from the oem design.
Mazda did a better job than most in designing the intake, but it is designed for all environments, etc in mind.
I really dont think a large increase of airflow will be the result of modification. But I do think that throttle response and equal flow can be helped.

Speaking of alternators--i wish we had the latest design in which most of the voltage output is done during decel only.
For street use I wouldnt underdrive the alternator.

 

you want a smooth long radius entrance into a port, but not having it stick up on a tube like a velocity stack within a boosted plenum. You would want the plenum baseplate to be even with the entry surface of the velocity stack, at which point it's not really a velocity stack. It's what I explained in the first sentence.

NA intake and exhaust flow dynamics are out the window in a FI application

 

Ok--I see where you are coming from--I think. The classic plenum with the v stacks inside it?
I am thinking about something a little different. Here is a very rough idea of the shape---not the manifold--just the shape, i am thinking about.

http://image.popularhotrodding.com/f..._manifolds.jpg

The runners--I believe--- can use a little more funneling/trumping affect to help with air flow velocity plus more differentiation is needed between the primary and ssv runners. As you know i have a different UIM than others without the pettit kit. So mating the uim to the lim differently is a little easier.
Thats my goal anyway. In time. First i am going to do a slick build.

 

I do not have a photo of the Hymee plenum however, the inside does have a funnell shape to it. Perhaps, someone else who has the kit can post a photo.

I do not want to take mine apart now as it was a struggle to get it in place the last time due to the extra machined metal to fix the boost leak.

 

I think my sputtering is due to the coils as they have white arcing marks at the base.

 

/\Highly unlikely from your description .

More likely to do with a temporary over-rich mixture . If you logged while reproducing the issue you may get a better idea .

 

You are probably correct. I will get new coils installed and then take the car to the tuners so it can go on the dyno to replicate the issues.

The dyno is long over due as they where very conservative at the time of installation so we may be able to run a touch leaner.

I have enjoyed the problem solving aspect around the problem and learnt a lot in the process and it got me working on parts of the car I would not have dared to in the past.

 

Comes with the territory and all part of the "fun" of FI .

 

there is always the point where you no longer care about knowledge and just want the problem to go away, even if its the magic garage fairy that fixes it one night.

 

lol--i know that feeling. But is it good when you learn about something.
I would suggest in upgrading the ignition system?

 

It is starting to get that way. I just want my car to right so I can start tracking again. The new season has started and I have already missed the first session, each session gets you points so if you miss a few it becomes more difficult to accumulate points to get a trophy placing.

Apart from getting the trophy I am also motivated by watching my lap times drop. When I first tracked at lakeside raceway my lap time was 1:08.85 and now they are 1:02.02. There was some suspension and camber changes along the way.

My goal was to get down to around 58 seconds, this is a time achieved by a Porsche GT3RS on slicks. So my plans was to have a road going car that is capable of matching the Porsche.To achieve this I was going to switch to softer compound tyres and FI. Time will tell if I need to up the boost however, I am willing to have fun trying to meet my target.

While I was able to drive 3000km to track at Wakefield raceway for the nationals last year the car has always had minor issues preventing me from having a go at Lakeside.

 

i would suggest getting the best tires and brakes you can get--braking is one of the 8's strong points.
Weight reduction is also a major goal of the real track addict.
Welcome to the madness.
OD

 

I am currently running on 2 year old Bridgestone RE55s. I have project Mu slotted rotors up front and DBA slotted rotors at the rear all with project mu HC+ pads. It seems to grip well however, I need to upgrade to braided lines next.

I want to use the car on the road as well so weight reduction will be minimal. I have relocated the battery to the boot which should help a bit. I may look into taking out the passanger seat when I go to the track.

I usually only do one alteration per track day so I can measure the benefit of each change.

 

Just strip the bastard, not one piece a track day the whole thing!

 

you are not running real track tires? Well--heck there is your time right there. Get some R6 hoosiers, light rims and better brake pads ( Cobalt or Hawks dt 60's for ex) and you will be surprised how it changes the car.
Zoom-Zoom!

 

Sticky rubber is going to be my next updrade. I think it will drop another 2 seconds which takes my time to 60 seconds. Then there is the unknown factor of the extra power from the supercharger. If it is worth another 2 seconds then I will get to my target of 58 seconds.

This track is very quick and it has the highest average lap speed of any track in the country and it suits the RX8 with lots of high speed corners. I think some aero improvements will hepl as well.

 

Noticed something odd yesterday. I think it has been happening for a while however, it was so obvious that it was worth a mention.

When I start my car from cold the idle does not hold at all. However, after about a minute it is fine and I do not need to keep my foot on the accelerator to keep it on idle. Yesterday I noticed that the interior lights dimmed at the exact same time the idle settled. Therefore, there must be some electrical issue that is causing my cold start idle to play up.

Any ideas on the cause of the problem? This problem is only aparent when starting from dead cold. If the engine is slightly warm then I do not have the initial problem.