I dont think there is a good bolt in solution. I thought of the shane intake as it has room to slide back and fourth in the larger tube and it may have the room to push forward some.

So a modded AEM/mazda speed unit the best bet?

 

you can trim the MAF or the TB or both. if you measure between the stops on the maf pipe and TB and you don't have 45mm you might as well not cut anything and find another solution like the AEM or go custom. you need to find 5-10mm between the two and have 15mm on the maf and TB to clamp to. a silicone hose coupling is normally around 76mm long or so. but you can trim them down.

I'd choose a cheep and flexible coupling from china.
the autobarn88 ones are useless for boost but have got the flexibility you want to stop transmitting vibrations from the engine to the chassis.

next best would be a SFS as they are flexible but very expensive to cut up for a test.

 

let me come in here.
You have to remember that with a supercharger you are dealing with things a little different than a turbo. A SC is a positive displacement pump--right. This means it is going to push a certain amount of air through it regardless. But we dont want boost all the time. So we have a bypass valve.
Now while the bypass valve does it job--its recirculating this pumped air--right? Ok when it does this many times a second it causes a pulses. These pulses affect the maf and thats the reason we have to have a higher idle speed--Pettit guys idle at 1.2K. Higher the rpm makes these pulses occur very close together--smoothing them out. So it doesnt affect the maf as much.
Now if you have the TB closer to the SC this will intensify this pulse which will have a more profound affect on the maf during decel and the maf trying to adjust at idle.
You could try a screen between the TB and the maf also--but i dont think that will work? But worth a try. Petti has a maf pipe he can sell you.
Just be sure to get cold air to whatever filter you get--the sc will have a longer life if you do. Hot underhood air is hard on a SC.

 

^ is the valve pulsing open and closed? I say it isn't.

 

I thought SC's need a higher idle speed because they drain power from the engine

 

perhaps instead of pulses a better word would be "waves". There are lobes on the sc shaft and as each each one of those lobes grab air it pumps. The valve? No it doesnt open and shut.
Turbos also grab air with their compressor wheels--but they have many more blades ( versus the sc rotors) and they rotate at a much faster rpm. Their blades grab less air individually than a SC lobe and they dont have this affect..
No superchargers dont idle faster because of the mechanical drive--actually they only take about 1/2 hp to turn when they are off boost. The corvette sc engine idles like normal for example--maybe 100 rpm more than the non s.c. one.
od

 

No it has a long narrow air filter inside, so to do that you will have to shorten the filter and at that diameter it will not have enough surface area. Building a custom full 3.5" diameter intake is not that hard.

 

so how much torque does a V8 have at idle vs a rotary ............

 

my SC easily idles below 1000rpm. I'm not sure how much hp it consumes but I would hazard a guess that due to a 9.49:1 internal step-up it could be more than a twin-screw.

 

My car idles perfectly at the stock idle rate so I am happy to leave it at that level.

I just need to adjust the intake and MAF placement and then I am in supercharged RX8 heaven

 

I assume building a custom intake involves correct tube size, clamps,bends, screens and pod filter ideally in the bumper. Then experiment with MAF placement until optimal performance is achieved.

Do you think a re-tune will be required after completing a change in intake system or does the ecu adjust itself automatically.

 

then why are you trying to change the MAF? if it will idle like std then I doubt you have a MAF issue.

 

ug yes i am a little confused?

 

Look you are making this way too difficult. You need a minimum amount of straight tube flow length before and after the MAF. This is well documented on the forum. Same for a flow straightening screen or two. You currently don't gave that and I don't think you can achieve it with the air filter in the engine bay due to the relocated TB position. Aside from that the preferred tube is 3.5" OD x 0.063" wall (3.375" ID). A weld on MAF bung can be easily purchased. Then you need to get a suitable size filter positioned in the front bumper and whatever else is needed to make the rest of the piping happen. Don't try to over think/complicate it beyond that.


.

 

Only problem I have is the car fails to catch the idle on deceleration when above 2000rpm. I have become accustomed to this and now able to dab the throttle in time to stop it from stalling.

And when it idles from here it is perfect and I do not need a higher RPM to keep it going.

I am sure MAF relocation and longer tubes should resolve this problem.

 

Thanks Team, I will start looking into gathering the appropriate materials for the job.

 

Doubtful but worth doing for best maf operation .

 

This particular problem is well documented since the early FI days. Perhaps a few people have forgotten.




.

 

true---also some have found that the neutral switch on the trans is bad and that was causing some of their problems--but at times mine still doesnt want to catch without a little blip.
Look at your tune also. You may be injecting a little gas after throttle lift. Some tuners do that to try and help cool the combustion chamber.

 

Took the car to the track today as everything was working well. However, as soon as I got on the track one of the seals blew out causing hesitation above 5000 rpm. Drove the car in at the end of the session and discovered the seal had popped out.

Also of concern is that oil was being blown out of that same location. This would mean that oil is traveling through the inter cooler and then into the engine. People reported seeing black smoke on gear changes.

It was a very hot day with ambient at 95F and the oil peaked at 230F.

 

Hmm Ill have to put in a bit of liquid gasket into that seal when I install mine.

 

It survived its first track day. The unit was readjusted recently as it was hitting the fire wall. Perhaps, this realignment may have disturbed the seal.

What are your thoughts on the oil blowing out of that seal.

 

Hey SKC

Gave me a fright there, thought you meant a engine seal component.

What i can say is, with the limited knowledge of your S/C setup, have a look at your intake side of things and see how much oil is in that pipe.

I saw first hand a promaz turbo setup, with a badly setup catch can, gushing engine oil out when the I/C pipes were removed. (car was not started), meaning that much oil was in those pipes!

Combined with tracking environment and running in boost you could very well have been blowing oil through causing the seal to pop out, and your engine burning extra engine oil causing the black smoke.

Regards
Jason

 

I cant help but wonder if it is your SC pressurized engine oil lines that were later changed by Mark to a closed SC oiling system.... I wish you would have set your car up that way from the start. Those lines were known to cause many issues and that was the reason he changed it to a closed set up.

 

2 things.
1-on track with an FI engine it is best to go out with the oil level a tad down from full. Same for the SC oil level.
2- you have to have a great catch can set up--it doesnt need vacuum. Use a big line (big as you can within reason The little stock one is not big enough. For a back yard fix before going out you can also break the seal that the oil dipstick has--just pull it back a little--but it COULD blow some oil out --probably wouldnt --but it could.
You are obviously getting blowby in the engine--that in itself is not necessarily something to be concerned about. Just be sure to change oil after a track event!

its going to be a bitch cleaning the intercooler?