JaredKaragen

Well; I figured I would share over here unless someone else posted my car:







Yes; still rockin PVC; it aint a HMT if you don't... haha!





Long story short; alot of tuning needed, and R&D on the bypass valve in the JRSC is in progress (without heavy modification, and keeping the overall JRSC setup looking stock) so once it's done and works like it should [I.E. no exponential rise in boost due to the bypass valve staying closed when turbo is spooled up], I will buy an edelbrock kit just as a slap in the face of the CHP and test-only smog =)


#1 Question: "Why" [generalized]

#1 Answer: "Because I can, and the parts were lying around."

Bone1

Blundar and me thought about this, or using twin chargers. The bypass operation was an unknown though.

AKSC + JRSC, intercooled, +50 shot dry to help cool the JRSC.......

Myself, I've always thought the JRSC manifold sucked for even flow.

Oh yeah, welcome you long lost NEWBIE!!!!!!!!

RotaryGeek

I remember reading an article in (i think) sport compact car about how twin charging works. It wasn't 5 pounds of boost from sc + 5 pounds from turbo = 10 pounds. It had to do with ambient air pressure (14.5 i believe) and how it compresses the air twice to give it way more air per cubic inch (example only, im not 100% on anything here). Like the turbo takes in 14.5 ambient and compresses it to (at 5 pounds) 19.5, then the supercharger takes the air (it doesn't care that it is already compressed, its still going to work the same amount) and recompresses it to another 5 pounds, something about having to square the numbers to find the actual amount of boost. But in the end, it made lots more pressure on less boost. Meaning it can spool up much quicker and provide more boost at the same time. Ill search for the article. Looks good to me though, i like your project. And of course, post ****.

RotaryGeek

Taken from http://forums.sportcompactcarweb.com...ing/index.html

i think i know what you are talking about. it is all about the ratio at which the turbo or supercharger compresses. I am going to make numbers easy, i don't have my handy dandy ti-89. Say you are running a turbo at 14.7 pounds that is the gauge pressure meaning that the actual pressure is 29.4psi on the absolute scale. meaning it has like a 2:1 compression ratio. run that same kind of ratio on the supercharger and you will end up with 68.8psi(absolute) so subtract 14.7psi to get the gauge pressure which is 54.1psi quite a lot, tell me when you run that kind of boost safely. basically you have to remember that these numbers are multiplicative and not additive, and you have to work on the absolute scale and not the more common gauge pressure.

psi(gauge)=(ambientpressure(14.7)*compression ratio of compressor1*compression ratio of compressor2)-14.7psi

The only thing i don't know is if a eaton-roots supercharger would act predictably according to that equation since it is not a compressor, it is a blower.

If anyone sees a mistake go head and correct me. Engineers make mistakes too.


I guess this guy read the same article i did, he just held on to the info longer lol.

JaredKaragen

Trust me; I have known about compound pressure for quite some time... I normally point out the benefits of a dual-stage air compressor vs a single stage and people see it.

My ingenious plan is using turbo suction next to the air filter to put a vacuum on the JRSC's bypass valve (switched on via the ECU at 6.5PSI)... currently using an OBDI PCS, but it's restrictive and I need a bigger valve such as an OBDII type.

Yeah; Long lost newb I guess you can say that.. no clue when I joined... just browsed here mostly.. looking for different ideas and people's way of making things fit.

I have already got the car to sit at 1BAR solid without spiking and am hearing the WG open... but if it's happening at 1 bar I am still not getting enough suction on the valve and the problem is clearly seen; but if the turbo's WG is opening @6.5PSI (it's plumbed to the non-compressed side of the SC before the throttlebody) that means even with the restrictive OBDI PCS there is enough suction to open the valve... if it drops under 6.5, it will release the valve and allow the SC to kick back in... ECU makes it easily adjustable to make the switchover practly un-noticable.

OMG.. it's probably been about 3 months or so since I have been on PGMFI.org... lol