Wait not sure where your going with needing 2 bov for "flow"

 

Superchargers always give x amounts of gulps of air, in other words its a fixed number. In other words the faster the rpm, the more gulps of air you get each second. When you let go of the gas, throttle shuts and leaves the intake a closed chamber however the supercharger is still spinning with the engine at say 6k rpm.
Now on a closed system with no bypass/bov the number of air particles inside the intake would just climb and pressure would build up. If you have a small bov that can only flow 10lb/min while the suppercharger is flowing 15 or 20, even though the 1 bov is helping the air particles escape, it just doesnt allow enough particles to escape vs the rate they are being inserted so the pressure will continue climbing. In other words the bov isnt big enough and doesnt flow enough to turn the rate around. If that happens the pressure inside the intake keeps climbing and when you step on the gas you get a big boost spike with whatever pressure has built up.

Personally for supercharger application i wouldnt use a bov, i'd use a wastegate like the one you use on a turbo.

When you let go of the gas and the big bov or 2 open, the pressure inside the intake/ic drops while with a wastegate it would remain whatever psi you set it at. That would also protect from boost spikes over whatever your wastegate is set at.

 

you're overthinking it. none of the sc's used on miatas will ever flow even REMOTELY enough air for that to become an issue. You don't need 2 bov's. Or even 1 big one. Just 1 regular one is enough to relieve any and all pressure when its open.

Only time you'd have enough flow like that would be with a 40r turbo or something like that.

 

The MP62 twin screws wont do it from a redline shift?

 

I'm using dual throttle bodies and no BOV. The overpressure generated at lift exits backwards out through the bypass valve. I am only using 6psi max though.

 

nope......

 

[QUOTE=triple88a;763100] stuff saidQUOTE]

Leaveing your bypass valve hooked up sovled all problems you hypothesis-er-ized (made a new word) i believe. That's how i have mine.

 

 

Man that sound is sick. I do wonder whats the psi at the IC as soon as you let go of the throttle though.

 

0

 

Right I believe ya, just cant help it but wonder as i havent seen it lol.

 

29.84 in, it's every 0 out side

 

full rev run with 2mm bigger pulley.

 

how "loud" did it make the car? at idle and "off" boost driving? (can kinda tell by teh vid, but not really...)

really is it annoying? and do you think there would be a benefit to using a larger TB?

im flipping tired of idle droop and stall at near every light and bogging from takeoff.... trying to make it more street driving friendly.

I bought timtheteachers silver 03 (m45, tdr IC ect)... so its been around MSR alot.

Later,

Kyle

 

Your sol, that car has a MAF so you have to run a TB on the blower. Stock with bov will only work with a MAP. When you get a real ecu send me a pm and we can talk more. I would get on the MS2 group buy asap https://www.miataturbo.net/group-buys-member-discounts-23/enhanced-megasquirt-group-buy-all-miatas-90-05-a-60486/ (unless i'm wrong i remember it being another tdr power cards are good enough car)

When i had my car set up the way yours is i was able to get it to not die at lights, 1/2 is driving still, 1/2 is getting the idle screws right. i can help you there.

It sucks with my car as it's stripped. I drove to and from work (30 min each way) for 2 weeks and it was fine but don't expect to talk to a passenger or hear the radio. Having carpet helps get the sound down. On the gas it sounds the same as before.

Big tb is worthless with the relocation and bov imo as the only reason to get the big tb in to have less restriction pre blower and my system removes the restriction. Less money for same power and better drive. i will put it this way, car feels like it has a v6 out of a g35/z350.

 

thanks for the reply.

it has the EMU (with maf..) i have the greddy map sensor and harness to add to it and WBo2. i think i can program it to run off the map and send the signal to the stock ECU as if the maf is there and doing fine.

theoretically i can run a BOV plumbed back into the tract post MAF, or prob dump it as IIRC it cuts fuel when the TPS hits closed... hence my stalling issue.

cant MS because plug in inspection unless there is another way, im all ears.

If you know some tricks to get it to do better, im all over that. I am going to clean the IAC and EGR stuff this weekend, it still has 3 emissions not ready faults and no CEL codes... I think the rear o2 sensor is failing or the install was not done well, was spliced in. this car has some quirks, but they are expected...

 

Sell the greedy, get MS. As for inspection you will have to do like every one else and once a year pull the charger belt, install stock injectors and drive the car for 150 miles then inspect. Or find someone that will sell you stickers. We all go though the same deal every year. At least you have a egr and rear o2 year around and don't have to put those back on.

If you want to try the post maf dump i'm all for it.

 

oh don't get me wrong, i would switch in a heartbeat, just don't have the play money or time to spend at the moment. (school again...) I bought the thing and all the stuff on it was like a super awesome free bonus.

I could then run the big TB pre supercharger and the regular one at the manifold, and do the belcrank deal that m.net is all jiggy about....

will let you know when i have time to do something to fix it....

Kyle

 

duel tb imo are stupid. You still get the super charger equivalent of compresses surge. mp45 on low boost it's not so bad but it's still there.