Sesshoumaru

iTrader: (1)

oh btw that last post was 666 of yours

RotorMotor

iTrader: (5)

yeah, but the temps should basically be the same w/ BNR stage 3's, or a big single after the intercooler... both temps should end up VERY close to each other

basically i think the point im trying to make is that i feel you would be better off with some bnr stage 3's because of the faster spoolup, unless your trying to run like 34psi

ebb

Rotormotor, there are quite a few more factors involved in detonation than octane and boost. I run 17.5 psi on 91 octane all the time, it is all about having enough fuel and cooling the air. There is not limit, I would say, if you can keep air temps down and have enough fuel.

Sesshoumaru

iTrader: (1)

ebb there are more than that too. like timing and diminishing returns.

i could go either way for turbos. Depends on the application. I like the fact there is only one to break on a single or wear out but spool is always a big concern for me

twins can easily put down the power of a single. It depends on the turbos and that is what i was getting at.

it's all about the flow........

ebb

There are no diminishing returns as long as you maintain the cool air temps. timing is definitley a factor, but my point was octane rating is not keeping people from running high boost. If you cannot make the boost you want while keeping temps inline, time for a bigger turbo-its out of the efficiency range and just putting out heat.

Sesshoumaru

iTrader: (1)

ugh........matter can only be compressed so much

that oxygen - the closer he get's to his buddy the more he hates him. Therefore you have to persuade him even harder........then he hates u more and pushes back.....and u push harder.....he pushes harder back........

just like electrons and protons........

**** sometimes just don't want to fit in the suitcase and without break'n the damn hinges or causing a black hole it's not going to fit.

the work u get for taking that extra toothbrush is just not worth the 1hr it takes u jumping up and down on that suitcase.

ebb

I don't think any of us have to worry too much about that. 15-25 psi is nothing, just look at cars running 50-75 psi like the old cart cars.

ebb

I am sorry, I do not disagree with you. There is a theoretical limit, just we don't even come close. How are all the high horsepower rx7's making it?--more boost, bigger turbo.

What is the point of diminshing return on an rx7? Tell me so I can aim just shy of it.

I once read of a buick running a 7 second 1/4 at 45psi.

Sesshoumaru

iTrader: (1)

it's like the superchargers that take 200hp to run but make 1000hp.

There is no definate boundry but for every dollar you put in u get less and less back

but i guess there's no point in arguing since were not using laws of thermodynamics.

pv=nrt

is why it wont' work and were not even on the quantum level yet. Why doesn't air stay at 12psi if there are no opposing forces or so far away from them that it doesnt' matter? They are opposing each other on a molecular level and that is why we are at 1 atm now. Even at low pressures it apparent they repel. We are entering the world of charge nuetrality and i dont' have another argument left in me.


i guess that's all i can say unless i use cryogenically hardened squirrel turds submerged in liquid nitrogen to cool intake temps.

but i can get those for free

cavellm

Maybe this is a stupid question... But is the location of the stock bov in a bad place? I would think that Mazda would have put it on the side of the IC closer to the engine than the turbo. When you have all that air in the IC pipes and IC itself, you release the throttle under high boost, and all of that is still in the piping.

I was thinking that's why most all aftermarket bov's are on the out side of the IC. So it releases more air in the system.

RotorMotor

iTrader: (5)

then will someone please explain to me why premium gas exists? why didnt mazda just tune it properly to run on 87 octane???

ReDLiNe@t9

that was already explained on the first page of threads

Sesshoumaru

iTrader: (1)

if it was it prolly wasn't explained very throughly.

i don't remembering anything about flash points.

i think there are some nice threads on the 2nd gen section not sure on the 3rd or not. prolly.

basically the higher the rating the higher the flash point and harder the fuel is to ignite. This resiliance to unwanted combustion due to heat (higher flash point) is what makes it good for high boost applications where heat is present.

you can actually lose hp by using higher octane. The NA guys never run premium b/c of that.

I beleive this is due to the complete combustion of the fuel due to the lower flash point.

CRX7

Beautiful, its like poetry.

Sesshoumaru

iTrader: (1)

i liked this one actually

*** crap..........wtf.......isn't all crap *** crap?

12ARX

Its still hasn't been answered... the original question was show me i did a good thing by buying it...Well prove to me the compressor surge is doing damage to the turbine blades or shaft... Why did turbo F1 days never use them (60+ psi) ? Why did saab invent them just to keep it quiet for the everyday motorist? Prove shaft speed slows down excessively with backlash of air? What testing has been done to prove the need for a $100-$400 peice of shiny alloy... Just want to keep this open as no proof has been given...Has anyone had a turbo fail just because no BOV?

Tom93R1

iTrader: (2)

It has been answered. Basically you wasted your money buying it because teh stock one does the job plenty well. Read the thread again and you will see that.

paw140

Given two different setups, each with a different turbo, but with identical engines, your explanation doesn't make any sense. I asked this question a while ago and got some good responses.

https://www.rx7club.com/showthread.p...ighlight=turbo

RotorMotor

iTrader: (5)

maxcooper sums it up in the last thread very well!

"12 psi in the manifold is 12 psi in the manifold, no matter what turbo is pumping it there.

The single makes more power for two reasons:

- The 12 psi in the manifold from the single is cooler than the 12 psi from the stock turbos.

- The 12 psi in the manifold from the single is fighting less pressure in the exhaust system to enter to the combustion chamber, so you flow more with the freer-flowing exhaust afforded by the larger turbo (and less convoluted exhaust manifold)."

RotorMotor

iTrader: (5)

yes yes i know all about flash points etc.... you CLAIM that there's not a problem w/ pre-detonation @ 20psi on 91 octane (or that it is not a problem if the car is tunes for it).... if this is so (which i am still skeptikal becaue why would they make 104 octane gas) im asking why mazda didnt "tune" the FD for at a lower PSI (10PSI which it is) to run on 87 octane.. if its all in tuning.

flash point is all about pressure and heat right? so are you trying to tell me that if i had a nice cold intercooler i could use 87 in my FD with not a worry???? im pretty sure pressure has alot to do do with it

Sesshoumaru

iTrader: (1)

well yes.

that's what i meant by psi, tb, and temp have to be the same

12psi is 12psi just like an 6 inches is 6 inches.

i'm not debating that.

the reason 12psi isn't always the same power is b/c the temp in the pv=nrt. His sentence referse to PSI only. He says nothing about volume or temp. Since the temps are usually larger for a smaller turbo and have the same psi the volume would have to be decreased

basically you have a ration since nr are constants.

p=nrt/v

and the reason bov are not put in is b/c they get new turbos every race so they dont' give a ****.

Sesshoumaru

iTrader: (1)

i never said this

RotorMotor

iTrader: (5)

^i appologise Sesshoumaru! the octane stuff was directed at ebb.

ebb-> "Rotormotor, there are quite a few more factors involved in detonation than octane and boost. I run 17.5 psi on 91 octane all the time, it is all about having enough fuel and cooling the air. There is not limit, I would say, if you can keep air temps down and have enough fuel."

Sesshoumaru

iTrader: (1)

ok i'll take that back

volume is constant so the n is changing (under motor environment)

pv=nrt

pv/rt=n

so if we keep pressure the same and the volume.

and are able to lower the temp. You gain more o2 and more power.

DCrosby

There are two places for the BOV, both with up and down sides...

Before the IC and After the IC

Before IC, Since pressure builds at the trottle body when it's snapped shut the wave has to build back all the way through the IC and esape before it hits the Turbo..
Pro: You're not cooling the air (IC) you're letting out into the atmosphere
Con: Pressure builds at the TB and why wait till it almost gets to the turbos, let it off where it builds...

After IC:
Pro: Pressure gets vented at the place it builds, and has no negative effect on any of the systems from TB back to Turbo
Con: You're letting air escape that has been cooled by your IC, and your IC needs to get rid of that heat.

Some people put two BOV's in to get the best / worst of both worlds, at a diminished Con.

As for the stock BOV, all I have to say Is when you start modding, all the if it was good enough for mazda crap goes out the window since you're re-designing teh system, you can't take out the foundation of a building and expect the static to work with a new foundation...

-DC