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Author Topic: Boost control & rocketchip, please help me understand them....  (Read 12352 times)

Rocketman

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Boost control & rocketchip, please help me understand them....
« Reply #15 on: June 04, 2009, 10:40:00 AM »

Sure just let me know we'll figure it out  
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rcicustoms

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Boost control & rocketchip, please help me understand them....
« Reply #16 on: June 06, 2009, 08:52:00 PM »

well we went out tonight, and took the capri out on the highway..its a cool dry night here...
 
on 30 psi fuel pressure,
 on the dsm units,      
at 17 psi, 5500 rpm, my afr was an 11.6
at 18 psi, 6000 rpm, my afr was a 12.2
at 19 psi, 6500 rpm, my afr was a 12.8
and at 20 psi just before redline (i let out at 7000 rpm)it hit a 12.6 ... witch means i hit the top of the turbos efficientcy and it actually got a hair richer cuase the turbo couldnt keep up...

and to think im doing this on a high compression N/A block...
 with just a corksport tune and
old fashion- listen, drive, frig, listen, drive, frig.. tuning... all i have is a base map, an adjustable FPR, and a boost controller. to tune with. and i know im losing power becuase im stupid rich thru the rpm band . but im pushing 20 psi on a na block. rich is safe.. ill change my oil if i get cylinder wash. as opposed to try to convince the wife i need another motor for my "cheap" toy...

oh and rocket, all the first gen (blue top) DSM injectors are low impedance.. but a resistor box is simple to make from 10.00 worth of crap from radio shack...

and gus, yes i looked at the rx7 injectors and yes there high impediance.... plug and play
but i believe there 380 or 400 cc units and i got a good deal on a spotless set of 450s
 
we had a project b18 civic turbo dynoed last week at 320whp.. with dsm 450 units so im not gonna run out of fuel with the bigger turbo im putting on soon...
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randyshear

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Boost control & rocketchip, please help me understand them....
« Reply #17 on: June 07, 2009, 12:43:00 PM »

Well I am about to be on my way to pick up the XR2.. I will need the boost control & the chip. This is going to be fun.. I will have to pace myself, I can't overspend.. LOL..
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-Randy Shear

Gostlrs

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Boost control & rocketchip, please help me understand them....
« Reply #18 on: June 07, 2009, 05:34:00 PM »

thats what i am doing as well. i am doing the supporting mods first before raising the boost. i have already put on a FMIC and Intake. Exhaust is next then gauges. after that i will get the boost controller and bump it to about 10 PSI then get the rocket chip and go all out
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rcicustoms

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Boost control & rocketchip, please help me understand them....
« Reply #19 on: June 08, 2009, 04:46:00 PM »

rocket... i got on rc engineering and injectordoc sites.. and they say spray pattern is unaffected by pressure, and is built into the injector pintle... the flow rate is most effected by pressure and is why they say each psi fuel is equal to 10 cc flow ...
 for example if you were to obtain a 450cc injector which is rated at 450cc at 45psi and you run 50 psi your essentially running a 500cc injector... or 500cc fuel will flow out the injector each minute...450cc/min +5psi = 500cc flow...the other factor being pulsewidth is controlled directly by the ecu...

can pulsewidth be tuned for certain rpms at certain loads??? or is that preset into the ecus base map???

so essentially im running a 450cc injector rated at 450cc at 45psi and ive turned it down to 30 so im running a 300 cc flow per minute estimated.
more than likely higher, becuase my psi guage is located on the rail near #1 injector it reads how much pressure the #1 inj.sees so pump pressure should be higher ...ill sit down and do the math sometime and let you know more about the setup....Joe
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Gus Kelley

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Boost control & rocketchip, please help me understand them....
« Reply #20 on: June 08, 2009, 08:07:00 PM »

Hey RCI! This is interesting. I was under same understanding as Rocket only because this subject has come up several times while speaking with race car guys. But I can't dispute your source.  Gus
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rcicustoms

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Boost control & rocketchip, please help me understand them....
« Reply #21 on: June 10, 2009, 05:13:00 PM »

hey i could have been told wrong or misunderstood but all i could find says the spray pattern is determent by the injector itself... not pressure...
i also read up alot on low and high impedance..

 and the low impedance injectors are mainly used for larger applications, such as 500cc/min or higher.and for performance apps becuase of the faster responce, becuase a saturated injector takes quite a jolt of electricity to initially open it (hence the need for a resistor box ) it opens very quickly and responds quickly to changes in demand...

 high impedance use a much lower jolt to initially open the injector and only requires the power to hold that peak power level to stay open...(peak and hold) aka it dosent get as warm due to the low current, wich in turn increases longevity and reliability... and as an automaker your more concerned with longevity than responce... hence most mfgrs use a high impedance setup... where most of your higher performance models will run a low impedance for the responce of the injector...

another cool tidbit to note, is that a high impedance ecu will fry if you run a lower impedance injector....(without resistors)  an  ecu for low impedance injectors will run high impedance injectors flawlessly without mod or frying...
so essencially a dsm can run either kind without mod to anything ... all injectors are plug and play on them cool huh.....
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Rocketman

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Boost control & rocketchip, please help me understand them....
« Reply #22 on: June 10, 2009, 05:53:00 PM »

Joe -

You've got your injectors mixed up a bit...low impedence are "peak & hold", high impedence are saturated type.

Low impedence have a high impulse current (peak) which slams the injector open - giving it better response - and require a lower current to hold it open (hold). These injectors require special drivers in the ECU to deal with the large peak currents. Running them in a normal saturated ECU will is possible with a resistor pack but they wont respond as fast. Running them without resistors will force an overdraw of current through the injector drivers and generally burn them up.

High impedence injectors require one single low current to open and hold them, nothing fancy. Our injectors are saturated type
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rcicustoms

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Boost control & rocketchip, please help me understand them....
« Reply #23 on: June 10, 2009, 06:37:00 PM »

damnit rocket, you know what i mean ......
No, srsly. the rest of the non dislexic information is to the best of my knowledge correct....

(peak and hold)'mumbles" (saturated) "mumbles" (damnit rocket).....LOL

ok, my thinking when tuning the fuel system was this:
the ecu and pump do the same thing, no matter what valve is on the end...(injector).
so where the stockers ran lean, and the little turbo was heating air, it blew up ....
so this time, i was gonna get way more inj. than i needed.. and turn down the pressure to obviously get it to run normal on the idle ...then i could incrementally turn the boost, and fuel, up.. while watching the afr the whole time...
and as i posted in another thread (i think) im running 30 psi.(fuel) and still staying in the 12s afr all the way to redline.. with 20lbs. (out of efficientcy) boost (it crept there due to the vj-14s incredibly small wastegate hole)
the boost controller is set at 18psi with normal temp and humidity........
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220hp@18psi
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