Check valve, MAP clamp or 2 bar MAP ?

[Nubira2.2]

i have 450cc injectors and piggyback

why would i need them ? (Check valve, MAP clamp or 2 bar MAP)

i can control the MAP signal with the piggyback, right
so i can keep it out of the 5v limit
and having bigger injectors i can supply enough fuel without going over 5v

reading the manual i can change the MAP signal + 50% and - 50%

wouldnt that be enough for getting a good tune with the 450cc and 4psi?


my MAP signal reaches 4.9 volts
with the 450cc's isnt that pig rich?

there are many ideas running through my head

please show me the way to go ...

[ubuyau]

i have 450cc injectors and piggyback

why would i need them ? (Check valve, MAP clamp or 2 bar MAP)

i can control the MAP signal with the piggyback, right
so i can keep it out of the 5v limit
and having bigger injectors i can supply enough fuel without going over 5v

reading the manual i can change the MAP signal + 50% and - 50%

wouldnt that be enough for getting a good tune with the 450cc and 4psi?


my MAP signal reaches 4.9 volts
with the 450cc's isnt that pig rich?

there are many ideas running through my head

please show me the way to go ...

2bar i think would do ok - that way you can actually read how much pressure is being run.
Check valves will bleed off boost pressure from stock MAP sensor (maybe protect against physical damage?), but if you use 2bar you wont need them.

4.9V and 450cc injectors will have them open for the longest duration - yes very rich!

Watch knock, AFR and EGT though - remember if you scale back the MAP sensor reading it'll change the ignition timing too...

--Tim

[PrecisionBoost]

You'd probably be fine with a check valve..... keep in mind that one of the purposes of a check valve is to avoid damaging your factory 1bar Map sensor.

I while back I posted an internal schematic of a map sensor and showed how it bends under pressure ( which gives the voltage output to ECU )..... if you go outside the factory rating it's possible to break/snap the MAP sensor.

Odds are you probalby won't at 4psi.... but you might want to run down to the local scrap yard and pick up a check valve from a turbo car for a buck or two. (pretty much every turbo car will have atleast one check valve somewhere in the engine... you can test it by blowing on it.... it's like a PCV valve.... one way there is very little restriction.... the other way is completely closed)

Hmmmm.... speaking of PCV... I suppose that would also work in this case.... it only lets air escape from the crank case.... it won't allow air to be sucked into the crank case.

If I were in your shoes.... I'd probably use a 1 Bar sensor with a check valve going to the ECU and then install a separate 2bar for the piggyback

There are many options.... each one involves some tuning to make it work.

[john_trickle]

I was looking at this site this morning they have the 2 bar and 3 bar map sensor so to be sure i can use the 2 bar map sensor instead of the check vavle is this correct.

http://www.haltech.com.au/map_sensor.htm

john

[john_trickle]

I was looking at this site this morning they have the 2 bar and 3 bar map sensor so to be sure i can use the 2 bar map sensor instead of the check vavle is this correct.

http://www.haltech.com.au/map_sensor.htm

john

My dyno put in a 1 way check valve and ive had no problems what so ever.

john