lumpylude

i've got a 94 hatch, with a z6. i bolted on a jrsc, made some pulleys, got a custom chip from "phearable," aaaand its pretty hack. on a cold start, this thing flies, but when warm, its a dog. i've learned that timing advances at higher rpms, and this seems to be my problem. chip was mapped for stock injectors/pump (less $$). i search, and now i believe i need a fuel controller? or something that stops me from advanced timing at higher rpms?

bad idea, if i leave my iat sensor unplugged, it goes fast. and my timing is adjusted backyard style too... err, maybe not adjusted... guessamadjusted...
might be alot, i'll keep searching, this thing is being driven daily till she blows.

Spawne32

iTrader: (3)

couple things...

are you still using the FMU?
are you still using the switch/relay system that is rigged to the IAT sensor wiring?
you said you have a phearable chip, what tuning program is it running?
is your map sensor setup to read boost, or is it reading pressure before the supercharger?

lumpylude

muhaha, yea
i never had an "fmu"...
switch/relay for iat wiring? never heard of it, i mean, i am a mechanic, so i do know things, but no, no relay/switch... good idea though...
i emailed phearable and told them what i had... a tuning program? problem is, i figured out all this so far, this was my first out reach to the ht community. they "mapped" something up so i boost, and yes, my map is reading boost. phew, at least theres one thing that matches.

Spawne32

iTrader: (3)

included in the JRSC kit is a pressure switch which screws into one of the intake manifold ports, funny looking thing with a plug on the end, the wire that pushes onto that goes to a relay which is wired into the harness that runs to the IAT sensor plug. Upon reaching 1psi, it triggers the relay, which puts out the maximum amount of voltage that the IAT can send to the ECU, essentially telling the ECU that the IAT is pinged out... probably like 280 degrees or so, in return, the computer retards the ignition timing somewhere between 4-6 degrees, i forget what the exact number is.


If you dont have this, then chances are your ecu is just using the factory IAT retard tables, which progressively retard timing from 160 up to 280 degrees on a scale that is something like -2, -3, -5, etc etc. The factory IAT tables are not designed for use with a supercharger, and IAT's are inherently higher with a roots blower, so if no modifications have been made there, as the air temp gets hotter, the ignition retards.

At idle on a 45 degree day i see about 102 degrees IAT after the blower, on an 90 degree day in the summer after a few pulls, i saw 212 degrees.

daveb91

The switch is not needed if they have a bin program tune...

Spawne32

iTrader: (3)

really, how bout that lol

Jaker

Plus, the relay setup actually fools the ECU into thinking that the IAT is really cold, which means more fuel. That was the whole premise of the thing. It was intended to combat throttle tip-in detonation. You mash the throttle, the pressure switch sees boost, closes the relay which fools the ECU into thinking the air suddenly got really really cold, and it dumps extra fuel coincident with the throttle mash, which helps with the "throttle tip-in detonation".

What many people don't know (and I learned from someone else on this site) is that the stock Honda OEM programming of the ECU has an IAT fuel correction which leans out the fuel as the air gets hotter. It actually makes sense for an OEM setup that as the air gets hotter, it is less dense, and needs less fuel. But in our case, the supercharger is forcing lots of air (though hot) into the engine, and the last thing we want is a leaner mixture. The highest temp correction takes out 5% fuel.

There's a pretty good chance your not getting enough fuel with that chip if you're still using OEM 240cc/min injectors. When the engine is cold, the ECU is adding extra fuel, but once the engine has warmed up, and that extra fuel is gone, you're probably running lean. Have you got a wideband oxygen sensor setup that you can use to monitor your air/fuel ratios? If not, I'd stop boosting right now until you do. I bet you're pretty lean. Also get bigger injectors and get it tuned.

Spawne32

iTrader: (3)

thats actually a big misconception that it affected fuel by making it seem like it was cold air, the unit actually adds voltage showing extremely hot air, which is what protects the engine from detonation by retarding the timing, the pig rich conditions for fuel come from the FMU only. I had to learn this myself before i could figure out what the problem was.

Jaker

You know, you might be right about that. However, also keep in mind that it also leads to the lean out I mentioned from the IAT compensation.

Spawne32

iTrader: (3)

it does, but thats where the FMU takes over, which is why its important to dial it in, the problem is you cannot adjust for tip in with the FMU so it leaves you pig rich in some areas, usually in the low rpm's

lumpylude

ooooh too perfect, guys... to answer the question, no, i do not have a wideband o2. i havent monitored anything. this is totally backyard, and so far i've proved 'em all wrong. just looking for the cheapest way to make it the best as possible. every day and night i learn something new. another thing is an intermittent iacv code, buuut trying extra others doesnt change anything.

lumpylude

ok, so how bout since i have no fuel management system, or much of anything to monitor air/fuel ratios, no idea what kind of tune is in this chip, how should i go about making this possible? an fmu and a jerry rigged pressure switch for tricking the iat? when i got the chip i told them to make it for stock injectors/pump. is there a way to makeshift an always cold condition? eh... , but seriously, thanks

Spawne32

iTrader: (3)

no no no, you dont want any of that shitty JRSC stuff, your already 1 step ahead of where you started, now you need to look into what you need to get dyno tuned properly.

CPT Del sol

yeah bro i had a jrsc d16y8 tuned w/ s100, 310cc injectors, h/i/e and bisimoto cams made 182whp with the stock pulley. Ran great and hard night or day.

DYNO TUNE = CLEAN SMOOTH RIDE