Ok this is a question that will defenitily draw flames and few angry outraged professionals but my curiousity urges me on. Considering its run through the afm how much boost could the stock n/a fuel system handle on 93 octane gas before detonating?

The thought crossed my mind while i was fiddling with a cheap supercharger i recently aquired(for free). I plan on hooking it in the inefficient but cheapo method that was highly discussed here a while back. Of course im gonna use a safc and wideband to tune it. Not looking for massive gains just a cheap fun summer project to keep me entertained.

 

I don't think anyone would suggest running boost on the stock n/a FUEL. Upgrade at least to the TII injectors and a better pump.

As far as the ecu, as much as you can run with piggy back tuning and enough fuel.

 

your thread title says "how much boost can the stock NA ECU handle." but you are asking how much boost the stock fuel can handle...

the stock NA fuel can make like 200whp i'd say, and the stock NA ECU can probably handle about 2-3psi before you ruin your apex seals' universe with detonation from no timing retard in boost.

 

wow. This is what I have been screaming the past few weeks each time this comes up.

With proper fuel upgrades and a fuel comp you can succesfully run fine. Now under high HP applications I do not know, but I don't think the NA ECU will pull the timing back enugh to handle that load of boost.

The prob with the NA ECU is the fuel map and timing retarding. Fix this your ok.

Does anyone know how the combination of using a boost sensor would help?

 

The 200whp claim is false. Kahren proved this, the motor he built that did 195whp (or whatever it was) had to be backed off before redline because it was running too lean. It was because of the ECU according to him.

Also, remember that the amount of fuel the stock injectors can handle that people quote, for the n/a cars, is with afr's safe for n/a's, not boosted applications. With boost you'll want to run a more rich ratio.

Stock TII injectors at least with an upgraded pump and piggy back to control it.

 

The stock n/a ecu will not pull the timing back for ANY boost, it has no maps for boost and wont retard timing like the TII ecu. You just need to run stock timing and upgraded fuel with proper tuning for it to all work right, Sonikrat proved this enough with his BNR stage 3 on s4 n/a block.

 

thank you.

 

SO in short strapping a sc to a unmodded n/a means certain death, even with a huge pulley and very very low boost?

 

I personally wouldn't suggest it.

 

it would cause short comings.

 

Thx. Thats what I have posted several times. Followed by flames that it was incorect inforamtion.

 

My friends S4 lasted maybe 500 miles @ 10psi with a supercharger and no other upgrades. Fun times

 

*sigh*

Shoo, most of you. Out of this thread. Outside, with your voltmeters.

The NA ECU does not know what boost is. It has a 1 bar pressure sensor. It's pegged out somewhere around atmospheric pressure, and is unable to read any higher - boost will just show up as atmospheric pressure to the ECU.

However, the increased airflow WILL show up to the ECU, and it will happily schedule more fuel to match the airflow - but the fuel schedule is for NA motors. There's no boost enrichment, and there's no timing retard. As far as the ECU knows, it's providing fuel to a NA motor with really big ports and really big intake/exhaust - it's flowing a lot of air, but it's still a NA motor to the ECU.

Will a few PSI cause problems? Probably not. Is it a good idea? Not really.

-=Russ=-

 

Josh (Mariah Motorsports' head mechanic) is currently running his S5 GXL with a TII engine at 7 psi with no problems on the NA electronics. What he's done to compensate is just rig a RRFPR and run 680 secondary injectors as well as retard the timing 3 degrees. So yes, it is possible. and safe if done correctly. On a side note however all would need to do to run the Turbo ECU (assuming you've a set of turbo injectors on hand) is wire in the two knock sensors as the NA ecu does not use them. Other than that they swap out just fine.

By the way, you'll get a CEL whenever you're in boost as the NA ecu doesn't know what the hell it's seeing. We call it his 'Boost Indicator' light.

 

You also need an AFM/Pressure sensor, and I've never got a CEL on any of my many boosted n/a's.

 

Must be due to the pressure sensor. Running the NA afm hasn't seemed to cause any problems. Actually not running the turbo pressure sensor hasn't caused any problems either.

 

It'll work, but it's one of many hack-job ways of doing it, considering the voltages are all wrong, so you're pulling timing and advancing it and doing all kinds of crazy **** at the wrong times since the TII ecu is especting a different map sensor, as well as an AFM. Anything works, hell swapping in a honda engine works, but we usually don't go suggest it.

 

on my old setup with na ecu/ etc
check engine light comes on when its under boost
N351 ECU / N350 all
*shrugs*

when i tride between the T2 AFM and NA AFM, the T2 AFM makes the car run leaner... believe it or not... havent tried boosting it past stock in that configuration though.