Why do i need to buy a new ECU !!

[Ignition-Kid]

Sorry guys, my question may sound stupid, but i really don't get the whole idea of getting a piggy back like PC or a New ECU like Mega Squirt or any other not-stock ecu !!

i mean the restrictor will limit my air-flow but the stock engine comes with a set of sensors which i think can cope with the limited air flow !

i just need a clarification on this subject, i don't get it at all !

[Ignition-Kid]

Sorry guys, my question may sound stupid, but i really don't get the whole idea of getting a piggy back like PC or a New ECU like Mega Squirt or any other not-stock ecu !!

i mean the restrictor will limit my air-flow but the stock engine comes with a set of sensors which i think can cope with the limited air flow !

i just need a clarification on this subject, i don't get it at all !

[Kirk Feldkamp]

Don't let us tell you what works and doesn't... go ahead and try it out yourself. Just because everyone else does it one way doesn't mean you can't make it work another way!

-Kirk

[VFR750R]

Most stock ECM's use TPS, and not only will you not being using the same throttles as stock, but the restrictor will change airflow vs throttle position.

Also, yes, stock emms look at barometer and air temp for compensation but a factory barometer sensor (located inside the ECM) has a limited range which is less then the manifold vacuum you will produce with a restrictor at high rpm, and you'd still need to be able to reference that internal factory sensor to your manifold.

You're intake runners, and exhaust are also different then factory and would need adjustments made to the factory ECM to correct for those VE changes. Carburetors correct for airflow directly, an advantage shared by ecm's set up with mass airflow sensors. No factory 600cc engines have them.

I suggest you do some research in engine controls, the sensors typically used for different engine applications etc. I highly recommend going to barnes and noble to the automotive section and reading the books there for free, and when you find a good one, buy it.

I'm looking at one right now titled "How to Tune and Modify Engine Management Systems". It's not really in depth, but covers most of the major issues of tuning factory ecms to fit modifications done by the owner.

You'll find that factory engine management systems don't have provisions for FSAE use, as they were never intended to be run with a restrictor, common plenum, and single throttle.

[Ignition-Kid]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:
Most stock ECM's use TPS, and not only will you not being using the same throttles as stock, but the restrictor will change airflow vs throttle position.

Also, yes, stock emms look at barometer and air temp for compensation but a factory barometer sensor (located inside the ECM) has a limited range which is less then the manifold vacuum you will produce with a restrictor at high rpm, and you'd still need to be able to reference that internal factory sensor to your manifold.

You're intake runners, and exhaust are also different then factory and would need adjustments made to the factory ECM to correct for those VE changes. Carburetors correct for airflow directly, an advantage shared by ecm's set up with mass airflow sensors. No factory 600cc engines have them.

I suggest you do some research in engine controls, the sensors typically used for different engine applications etc. I highly recommend going to barnes and noble to the automotive section and reading the books there for free, and when you find a good one, buy it.

I'm looking at one right now titled "How to Tune and Modify Engine Management Systems". It's not really in depth, but covers most of the major issues of tuning factory ecms to fit modifications done by the owner.

You'll find that factory engine management systems don't have provisions for FSAE use, as they were never intended to be run with a restrictor, common plenum, and single throttle. </div></BLOCKQUOTE>

Thank you so much, Very helpful.

[Mikey Antonakakis]

Also, if for some reason the stock setup could be configured to work in a FSAE car, I think they all use narrowband sensors, and the fuel maps will be radically different above a few thousand rpm (especially above 9k on a n/a 600). The narrowband sensors wouldn't really be able to compensate for it.

The Performance Electronics ECU is good for beginners, and if you have competent electronics guys, MegaSquirt is good too (it's usually more of a pain to set up, but has more features).