Motor Stamping A2orA3?

[esmith13]

By "pretty good" do you mean no bogging or knocking? I would think it would run real lean and rich at points considering how the cams are totally different. I guess if the O2 sensors are good, they can compensate in closed loop operation, but I thought these engines go into open loop at WOT.

You are 100% correct... you should never drive WOT with these setups... But aside from that they will run ok. the sensors can compensate. When these swaps are done and the car is driven to the dealer with the A3 ECU to get the A2 ECU flashed for the key, it is recommended to stay under 4000rpm and the car supposedly drives perfectly fine. Above that i dunno if it knocks, pings or blows up... Noone's been stupid enough to find out - or at least not stupid enough to tell us they were that stupid... ;)

Greywolf, there would be problems... The A2 motor is higher compression so the car would run leaner even with A3 cams and a A3 map.

Eric

[NemesisITR]

no, if it's an a2 head and an A3 ecu it'll run pretty good actually... no vtec tho.

if it's an A2 motor and head and an A3 ecu it would run like SHIT.

People have actually driven cars in BOTH scenarios from the installer to the dealer for the key to be flashed to the A2 ECU...


Eric

Ummm...it actually would run like shit with both setups. Since the "vtec" engages in the Si at 2200 the A2 would have its lobes activated at a very low rpm resulting in loss of power and torque. Dosent matter if its an A2 head swap or A2 motor swap the A3 ecu would make it run crappy either way do to the fact the vtec is engaging at the wrong rpm (i.e. same head either way you look at it).

Look at the old bseries motors, if you drop the vtec really low you end up loosing torque same with the A2. And since the A3 has only vtec on the intake cam the A3 ecu would only be activating the intake vtec on the A2 head/motor.

[esmith13]

the 2200rpm kick in will not change lobes on the A2. The A3 has no higher profile lobes and nothing will cause the switchover to ever occour. the A2 would run sans VTEC with an A3 ecu - remember that...

Your confusing VTC with VTEC... We don't have VTEC/secondary lobes... they'd NEVER engage on the A2 head

Eric

[NemesisITR]

the 2200rpm kick in will not change lobes on the A2. The A3 has no higher profile lobes and nothing will cause the switchover to ever occour. the A2 would run sans VTEC with an A3 ecu - remember that...

Your confusing VTC with VTEC... We don't have VTEC/secondary lobes... they'd NEVER engage on the A2 head

Eric

Well, im not sure,but I do know that I solved that problem with throwing out the A3 and getting an A2. Atleast that way I know I have true VTEC. With his engine I really dont think he has an A2 sounds like he misread the number, cause mine looked like A3 when I got my car back and I had to look at it really hard to see what it said.

I was only going by what ive seen and what ive seen is on a Honda scan tool vtec on the A3 motor is activated at 2200 rpm. I do know the Si doesnt have full vtec like the A2 but it does have vtec. So I was thinking it would set off vtec on the A2 at a lower rpm. Thats all.

[CaTiRo]

is vtec on the a2 like vtec on the b-series?

[smilla0]

the 2200rpm kick in will not change lobes on the A2. The A3 has no higher profile lobes and nothing will cause the switchover to ever occour. the A2 would run sans VTEC with an A3 ecu - remember that...

Your confusing VTC with VTEC... We don't have VTEC/secondary lobes... they'd NEVER engage on the A2 head

Eric

We do have a real VTEC, but only on one of our intake valves. The one valve has a super low lift lobe that it follows below 2200 rpm, and above 2200 rpm, it latches onto the other lift which is following a higher rpm lobe using a VTEC engagement. The other intake valve is always following the higher rpm lobe. It doesn't have a low rpm lobe. Neither do the exhaust valves. It's basically 1/4 VTEC. The A2 just extends this so that all four valves can switch lobes. The effect is the same as full VTEC (to increase the "Reynolds number" of the flow at low RPM) just less dramatic.

Not 100% sure about this, but I believe both VTEC systems are activated by a single hydraulic line, so if the VTEC pin from the A3 ECU is hooked up to the VTEC pin on the A2 harness, it should engage it just as it would on an A3 engine. Someone correct me if I'm wrong.

[esmith13]

So basically what your telling me is we DO really have VTEC just like a TV on sale for "under" $500 cost $499.99...

.... Great...

Eric

[smilla0]

Yeah, but hey, at least we have VTEC on that one valve. If we didn't then it'd just be a Toyota :P

[esmith13]

oooo, don't say it THAT way!!!! :eww:

Eric

[VIZHUNZ02SI]

let me get this straight
u can run an a2 off an a3 ecu vice versa
but u cant run an a2 head with an a3 ecu
i dont get that

[esmith13]

no, you can temporarily run an A2 or an A2 head on an A3 ecu. It's MORE dangerous if it's an entire A2 motor than just the head because there is higher compression in an A2 motor. In both cases it is said you HAVE to stay under 4000rpm to protect the car from being in a "very bad place" if you know what I mean... That's how all the DIY swaps are done. you need to drive the car to the acura dealer to get the A2 ECU flashed to the Si's Key and immobilizer...

Eric

[Gasp23]

So what is it? What do yo have man!?!?!?! Lol, everyone is discussing about the possibilities but we don't know what you are running.

[esmith13]

He's runnin an a3 and we all know it... we're just having fun with the "what if" stuff....

Eric

[VIZHUNZ02SI]

so if i come accross and a2 head
how much woulld that cost to get them to flash my key ecu and immobilizer
but wouldnt its be easier if you got a ctr head wouldnt that work with the a3 ecu

[Graywolf]

why would you go through the work to swap the head without the ECU, it would not benefit you at all. It would run, but you'd be better off porting and polishing your a3 head.