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Discussion Starter #1
Hello. I've done a bit of research and understood quite a bit about how to tune this engine. I do have a few question that i need to ask regarding tuning with p72 ecu. Assuming everything is wired properly and iab is controlling 1st solenoid. How is the first stage(0 to 3000rpm) tuned? Like below 3000rpm the car is running on 12v, so does this mean i am looking at the area below 3000rpm on the low cam?? Another question is whether this engine can be run on 16v all the time? That would mean the first stage is eliminated and then could the p28 be used to tune like a regular vtec? Looking forward to any help, thanks.
 

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Yes, the first stage would be the low rpm area on the low cam map. You can use anything that can supply 12v to the solenoid to operate either vtec stage. An RPM switch or any output with neptune/crome that can operate a relay at a specific RPM could be used with a p28.
 

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Discussion Starter #3
Thanks for the response. Is it also possible to eliminate the first stage completely and run 16valve throughout? And then tune like a regular vtec engine?
 

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Another question is whether this engine can be run on 16v all the time? That would mean the first stage is eliminated and then could the p28 be used to tune like a regular vtec?
If you want this, get a Y8 yeah instead. I would not suggest you try this at lower RPMs since the activation of the vtec(any vtec solenoid) essentially opens up a rather large(with respect bearing passages) oil passageway that will starve the rest of the engine of much needed lub. Aside from that, it requires more pressure from the oiling system than the oil pump can provide at those lower RPMs.
 

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Discussion Starter #5
Ok thanks for the info. So running on 16v all time is a bad idea. So using iabs for the 1st stage using the p72 ecu seems pretty simple enough from what i've researched. I'll do a little more research on the rpm switch idea, but this might involve more electrical knowledge which currently i do not have. Anyways, thanks for the help.
 

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Yep, just get a z6 or y8 head if you want single stage vtec.

That being said I drove a B16 for quite a while around 2001 with just a toggle switch for vtec, my RPM switch had become unreliable and this was before the makers of turboedit had figured out how to activate the vtec with the auto solenoid.

When I was planning to do any racing or performance driving I would flip on the switch and leave it there, it wouldnt go into vtec at idle, but if you touched the gas and brought it up to 1200-1500RPMs it would drop into vtec and stay there 100% of the time, even when idling. The stock b16 cams were so mild it barrly had more than a mild lope at idle.

So it is possible, but its not a good idea.
 

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Exactly. And another thing to note is that while tunning, the low end can make the upper RPM richer.

So running in 12v at maybe 5-6 load cell and below keep it near 14.7. But the 3stage, especially in the low load cells can handle 16+(It's either 16 Or 18 where the NOx's are at the same level as stoich and better). You do have to figure out timing going higher though. And freeway crusing you can still be in 12v mode even in an SI trans.

Looks like you are approaching this correctly. I also remember finding a PDF going a bit more in depth if you want to really dial in the lean-burn attribute.

I used a N02 output in S300, because it had RPM, load, and TPS calculations included.
 

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Discussion Starter #8
Thanks for the help guys. I've seen the iab kit for the p28. Does anyone know how to add iabs to a jdm square case ecu, for example the p08 ecu? And is the d15 3stage vtec head similar to a y8 head? I'm asking so i know which basemap to start with. Thanks for the help.
 
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