I have a 1990 b16a in my 93 cx. I'm currently running a chipped p28 ecu. The p30 ecu was tuned for a 10:4 compression ratio and my engine has a 10:2 ratio. Just want to know if it's absolutely safe to use the p30 ecu on my engine. The engine has a trusted 5k miles on rebuild which is the cause for my concern. the engine was broke in with the proper obd0 ecu. (whatever that code is) I'm specifically concerned about the different compression ratios. I'm not ready for a tune yet and want the 92-95 p30 ecu for more hp, ft lbs of torque, and higher rev limit as opposed to the proper 1990 obd0 ecu. maybe someone has better/correct info on that. maybe somone with good tuning experience can shed some knowledge???

 

Er. What different compression ratios?

 

If your car is running properly and safely right now, just keep it the way it is until you have the money for a proper tune. You could theoretically run the P30, but why risk washing your cylinders with a tune that's set up A) to run more conservatively, and B) not for your engine?

 

grumblemarc.. as i've read on the internet, the 1990 b16a has a compression ratio of 10:2. the p30 ecu was meant for 10:4. jbpnoman.. so if I tune on the p30, well it be proper or do I need to change something out? maybe it will have more longevity tuning on the proper ecu? Is it the pistons or the rings that change compression?? how can I do this right? what should I do before I tune to keep engine in great shape?

 

I'm having a hard time offering a direction here without the readings from a Wideband O2 sensor - it sounds like you are really trying to make sure you have it right - a wideband sensor is a Very useful tool and will tell the tale no matter what we theorize.

 

10.2:1 to 10.4:1 is not that drastic a change. if you were going a full point or more +/- then you should start worrying.

you're over thinking this.

 

Yes how about run good gas all the time and call it good?

 

should be running premium regardless

 

I always run 91 octane. I'll do some research on a wideband o2 sensor to see if it's my next toy. Just to be clear, what kind of issues (if any) can happen to the engine? what warning signs may occur?. I intend to track this engine in the near future, and keep it as my daily driver as well? thank you for the info so far.

 

I have a car with a 89 b16a running a p30... Have a MTX-L hooked up and it is feeding the ecu with a narrowband signal... it runs fine the ecu has more then enough adjustment threw short and long term fuel trim to run the car at 14.7 your fine as long as you do not have a O2 code...
I also own other cars with S300 and have street tuned them all... you will be perfectly fine... don't worry about it for a milli second...

 

thank you jdmaf. I have two o2 sensor codes due to a bad o2 sensor. I'm told it puts the ecu into a safe mode and dumps extra fuel into engine. I have a ctr intake mani and a fuel pressure regulator set at 36 or 38 psi. what problems can occur? getting new o2 sensor asap. is there any other correction I should make?

 

dude 10.2 to 10.4:1 compression ratios is tiny. not even worth mentioning.

no problems are gonna occure dude. 0.2 difference doesn't even translate into 1whp. 1.