Any difference between the two? Advantages/Disadvantages? Let me know, finishing the swap this weekend...just need to know which ECU to go with. Thanx!

 

The stock GS-R P72 OBD1 ECU runs DANGEROUSLY lean when paired with an H22a motor.

You'll need a V-AFC controller and dyno time to make the P72 work safely.

Andrew

 

Doh! Thanx for the info. I guess it's P13 then.

 

it may run lean..
but it also runs alot stronger in the 6500+ rpm

the best would be a combination of p13 for sub 6krpm and mugen spec b18 for 6K+rpm

 

It makes more power there because it is running lean. It hits 15:1 Air/fuel ratio and higher there. You can make more power running lean... But not for very long...

Also, the other thing that I did not even think of is: What H22a do you have? The 97+ with saturated injectors? Or the 92-96 with peak and hold? You can't safely use the GS-R ECU with peak and hold injectors anyway...

Andrew

 

Oh crap, didn't even realize that. It's a 98 H22a4 going into a 95 Prelude Si. Are the two compatible? Or what other differences are there between the two generation engine and chassis?

 

you can run the p72 on the 98 h22a4 tou just have to convert it to obd1,also about the injectors 97+h22's have saturated injector so it is safe to say you can run the injectors with this ecu but it would be wise to chip the computer and add more fuel and different ignition timing,good luck

 

Yep, that's right. And that's probably your best option in this case - Chip a P72 with P13 maps.

In theory, you can use the P13 with the saturated injectors... But I haven't heard of anyone ever having success with it. The people that have tried the P13 on a 97+ car have had all kinds of CEL codes with that setup.

Andrew

 

But this is on a 95 car, or are you referring to the OBD-II engine? It's a 98 H22a4, going into a 95 chassis. See the conflict here?

Can I run the P13 with peak-hold injectors on the H22a4? Or does it only take saturated?

Basically, I'm trying to fit the H22a4 into an OBD-I system...is that possible? Thanx for the help guys...I'm bound to get this car running sooner or later!

 

yeah you can run the peak and hold injectors on that motor,i ran the p13 on my motor for a while with the saturated injectors and the car was leaning out so opted to get the p72,but good luck with it

 

i have a h22a with p72 and hondata stage 2 setup
with a peak and hold injector and its running fine
i have a type-s program on my hondata and **** this
ecu runs better than p13 chips any chip program

 

What is the difference in saturated vs peak and hold?
http://service.gm.com/gmtechlink/Feb.../fi%20test.htm (Great article. MUST READ!)
http://www.twminduction.com/EFI/EFIInjectors.html
http://www.supras.com/~riemer/sonict...rs/RCtech.html

Andrew

 

The chassis is irrelevant to what ECU you use. You can swap the motor into your lawnmower if you want...

The real issue is what fuel injectors you are using and what injector driver you are using with them. The injector driver is built into the ECU. Most Hondas of the OBD era use saturated injectors. Honda B-series motors (like the GS-R) have saturated injectors. One of the exceptions is the 92-96 Prelude, which has peak and hold injectors (h22a and h23 at least - I don't know about the f22).

Some ECUs with Peak and hold injector drivers are capable of driving saurated injectors as well. As Rudy 94Si found out, this works to an extent but sometimes not very well. What can happen in the "peak and hold driver with saturated injectors" scenario is that the saturated injector may only stay open for a fraction of the injector pulse width. It opens on the "peak" signal, but the closes early during the "hold" transition when the ECU thinks the injector is still open. This can cause unpredictable fuel delivery - running lean is usually the symptom.

In general, the injector driver should match the injector. The general consensus is that a saturated injector driver should never be used to drive peak and hold injectors. (Although many Honda people try and and apparently get it to work OK... for at least a while) Then you have standalone EMS packages like Electromotive TEC-II/III , FJO 341B, and Haltech E6x series which can be configured to drive either injector type because they were designed to be able to drive both types.

Andrew

 

So you're saying if I stick with an OBD-I ECU, I should run 93-95 H22 injectors?

 

That'd be the easiest way! -And the F22 uses the peak and hold injectors as well. The resistor box is the same part number for all 92-95 ludes.


[Modified by kevie88, 4:31 PM 4/16/2002]