Dual Point Fuel Injection to Multi Point Fuel Injection
 

I am a Honda Driver. Some of the Honda made in the late 80s/early 90s ran on Dual Point Fuel Injection (DPFI). The later ones all ran on Multi Point Fuel Injection (MPFI). The difference is simple. On DPFI there are two fuel injectors for the four cylinders. On MPFI there are four injectors for the four cylinders.

The cars that came with MPFI were the SI models and the HF models. The DX models call came with DPFI.

I began asking people a few months ago about the potential benefits of upgrading my DPFI engine to MPFI. The upgrade only costs about $100 if you pull the parts from the junkyard yourself. Many people said that the benefits would benefit fuel economy, and others said it would hurt it.

Those who said it would help said it is because the ECU (car's computer) will be able to control just the right amount of gas for each cylinder, thus not wasting gas. Others said it would hurt fuel economy because the extra horsepower gains caused by this upgrade. With conflicting answers, i feel it appropriate to find out ourselves.

I propose that we measure the benefits of switching a DPFI car to MPFI.

This study requires 5 volunteers. Those volunteers must read guidelines for conducting a proper experiment explained on this website. This can be found here: https://www.gassavers.org/node/3

Reply to this thread if you are interested in participating in this experiment. This is also where you will post your final results.

Matt

mpg vs. speed - metro graph
 

Also, I think it should be noted that it will be important to differentiate those switching from DPFI to MPFI found on Si models and MPFI found on the HF, VX, CX, and other economy-centric models.

BMW C.L.E.V.E.R. Concept
 

Very good point. I may have to add a second variable to the mix, or even a third. I might have to add ECU and Intake type as a variable.

Since most people are upgrading for power, I imagine most people will be upgrading to the SI intake and pm6 ECU. Either way, volunteers should note which intake and ECU combo they are planning on using.

New forum guidelines, FAQ
 

hey. got an 89 civic hatch dx. d15b, 4 speed tranny, cai, dpfi

have all the parts to swap to mpfi just havent done it yet. waiting on some help as i am wiring inept due to being color blind.

anyway, interested in being a test subject. what do you need from me?

until the gaslog is back and running...
 

Very cool. Just read the testing proceedures listed at the top of this forum (www.gassavers.org/node/3). When you have your five locations all recorded, swap to MPFI and then do the same five trips again. Remember to fill up at the beginning and end of each trip to get an accurate idea of gas mileage.

Thanks for volunteering. We all look forward to seeing the results.

I hate to admit it but....
 

Diemaster has done this
 

Diemaster has completed the swap and has noticed an increase in fuel economy.

Diemaster, will you please post your results after doing the MPFI swap?

Quote:Diemaster has
 

I saw about this, it was crazy the increase was.

i was getting ~19-21 MPG w/
 

i was getting ~19-21 MPG w/ DPFI but now with MPFI first tank was 38.4 mpg. now that i'm ajusted and "tuned" it's getting 30-32 MPG i'm young so i like to floor it :P but if i fether foot it i can get 38 again :D

Re: i was getting ~19-21 MPG w/
 

That is absolutely amazing. I'm wondering how much of an improvement I would see on my engine. I was getting 38mpg with DPFI before. Now I get around 32mpg after my head gasket fiasco.

It seriously makes me wonder if I'm going through too much trouble by swapping in a more efficient engine. Perhaps I could have seen the exact same mileage had I just switched to MPFI.