3.1 block compatibility??

[Intimidator1]

Hello, My 2001 vmax 3.1 225 efi bit the dust. It has 66x pistons in it. I can get a great deal on a rebuilt 3.1 block with 69l pistons (think its a 250 ) . Can i use this block for my motor and use my electronics/ computer ?? Thanks

[CJ1]

That is what hydro Tec built for me and it is still running great 2 years later. Cj

[Rich Z]

I wouldn't recommend using a 250 block with 225 ecu. One low flowing injector will eventually blow that motor. Yes, it may work on some motors but my friend wasn't so lucky. His blew up after 30 min run time.

[CJ1]

I'd love to find a 250 ECU. Any ideas Rich? New was too steep. CJ

[Rich Z]

no, sorry... only one 225

[jrbritt]

cant he send it to simons motorsport and reflash it to a 250???

Simon Motorsports
1940 Joe Crosson Dr. #14
El Cajon CA 92020
760-440-9334

[HaulinBass]

cant he send it to simons motorsport and reflash it to a 250???

Simon Motorsports
1940 Joe Crosson Dr. #14
El Cajon CA 92020
760-440-9334

Not an efi. Hpdi and 4 stroke ecu are the only technology that has been developed for reflash.

[Rich Z]

The only way I know to make a 200 or a 225 ecu work safely on a 250 is to use an adjustable fuel pressure regulator. By increasing fuel pressure from 36 to 38psi you just added 2% more fuel delivery. Also, an existing 36psi fuel pressure regulator can be modified to increase fuel pressure. We use a guage to test regulators for high performance applications. A regulator is noting more but a spring and a diagram design to by-pass exess fuel pressure. By increasing the preload on the spring you can increase the fuel pressure. Roughly, for every 1 psi of fuel pressure increase equals to 1% more of fuel delivery to injectors.

[onttr22]

I ran a 200, 225 and 250 ECU on my phase 3 250. All will work but as Rich points out a regulator is recommended.

I noticed a difference with all three. The 250 ECU you could hear the difference I think they affect timing as well.

[DLAB]

I ran a 200, 225 and 250 ECU on my phase 3 250. All will work but as Rich points out a regulator is recommended.

I noticed a difference with all three. The 250 ECU you could hear the difference I think they affect timing as well.

The only problem Yall are missing in this thread is that I believe the Porting is different from the 225 to the 250. From my understanding.....

[onttr22]

Yes the porting is different.

[Rich Z]

Funny how a simple question by OP got all twisted. The 250 block does have higher porting and perhaps needs a little more timing. It also has 1.75 gears as opposed to 1.82 on 200 and 225. A 225 ecu can be used on a 250 block however, injectors should be validated and fuel pressure increased for safe operation. The motor still won't be as strong as a true 250hp motor. IMO, it's just not worth it!

[CJ1]

Yes the porting is different.

You still looking for 3.1l heads? I have a good set of 250 heads I'd swap for a 250 ECU and $$$ on my part. PM me so I don't mess up the OP thread any more than what I have! CJ

[Intimidator1]

So all i have to do is get a 250 efi cdi and I should be good?? Rich, you cleaned my injectors for me less than a year ago, Thanks. All other parts look the same from a 225 to 250, just a cdi differance. What is the differance between the 2 cdis?

[ClarkBird]

Bringing this thread back from the dead.... there may be someone out there who benefits from the information below.

I just did this swap - 250 powerhead on top of an original 225. As Rich mentioned a difference in timing, the requirements of the 250 are 20° total advance vs 18° total advance on the 225. I have spent hrs scanning the various data for different motors in the OX66 line. The only motor besides the 250 that calls for 20° is the V200TR. However, it's tough to ascertain specific models because they are all over the place when you start including the saltwater motors. The 69L cdi sure is tough too come by. I'm an internet super-ninja when it comes to finding things and thus far, there are just none out there second-hand. Even tried to order a new one through various suppliers and at the present moment, there are 3 in Japan with no way to find out if they will actually make it to the States. I did, however, place and order through MegaZip so we'll see if they come through.

Regarding fuel pressure - both motors, in my case, run the same fuel pressure regulator (66k-13906-00-00) even though the 225 calls for 35.6psi vs 38psi on the 250. Checking pressure on my motor - I get 38psi so I'm calling that good.

One thing that is different is the oil pump. The 250 (69L-13200-02-00) does produce more volume (53.5oz/3mins +/- 5.3) than the pump for the 225 (65L-13200-00-00 / 39.6oz/3mins +/- 7.6) so that was the first thing I changed.