2.5 MZR questions

[gtwiss]

Can someone give me a rundown of the 2.5 MZR motor that is used in the P1/P2 category.
How much of the original motor is actually used in its race form?

Best,
Guil

[ace37]

Since you aren’t getting much.

Give the guys a call at Elan Power Products if you want the real deal. Or reach out to one of the people running them. If you do, post up what you learn for future posterity and all.

I called them asking for a general idea on rebuild costs as part of my due diligence before buying an IMSA-spec DP02 for NASA. I was not asking for a quote at all, so take this for what it is. I understood that a typical rebuild might be something on the order of $10k with a fair bit of room for variation depending on what parts are needed and if a person is sticking with the 2.0 of going up to 2.3. They said because the increased displacement lets you move more air, the 2.3 gives a noticeable improvement in power for not a lot more money, but it was more money than the 2.0. They recommend a refresh after about 25 hours.

Thinking if 2.3 is better than 2.0 for not much more, I also asked about the high spec 2.5 variant I had heard about, and they said the 2.5 running in the fast SCCA cars is a whole different animal as far as cost, and the costs can basically go as high as you want. I got the feeling it was easy to spend 2-3x as much on the refresh. Additionally, they said they are usually built with a considerably shorter service life.

That’s not much to go by, but it bumps the thread for you, so perhaps someone else can comment.

[David Ferguson]

The 2.5 isn't legal for P2, only the 2.0L version. In P2, engines have stock internals, but free external components with a specified flat plate intake restrictor. The P2 rules are pretty clear about what is allowed.

[SeBeco]

Can someone give me a rundown of the 2.5 MZR motor that is used in the P1/P2 category.
How much of the original motor is actually used in its race form?

Best,
Guil

As ace37 suggests Elan Power are the guys to talk to regarding Mazda 4cyl engines. They build all our 2.0, 2.5 and 2.3 turbo engines.

[gtwiss]

Although my car has a very good 12a Drummond that was rebuilt by Lee Follansbee, my recent
acquisition of a more modern JFR box has made me consider going to the biggest 4 stroke
motor I am allowed (in the words of a famous racer). The fact that I will have to make major mods
to fit the JFR in my Beasley is a part of the reasoning here. I also have some nice P2 illegal
undertray parts that I could add to the mix, being also P1 legal with a change to the MZR..
This shouild help to explain where I am coming from.
David is correct also in that the rulebook will be explicit as to what we can
do to a motor for P1 or P2. I should have been more specific in what I was looking
for with regard to the MZR in its P1 form like what if any of the variable valve timing
is retained, are any systems deleted(balance), what kind of compression,redline,induction??

Best Regards,
Guil