excalibur 330 to 383 stroker I build

[Yoshihiro]

Hey guys.

I builded ex330 to 383 stroker.


I used eagle rotating assembly kit and neutral balance flywheel.

Also, I use stock MEFI injection system and any other component.
However, I needed to rewrite the MEFI file.
It needs exclusive softwere.

It has power more powerful than ZR450 and ZR409.
It has around 450hp to 500hp.

[cazman]

Great. How do you know what horsepower gains you achieved?

That increase sounds like too much without a large cam. Why do you think the MEFI file needs to be rewritten?

[Yoshihiro]

It has same as automobile custom 383 engine.
they have around 450-500hp with same specs.
Also, this engine has larger cam　and aluminum heads.

I have drived ZR450 and owned ZR409.
This engine have more power than them.

Stock MEFI has calibration file for 350 engine.
Also, ZR409's MEFI has calibration file which is different in 350.
Stock MEFI is not optimized for 383 and larger cam.

So, I need to be rewrite it for optimize and safety.
I can acquire more power by optimizing MEFI.

The 383 engine may run by stock MEFI.
But, I believe it gives a damage to engine and cannot get a maximum horsepower.

[cazman]

Looks nice. What do you think can be acheived with only the stroke kit? Same cam and same MEFI code.

Also, don't you think the large cam has too much overlap for a marine application?

[Ryan1776]

What are the cam specs and compression?

[Yoshihiro]

No.
This project needs to rewrite MEFI calibration.
Only stroker kit without recalibration is Lean burn.
So, I think pistons will melt.

Also, I builded 4"bore and 3.75" stroke (377ci) with normal cam and vortec heads.
It installed to ski nautique from ZR409. 377 also needs rewrite MEFI.

It has awesome idle and big power than ZR409.
larger cam is rough idle.
I think normal cam and normal vortec heads are better for marine application.

But if you need to rebuild 350, I recommend stroker 383 or 377.
And you must rewrite MEFI or change to carb.


I have MEFI BURN softwere and 377 and 383 calibration files and unlock password.
However, MEFIBURN.com will help your rewrite MEFI.

[Yoshihiro]

cam is 242/248 degrees of duration at 0.050, 0.540/0.562-inch lift with 1.5:1 roller rockers, and 110 degrees of lobe sep.
compression is 10.5:1.

[aZ`]

excalibur 330 to 383 stroker I build

That's a big stick for a towboat! Interested to see how it goes. Question. Do these things run a hyd roller standard?


Sent from my iPhone using Tapatalk

[Ryan1776]

AZ- LOL NO SH_T! I was thinking the same thing! With no converter to get into the powerband, I hope its not too doggy down low. At least the lobe sep isn't too bad.
Gonna wanna use a 9" prop to build RPM!! lol

[Yoshihiro]

Yes.
I used standard hyd roller lifter.

[Yoshihiro]

I think it has a little higher powerband.
However, it has a lot of torque than ex330.
So, I don't feel it.

[aZ`]

So the ecu has already been remapped? Sorry I thought it still had to be done.
What boat is this in? If in a wakeboat can you get us some video or 0-23mph times with full ballast. If in a ski boat have you re propped and what mph will it do?


Sent from my iPhone using Tapatalk

[TRBenj]

excalibur 330 to 383 stroker I build

Cam doesn't look too aggressive for 383ci to me. We do have a high stall TC... It's called prop slip! Got WOT from idle sometime and watch the tach, lol.

I think most here would be interested in hearing how you modified the ecu... Did you unlock it and modify the fuel tables or did you have them start from scratch? Are marine 377/383 tables available or did you use automotive?

[Yoshihiro]

Yes, I already remapped.

this is 330 fuel map in 1200-3600 range.


this is 383 fuel map in 1200-3600 range.

377ci into 2002 ski nautique.
383ci into 1994 sport nautique with over 3000 lbs ballast.
Also, my friend will make 383ci and install to 2003 SANTE in this summer.

I can take video in this week end or next weekend if it's sunny.
ski nautique have ACME prop.
I check the size of prop in this week end.

[Yoshihiro]

I modified original ecm.
I unlocked it and write modified fuel and spark tables.

I got 383 and 377 map and softwere from mefiburn.com
They can rewrite ecm and send back if you send it to them.
If you bought mefiburn program, you can rewrite it by yourself.