Raylar Upgrade Package for 525EFI Coming in August
 

For those with out-of-warranty Mercury Racing 525EFI engines, http://www.boats.com/boat-content/20...ge-for-525efi/, this could be worth looking into when Raylar starts offering it in August.

525 to 675 is more than 100hp.....

We did virtually this exact same thing to my 500EFI's a couple years ago. Heads, Cam, monoblade TB, upped compression, 540C.I. Made peak power a little low (630@ 5,200) and almost made too much TQ (700@4,300). Dyno numbers fully dressed at Precision Marine. Could have changed the cam to make more HP (at a higher rpm) and less TQ which the XR's would have liked better!!!


and BTW: For what I spent on the entire project, $15K to re-fresh/re-power a tired 525 isn't a bad deal at all!!!

Yes but then he'll have to get another drive. I don't think even a bumped-up XR will handle that hp/tq.

It's worth noting that with the Raylar upgrade the engine remains naturally aspirated. When I spoke to Ray Brody of Raylar, he took pains to emphasize that he wanted to maintain the reliability and durability of the original 525EFI. Hence his decision to keep the engine naturally aspirated.

Because the Bravo XR is rated at 600 hp, it is technically beyond its limits with 675 hp and it would be prudent to upgrade the drive in this application. I know people will jump in and say they've run Bravo XRs with much bigger power and that their incredible throttling touch and experience have gotten them through without a failure. Power to you if that's the case.

But I've also seen them fail in big-horsepower applications where the driver's involved had incredible throttling touch and experience. Luck is a factor.

As for the price ... that's a tough one. Raylar certainly isn't giving this package away. On the other hand, the company has built a strong reputation with its upgrade work for the 496, and I have no reason to believe they haven't done their homework with the 525 package.

For sure, it's a conservative upgrade. But (again), from what I've been told they were after reliability and durability.

We use the CPE Method = Carefully Planned Engines!
 

Thought I would chime in here and clarify some things:

First, the New HP675efi package Raylar will be offering for the HP525efi Mercury Racing Engine is not a kit or a simple bolt on package upgrade. I have attached a complete description of the upgrade package and it includes the reasoning for holding this package to 675 HP and it does include a full one year warranty on the new upgraded engine.

Second:
The Merc HP525efi produces on average about 540HP so the new Raylar package provides a 135HP increase in horsepower for the engine that will still be operating normally aspirated on 89 octane fuel and will be producing about the same torque levels as the HP600sci engine that are mated to the same XR Bravo drives as offered from Mercury and as hundreds are operating in the boats now without any large failure numbers or issues.
Raylar could have turned up the horsepower level on this package beyond 675hp but we felt it was important to respect the horsepower and torque level capacity of the Bravo XR drives and we wanted to use a milder camshaft profile that would not approach the edge of reversion issues.

Third:
For those who think you can take a stock or even reworked HP525efi Mercury Racing engine and turn up the horsepower to 675HP with just some overbore, head work and camshaft and no replacement of the HP525 intake manifold, you got a learning lesson coming as the intake is the big problem and limiter. Raylar solved this intake manifold limitation with a complete new intake manifold plenum, which fits right in the stock location and height and keeps the clean look of the HP525efi.

Some seem to think you should supercharge the HP525efi up to a 775HP level. I know its very doable and a few have already tried that with some early success. My argument would be if it was that easy to put 775HP to a Bravo XR drive , why did Mercury develop and offer only the NXT drive at that power level. Yes you can change the drives to NXT's, IMCO's, Indy, etc, but you better get your wallet open and let about a minimum of another $20K to $40K per drive come pouring out for that necessary upgrade!

Look, there are no cheap easy fixes for an HP525efi that offer a 125-135HP power increases to this engine package that will be reliable and sustain the usability of the Bravo XR drives as equipped. The Raylar package is not purported to be cheap, but it is easy, just ship us your stock HP525efi and will ship you back a beautiful, well engineered and operating engine with a one year warranty and 675HP in a turnkey, reliable 89 pump gas engine that will make a huge improvement in the performance levels on your performance boat!

Thanks for your Ear, hope you are reading and expanding your knowledge of what makes engine upgrades tick!

Best Regards,
Ray @ Raylar

Give me a whipple and a tired 525 and I can give you back a bunch of metal.

Freshen a 525 to handle a whipple with 850hp.....let's see....hmmm that plus the whipple for 15 grand? I don't see it. Not even close.

I think that 15k is cheap to freshen a 525 and up the ante like that.

Ray...if you look above at my post I mention doing nearly the same thing with 500EFI's......Mark at Precision said the exact same thing you just did, even with the plenum mods we made I was still holding the engine back due to lack of air-flow.

Is it safe to assume this same kit could be used on 500EFI's? Seems everything your replacing would fit that motor as well...except for the head work being done.

Also, is it a 540 or 555 C.I., the PDF file says 555? What is the compression ratio? Mine was raised to 9.75 and 89 is a little low, 92/93 is prefered.

you are out of your league...