DBR kit for Mercury 300xs

**TraceF3** · 06-25-2020, 08:05 AM

I'm interested in the components, installation, and performance gains. There isn't much on the website in the way of specifics other than claims of HP gains.

If you have a DBR kit on a 300xs please chime in.

Thanks in advance

**mikesufka** · 06-25-2020, 08:12 AM

My buddy spent $5000 a motor ( X 2 ) on a 30 Motion and barely noticed a difference. I just texted him to get specifics. I know Dale Rayzor did DBR kits on a 28 Skater - he'd be a good guy to talk to.

MDS

**mikesufka** · 06-25-2020, 08:23 AM

OK - he tested back. Was suppose to gain 25 HP / motor. He noticed slightly better mid range and little on top end. Just one opinion - good luck.

MDS

**Turborr** · 06-25-2020, 08:38 AM

Is Dave Bush still flashing ecu's?

**TraceF3** · 06-25-2020, 08:39 AM

Yes

**JPEROG** · 06-25-2020, 09:48 AM

The biggest gain is being able to run a smaller wheel for accel. and being able to over rev it on the top side to maintain your mph. I never noticed anything other then that. The other issue is that XS motors fall off after 6200 and compressors are not happy being turned much harder as either. I did mine mainly to avoid hitting guardian at high speeds and dealing with the shut down process.

Joe

**TraceF3** · 06-25-2020, 09:57 AM

Joe your opinion is always appreciated. I found the DBR kit researching about the water ingestion. My GF was driving recently, I was in the back at ~85 and I could see the water rising up the rear of the cowling. What would you recommend if anything?

**RvrDave** · 06-25-2020, 10:17 AM

I opted for the DBR on my 2015 300xs. I noticed sharper bottom end and midrange power. Plus 2-3mph on the top end number. This may be from being able to over-rev a few hundred more RPM.

To me the only draw back is increased engine noise due to modifications to the front of the engine cowl

**JPEROG** · 06-25-2020, 11:32 AM

Originally Posted by TraceF3

Joe your opinion is always appreciated. I found the DBR kit researching about the water ingestion. My GF was driving recently, I was in the back at ~85 and I could see the water rising up the rear of the cowling. What would you recommend if anything?

A wing to break the air off of the backside of the cowl and eliminate the low pressure area is the best answer "others have it put in place not sure why we don't". You can also divert the water drop on the back of the exhaust plate with a tube "doesn't look good but its effective".

Joe

**TraceF3** · 06-25-2020, 04:18 PM

I had to chew on what you wrote. So it's primarily the exhaust port water being lifted up behind the engine cowl? Between the flush port and pee hole? My L/U is running so high there's a lot of water coming up back there...

**sniper3726** · 06-25-2020, 09:06 PM

I had L1.1 DBR tune on a 22ft similar hull , but with a 1600 lb hull weight , I may... have noticed slight midrange gain , or a least I wanted to feel it . I saw no top end gains .

**sniper3726** · 06-25-2020, 09:10 PM

Originally Posted by RvrDave

I opted for the DBR on my 2015 300xs. I noticed sharper bottom end and midrange power. Plus 2-3mph on the top end number. This may be from being able to over-rev a few hundred more RPM.

To me the only draw back is increased engine noise due to modifications to the front of the engine cowl

Oh yeah , the noise , it gets old after awhile

**JPEROG** · 06-25-2020, 10:07 PM

Its the water from the exhaust that gets pulled up and swirls due to the low pressure area behind the cowl. There is very little water lifted from the cavitation plate and or lower.

Joe

**river rocket** · 06-25-2020, 11:04 PM

Here is what it did on my boat. It was absolutely worth it for me. It turned my 28 Promax into my favorite prop for all around boating. It wasn't a big top end wheel but it would pull so much harder with the DBR. Every prop I tested was around 2-3mph faster.