Cobaltchat.com

Hi All -

I've been following this group for the past year while I research a new cobalt and the expertise has been invaluable, so thank you! I know there are several past threads discussing various engine options for the R5 but some of them are a bit dated (e.g. prior to the gen 5 engines) and I still have a few outstanding questions on the Volvo 350 (5.3L) vs. 380 (6.2L) for a new R5:

In the attached prop chart, it looks like top sped for the 350 is 52 MPH with 3.1 secs to plane. There's 2 entries for the 380 (excluding the forward drive) that seem to have the same props but different performance figures - one says 54 MPH / 3.5 secs to plane and the other says 53 MPH / 2.9 secs to plane. So based on this my questions are:

1) Why are there 2 380 entries and what's the difference?
2) I understand the 380 should give a few MPH more top speed, but should the 380 be slower or faster to plane than the 350 (the data conflicts with the 2 entries)?
3) Besides top speed (which I don't care that much about) and hole shot (question 2), what other performance differences should I expect? Some of the threads seems to suggest the 380 may perform better with a full boat or pulling tubers, etc.?
4) Any thoughts on potential differences in noise levels? I've seen some complaints that the 380 is high pitched, but not sure how that would compare to the 350?

Thanks in advance for the help!

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Hey CN. Welcome to the CobaltChat forum. So glad you found us!

I'll let others chime in on the prop charts and engine specs for the R series.
Would you be able to provide a link for the prop chart? ...or maybe a little more information from it that includes the notes? It might shed some light on the R5 configurations for testing. Could also be a typo on the two 380 numbers. Unfortunately it's not that uncommon in these types of charts.

Any pics of your Cobalt?

Again, welcome aboard mate!

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All good questions.

There are two sets of Volvo data because Volvo performance is so unpredictable they have to offer two choices depending on the mood of the Volvo on any given day. So go Merc. Lol

Seriously, I don’t have the experience with a R5 to answer your questions, but I will offer my opinion. I’m sure the 350 will be plenty sufficient. If I was buying a R5 I wouldn’t let a 350 kill the deal. If I was ordering I would 100% go 380 or any 430 if the budget allowed.

If top speed isn't a concern, I think you would be fine with the 350, but depending on how you use the boat. If you are regularly pulling an adult wakeboarder with a full load of passengers, I'd opt for the 380 for the added low end torque (you are pulling a wakeboarder at 18 - 23 mph typically).

I'm not sure about the noise difference between the 350 and 380, but I thought our 350 was noisy until I spent several weekends surfing behind a Centurion surf boat with an inboard and got back onto my boat, which by comparison seemed almost whisper quiet. I haven't read many complaints about the 380/430.

Good luck!

Wow CobaltNewbie, I like the way you operate. You came to the table prepared. I have an R5 with Volvo 350, and I'm totally satisfied with its performance. I pull a huge tube with too many teenagers, and the R5 performs well. I really don't care about top-end because my wife screams at me when I go too fast .... I tend to follow the "Happy Wife. Happy Life" mantra. But ... don't tell my wife, I have hit the top end reported on the speed chart, well - at least my Garmim told me so. It really comes down to how you're going to use the boat, and what your expectations are. If you're wanting be out of the hole 0.40 seconds more quickly than the 350 can deliver ... the 380 is the answer. The hard part is over - you've chosen a Cobalt R5 ... picking the power unit is the easy. Have fun with the process ... you're spending a lot of money. Get what's important to you. At the end of the day, an extra $10-$15k isn't really going to matter in 5 - 10 years.

Dealer I bought my cobalt from stocks all their r5’s with the 380. I have the 380 in my r7 and I wouldn’t want any less. I’m on a large lake so cruising speed is a big deal to me. If I were buying an r5 it would have at least the 380. Planing speed is a blink difference. Get the 380

If it was me making this thread it would be 380 or 430

I blame Tuscany on the noise argument. He had over sensitive ears
Maybe because he doesn't have a 380 and he's actually is heading the roar of the beast 430!!
So I was on tgrace98 boat and honestly that 380 purred! I really was surprised how quiet it was. I think my boat engine is much louder. If you really don't want to hear a whine get captains call!
I love the sounds of a engine so let's hear them!

BLUE MOTOR!!

dustinm wrote: Thu Oct 15, 2020 7:53 pmBLUE MOTOR!!

I can confirm the Volvo Prop Charts are spot on.
@ 5850 RPM - GPS Speed = 52.7 mph
5.3L V8-350-CE
It was choppy this morning; I apologize for the blur.
The depth reading isn’t correct, but I’ll save that for a different (old) thread.
My buddy has the 380 in his R7 Surf; there’s no discernible difference in the noise level between the 350 & 380 to me.

Luv2HuntAR wrote: Sun Oct 18, 2020 11:31 pm I can confirm the Volvo Prop Charts are spot on.
@ 5850 RPM - GPS Speed = 52.7 mph
5.3L V8-350-CE
It was choppy this morning; I apologize for the blur.
The depth reading isn’t correct, but I’ll save that for a different (old) thread.
My buddy has the 380 in his R7 Surf; there’s no discernible difference in the noise level between the 350 & 380 to me.

That is pretty good. My R3 with 1/2 tank of gas and a very dirty hull at the end of 3 months of wet slip hit 50 mph with the same engine. till think 'd opt for a 380 in that boat.

Thank you all for the very helpful advice on this. Now just need to find the right boat.

CobaltNewbie wrote: Thu Oct 22, 2020 7:37 pm Thank you all for the very helpful advice on this. Now just need to find the right boat.

https://omaha.craigslist.org/bod/d/vall ... 47467.html

https://www.clearlakeboats.com/default. ... linventory

If we didnt have a down payment on a new boat at another dealer this would be mine

Big Block Power wrote: Thu Oct 15, 2020 8:14 pm

dustinm wrote: Thu Oct 15, 2020 7:53 pmBLUE MOTOR!!

Someone posted on the Cobalt FB page their R5 with a blue motor. Wonder what top end is on that thing?