TheSamba.com :: View topic - Bostig vs. subaru: which one is quieter or smoother?

Thu Oct 17, 2013 9:37 pm

Another "vs" type question, I hope it is novel enough to not annoy people here.

I've ridden in two bostig converted vans, and found them both to be a bit louder or buzzier than my stock 2.1 van. I have not ridden in a subaru converted van. I am wondering if anyone can comment from experience about which of these two conversions tends to provide a quieter or smoother ride?

Thanks.

Thu Oct 17, 2013 9:39 pm

Please not again. This is why mods need to be able to stop threads before they start.
Why not post this question in one of the many existing 'which conversion is better' threads?

Thu Oct 17, 2013 9:48 pm

noganav wrote: Please not again. This is why mods need to be able to stop threads before they start.
Why not post the question in one of the many existing which conversion is better threads?

Because, having read all those threads, this question is not addressed, and it is a very specific question. I am not looking for opinions on any other aspects of the conversion which are usually discussed (power, mpg, ease of I stall, etc.)

What's the big problem?

Thu Oct 17, 2013 9:52 pm

None of these 'vs' threads ever reach a definite conclusion because it is a matter of taste. Even so, there are many threads already on the Bostig vs Subaru topic. With every new topic, finding information gets more difficult.

Thu Oct 17, 2013 10:15 pm

here we go again, moderators get ready

Thu Oct 17, 2013 10:33 pm

seems like you may already know the answer

I've driven both conversions with an auto trans.
The bostig didn't have the shift governor mod and the Suby did.
Even though the Suby was allowed a higher rpm, it was still noticeably quieter.
But the Suby van also had sound deadening, not sure if the bostig did...

Anyways, I agree with the above comments. This question should be placed in an existing thread.

Thu Oct 17, 2013 10:40 pm

This is a legitimate question and IMO it is deserving of its own thread. If smoothness and noise level were commonly talked about on these "vs." threads, then this would be redundant. But these two aspects of the conversions are not what is usually compared and they are worthy of discussion.

Now on to the OP's question. I have never ridden in or driven a Bostig, but I own a Subaru 2.5 and a Wasserboxer van. To my ear, there is no doubt the WBX is quieter. In fact, it's hard to beat the WBX for interior sound level. The first EJ25 conversion I did used the stock VW 4 speed with stock gearing and I always felt like it was pretty loud on the highway. With my EJ25 running the Subaru 5 speed - and turning much lower rpms on the freeway, I'm completely happy with the noise level.

I am curious to hear how the Bostig compares.

David

Thu Oct 17, 2013 10:59 pm

Why are people so against discussion?

If you're not interested in reading a thread, then don't. Move on to one that you are.

I've read countless engine conversion discussions, and think the question here is an interesting one.

Thu Oct 17, 2013 11:05 pm

Much of it really depends on the quality of the installation: attention to detail, header and muffler choice, etc.

Quietness depends more on the mechanic than the designer. Vibration's a different story.

The inline four cylinder engine has a built-in imbalance with the rocking couple created by having the two inner pistons/rods/crank throws travelling opposite from the two outer assemblies. This creates a vibration around 3200 RPM that's impossible to tame, even with balance shafts.

Boxer engines are inherently better balanced and are smoother - almost vibration-free.

I chose the Subaru boxer for the smoothness and the wider torque band - the 2.5 Subaru engine has a lot more power down low and suits the T3 platform better. So I spend more time under 3000 RPM than I'd be able to with an inline four. YMMV

Fri Oct 18, 2013 12:18 am

Hard to get a definitive answer. I believe that Bostig only has one type of exhaust system available, of course it would be easy to swap to a different type of muffler, but the header would be harder.

There are at least 3 types of headers available for the subaru 4cyl. Small car, Rocky mountain westy and Vanaru and they all sound slightly different plus they can all have different types of mufflers bolted to them.

I wouldn't base your decision on this, Subarus can be very quiet with a quiet muffler and I'm sure the Bostig can as well.

Fri Oct 18, 2013 4:21 am

A significant amount of noise can come from the intake system with a Subaru conversion. A stock WV set up includes an air box/filter and snorkel. When I first installed my 2.5L I had the Subaru air box in the rear pillar area but no snorkel. It was very loud under acceleration. I swapped the stock muffler back on from the Small Car one I had installed. It took some of the edge off of the sound but it was still loud. Once I hooked up the stock VW snorkel to the Subaru air box it quieted down considerably. Since I was switching from the right to the left pillar I had to modify the snorkel to make it work.

Fri Oct 18, 2013 5:00 am

my bostig is loud as hell
cant get the muffler to tighten up enough to seal a leak at the clamp

Fri Oct 18, 2013 5:28 am

This is a very difficult comparison, as stated before due to the variables involved.
Heck, one guy just stated how loud his bostig is, but then admitted to it being a personal problem. HOWEVERY, plenty of people will read that as "My bostig is loud as hell." and forget about the rest. And, plenty of people who see that conversion in person or take it for a spin might not know of the personal problem and just think that's the way they are.
Furthermore, for years bostig converters used aftermarket motor mounts only recently discovering that the actual Ford mounts quiet it up and remove vibration in absolutely spectacular ways.
So if they're like the majority of the Bostig's out there, still running the aftermarket mounts, yep..... big room for improvement.

Again, it's impractical to really compare.
I've driven and seen dozens of swaps ranging from some really poorly done subaru swaps where the exhaust was hung to the body (and thus vibrated and was loud), to really incredibly done 1.8t swaps that were shockingly smooth. I for one don't find my bostig install to be any worse than the factory engine (And remember, different people's different factory engines vary a ton!), but I do find it to be different.
The noise and vibrations it produces are at different spots from what people are used to after 20 years of driving the same car, so it's quieter and smoother at different spots as well.

As stated, intake noise can be a big deal as well and often s overlooked. Luckily it's standardized in the bostig swap and syncro owners even retain the stock snorkel setup.

There's no way to compare it.
There just isn't.

Fri Oct 18, 2013 5:30 am

'95 2.2 Subaru here with stock Subaru intake mounted in DS pillar, Kennedy header and walker exhaust for WBX. I can not hear the engine running at idle or on the hwy. I can hear it around town when reflecting off an adjacent wall. when first installed I used to try to restart thinking it was not running.

Vibration is not felt either with Kennedy mount using original Subaru mounts.

I surprises me that anyone thinks the Subaru is louder than a 1.9 WBX.

Fri Oct 18, 2013 5:53 am

Isn't discussing Vanagons what this Forum is all about? So what if the OP brings up a question that might have been answered in the past. Some new insight might be around now that wasn't there in the past.

With that said, I haven't had the opportunity to ride in a Bostig converted van, but the Subaru vans that I've driven have been smooth as silk.

Fri Oct 18, 2013 5:58 am

Jake de Villiers wrote: Much of it really depends on the quality of the installation: attention to detail, header and muffler choice, etc.

Quietness depends more on the mechanic than the designer. Vibration's a different story.

The inline four cylinder engine has a built-in imbalance with the rocking couple created by having the two inner pistons/rods/crank throws travelling opposite from the two outer assemblies. This creates a vibration around 3200 RPM that's impossible to tame, even with balance shafts.

Boxer engines are inherently better balanced and are smoother - almost vibration-free.

I chose the Subaru boxer for the smoothness and the wider torque band - the 2.5 Subaru engine has a lot more power down low and suits the T3 platform better. So I spend more time under 3000 RPM than I'd be able to with an inline four. YMMV

This sums it up just about perfectly. Minor technical clarification...

The 4-cyl vibration is a second order imbalance and it acts in a vertical plane, just like a rocking moment, but there is no rocking. The engine block wants to move vertically as a unit. This is due to the different piston accelerations at the bottom/top of the stroke. i.e. 2 are at the bottom, two at the top, primary masses are in balance, but secondary inertial forces are not.

The 5-cylinders have a true rocking moment, due to a 2.5 order imbalance resulting from the end cylinders moving in opposite directions.

I have not driven a Subaru, but as Jake has said, it should behave like the water boxer, perfectly balanced. I have driven a Bostig, and I found to really make it come alive you had to get the revs up. Lots of fun to drive, but I did find it a little bit buzzy up around 5K to 6K. I would not say that it bothered me at all, just something I did notice. I naturally seem to want to spend my time in the 2K to 4K RPM range.

RonC

Fri Oct 18, 2013 6:09 am

Vango Conversions wrote:
I wouldn't base your decision on this, Subarus can be very quiet with a quiet muffler and I'm sure the Bostig can as well.

Well said! And I like some frigging sound :-) Same goes for my customers.

Fact: If well install you can put a 5 cent on the side on top of the air plenum.
so that close the Subaru idle thing.

Highway: Want the stock engine sound use a stock exhaust and air filter box.

It's funny because you just can't quiet down a Westy at 65mph, the pop top is making wind noise so is the rest of that 25 yo van. I mean I don't get you guys trying to quiet down a westy???? I like it like that and I want a tuner air filter :-) When you press that gas pedal it scream!!!! ha ha ha.

I have heard a Bostig some year ago and I liked the sound also!!!

I mean your NOT driving a BMW or any recent modern quiet car.

Don't you listen to music wile you drive long run???? Me it's full blast.

Here is a automatic Subi van test drive:

here is a Turbo automatic test drive:

Here is a stock 4 speed test drive:

Cheers, Ben

Fri Oct 18, 2013 6:31 am

Yup, that's one of the reasons I went with the Subaru ... The balance and the related smoothness of how it runs. Very similar to the water boxer but with more power. Other then that it's basically how you build it. I have all performance exhaust with a turbo and specifically tied it all up to the engine so there is no vibrations transferred to the body to resonate to the front of the cab. Even with the performance exhaust the van is much quieter then it was before the conversion. Initially my wife and I couldn't even talk to one another we'd have to yell to get any conversation going. Now she wishes she couldn't hear me talking because I'm mostly talking about the van when we are out and about. I do like the deep rumble the van makes when I walk on it though. Mind you I did put a bit of sound deadened in there as well, mostly just under the tank for the time being, but that's gotta help a bit too.
I'm sure bostig can be as quite as you'd like it to be with the right exhaust system.
I suppose this just goes to show you really need to have a well thought out plan together before you start your build.

Cheers,
Mike

Fri Oct 18, 2013 6:57 am

My Bostig is loud
I also don't run a focus airbox and
my muffler is loose due to clamp being non cooperative

Fri Oct 18, 2013 6:59 am

Mike, be honest :-) Your stock engine had an exhaust leak :-)

they all leak.

I do think that a tight 1-9-2.1 are very quiet... under 60 mph :-)