TheSamba.com :: View topic

Fri Dec 24, 2010 4:02 pm

jyl wrote: BillM wrote: The new Turbo page on the website looks great Jim.I wonder who that really lucky guy getting the install in January is :D

Bill
87 Westy
Zetec

Well, I hope he remembers to post plenty of pictures . . .

I....I mean he will.....so excited.

Fri Dec 24, 2010 4:11 pm

dredward wrote: . laughable in my humble vw engine loveing opinion.

Dude, You need to look up the definition of humble.

Fri Dec 24, 2010 9:55 pm

BlackDogVan wrote: @ the Bostig crew - give your CAD guy (or girl!) a raise. Very nice.

:D Thanks, that made my night! No raise needed, but I do love compliments though!! :D

-Nate (the cad guy)

Sat Dec 25, 2010 12:03 am

Not only is Nate very talented, he is also funny as heck and quite handsome in his own special way...

Okay, it was mostly a compliment...

Merry Christmas Nate.
JB

Sat Dec 25, 2010 7:19 am

One interesting fact about Nate....
He does not come from a vanagon background!

I think we've got him hooked based on the quality of work he's putting in!
Very impressive stuff Nate!

-Craig

Sat Dec 25, 2010 7:42 am

:shock:

Merry Christmas to you as well J.

and yes Craig I catch my self wanting to hit the open road in a vanagon all the time!... though I could just need a vacation :-D

Maybe if I catch my breath at the shop before my wedding in march I'll have time for a honeymoon! (if not the fiance might kill me :lol: )

*wanders back to reading, listening, learning, and definitely laughing*

Sat Dec 25, 2010 9:54 am

here is a question about the new bostig turbo system:

with the usual tuning what kind of mpg increase can be expected, if any, over the stock 2010 bostig?

has anyone tried to tune it for maximum mpg instead of power? what would be the possible max mpg on a 2wd westy?

Sat Dec 25, 2010 3:47 pm

Pretty sure you're not going to see a MPG increase. If the system is set up right you should only see a slight MPG decrease IF you keep your foot out of it, but then what's the point?

Pretty rare for power adders to give you a boost in mpg on a gas engine.

Sat Dec 25, 2010 7:29 pm

Should be more efficient than a non turbo gas engine of similar output tho.

Sun Dec 26, 2010 4:07 pm

veggieryan wrote: here is a question about the new bostig turbo system:

with the usual tuning what kind of mpg increase can be expected, if any, over the stock 2010 bostig?

has anyone tried to tune it for maximum mpg instead of power? what would be the possible max mpg on a 2wd westy?

Power corrupts, and it does so when you have more under foot as well.

Here's basically what we're dealing with:

Brake Specific Fuel Consumption(BSFC) is the mass of fuel used per horsepower per time and how fuel efficiency is most commonly expressed. Turbos can lower BSFC of an engine in various ranges(making for better efficiency), but they may also increase it, this will depend on the tuning of the setup. Like most turbo setups we increase BSFC in some ranges(cruise), but lower it in others(WOT). This is intentional and done for safety reasons. Using rich mixtures to ward off knock is virtually universal in turbo applications, and we are no different. So power levels demanded, AND how/when they are demanded have effect on fuel consumption.

Scenarios:

I) Worst case fuel economy:
If you drove around all day "digitally" and only ever had WOT or brake, you would dramatically lower your mpgs, just as you would without a turbo and because of the style of driving, but with the turbo they would be even worse because the Brake Mean Effective Pressure (BMEP, average pressure exerted on the piston top, basically the capacity of the engine to do work) of the turbo engine is higher than the NA engine AND the BSFC of the turbo would be worse in those conditions due to the range of operation and an almost constant rich operating condition. Not only are you actually able to demand more power, you're using more fuel per HP to do it... worst case scenario. MPGs in toilet.

II) Best case fuel economy:
Fixing engine load in the zone for lowest BSFC and usable BMEP, without pushing into danger zones. Of course running an engine in a vanagon at a constant load range isn't going to happen, but cruise is where this is closest. If you were to drive at the same or lower speeds as the NA vanagon, you may see a gain here over NA zetec. Perhaps 5-8% better than NA... but that means not entering into zones where BMEP or BSFC is higher than the NA, which is unlikely as you'll see below.

III) Average tested:
When we drive, we been observing about an 8% loss overall in MPGs vs NA. However this is because the power output is higher, we cruise at higher speeds, and we accelerate much faster every time we accelerate. I would not be surprised to see the MPGs increase for a given driver over time as the new power novelty wears off and power demands from the driver become more conservative. We have seen this for the NA conversions themselves. But unless you are specifically driving for MPGs, I don't think we'll see a big improvement.

What I would like to see is no losses while delivering more power. In going from boxer to zetec, we see an increase in power delivery and an increase in mpgs. The decrease in BSFC is enough across the board and at higher power levels to allow both. I would not expect to see this going from zetec to zetec turbo however. What one can expect though is WBxer mpgs averages with zetec turbo power potential, which is a pretty neat trick on it's own. We'll have more figures as we log more and more miles. While it's theoretically possible to get even higher mpgs with the turbo, we are limited by safety in operation(top priority), but mostly by the drivers foot.. which despite all claims of "I always intentionally drive for best mpgs" always degenerates into use of the power under foot, since power corrupts. The first customer to tell me they were looking forward to seeing how high they could get their mpgs because they always drove responsibly was also the first customer to get a speeding ticket in a zetec for doing 90. He was our very first conversion customer, and this trend has not changed since then.

Also gregor, I sent you a pmail/log request/couple things to check for your lack of power and "bostig hater.... smooth as a trainwreck" sig. You should be at ej22 power levels, and it should be smooth. If you have an issue just contact us, we will resolve it. We will still help you even if you hate us.

Jim Akiba

Sun Dec 26, 2010 6:40 pm

Interesting.

Would it be far-fetched to assume that the optimal gear ratios for the turbo Zetec will be different than for NA ?

JMR

Sun Dec 26, 2010 9:23 pm

jmranger wrote: Interesting.

Would it be far-fetched to assume that the optimal gear ratios for the turbo Zetec will be different than for NA ?

JMR

Having driven Turbo Charged Vanagon's (Gas) for many years I have to say the fuel mileage can vary greatly from pretty darn decent to really crappy. ... Overall we do see an increase in fuel mileage over the stock Boxer engine BUT with almost twice the power too. So the way we see it, it's a win win for both. Great power when you need it and decent fuel mileage when at cruise speed.

The newness will wear off and you'll get better than 8% decrease from your previous mileage.
I really enjoy having the smaller 4 cylinder fuel mileage with about 3.6L of grunt power (Doubling the 1.8T) :D The definition of what Fuel Efficient Turbo Charged engine's to me means, the power's there when you need it and SO is the economy.

As for gearing and Turbo Charged Vanagon's (Gas). We have seen a decrease in fuel mileage lowering 4th gear to a .77 . This is due to the Turbo Charger having to increase pressure at lower RPM to keep up with the head wind at freeway speeds thus injecting more fuel. Right now I am trying a .82 forth gear (stock is .85) with great outcome. RPM is slightly lowered but not enough to cause higher boost pressure. Fuel mileage is back up where I want it.
I like to see my RPM's (70 mph) around + - 3700 for best of both worlds.

Sun Dec 26, 2010 9:32 pm

jmranger wrote: Interesting.

Would it be far-fetched to assume that the optimal gear ratios for the turbo Zetec will be different than for NA ?

JMR

Not at all, but we developed the system with the stock gearing as the target. The nice thing one can do will be to move to a larger diameter tire which will lower revs at speed and lower BSFC at cruise, which is the best place to try and increase efficiency. This is much less risky and invasive than gear changes. With the NA this isn't possible, but with the additional torque of the turbo, it becomes possible to do this. A gear change etc in the trans is always possible, but people often fail to consider the cost of gear changes, and the long term cost of having custom gearing. You are far better off being able to use off the shelf and used stock transmissions than having to depend on custom setups. One replacement incident could easily erase any efficiency gains had via custom gearing cost-wise, vs being able to rely on any vanagon trans you may happen to come across. It's the system's total susceptibility and cost reaction to failure that must be considered as well, not just the spot check efficiency of the well functioning system which doesn't account for failure. You can have the most efficient setup in the world, but if it's rare and costs an arm and a leg when it fails, then you aren't much better off unless it never fails or needs work, which is virtually impossible.

Jim Akiba

Mon Dec 27, 2010 10:03 am

jmranger wrote: Interesting.

Would it be far-fetched to assume that the optimal gear ratios for the turbo Zetec will be different than for NA ?

JMR

I don't think its safe to assume anything until the tire diameter is known. Just moving up to a ~27" tire diameter can substantially increase the final drive ratio with the stock 4th.

Somewhere here there's a thread about this topic where someone with 30" tires and a .77 4th and surprise, surprise, wasn't very happy with the results. There was talk about changing the R&P. How's that for efficiency?

Stephans's experiment with a .83 should speak volumes about the topic.

Marc

Mon Dec 27, 2010 10:32 am

Gorge Runner wrote: jmranger wrote: Interesting.

Would it be far-fetched to assume that the optimal gear ratios for the turbo Zetec will be different than for NA ?

JMR

I don't think its safe to assume anything until the tire diameter is known. Just moving up to a ~27" tire diameter can substantially increase the final drive ratio with the stock 4th.

Somewhere here there's a thread about this topic where someone with 30" tires and a .77 4th and surprise, surprise, wasn't very happy with the results. There was talk about changing the R&P. How's that for efficiency?

Stephans's experiment with a .83 should speak volumes about the topic.

I knew I was forgetting something.. :wink: I'm running a 27" tires.

Mon Dec 27, 2010 10:39 am

Thanks all for your feedback.

I asked because
- I feel that a fair amount of engine swappers rebuild their transaxle at the same time
- A PO put a 0.89 4th in mine. For the WBX, it's both a gain and a loss, but if/when I swap, I will re-gear no matter what.

JMR

Mon Dec 27, 2010 10:43 am

I will let the world know in a few days how my tranny gearing is with the Turbo. Its very close to done and so far ..NICE...Even feels like its got more power with just the new injectors (part of the kit) in it. Get to run it with boost shortly. I take data logs at every step and Jim gives me the OK to proceed to the next step if it all looks good. The Bostig boys are very careful to make sure all is well before I take it out and thrash it.
Stay tuned.
Daryl of AA Transaxle

Tue Jan 04, 2011 6:39 pm

@Daryl: How's the turbo install going?

Tue Jan 04, 2011 8:44 pm

Got about 200 miles on my Turbo setup.
Frickin Awsome....I am one happy camper...
The wait was worth it definately. Took a guy for a short test drive today. After he punched it in 2nd, he was hooked and I could see him wondering what to sell to get one for his van.
The kit went together very nicely and relatively easily for me. The rough install documents were surprisingly good. Surprisingly few glitches in the whole procedure considering this is an early kit.
Kit came with the Turbo, intercooler w/2 fans, piping, hardware, heat shields, DashDAQ unit for datalogging, Zeitronix logger, Saab APC, Wideband O2 setup, new injectors and plugs, wiring and install destructions. All I needed was there. It all fit. Its all good quality and nicely done.
I got almost 16 mpg on the first 120 miles with a heavy rt foot and a big grin on my face.
Tranny is still good with stock gearing as the little motor will spin up to 7K wihtout complaint. No problem going up hills or keeping up with the best of them at over 80 mph. I run just shy of 27" tires and its all a good match for my 5300 lb rig.
Jim insists on regular data logs to keep an eye on how she is doing and has been johhny on the spot for the few questions I have had so far.
They are very careful to make it all right and make it last without frying a piston.
Do need to use 92 octane fuel to keep the ping down.
The rest is up to me to maintain it and wait till he OK's the jump to 12 lbs boost after we are both happy with it all.
All in all, I am very pleased and glad I did this conversion.
There are several good engine options out there and I am glad I did this one for sure. Do your research, ask questions and test drive each if you can and take your best shot.
Daryl of AA Transaxle
425-788-4070

Tue Jan 04, 2011 10:15 pm

Any ideas how the turbo setup would be with an Automatic Tranny? I've heard from a few people that the AT gearing and the Bostig setup aren't matched well, and have spoken to one couple that have a Bostig+AT and they weren't happy with the continual gear hunting at highway speeds. Wondering if the Turbo setup tweaks the gearing just enough to make the auto transmission happier.