Hello! Log in or Register   |  Help  |  Donate  |  Buy Shirts See all banner ads | Advertise on TheSamba.com  
TheSamba.com
 
My Baja build
Page: Previous  1, 2
Forum Index -> HBB Off-Road Share: Facebook Twitter
Reply to topic
Print View
Quick sort: Show newest posts on top | Show oldest posts on top View previous topic :: View next topic  
Author Message
las912
Samba Member


Joined: April 02, 2014
Posts: 51
Location: Denmark
las912 is offline 

PostPosted: Sun Apr 23, 2023 11:41 am    Post subject: Re: My Baja build Reply with quote

Yeah that looks like a simple yet effective upgrade, thanks for sharing.

And thanks for the compliment on the color, I like it too even though pictures are pretty forgiving Smile
Back to top
View user's profile Send private message Gallery Classifieds Feedback
las912
Samba Member


Joined: April 02, 2014
Posts: 51
Location: Denmark
las912 is offline 

PostPosted: Fri May 12, 2023 2:48 pm    Post subject: Re: My Baja build Reply with quote

Since last post I've gotten a lot done.

Before the project began I bought a chinese AMR500 supercharger for the build and decided now was the time to begin constructing the brackets and what have you for it.

The rear cage is painted and ready to go on, just need the last pieces done to the engine...

I wanted to use the original fuel pump and didn't want to build a setup that used the intake for the locating support to the compressor so I had to work around that.
I will take some better pictures once I'm finished with the engine.
At the same time I replaced some aftermarket push rod tubes, the ones you screw in. They leaked like crazy btw, and the narrow end was mounted towards the heads so 4 of the pushrods where worn pretty bad from rubbing the tubes.
I mounted a used set of high lift rockers, plugged the oil pump and mounted a filter, the "easy" full flow system. Drilled the lower right engine case for a temp unit. fabbed up some levers to route the throttle cable up to the carburettor.
Anybody been in the same situation knows that everything takes forever when you have to invent everything as you go along and there are literally 1000 things you can't even see that's been done...

Oh I also deleted the left side heater air supply thing and fabricated a small shroud to cool the compressor, I'll see if I can remember to take some pictures of that later.
Image may have been reduced in size. Click image to view fullscreen.


Image may have been reduced in size. Click image to view fullscreen.


Image may have been reduced in size. Click image to view fullscreen.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
mikec4193
Samba Member


Joined: July 15, 2014
Posts: 287
Location: Mechanicville NY (Upstate)
mikec4193 is offline 

PostPosted: Tue May 23, 2023 2:21 pm    Post subject: Re: My Baja build Reply with quote

There are couple of those Super Beetles on YouTube that you might wanna check out...

https://www.youtube.com/results?search_query=dust+buggy

This couple here did a bunch of modifications but it was still street legal in the end...

Looks like you got a handle on this project for sure.

MikeC
_________________
Dad bought his first Beetle on Dec 17, 1953.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
las912
Samba Member


Joined: April 02, 2014
Posts: 51
Location: Denmark
las912 is offline 

PostPosted: Fri May 26, 2023 11:53 pm    Post subject: Re: My Baja build Reply with quote

Yes I've seen lots of their videos, great inspiration!

I try to keep my car street legal too, but might need to bend a few rules slightly....

The engine is more or less complete and running. I experoíenced something I've never seen before to this extend, Heat soak and vapour lock.
The engine would start and run ok for a few seconds. Then it would hesitate on throttle and finally die off. It would then start hissing and boil all fuel out the carb. throat.
I painted a few black dots on the comæpressor and on the the carb to get a better reading with my IR temp. gun and found out I needed to drop the temp of the fuel and carb.

I then made a phenolic spacer og an old cutting board and found some heat repelling hose covering for the lines hoping it would be enough, and it seem to have done the trick.

Image may have been reduced in size. Click image to view fullscreen.


Image may have been reduced in size. Click image to view fullscreen.


Image may have been reduced in size. Click image to view fullscreen.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
las912
Samba Member


Joined: April 02, 2014
Posts: 51
Location: Denmark
las912 is offline 

PostPosted: Sat May 27, 2023 12:21 am    Post subject: Re: My Baja build Reply with quote

https://youtu.be/8BdOkL4VXF8
Back to top
View user's profile Send private message Gallery Classifieds Feedback
oprn
Samba Member


Joined: November 13, 2016
Posts: 12632
Location: Western Canada
oprn is offline 

PostPosted: Sat May 27, 2023 5:09 am    Post subject: Re: My Baja build Reply with quote

I am curious about your use of the vacuum advance. You have it hooked up below the carb. The effect would be that you would have about 10* additional advance immediately on start up, at idle and it would progressively go away as the RPM/engine load increased. This would likely result in a fast idle that would be hard to tame. On the road then most of the advance would be from the mechanical advance.

Is that what you intended?
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)
Back to top
View user's profile Send private message Gallery Classifieds Feedback
las912
Samba Member


Joined: April 02, 2014
Posts: 51
Location: Denmark
las912 is offline 

PostPosted: Sat May 27, 2023 2:04 pm    Post subject: Re: My Baja build Reply with quote

I actually believe having full manifold vacuum makes the driveability better and it guarantees that there's no vacuum advance at higher engine loads where there's potential for boost.
When the mixture is lean at lower speeds I will have a strong vacuum signal and lots of advance.

Now I haven't driven this car with this engine configuration yet, but my old 912 with a turbo build is set up with manifold vacuum as well.

I do plan to limit total advance in the future if I need to, but for now I will just drive and see if it makes any funny noises Smile

I also made a boost outlet on the left intake manifold for a boost gauge, during test I hooked it up to a gauge and found a very strong strong vacuum signal, but very pulsating and was actually able to see boost when I blibbed the throttle.
At first I considered taking the manifold vacuum below the compressor but decided against it and made it as you can see on the pictures.
My thinking was that the signal below the compressor could be quite a bit slower than above it. I imagine you open the throttle and the carb squirts a portion of fuel and goes to main circuit running fat but the engine rpm's haven't reached that condition yet and the compressor will now act as a restriction and give me lots of advance with a rich condition.... Well that's my little theory, might be wrong though.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
las912
Samba Member


Joined: April 02, 2014
Posts: 51
Location: Denmark
las912 is offline 

PostPosted: Sat May 27, 2023 2:27 pm    Post subject: Re: My Baja build Reply with quote

Oh and I forgot to answer your question. No problem with a fast idle on any car with full manifold vacuum.
The starting point for many carb problems is the idle and the positioning of the butterfly valve. At idle it should be closed! All the way.
Once the butterfly is closed it's easy to adjust the right amount of bypassed air from the idle bypass screw and the idle circuit should work as intended too.
The main problem with carbs as I understand it is that people likes to adjust idle on the butterfly, and once you do that it's impossible to dial it in. Your essentially trying to adjust idle on the progression circuit! And if you manage to do that, you will have it fall flat when accelerating and all sorts of trouble.

I was a bit surprised how rough and shaky this engine ran and I had to up the RPM's some to smooth it out. I suppose the compressor makes it that rough at low RPM's.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
oprn
Samba Member


Joined: November 13, 2016
Posts: 12632
Location: Western Canada
oprn is offline 

PostPosted: Sat May 27, 2023 7:51 pm    Post subject: Re: My Baja build Reply with quote

I kind of thought that was what you were up to!
las912 wrote:
I do plan to limit total advance in the future if I need to, but for now I will just drive and see if it makes any funny noises Smile

Depending on how high your boost pressure is, what your starting compression ratio is and what grade of gas you are running that might be fine. You still may need boost retard though.
las912 wrote:
At first I considered taking the manifold vacuum below the compressor but decided against it and made it as you can see on the pictures.
My thinking was that the signal below the compressor could be quite a bit slower than above it.

I have not run a supercharger but my gut feeling is that it would indeed be better below the compressor. I would worry that on a sudden deceleration the vacuum signal would spike high at the same time that there is still boost in the intake and give you a few harsh piston rattles before it all settles out. Hooked to the intake below the compressor this could not happen.

Just armchair speculation of course.
las912 wrote:
I imagine you open the throttle and the carb squirts a portion of fuel and goes to main circuit running fat but the engine rpm's haven't reached that condition yet and the compressor will now act as a restriction and give me lots of advance with a rich condition.... Well that's my little theory, might be wrong though.

I believe the opposite will happen. Sensing below the throttle plate the vacuum will instantaneously drop to zero and you will loose your extra advance right when you need it to start that rich mixture burning causing a hesitation.

Carry on and let's see which way it goes.

As for your idle it sounded like about 1500 rpm or more to me but you may not be done adjusting yet.
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)
Back to top
View user's profile Send private message Gallery Classifieds Feedback
las912
Samba Member


Joined: April 02, 2014
Posts: 51
Location: Denmark
las912 is offline 

PostPosted: Sun May 28, 2023 12:30 am    Post subject: Re: My Baja build Reply with quote

This project is all armchair speculation! And to be honest that's the kind of projects I love the most.

There is so many variables and unknown when you design and build something like this, that at some point you have to do something and if it doesn't work you redo it.

I don't have a tach on it yet but I think your right. This video was when it had heat soak problems but regardless I still think it will be somewhat high.
Like I said I felt it was very "shaky" at lower rpm's and I just adjusted it to where it felt it ran best.

Once I get my fuel tank back in I'll make another video where I give it some pedal, it sounds so brutal Smile
Back to top
View user's profile Send private message Gallery Classifieds Feedback
BFB
Samba Member


Joined: November 03, 2014
Posts: 1689

BFB is offline 

PostPosted: Mon May 29, 2023 12:13 pm    Post subject: Re: My Baja build Reply with quote

You should run a gauge and check the vacuum under the carb at WOT, dont assume that it will have 0 vacuum at WOT like N/A. Some draw through turbo set ups will still have vacuum at WOT and thats why some draw through carbs are turbo prepped. Not all need it though..
Id assume it all depends on boost / cfm, and size of the carb and id bet with a small single barrel that the supercharger will draw pretty hard on it and will have vacuum under the carb at WOT. Which if so, will mean your dizzy will be advanced while under boost. You’d be a lot better off with the timing retarding a little too soon than too late.
Also, those mounting brackets look really good
_________________
Forced induction can overcome a lot of obsticles that gets in it's way
"You are the Engineer and the Mechanic.  
Build it your way not the way someone else does it. Their way might not work for you." - clonebug
An interesting thing happens in forums where everyone starts parroting the same thing and "common knowledge" takes over.
“ The monkey see monkey do mentality seems to run deep in VW people. "Gene Berg said it was so 30 years ago so thats the way it is" “ - bdkw1
Back to top
View user's profile Send private message Send e-mail Gallery Classifieds Feedback
las912
Samba Member


Joined: April 02, 2014
Posts: 51
Location: Denmark
las912 is offline 

PostPosted: Mon May 29, 2023 1:34 pm    Post subject: Re: My Baja build Reply with quote

It's a good point I have already given some thought, but decided the supercharger was nothing more to the carb than a larger displacement engine underneath it, and even on those larger engines the manifold vacuum works fine.
Previous owner put another engine in this one, a 1300ccm, it should have been a 1600ccm. The carb I have used here is a Pict 34 for the 1600, so I think the bore is sufficient.

Like I always say "I could be wrong" and I'll be sure to let you know once it's ready to move under it's own power.
And these small problems, be it theoretical or practical, are actually super cool to think about, discuss and learn from.
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Hebbelille
Samba Member


Joined: January 08, 2019
Posts: 5

Hebbelille is offline 

PostPosted: Mon Mar 25, 2024 10:58 am    Post subject: Re: My Baja build Reply with quote

Thanks for sharing!
Interresting build.
I’m interrested in what tyres you have choosen?
I’m building a «type 82E/type 87 lookalike», and looking for what kind of tyres to use.
The type 87 used 200-16 tyres. I will use 15 inch/ 5,5 inch rims (5/205).
I suppose that 215/80-15 will have about the same hight as the 200-16. The 235/75-15 is also close, but a little to wide for this build.
What size/brand do you choose.

«A norwegian living in Finland»
Back to top
View user's profile Send private message Gallery Classifieds Feedback
Display posts from previous:   
Reply to topic    Forum Index -> HBB Off-Road All times are Mountain Standard Time/Pacific Daylight Savings Time
Page: Previous  1, 2
Page 2 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

About | Help! | Advertise | Donate | Premium Membership | Privacy/Terms of Use | Contact Us | Site Map
Copyright © 1996-2023, Everett Barnes. All Rights Reserved.
Not affiliated with or sponsored by Volkswagen of America | Forum powered by phpBB
Links to eBay or other vendor sites may be affiliate links where the site receives compensation.