Shoptalkforums.com

Then your lucky, none of the people I know could tig weld. And it would have been easier to learn 20 years ago

Yeah I wish I would have learned 20 years ago too. Although there hasn't been anything yet that I couldn't just mig weld and be perfectly fine.

Hi again, I have driven the car a little bit since last post, not much though as I had to take the slipping clutch into account.
I have not done any jetting but I could swear that after the first few runs it has developed a serious fat condition at idle, maybe my floats have imploded after the 7psi run a while back.
The positive thing is it pops and bangs out the exhaust at de-accelerating, turns some heads
Now the engine is out.

Over the past few days I have been tinkering with a dual mechanical fuel pump drive. It's all made as I went along, no drawings and such.
One thing I messed up was the spacing between the pumps as I didn't have 2 at the time I started making it. Of course there was not enough clearance and I had to make a 5mm spacer under the one towards the cooler......

It's a tight fit, and I did file a little indent in the alternator and the stand.

Do you guys know where to get solid IDF floats?

This time around I'm also working on the carb linkage, the water injection, air filter and oil breather.

That's a pretty wild setup definitely one of a kind:)

Yeah and I hope they work

I'm doing the fuel lines right now, also hope they turn out good.

What is the reasoning for two pumps????

Hmmmm I don't know!

Hahaha no, it's because I get these stupid ideas in my head. For some crazy reason I didn't want an electric pump, I wanted to keep it old school and simple, simple when and if it works!
One referenced mechanical pump should be able to deliver around 120-130HP at most and I'm aiming for 160-200HP.
I figured two would be perfect, same pressure but a bit more flow. Obvious not double. but enough for my HP goal.
Also I can't think of many things that are cooler than a dual mechanical fuel pump, and I kind of fell in love with the idea.

One of my biggest concern with this setup is how much boost I can run! I'm really hoping for 15psi/1bar

The stock pump and feed line is capable of 170 hp and possibly more......

I boost referenced a stock pump to 13 lbs for 7000 miles on my original build. I never had fueling issues that I know of.

I did have detonation issues but I fixed that with W/I and EFI.

Still a fun project. I look forward to seeing how it works out.

Clonebug wrote: ↑Sun Jun 23, 2019 2:43 pm The stock pump and feed line is capable of 170 hp and possibly more......

I boost referenced a stock pump to 13 lbs for 7000 miles on my original build. I never had fueling issues that I know of.

I did have detonation issues but I fixed that with W/I and EFI.

Ok, that sounds perfect for my plans then.
I think the fuel line on the 912 is bigger than the bug. The outside diameter is 8mm and I'm guessing 6mm ID
And if you ran 7k miles capable of 13psi, then the 2psi+ shouldn't be a problem.

Did you fix the detonation by going EFI over carb? I'm thinking float here, I'm having a hard time finding solid floats for the IDF.

Buguy: So do I!

All the IDF floats I have had were solid, even seen IDA with phenolic (all though brass hollow is more common). Neat fuel pump array

Ok, I haven't really checked it yet.
But in a few days I will take the carbs apart and hopefully they are solid.

I also have got a lot done in the last few days, I'll update in a day or two

Ok, first thing after the pumps was building a fuel "rail" to tidy up all the fuel lines, make sure they were secure and something that looked good.
In the past I wouldn't get much done because it all had to look like a factory made piece, and when it didn't I'd lose interest!
The new me kind of accepts that it might look home build, but if it's made good, then it's actually a good thing all in all.

The Y splitter for the intake was leaking right in the worst spot when I pressure tested it, in the narrowest point of course, but good thing I did. A leak on the vacuum side of the pumps could have been a hard one to find later on.
All the fuel lines are not attached at the moment, it's still only a mock up.

By the way, the rail is made up of some lengths of old hydraulic steel tubes I had and 6/8mm bolt drilled and machined to fit. 4 with 4.5mm ID for the pumps in/out (pumps only have 4mm ID. 5 with 6mm ID for the rest.
Then on to the carb linkage.
Because of the twin pumps the original hole for the linkage cable had to be removed. The arm that the cable attaches to also had to be shortened.
This was a tuff nut! The new location meant drilling through some vanes inside the housing at a steep angle, or rather filling and what have you....
I got the job done and installed/welded a length of the HY tube to support the original cable guide rod and stiffen up the fan house. I actually forgot to put the guide in there in the photo, but it fits.
Also closed the elongated holes inside and in the back of the housing for better air pressure inside.

I mounted the hex bar for the linkage onto the housing and fitted it with 10mm bolt drilled for grease nipples, the ends were turned down to 8mm and screwed into the rod from each end.

Because of the now shorter arm for the cable I had to find an angle that would give me full travel on the carbs with roughly 38mm cable pull. After messing with it for quite some time I ended up with around 35mm cable travel from zero to full gas.
Hooked up the second carb, the one without a stop on it, and found it to open quite a bit beyond what should be full gas...... Bummer, somehow the geometry was completely of. After reshaping the arm for the right carb I finally got them to operate somewhat identical.
I also had to make custom connecting rods for each side as the original kit had much shorter rods. Besides all was in inches, I don't really like that, so I changed it to mm in my own design.

Next up was converting the fan shroud to accept the original flappers. It had its own challenges and because of my turbo manifold I cant mount the actuator in the original place. That I'm still working on!
But I also wanted some indication if the flaps were open or closed, one of my biggest concerns with this.
Look at how I solved that.
I welded a little spacer onto the shaft, put an arrow on it and voila, visual indication in place

That is too cool I'm loving the arrow