Building a S2 mk2 golf

[Flat on my back]

Its called 'phut testing'. Goes like this:-

Apply power, wait for 'phut' sound, look for smoke and then listen for the 'bang'.

If none of the above happens design is satisfactory, if some of the above happens design needs modifying?

[repo]

And by any means I am not flaming/hating/trolling/wa'eva. Just sharing some ideas.

Keep up the good work, that one's gonna be a piece of adrenaline rush.

[gnutz2]

I agree with the fatigue. I have done quite a few intakes. Problem is, if they crack, it pretty freaking hard to weld it back together without having huge amount of soot and debris on the welds.

Another matter is a mild sneeze back to the plenum. Which take place every now and then, especially when making initial setups for bank engine management, and cranking for the first time. In those case You easily may produce 20 bar peak into the plenum, and I can guarantee You, no support fingers inside a plenum will hold that. Reminds me of a certain Merc intake, I had to remove with a crowbar after first cranking trial. Aftewards customer blew the same intake once again, this time with a minor ~2,5bar overboost, in a setup that gave more than 510hp with 1,2bar...

Well, round shapes take both vacuum/overpessure cycle kind of stress, and high boost type, better than cubical one. You can see this easily, by taking a look how they shape high pressure tanks and gas cylinders. They always have round shapes, never large planes.

It's pretty simple maths after all. One psi means one pound of load for every square inch. In this golf plenum there are easily what? 120 square inches (6 x 20in)? Then You release the throttle, you get 10 psi vacuum, which causes 10 x 120 = 1200lb stress inwards.

Then You open up the throttle, and run with 2,5 bar / 36psi, and cause 36 x 120 = 4300 pound force that pulls the plate off from the welds.

Would You lift Your S2 with a crane, so that all load comes into that 2.5mm plate and those reinforcing fingers?

No because i dont have one

If it breaks i`ll just have to try another design.

[repo]

The backplate is 6mm and the sides are 2.5mm plate which is supprisingly strong, dont forget that the plenum is not finished yet because i have to weld in 4 internal rods to stop the plenum ballooning under 2.5bar max, and the five injector bosses which will stiffen it all up. I think the main issue is fatigue, because the plenum is subjected to +2.5 bar and -1.0 bar it puts the plenum through a lot of stress cycles.

I agree with the fatigue. I have done quite a few intakes. Problem is, if they crack, it pretty freaking hard to weld it back together without having huge amount of soot and debris on the welds.

Another matter is a mild sneeze back to the plenum. Which take place every now and then, especially when making initial setups for bank engine management, and cranking for the first time. In those case You easily may produce 20 bar peak into the plenum, and I can guarantee You, no support fingers inside a plenum will hold that. Reminds me of a certain Merc intake, I had to remove with a crowbar after first cranking trial. Aftewards customer blew the same intake once again, this time with a minor ~2,5bar overboost, in a setup that gave more than 510hp with 1,2bar...

Well, round shapes take both vacuum/overpessure cycle kind of stress, and high boost type, better than cubical one. You can see this easily, by taking a look how they shape high pressure tanks and gas cylinders. They always have round shapes, never large planes.

It's pretty simple maths after all. One psi means one pound of load for every square inch. In this golf plenum there are easily what? 120 square inches (6 x 20in)? Then You release the throttle, you get 10 psi vacuum, which causes 10 x 120 = 1200lb stress inwards.

Then You open up the throttle, and run with 2,5 bar / 36psi, and cause 36 x 120 = 4300 pound force that pulls the plate off from the welds.

Would You lift Your S2 with a crane, so that all load comes into that 2.5mm plate and those reinforcing fingers?

[drunkenalan20v]

lovely work, and getting some coverage on club gti http://www.clubgti.com/forum/showthread.php?t=148895 you should post a few pics on there.

[gnutz2]

I made everything except the exhuast manifold and the spark plug cover(wab).
This will blow your mind, all the body panels are ali! I was trainned at an Aston Martin specialists.
I have my own bussines doing race prep/fabrication/restoration. Just buying some new premisses in Otley. Then things will improove, I have run out of room!

You have skills i could only imagine of, i`m not far from otley tho, love to pop up when you get settled in.

[GT500]

Made a rather affective undertray!
14072007266.jpg

[GT500]

That midget is the bo@%ocks, did you make just the tank or other stuff.

So are you a self employed set up or working for someone, i`m looking to move into the same area like one off racing cars and the like and the golf im building will hopefully get me some work when it`s finished/

I made everything except the exhuast manifold and the spark plug cover(wab).
This will blow your mind, all the body panels are ali! I was trainned at an Aston Martin specialists.
I have my own bussines doing race prep/fabrication/restoration. Just buying some new premisses in Otley. Then things will improove, I have run out of room!

[gnutz2]

I got my torch from my local energas place, they seem to use the same fittings, easy upgrade.
I do alot of fabrication, Ali parts are mainly fuel tanks for race cars.
Last big job was the fastest Midget in the world!

[ATTACH]15254[/ATTACH]

That midget is the bo@%ocks, did you make just the tank or other stuff.

So are you a self employed set up or working for someone, i`m looking to move into the same area like one off racing cars and the like and the golf im building will hopefully get me some work when it`s finished/

[4WheelDrifter]

I got my torch from my local energas place, they seem to use the same fittings, easy upgrade.
I do alot of fabrication, Ali parts are mainly fuel tanks for race cars.
Last big job was the fastest Midget in the world!

[ATTACH]15254[/ATTACH]

I'll know where to come for my Midget project then.

[GT500]

[ATTACH]15256[/ATTACH]

[GT500]

[ATTACH]15255[/ATTACH]

[GT500]

I`ve not had any problems with mine so far, but im sure the sticking solenoid was an easy fix

Do you have any links for the torch as i`ve seen some very tiny torches with bendy necks perfect for getting into tight exhaust manifolds and would like to upgrade mine.

Do you fabricate a lot GT500, or is it just bits on the side?

I got my torch from my local energas place, they seem to use the same fittings, easy upgrade.
I do alot of fabrication, Ali parts are mainly fuel tanks for race cars.
Last big job was the fastest Midget in the world!

14072007264.jpg

[gnutz2]

is that an Dual plenum IM?
Well done!
Super!

No, its just plenum

[gnutz2]

I have the same tig set up!
Great piece of kit!
Have you had the gas solonoid stick in the on position? gas pouring out long after it should be.
Changed my tourch to a Binzel with a valve on the handle to stop the gas when it does its "trick".
I paid a bit more than that, made a new fuel tank for a Aston V8 first job, Tig paid for and some in its first job!

I`ve not had any problems with mine so far, but im sure the sticking solenoid was an easy fix

Do you have any links for the torch as i`ve seen some very tiny torches with bendy necks perfect for getting into tight exhaust manifolds and would like to upgrade mine.

Do you fabricate a lot GT500, or is it just bits on the side?