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Ibiza Mk4 Custom Gas Bonnet Lifters/Struts - Finally Finished!

Pabs

Active Member
May 3, 2004
5,933
3
Basingstoke
Mk4 Ibiza Bonnet Lifters

Well folks, I've been keeping it on the quiet up until now, as I wanted to ensure I could pull it off, but now I'm happy with the finished product, it's time to show you all my hard work!

So, as you're probably aware, the mk4 ibizas were never lucky enough to come with the hydraulic bonnet lifters as found on many other VAG cars like the Golf/Leon, so I went about designing some.

Unfortunately the Ibiza doesn't have any decent mounting points on the bonnet itself, so it required a bit custom work to knock-up a bracket.

My key area of concern was that I didn't want to irriversibly modify ANYTHING on the car. This meant no drilling or cutting.
I also wanted to keep to a totally OEM look, so that unless you really knew about the car, you'd assume it came like it from the factory.


Component List
2 x custom made Aluminium brackets
2 x Variable force Hydralic/Gas struts (www.strutsdirect.co.uk) Part Number #SD01-150 - approx £40
4 x strut ball-ends (M6 thread) - (www.strutsdirect.co.uk) - approx £5
4 x ball-head screw (M6 thread) - (www.strutsdirect.co.uk) - approx £5
1 x spray can of paint. (to match car colour) - approx £8 (mine was free)

Update: Not 100% sure on part number for ball-ends, but believe it is #SBJ4, 30mm long giving total length of strut =400mm.

Tools required
Allen Key for strut gas-release (supplied with struts)
Adjustable Spanner (Open)
14mm Socket


Design

To design this, I went back to my A-level Mechanical Maths lessons, in order to work out the strut specifications and force required to keep the bonnet open. Here are some assumptions that I had to make:

Bonnet weight: 15kg
Force Calculation Diagrams: http://www.solidcomponents.com/file...files/doc/final_stabilus_techn._info_a4_e.pdf

Force equation used: F1 = [(G x D)/b x n] x 13 (See url for more info)
Calculation Results: Approx 600N total

I opted for 2 struts purely for cosmetic reasons (symmetrical) and I also feel it supports both sides of the bonnet evenly. This is also a common design for aftermarket bonnet lifters. This also reduced the required force per strut by half, so max of 300N each. The gas struts purchased came at 400N each, so easily covered my requirements.

Unfortunately I found several equations that all gave different results - so I took an approximate average, ensured I could easily cover that force, and purchased components accordingly.

Just as an FYI - I checked similar vehicles and got measurements/forces from Spanny (thanks matey!!)
Lupo = 592mm + 280n
Leon = 664mm + 330n
Bora = 655mm + 350n
mk4 golf = 592mm and 350n

All of which you can see are considerably longer than my 400mm struts. (End to End, including ball-ends)

*****************************

Wing Mount
I found a 6mm bolt in each wing of the car, which was at a good distance from the bonnet hinge, and so here, I simply replace the bolt with one of my ball-head screws (and a washer)



Middle Section
Here you see the foam insert which is used to direct any rain water down the skuttle panel, rather than the wing of the car.



As my struts were positioned down the wings, I needed to cut away a section on these to make room for the struts when the bonnet was closed. I have checked, and to replace these with new foam inserts, it'd cost about £4, so I wasn't too worried about replacing
these if I ever needed to.



Bonnet Mount
This here is the custom bracket, which is made from high-grade aluminium. It has 2 M8 holes for the standard bonnet bolts, and the N/S also has an additional M8 hole for the plastic clip that holds the washer-fluid hose in place.









The hole for the ball-head screw is a threaded M6 hole, and the screw is held in with locktite. Mounting this is simple - I removed the bolts on the bonnet hinge, put the bracket in place, and then bolted it all together again.

I am a little concerned that I might need longer bolts as I'm not sure how much of the thread is actually securing the bonnet, but it is quite tight, so for now, I'm happy.


Putting it all together
Self explanatory bit really - but a few pointers:
The strut was put on in this orientation as it is recommended by the manufacturers to be mounted this way. This ensures that the oil lubricates the strut properly, and also prevents water ingress through the rubber seal where the plunger enters the main body.

The ball-end on the piston of each strut was done up tightly, and then the piston was rotated through 90 degrees to be able to mount onto my brackets (different orientation at each end)

Spring clips are put onto each ball-joint once connected to stop them popping off.
On each strut, there is a small grub screw that is used to bleed the gas out of the strut, reducing the pressure contained within.

These struts come shipped at max pressure (400N) which is too much for this purpose, so I bled around 10 very short bursts (less than 1/2 second each) until the pressure was about right. I am unable to find out the force now produced, but it could be measured by the manufacturer if required.

So, there you have it - feel free to comment on this - hopefully some of you might find all the research and hard work I've put into this useful! :)


Held wide open:


Held at about 3/4 open under it's own weight:
 
Last edited:

AndrewJB

Friend to SEAT UK & Cupra Racing
Aug 16, 2007
11,072
440
Maranello
Thats well good

when you gonna start selling them then? ,ive been after this for a while

theres a kit for the Fabia for one gas strut but it doesnt fit the ibiza :(
 

Pabs

Active Member
May 3, 2004
5,933
3
Basingstoke
cheers all.

Unfortunately I'm not going to make any others - but I'm more than willing to supply all relevant part numbers, dimensions for bracket etc etc.

As for if 1 strut would work - I'm not 100% convinced that it'd work - it's very hard to tell how much gas I've bled out of the struts - but I don't think I'd have bled out more than 1/2 the total somehow.
 

Pabs

Active Member
May 3, 2004
5,933
3
Basingstoke
Oh, and I forgot to mention, but yes - the Fabia kits "DevonUtopia" makes don't fit this - and didn't quite meet my OEM fitment expectations.
 

Pabs

Active Member
May 3, 2004
5,933
3
Basingstoke
i didnt think of that lol.
Don't get me wrong - I have no idea on how to judge/measure it - if I could do it at home, I certainly would! Unfortunately the company charge to have it measured, otherwise I'd do it.

Could always do this with 1, and then order another if it was too weak - but that would mean 2 sets of postage cost (think it was £6 for postage)
 

Pabs

Active Member
May 3, 2004
5,933
3
Basingstoke
Damo - I'll try and get my diagram scanned in so that it's easier than trying to explain/replicate in photoshop/paint etc.
 

Bondiblu

Enthusiast
Mar 18, 2007
1,650
1
Cheshire
Thats really good. I was thinking about doing the same a while ago, great job, and I really like the fact it is easily reversible.
 
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Damoegan

Sir Bob,a geordy legend..
Oct 15, 2007
8,994
3
Newcastle
Damo - I'll try and get my diagram scanned in so that it's easier than trying to explain/replicate in photoshop/paint etc.
Thanks mate :) Reckon I could knock up a few of them from some S/S angle I have at work in no time ;)

Could you post the exact strut you got from the site please?

Edit: Are they the SD01's?
 
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Pabs

Active Member
May 3, 2004
5,933
3
Basingstoke
Stroke is 150mm, body is 190mm, I think (from model number)

Add to that the length of the Ball-end sockets etc.
 
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