Bonnet hydraulic/gas lifters - DIY

[swinks]

Hi folks!
Just recently one of member from Polish Mitsi forum did nice and detailed write-up regarding diy on hydraulic/gas lifters. He agreed I can utilize his work and present on CVR4.
Let's roll then...

1. Preparation and choose of right strength lifter.
It was done based on several PC soft simulations. Final conclusion was that lifters should be approx. 580N each and long approx. 19cm to get bonnet on balance at height of 40cm.
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2. Search for right lifters.
It seems that the best choice in terms of money/value factors are lifters from Vauxhall Vectra B (up to 2003) hatchback version. Obviously lifters from rear door.
Lifters are:
- total expanded length 473mm
- length 188mm
- force 560N
There is additional advantage - diameter of strusts being only 18mm where typical is 19mm and more. We need a room to fit lifters don't we?
Here is one of many eBay auctions:
http://www.ebay.co.uk/itm/VECTRA-B-HATCHBACK-TAILGATE-BOOT-LIFTERS-GAS-STRUTS-/160703439781?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item256aabe3a5
Price is usually between 20 GBP and 30 GBP for pair shipped.
3. Other components we need to consider.
- lower mount point lifter to wing (chassis). This was tricky bit, we need something like ball joint.
Here is picture of desired piece:
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Thread diameter 8mm, ball joint diameter 10mm.
To be honest didn't search eBay for this, but know that there are plenty of them on Polish auction site, usually 2 GBP per pair. We need 4 in total.
Back to the point.
Now we need to adopt already existing mount bolt of a wing for lifter mount. All we need to drill out hole to 6.8 (7)mm diameter and tap one with M8 tap.
Now our ball joint will do 2 jobs: (1) being lifter lower mount, (2) being wing mount to chassis
Few pictures:
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- upper mounting point
This time we need to fabricate somekinda of plate adapter. The best are half-ready made "L" shaped brackets for joinery jobs you can find in any big DIY store, i.e. B&Q, Homebase, etc. Also angle grinder, drill, vice are must have tools.
Here few pictures to give you idea:
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And here detailed drawing:
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Once it's made we can use this adapter plate to mount upper fitting of lifters. Don't forget to use already purchased ball joint bolts.
Here is picture:
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And final result:
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[Colin Wiltshire]

looks great, was thinking of doing exactly this. I assume this will still be ok for a carbon bonnet?

[swinks]

IMO, yes...

[Nick Mann]

That's some serious effort there, kudos to the planning and design.

If you want to spend a little bit more, check out this thread:
http://www.clubvr4.com/forum/showthread.php?43077
On the second page there is a link to visual performance where they list bonnet dampers for our cars in a table, £40 delivered as far as I can tell.
http://www.visual-performance.co.uk/#/bonnet-dampers/4534361259

[swinks]

If you want to spend a little bit more...
Why???
That's the point of this thread. :)

Anyway, if any-one feels that need to spend much more money, then use this write-up and excess money can be donate to me via PayPal. :sweethear

[Nick Mann]

;)

Some people like to save a tenner and have the satisfaction of doing the job themselves, others like to spend the extra for it to be hassle free. I was just letting people know!

And as I said, kudos to the thought that went in to the DIY approach, it is very impressive.

[swinks]

Yes, I know Nick, just had a laugh :)
Anyway, brackets still needs to be fabricate, so not as much effort save.

[Wodjno]

Nice 1 Tomasz :) Send many thanks to the Originator of the write up /yes

Don't forget that this will give better airflow into the airbox as well /yes

[TAR]

looks great, was thinking of doing exactly this. I assume this will still be ok for a carbon bonnet?

I would be careful as the carbon bonnet is much lighter so you need less 'lift'. Probably only one of these is sufficient.

:happy:

[swinks]

Yes, Tim, recently had checked out and to a light bonnet we need somewhere 100N struts (same dimensions).

[Oggie]

I would be careful as the carbon bonnet is much lighter so you need less 'lift'. Probably only one of these is sufficient.

:happy:

I was told that because the CF and FG bonnets are so light and "flexiable" they have a habit of eventually foldign in half, from all the closing of the bonnet.

[purple_guana]

Very nice and handy to have especially in a very windy day when you need to check up under bonnet. not having to worry about the bonnet holding rod go loose and bonnet coming down on your head=P have had that happen.

[Qotato]

76394

Made these over the weekend.

[Davezj]

Those brackets look very strong and thick, will they and the strut fit in the space on top of the wing. It is quite tight in there.

do you have the correct size gas struts.
I have just checked on eBay and their seems to be plenty of vectra B struts available.

you can get a complete kit on ebay for about £40 struts and brackets for a steel bonnet. not good for carbon or fibreglass, struts are to strong.

[Qotato]

yeh theres a tiny bit of space after measuring it up, i have some captive ball head bolts from my old mans work ( they make prototype seats and things) to throw on when ready will be ordering the struts on Friday after getting these painted, always better to be stronger then for them to break. you should have seen the top strut cross member i made on my del sol that was soo over engineered but made the whole motor so strong.