Rear suspension - Coil overs for Spitfire Mk3?

[Northpole]

I hope someone here can help me out on my Triumph Spitfire Mk3 1968 powered by Hayabusa engine. Weight is 690 kg and distribution is 51% in front and 49% for the rear.

 

Upgrade of the rear suspension:

 

I have decided it was time to upgrade the rear suspension with a full CV jointed axle setup along with another diff with LSD and better ratio (3,55:1). The Leafspring, diff and the swing axles will be removed and my goal is to go the full independent rear suspension route.

These modifications will be custom made.

 

But, I have not found the right suspension yet, i.e. I am looking for Coil Overs or a good solution for the rear suspension.

 

Any good advice's greatly appreciated.

[super7guy]

Some USA choices are QA1 and Viking. You can cut down the spring perches to accept 2.25 springs. They also have 1.87 springs and bodies, if you want smaller shocks.

 

Wayne in San Diego

[sagamore]

This web page (link) has a great deal of info about converting the Spitfire to a more independent suspension.

[Northpole]

Thanks, but what I am seeking is what Coil overs (or suspension) are used in this conversion, this is not the first time this is done so there must be someone out there who knows what Coil overs are best to use.

[TheDingo8MyBaby]

I can't say what coilovers used are best for this conversion, but I can provide you with my recent experience purchasing coilovers.

 

I've spent a considerable amount of time looking for the right coilover for my car. Originally I wanted an adjustable shock that was rebuildable in the USA. A local shop near me worked on Penske and Koni - so I preferred to go through them.

 

The challenge is I was limited to 1.9" ID springs based on the amount of room I had. If you can fit larger 2.25" ID springs, your options are considerably more.

 

QA1 and Viking were some of the options here in the states, but based on my reading, the valving is not really appropriate for a lightweight car, and the differences between settings on two shocks could be massively different. The challenge with a solid axle rear LSIS is that the sprung weight is very low compared to the unsprung weight of the rear axle and these shocks are valved to suit a range of cars.

 

In the UK - I heard good things about AVO, Protech and to a lesser degree, GAZ. I did a bit of research and all seemed to have the problem as above. After doing a bit of googling, I came across a company called Procomp who cater to a lot of the locost and westfield sevens. I gave them all of my specs (sprung weight, unsprung weight, motion ratio and shock length at ride height, desired travel wheel rate) and they provide a custom built shock for me with the valving appropriate for my application. With others - you may only have 2-3 clicks of adjustment that are appropriate. The best part about it is - they use modified pro-tech dampers and will provide you with a print out of the shock dyno for the same price as if you ordered through protech.

 

I did consider going double adjustable, but it was double the price and with the appropriate valving, I wasn't convinced it would be worth it. If I was autocrossing the car and wanted to set the rebound for roll during quick transitions, I probably would have considered them.

 

For 400GBP total, I feel my money was best spent through protech. I haven't yet received them yet, but they will be couriered over from the UK in checked luggage later in January and I can let you know my impressions after I get them on the car. (I'm coming from Spax though - so any shock will likely be better!) Another challenge is shipping as procomp will not ship internationally, but a courier service such as transglobal express is a reasonably priced option.

 

Goodluck in your search!