Hi Guys,

I have decided I'm going to get my chassis re-powder coated since I am now adding a roll cage, so thought I would take the opportunity to make some chassis modifications whilst I am at it...

The chassis is an Original MK Indy.

My plans are as follows, add triangulation to the front.

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Add triangulation back to bulkhead unfortunately there is only room to do this on one side as turbos(yes two!)/manifold will be in the way, unless its worth while triangulating part way as per the blue in lower pic?

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Next Up is around the engine mounts, do you think I would be best off removing the existing triangulation front to back and replacing as per below? this setup will have a lot of torque (will be in the region of 450bhp with torque to match) I'm aware there is noting substantial where the engine mounts are currently located. And yes I am aware my current engine mounts are a little over engineered ha.

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Next up when faffing around with turbo plans I removed a big chunk of my chassis... obviously this now needs replacing..
This is how it currently stands

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What I'm proposing

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Triangulate the tunnel

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Move rear upper suspension pickup down wards and outwards, and remake wishbones 1.5" shorter to match, this should improve the camber issue that's present on the original MK Indy, and also raise the centre of roll helping the car to corner flatter.

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I will also triangulate this area but not given it much thought yet, and don't have a decent pic to hand.

Anyway if anyone would like to point out any flaws to my plan or other potential improvements

You only need one diagonal at the front.

Rather than add diagonals to the tunnel and bulkhead weld in 1/6" steel.

Here's mine


Chassis painted inverted



Chassis inverted side painted


Regards Mark

Ok so from this....

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To something like this (Also moved the inner rails inwards to triangulate further)

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Is there any reason MK have bent the lower rail so its made out of one piece rather than welding straight section?

You will have to ask MK

Have a read of the thesis word docs
Here

Then for the stuff I followed kitcaranalysis_V2.doc

[Edited on 31/12/13 by mark chandler]

Thanks not seen them before will have a look

Given the restrictions I have around my engine I have come up with the following

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Or given I do not need a deep passenger foot well, and could do with the extra space in the engine bay...

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If anyone would like to suggest changes attached below is a blank

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[Edited on 31/12/13 by Dan.]

No other opinions before I buy some steel and get mr angry grinder out?

not need so many diagonals, one of the diagonals in square strengthens enough, ant try "connect" diagnals.
to engine mounts diagonal are good, but enough one
Under engine i put screw reinforcement
Also put in corner (at diagonal) triangle plate stiffeners, at reduced tension of the welding seam

i have found few documents to frame stiffness optimization. email or need somewhere upload

light weights and stiff front:


how think about that?
blue one nood need- becaus engine at the point pull, other side press





[Edited on 1/1/14 by fregis]

Cannot do the right Y brace due to the locations of the turbo's, manifolds and wastegate's unfortunately, or the cross brace as that's where the oil tank fits and belts etc.

though you are right I probably have gone a little over the top on triangulation.

[Edited on 1/1/14 by Dan.]

Roll hoop and petty strut will stiffen the centre of the car

Hi,

Have a look here:http://locostbuilders.co.uk/viewthread.php?tid=148892 for inspiration. Made a definite improvement to steering feel.

Thanks for the input, dismantling the rest of the car will take place tomorrow and I'll get the cutting done, hopefully my local suppliers have what I need in stock. Also ordered a set of custom rear wishbones to match my new mounting points, I'll post pictures of progress and results of the suspension geometry of the new bones and mounting points :-)

hey dan. good to see another saab user.

i have this brace on my car



you will have to do this to clear the saab water pump outlet anyway


or you can do this


your rear upright carriers will need beefing up, they will bend trust me!! box up the back of them and then make a hole for the driveshaft to go through as the 3mm plate on the sides can bend.

sorry to say it if you have already spent out but i dont think your prop is up to it, i had to upgrade to a 4inch tube prop with lorry joints.

other than that great start.

couple of questions what box are you using? is it a bmw item? i went for the omega box its managed 3 years of my abuse so far!

and what are you doing with regards to dry sumping it? just running scavenge and keeping the standard pump or going the whole hog with a multi stage. oil control can be a real issue with these engines in longitudinal format as i have found out on two occasions.

this is the wet sump layout im running now that seems to be ok, but i am considering drysump options for the future, your thoughts would be interesting, if you dont have a solution yet then maybe we could knock heads together and develop a kit.

Great post many thanks for replying! Water pump is not an issue as I have already modified mine :-) but will be altering the triangulation anyway.

Didn't know about any issue with the rear carriers, I will box them in as suggested though!

Did you break your prop then? What power were you running?

Gearbox is from a T5 box from a TVR, basically the same box as a cosworth 2wd ratio wise but with upgraded internals apparently, so gives nice ratios and will hopefully last as it should be a fair bit stronger than the omega item.

I have a single stage scavenge pump pumping to the external tank, then feeding back through the modified sump to the standard oil pump, the setup is a total doddle thanks to the sump design, did the same on a friends car and it worked a treat.

Good to know there is another saab engined car about, I only knew of one other which also was built in my lockup, where abouts in kent are you from? I come down that way fairly regularly as I have family in Deal.

[Edited on 2/1/14 by Dan.]

Looking good Dan

So I have done a little work on this recently....

First of all increased the size of the engine bay by eating into the passenger foot well...

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Beefed up the front end with a little extra bracing and added 'r tube'

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Decided whilst I was at it I would re-design the rear suspension geometry..... (I can never leave things alone....)

Hello angry grinder... Out with the old...

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Moved outwards and downwards...

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Decided I didn't like the contact area they had so made new...

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Change in position

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New rose jointed arms with custom shorter upper bones held roughky in place to see how it looked (thanks Danny@MK)

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thought about different bracing options...

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Cut all the bits for bracing and left it for my friend Adam to weld up for me.... clearly he got bored as I found this additional roll protection welded to my car

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Welded up

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Mounts for cage welded in

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Engine in siute, yes the manifold does fit.... just, as does the dry sump pump

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Not sure what to do with the other side of the car yet, may put in a Y brace depending which manifold I use.

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Anyway that's it for now, the setup should hopefully strengthen things up nicely (when the engine bay is finished) and with the rear suspension modifications the car should roll less due to the centre of roll being raised nearer the center of gravity and the negative camber in roll significantly improved due to the shorter wishbones and repositioned upper mounts.

[Edited on 23/2/14 by Dan.]

Looking good fella, I've just added these 2 Y braces to the front of my engine bay and a removable one across the front. Could your Oil tank either go into the passenger footwell or drop to the level of the underside of the chassis to allow a full Y brace?


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Regards Dan

The oil tank is fine can position the Y brace round it, the issue is where the manifold is, I can get a y brace in there with the manifold that's in the pic, but I'd prefer to use the tubular I have, when I get the alternator and water pump back I'll weigh things up.

Collecting the waterpump and alternator tomorrow and have 3 days to make some progress, if anyone has suggestions for further improvements to the chassis i'm all ears as id rather get any mods done before its powder coated... actually surprised no one has asked about the rear suspension given The original MK Indy suspension geometry is a very talked about subject on here....

Looking like you are making good progress mate

Some more progress today, removed my external wastegate on my tubular manifold so I could fit in a Y brace, will have to reposition the wastegate when I get some stainless tube.

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