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Designing your own TB's.

6K views 107 replies 29 participants last post by  Animal 
#1 ·
Designing you own TB's.

evenin' all.

Having aquired a (soon to be un-mullered) 3.0L v6, I'm having a stab at building some tapered tb's for it. Sounds ambitious? Well it would be, except for a couple of key things.

the heads are basically the same as the 1.6 16v, except for having 3 cylinders per head.
the cylinder cc is the same as the XE (bore is 86mm, stroke is 85mm)

The main problems are that there's **** all space, as you've got to try and fit 6 tb's in the space 3.5 tb's normally fit in, and that the bonnet is going to have to be extended up so that the induction system will be long enough.

The basic paramaters are:

45mm throttles (sourced from heavily chopped varijet2 carbs)
throttle plate will be approximately 200mm from the inlet valves
overall length will be 35-40cm in length
each cylinder will have 2 injectors, one in the trumpet, one in just past the throttle plate. It'll use either all XE cream injectors or bottom ones V6 upper ones XE Cream)

I'm prototyping it using plastic (white chopping boards) as it's easy to cut and very cheap. Final system will be a mixture of aluminum and fibreglass.

It'll be controlled by an emerald ecu, as it's much cheaper than the alternatives, and can do everything that's needed.

The exhaust manifolds will need to be fabricated, as the std headers are dire (the 3 exhaust ports each side are connected together with a cast iron box). Which will be fun. again, the XE and 1.6 manifold design are available, and coupled with a few informative books on exhaust design, I'll have a field day with it!

The rev limit of the v6 can be approx 7750, as the stroke is similar to the XE, and ARP rod bolts will fit.

If the 1.6 16v can make 164bhp on TB's with std cams, i should be able to get 280-300 bhp if i can get the TB design correct and the manifolds effective.

I've looked into getting some cams made for it, and i'll need to get them cut from billet as blanks aren't available, so it'll end up costing about a grand :eek: for a set of 4 cams.... still, if the 1.6 can make 190 from the 284/278 cams, then the v6 could make 320 - 330 Bhp ish with 240ish ft/lb.

Understand that these figures are very ball park, and were obtained by dividing bhp by cc, then multiplying by the new cc then taking some off, to try and take into account the valve areas (The 1.6 has much more valve area which will help it at higher rpm).

Photo's to follow..........
 
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#6 · (Edited)
the above pic i've seen before, but the induction length is far too short, and there's a sharp turn in there somewhere. Which is why it never made the power it could have.

I'm planning to keep them as straight as possible, and to make them a hell of a lot longer. Mind you, the manta does have a shed load more under bonnet space! :D
 
#11 ·
Respect!

I'm actually quite excited about hearing the progress of this abbitious, though thoroughly do-able project.

That info you asked for I will find out in the next couple of days as I can't remember it off the top of my head so will have to email EP.

Today I received a little bit of Chrisbatt's machining and can only say it was spot on :)

Dan

PS is that a nova in the picture, if so ****in hell!
 
#14 ·
Me and my mate built an inlet manifold to bolt onto a dcoe inlet manifold for his C20LET in a mini using sds ecu. It was made from mild steel. Have a look around the sds site as they show a couple of manifolds that have been made.

What are you going to make them from

muppet
 
#15 ·
I was thinking about doing this on the 2.5!!

I summed up all the cost and the associated difficiculties and gave up!!

Not that it aint doable though!!

What I did think of was for and aft bank balancing, I was thinking of using each pair of throttles across the banks and so mounting the bodies laterally.

I gave up after it took me about 3 hours trying to design the inlet manifolds!!

But best of luck mate!!!!!
 
#19 ·
Love it. Keep us fed with a constant diet of photos and ideas. You should be getting close to 300BHP and 230lb-ft since the 20XE makes 200BHP/160lb-ft on TBs.

Emerald ECUs, that's what DVAndrews uses amongst others. It's
Dave Walker of CCC I believe?
 
#20 ·
i'd like to think so, but i'm not 100% on valve area differences. I'll do some measuring later.

emerald can supply an ecu which can do 6 cylinder sequential injection, with twin injectors per cylinder.

Come to papa!
 
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