GSlender's Track Beeotch!

gslender · Postby **gslender** » Thu Aug 28, 2014 12:45 pm

Looked into the problem, available space and chance that I can get the air-box to fit with reasonable amount of effort, including would I be happy even if I removed the brake booster etc...

I'm now selling the air-box and keeping the braking system as is!

There just isn't enough space around that area even with the booster removed. I'd still be very close to the clutch master, and close to the sub-frame, and still it would be a struggle (and perhaps even impossible) to add/remove on the angle insertion using the backing plate they are designed to work with etc.

So, I'm going to start looking at building my own air-box.

How? I'm going to use some solid balsa wood to help me design, shape and define the air-box that would fit. Making this in solid balsa wood means I can mate it up to the existing bolts on the ITBs and it is strong enough to remain in shape when pushed and shoved around existing pipes/hoses etc, but soft enough for me to sand, cut etc so that I can be confident of the needed shape. I can glue balsa together (and it bonds fairly strongly) allowing me to build up shapes and get the needed shape correct so that I'm confident that a copy of this solid air-box will be a perfect fit - as sometimes measuring gaps and spaces is even difficult when you have a tight space to work in.

As the balsa air-box will be a solid item, it is essentially a mold or template of the final item - allowing me to measure or shape steel, tin, ali or fiberglass, plastics etc in my attempts to build this. I won't need the car or engine and can make many attempts, panels or even give the item to a fabricator and they can make something that is essentially the shape of the air-box and provide back a finished product.

Idea would be to have it have a lid, or be in sections so that I can put in place, and then secure using the trumpets which are inserted inside the unit - or, if a backing plate was used, I would ensure the air-box can be dropped straight into the position, and not require any angle insertion like the Pipercross and Jenvey air-boxes do.

Thoughts? Suggestions on the approach and/or materials and/or fabrication options?

plohl · Postby **plohl** » Thu Aug 28, 2014 2:17 pm

Sounds like a slide plan.

gslender · Postby **gslender** » Thu Aug 28, 2014 3:01 pm

plohl wrote:Sounds like a slide plan.

Slide plan?

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plohl · Postby **plohl** » Thu Aug 28, 2014 3:08 pm

haha - solid.

I can't say that was auto-correct either haha.

Magpie · Postby **Magpie** » Thu Aug 28, 2014 5:07 pm

Watching to see the solution. G have a look at using 90mm trumpets as well into your solution.

sailaholic · Postby **sailaholic** » Thu Aug 28, 2014 5:26 pm

Qld - mx5 itb skunk works.

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Magpie · Postby **Magpie** » Thu Aug 28, 2014 7:20 pm

Brake Calculations
http://www.engineeringinspiration.co.uk/brakecalcs.html

MattR · Postby **MattR** » Thu Aug 28, 2014 8:19 pm

There is another solution to the problem that will effectively give you the room you want and get the pesky brake and clutch bits out of the way of the ITB's and airbox.

Have a look at some old 2 litre super tourers. They were, and I reckon still are, the pinnacle of production based race cars.

Where you have engineering solutions that saw things like hollowed out rear windscreen wipers on Mondeo hatches because it improved the aero flow to give them another 5km/h top speed, or where V6 tranverse motors were that low and pushed that far back that the drive shafts ran through the V of the motor. Plus the coolest racing cars ever, the Volvo station wagons, it was a pity they were banned from the BTTC though......

To fix the problem of the MX5 do what Nissan did with the SR20 in the Primera sedan. Basically they turned the head around on the block to swap the inlet and outlets over on the motor to meet regulations and give them the power they needed.

And on the brakes, my old Zed ran unboosted 1" master cylinder, up from the 7/8" boosted standard when I did the brake swap on it. The pedal wasn't that much harder than a standard Zed.

Have also run other cars unboosted as well, things like very cammy 4 cylinder Datsuns running twin 40 and 45 mm side draft webers, so no vacuum to be made from the one cylinder until you are at over 4500rpm.

gslender · Postby **gslender** » Thu Aug 28, 2014 9:20 pm

The issue isn't solved by having the brakes on the other side. The ITBs are just too close to the sub frame, and frankly there just isnt enough room for the std range of air boxes made by Jenvey and Pipercross.

So whilst I'm down that I've blown some $$$ on the Jenvey air box, I do get to build a custom box knowing there is simply no way to do it otherwise.

Who knows, maybe I can sell a few of them and recover the cost of the Jenvey box!

G

sailaholic · Postby **sailaholic** » Thu Aug 28, 2014 9:27 pm

Which part of the subframe are the close to? Might be another Jenvy vs Toyota difference.

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gslender · Postby **gslender** » Fri Aug 29, 2014 8:26 am

sailaholic wrote:Which part of the subframe are the close to? Might be another Jenvy vs Toyota difference.

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The manifold and ITBs are so long they extend over the subframe where fuel lines, loom and other stuff lie. Both Jenvey and Pipercross air boxes would be touching or require more room to fit on. If that was the only issue, then I'm sure you could make a new special backplate to avoid the problem, but given it just is another in a long line of issues - booster, clutch etc., it just seems better to build my own airbox and move on.

sailaholic · Postby **sailaholic** » Fri Aug 29, 2014 8:28 am

Yeah I rebent my fuel lines to give more space but your right there is plenty of other issues!

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Magpie · Postby **Magpie** » Fri Aug 29, 2014 9:21 am

G I'll be back in Brisbane by the end of September and I can bring mine around so you can get a look. I can get the airbox you borrowed to fit mine, however the PWR oil cooler lines are in the way. Have you moved the clutch master?

gslender · Postby **gslender** » Sat Aug 30, 2014 3:17 pm

Space available

The problem zone

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Magpie · Postby **Magpie** » Sat Aug 30, 2014 3:31 pm

A suggestion is to replace the Jenvey ITB bodies with a shorter version (they do make them). This will move the point where the trumpets attach back towards the engine so something like these could be fitted:

However they more than likley need to be angled towards the front as well as angled upwards. It looks like the 88 deg ones can be twisted but they only come in 42mm x 160 a bit long

I have a set of 90mm straight trumpets if you need to borrow them.

Look we have the same problem zones