Operation TLC

Chat to do with your MX5/Miata/Eunos Garage Ride(s).

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Magpie
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Re: Operation TLC

Postby Magpie » Sun Sep 28, 2014 11:16 am

Did the Rev9 kit include the injector bungs, linkages, vacuum block, TPS and idle control motor?

Not sure how you will be setting yours up, but if you are deleting the power steer and air con you will not need the idle control motor. If you do need one I will see if I can find mine as it was purchased but never used in my build.

WID060 http://www.jenvey.co.uk/home/accessories/idle-air/jenvey-dynamics/idle-control-valve-wid060
AVK2T2 http://www.jenvey.co.uk/home/accessories/idle-air/jenvey-dynamics/air-control-valve-kit-4-ports-avk2t2
ZIPP04 http://www.jenvey.co.uk/home/accessories/fuel-system/jenvey-dynamics/10mm-japanese-injector-pocket-plug-ipp04
TP1 http://www.jenvey.co.uk/home/accessories/throttle-position/jenvey-dynamics/jenvey-tps-tp11
CLS1 http://www.jenvey.co.uk/home/accessories/linkage/jenvey-dynamics/linkage-kit-single-cls1

The part numbers are the ones used by Competition Systems in Melbourne.

Based on my build and torque curve, I need the overall length to be 320mm from the end of the bell mouth to the inlet valve stem. The stock Jenvey kit is about 220mm plus however long the inlet port is, roughly mine is only 275mm. The issue is clearance to the booster for installing longer trumpets. The trumpets need about 40mm min clearance from the bell mouth to the air box structure. Socks could be used but they disrupt the airflow across the bell mouth.

Maruha stroker kit serious coin, plus you will need to sonic test a block to go to 85.5mm. Mine was sonic tested to go to 85mm and it takes a few blocks before you will find one suitable.

Cam durations? If you have not decided have a look at these http://www.catcams.com/products/camshafts/datasheet.aspx?ENGINE_id=231&CAMSETUP_id=959 however you will need to change shim over bucket like these http://www.toda-racing.co.jp/en/product/cam/bp-5.html.

Also congrats on doing the wrap on the car, I do not have the patience to do that sort of stuff.

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gslender
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Re: Operation TLC

Postby gslender » Sun Sep 28, 2014 12:53 pm

That 320mm seems crazy to worry about. At that length, the RPMs being targeted are....
For 2nd harmonic, RPM range is from 9324 to 11314 with a pulse strength of 10 percent
For 3rd harmonic, RPM range is from 7006 to 8006 with a pulse strength of 7 percent
For 4th harmonic, RPM range is from 5462 to 6108 with a pulse strength of 4 percent

I'm unsure why longer trumpets would make any difference, but alas that seems to be the fuss
MX5 91 NA6 LE completely stock and loving it!
MX5 92 NA8/ITBs Silver "aka Track Beeotch"

Magpie
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Re: Operation TLC

Postby Magpie » Sun Sep 28, 2014 2:18 pm

I'll beg to differ on the length, however this is a build thread :) If the RPM being targeted is lower the total length needs to be longer! I will get a copy of the dyno with 90mm and 40mm trumpets and you can see the difference!

Based on the RPM of my engine, a 8,200 redline the length should be 385mm. However, Competition Systems have stated that 320mm would be optimal. A redline at 7,200 equates to 435mm length, assuming a proportional difference then at 7,200 the length needs to be 370mm.

http://www.jenvey.co.uk/jenvey/throttle-body-selection-with-jenvey-dynamics
What is the correct overall system length?

Induction length is one of the most important aspects of fuelling performance engines.
In our experience an under-length system is the greatest cause of disapointment, with loss of up to 1/3 of power potential. There are a number of good books on the subject and the serious developer is referred to these and, in particular, dyno trials. A guide figure, from the face of the trumpet to the centre of the valve head is 350mm for a 9,000 RPM engine. Other RPM are proportional i.e. for 18,000 RPM the figure is approximately 175mm.

Any air feed system to an airbox or filter can have a large effect on the power curve and must be considered carefully particularly if the airbox is small.
The induction system is part of a resonant whole from air inlet or trumpet to exhaust outlet and the ideal length is heavily influenced by the other components.


The above is confirmed by http://www.racehead.com.au/?page_id=211 which for 9,000 RPM a 12" optimun length is 305mm and for 7,000 RPM a 14" optimun length is 355mm which wilst the length does not calculate out the same, the fact that as RPM drops a longer intake tract is needed. This site uses the For 3rd harmonic for optimun and the 2nd and the 4th harmonics as alternatives.

Therefore based on gslender's post the 320mm (12.5") and 3rd harmonic is correct for my 8,200 redline.

http://www.racehead.com.au/?page_id=211
RUNNER LENGTH

This brings us to the second important aspect of the intake which is the length, this is actually quite simple there are harmonic frequencies in the runner caused by the pulsing effect of the induction stroke and these are set by the rpm. There always needs to be a high speed section in the port of adequate length for the air to develop enough kinetic energy so this eliminates the last group of harmonic frequencies and the second is typically too long to be practical and wall friction losses would diminish its effect. After that comes an optimal length for any given rpm and some secondary lengths either side which also work well and will cross over at lower and higher rpm”s. A simple rpm based chart can be used to determine the correct length where you want your engine to operate. So it goes to reason that if you have an unmodified engine with low power output you would use an appropriate size itb probably quite small in diameter and a long runner and this will help that particular engine perform at its best regardless of the engine modifications


Sorry to clog up your build thread, maybe ITB length needs its own thread. G it took me a while to find out what the harmonic and ITB's were trying to say.

Another good site to calculate length is http://www.rbracing-rsr.com/runnertorquecalc.html. People wonder why a turbo build is so easy to do!

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taminga16
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Re: Operation TLC

Postby taminga16 » Sun Sep 28, 2014 6:12 pm

Badge removal. Try Dental Floss with a sawing action.
Greg.
When you turn your car on, does it return the favour?

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gslender
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Re: Operation TLC

Postby gslender » Sun Sep 28, 2014 7:03 pm

Magpie wrote:I'll beg to differ on the length, however this is a build thread :) If the RPM being targeted is lower the total length needs to be longer! I will get a copy of the dyno with 90mm and 40mm trumpets and you can see the difference!

<BIG SNIP>

Therefore based on gslender's post the 320mm (12.5") and 3rd harmonic is correct for my 8,200 redline.


From the common calcs, the peak RPM of 8200 would best be suited to runner length of 380mm or 15 inches. If you can get that length then yep, at just over 7800 and onwards, you'll hit the 2nd harmonic and see cylinder filling at 10% beyond volume (a noticeable benefit). So if you've got 320mm then no doubt another 60mm will help that peak RPM. Not sure it will do much for anything below 5000rpm, but if you're seeing a benefit at low rpms then that's great.

All I'm suggesting is that from my measurements, the 40mm trumpets make it 300mm, so another 40mm isn't going to be anywhere near enough for a stock engine that redlines at 7500. Even another 100mm won't be enough. Either we need to get the NB engines safely spinning to 9000 or find a way to make the runner length 17 inches (or around 430mm) - basically work out how to add 170mm trumpets to the Jenvey ITBs... !! :shock: :shock:
MX5 91 NA6 LE completely stock and loving it!
MX5 92 NA8/ITBs Silver "aka Track Beeotch"

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ndragun
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Re: Operation TLC

Postby ndragun » Mon Sep 29, 2014 12:35 am

Thanks guys. Will look through the links. I'm aware of the dramas with brake/clutch MC clearance, but until the kit arrives and I can visualise the space available in there, I can't add to the discussion sorry. I'm just faffing around with vinyl wrapping while I wait... ;)

Magpie wrote:Cam durations?


Cams are Kelford 235-C - adjusted for HLAs. Put solid lifters in the too hard basket for the time being...
http://www.camshaftshop.com/products.php?productid=41358#specs
1994 MX5 Clubman
Jenvey ITBs, ported head, Kelford 203-D cams, stock-ish bottom end, Maxim Works header, MS2
XIDAs, Wilwoods, 6ULs

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ndragun
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Re: Operation TLC

Postby ndragun » Mon Sep 29, 2014 12:50 am

Other mirror is wrapped this evening. Bit of a different approach this time round - experimenting with joints and knifeless tape.
So instead of stretching the wrap from the front of the mirror backwards, I've worked the opposite way. Wrapped the trailing edge of the mirror first, then will lap back over it and cut the join using knifeless tape.

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So we wrap the edge first and fold it back, then knife cut it... After that, lay a line of knifeless tape around the edge of the mirror. Then we wrap from the 'dome' of the mirror back toward the edge and lap it over the top. Pull the knifeless tape string to get a nice straight, smooth lap edge.

Image

Visible in light - but hopefully a bit more of a durable finish over time...
1994 MX5 Clubman
Jenvey ITBs, ported head, Kelford 203-D cams, stock-ish bottom end, Maxim Works header, MS2
XIDAs, Wilwoods, 6ULs

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ndragun
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Re: Operation TLC

Postby ndragun » Fri Oct 03, 2014 9:36 am

The wait continues... Still no sign of the ITB kit, so not much to do until it arrives. Still just pottering and planning.
Meanwhile though, a nice little Maruha timing cover has arrived, so the rocker cover has been chopped accordingly.

Test-fitted;

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The timing cover bolts exclusively to the timing plate (as do the standard plastic covers). There is a bit of play around the top of the cover, so you can tweak the timing plate a bit to pull it into a more snug fit against the cut rocker cover. It does look like it will potentially rattle around a bit though but we'll see...

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Top of the timing cover showing the bit of gap between it and the rocker cover;

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The timing cover at any rate was ordered through http://www.chikaramotor.com/ and arrived within 4-5 days of placing the order. Given they have a fairly nice online presence it was easier to order through them than directly from Maruha. I love a good online shopping website... :lol:
1994 MX5 Clubman
Jenvey ITBs, ported head, Kelford 203-D cams, stock-ish bottom end, Maxim Works header, MS2
XIDAs, Wilwoods, 6ULs

Magpie
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Re: Operation TLC

Postby Magpie » Fri Oct 03, 2014 12:07 pm

I'm jealous as I looked at the same timing cover but it never made it into my build.

Keep the forum updated on if it rattles as I may have to start on the list of things I wanted to do but never did!

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ndragun
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Re: Operation TLC

Postby ndragun » Fri Oct 03, 2014 12:41 pm

Magpie wrote:I'm jealous as I looked at the same timing cover but it never made it into my build.

Keep the forum updated on if it rattles as I may have to start on the list of things I wanted to do but never did!


Will do...
Next thing on the list to think about is hydraulics. Obviously we're aware of the space issues for ITBs. So what I wanted to start investigating was moving master cylinders elsewhere. What are peoples thoughts on the feasibility of floor mounted pedal boxes, remote resevoirs, a remote servo (if required) etc;

Image

Image

Just a quick eyeball and measure of the footwell, we have about ~250mm width x ~250mm height to play with for a pedal box... Not sure about depth, but it seems to be a bit more flexible choosing a floor-mount design (again just eyeballing it for now).

A guy I made contact with at OBP said he was aware of the bulkhead mount unit being installed in an MX5 before, but unfortunately wasn't aware of exactly what was involved. Certainly tempting though...
1994 MX5 Clubman
Jenvey ITBs, ported head, Kelford 203-D cams, stock-ish bottom end, Maxim Works header, MS2
XIDAs, Wilwoods, 6ULs

Magpie
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Re: Operation TLC

Postby Magpie » Fri Oct 03, 2014 3:27 pm

Pedal box, illegal for road use, I did look into this. However if you find the right person you could possibly have it mod platted.

If you are going to track the car an aftermarket pedal box will car you all sorts of issues with class.

Further, you will need to match your discs, calipers to your brake pedal setup. There are a lot of calculations involved in this to make the selection right.

You can move the clutch resevoir on to the brake and free some room up this way. The proportioning valve can be moved as well, again this make a little bit of space.

Stay tuned as there are a few people on here looking into the space solutions and hopefully something will come from this. Good news is MX5 Plus is going to be testing a solution on my car in a few weeks and hopefully this will become a product line for them!

Maybe I can convince MX5 Plus to put a tease photo into this, gslender's or my build thread :)

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gslender
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Re: Operation TLC

Postby gslender » Fri Oct 03, 2014 6:15 pm

Magpie wrote:Maybe I can convince MX5 Plus to put a tease photo into this, gslender's or my build thread :)


Convince them? Surely confirming what they are up to with a few folks with ITBs and MX5s would be the right move to ensure some sales. I'm only experimenting because it would seem there isn't another option, or at least nothing I've heard of that sounds even remotely promising.
MX5 91 NA6 LE completely stock and loving it!
MX5 92 NA8/ITBs Silver "aka Track Beeotch"

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ndragun
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Re: Operation TLC

Postby ndragun » Fri Oct 10, 2014 10:43 pm

I did hear about issues with class using pedal boxes... but honestly I haven't researched it further. Either way - all open for discussion. Getting a bit frustrated at the moment since the key parts (ECU, ITBs and cams) are taking their sweet time to arrive and I've run out of things to wrap in carbon fibre vinyl for the time being!!

A few bits of bling have arrived though, which has kept me vaguely entertained;

Image

Nakajima oil filler cap and some shiny new rocker cover bolts

But more importantly, Maxim works header;

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1994 MX5 Clubman
Jenvey ITBs, ported head, Kelford 203-D cams, stock-ish bottom end, Maxim Works header, MS2
XIDAs, Wilwoods, 6ULs

mitch_f1
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Re: Operation TLC

Postby mitch_f1 » Sun Oct 12, 2014 9:25 pm

Where'd you get the headers from?

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ndragun
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Re: Operation TLC

Postby ndragun » Mon Oct 13, 2014 9:28 am

1994 MX5 Clubman
Jenvey ITBs, ported head, Kelford 203-D cams, stock-ish bottom end, Maxim Works header, MS2
XIDAs, Wilwoods, 6ULs


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