GSlender's Track Beeotch!

gslender · Postby **gslender** » Sat Aug 09, 2014 5:55 am

I love working with the tuning tools that are available with MegaSquirt - they are just soooooo god damn cool!

In the pic below I'm using a scatter plot of TPS by RPM filtered by MAP to determine the ITB load switch points - ie when does the TPS position result in MAP being greater than 89kpa. You can easily see the curve shape, and how at different RPMs, more/less throttle is needed to meet the air needs of the engine.

This is then used to build a curve in the ECU so that it knows when to switch from Speed Density (ie MAP) to Alpha-N (ie TPS) tables (in a blended mode called ITB Load). When tps is below the curve (at that rpm), it favours MAP on the tuning table, when tps is above the curve (at that rpm) it favours TPS on the tuning table. So cool!

sailaholic · Postby **sailaholic** » Sat Aug 09, 2014 9:00 am

Pretty cool g. What is the advantage a straight alpha n tune.

gslender · Postby **gslender** » Sat Aug 09, 2014 10:02 am

sailaholic wrote:Pretty cool g. What is the advantage a straight alpha n tune.

Alpha-n isn't as easy to have smooth and tunable sections below the switchpoint - ie when map < 90 and tps small movements (like in low RPM) when you have less than 5% tps movement it can go from 100kpa to 30kpa... so you can imagine the throttle is on edge knife and the tuning is hard. In those situations you'd rather just switch to SpeedDensity (MAP based) but you're running alpha-n (TPS) for the above switchpoint areas, so you can't.

The normal solution is to use two tables blended - so you tune a MAP based table and then a TPS based table, and then figure out where/how to blend them. Not easy.

ITB Mode (blended speed density and alpha-n) exist on 1 table and its like tuning just for speed density - once set up, really easy to work with, very tunable and the auto-tune tools all work with it (because you're not blending a table).

MS3 docs explain it in more detail...
http://www.msextra.com/doc/ms3/ITB_Load_Mode.html

G

sailaholic · Postby **sailaholic** » Sun Aug 10, 2014 8:00 am

hey G, did you get someone to come and change your brake lines or did you do it yourself for the bias adjuster?

gslender · Postby **gslender** » Sun Aug 10, 2014 8:39 am

Paid $150 cash for a local chap and he did everything at home in my garage including the bits needed. Just ring a few brake places and ask them. The first place I rang said yes, they'll do a job at home for cash (wink wink).

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sailaholic · Postby **sailaholic** » Sun Aug 10, 2014 9:43 am

Sweet, thanks I will do that.

Magpie · Postby **Magpie** » Sun Aug 10, 2014 9:48 am

Be interested to know as well

sailaholic · Postby **sailaholic** » Sun Aug 10, 2014 9:52 am

Haven't you already done yours mark?

Magpie · Postby **Magpie** » Sun Aug 10, 2014 10:40 am

No running a NB8B proportioning valve only, never got around to the bias because of the ITB air box, trumpet length, booster delete etc school of thought.

gslender · Postby **gslender** » Mon Aug 11, 2014 5:26 pm

Waiting for this to be shipped...

When it arrives I'll adapt the backing plate and re-route the air temp sensor, install the NB idle valve and probably re-look at the idle lines and distribution block to work in with this new setup.

Heck, I might even throw the strut brace away... as it won't be needed apparently !!

G

sailaholic · Postby **sailaholic** » Mon Aug 11, 2014 6:53 pm

Very interesting looked at these years ago when the Jenvy kits first came out.

Did you get a top opening or a bottom opening one?

For memory there was two thickness as well?

Super keen to see how you go with it.

gslender · Postby **gslender** » Mon Aug 11, 2014 11:13 pm

Top opening. Only one thickness it seems.

Hoping it all fits without too much pain !

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gslender · Postby **gslender** » Fri Aug 22, 2014 1:37 pm

E85 sensor arrived - now time to install

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gslender · Postby **gslender** » Tue Aug 26, 2014 10:38 pm

So the air box arrived.

But it won't fit !!!

No way it will get over the last trumpet and I can't see how any air box would.

Might have to remove the brake booster!

As even with the trumpet removed, air box isn't centred due to contact with booster - dang, damn and big sux!

Otherwise it looks good

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sailaholic · Postby **sailaholic** » Tue Aug 26, 2014 11:13 pm

Ahh bummer! Despite what others might say I'm not sure moving the booster alone would do the trick. A under twin master set up would possibly be required.

Looks like I have a bit more space to play with so may get away with a fabbed airbox that tapers at the back to allow fitment.

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