My 1992 GTI

**DocWalt** · 01-09-2014, 07:59 PM

Update on the trans situation... More money than I expected, but full rebuild and brand new diff.

Swaybars will be here tomorrow.

I replaced the MAT/IAT sensor with the open element style sensor and it's a LOT better to tune with. The closed element style sensor heatsoaked like crazy and generally sucked. I'm unsure why I wasted so much time with it.

I've spent a lot of time making the idle work well, and here's the results.

Here's the AFR map that I'm aiming for. This map is what tells the MS to trim fuel while driving around. It's also what the VE Auto Tuning app aims for, so you can use the autotune to get your tune really close, which is what I did. Note that I've set the idle area on this map richer than reality so if I decide to use the autotune in the future it won't lean out the idle since lean idle is really unstable.

Ignition timing map. MS will use this map to set the ignition timing based on load, RPM, and some other factors. Notice that it's targeting the stock 6 degrees of advance in the little "pool" at idle. MS will advance the timing if the idle drops too low which pushed the idle RPM back up. Works well!

Volumetric Efficiency map. This tells MS how much fuel to inject at certain loads and RPMs. I need to smooth it out a bit at some points, but it idles very well, and drives smoothly. Plus it makes tons of power at a safe 12.5-12.7 AFR at full throttle. I'll probably lean it out a little bit to make a little bit more power.

I need a new battery and I forgot to change to lightweight oil for winter, so it's not very nice to start up when it's cold out, but oh well. I'm really liking MegaSquirt.

**Alex3000gt** · 01-09-2014, 10:35 PM

Change to that light weight oil! Save yourself startup wear and tear!

Alex

**DocWalt** · 01-13-2014, 08:39 PM

Eh, new engine is going in soon enough.

I think I need to add a bit more fuel at cranking, it spins over a few time then slowly catches itself. Takes off really well and runs superbly after that though. Awesome

Also, catches itself about 99% of the time when dropping to idle. Hot starts make it idle surge until you drive around a bit and cool it off, I'm hoping that having an airbox sucking cold air will help that a lot. I'm not sure it will help the IAT sensor heatsoak issue though. Unsure how else to tune around it without messing with the way it will run when it's actually sucking hot air.

Also, sent the money for my trans. Everything is rebuilt and waiting for the LSD to arrive. LSD: Peloquin Transaxles

**DocWalt** · 02-01-2014, 04:02 PM

Picked up a brand new OEM coolant expansion tank today. I'm tired of mine flashing the low coolant light at me, more Meyle junk...

Also, did some video work...

**Alex3000gt** · 02-08-2014, 02:51 PM

Had to tow Kenny back from the track today.

**stealthee** · 02-08-2014, 05:08 PM

Dat wheel gap..... Looks like my car did when I bought it.

**DocWalt** · 02-09-2014, 03:28 PM

lulz. broke my throttle body today.

**DocWalt** · 02-11-2014, 09:49 PM

My brother fabbed up my Digifant to 3" air box today. Needs some longer bolts to mount the cone filter adapter, and needs some sanding and painted up so it looks factory, but it's going to be extremely effective. It will quiet down the insane intake roar I have, but it will make tuning a bit easier since it will be sucking cooler air. I might need to pop out the intake venturi to let enough flow in, we'll see if I'm pulling any vacuum at WOT now.

This is what the airbox looks like without the MAF mounted: