I have been reading, re-reading and researching and here's what I have come up wtih so far for my application.

Hardware
$175.00 MS1 PCB V3.0 w/o current limit protection
$199.00 LC-1 (I have no o2 sensor so I might as well do it right)
$ 45.00 MegaSquirt-n-Spark_Extra Daughter Board kit w/o EGT amplifier
$ 8.00 o2 Bung
(Still half the price of slappin a Holley on there!!!)
All set on relays and fuses and wiring harnesses materials.

Here's my application:
74 VW Super Beetle
street port 13b NA
keeping aux port functionality
this is not a daily driver but I don't want to have to compromise drivability and fun, megasquirt sounds like the answer for this.

I am fine with hackin up my CAS wheel
I think I will just get a TPS off of something at the junk yard.
Got a laptop and DB9 to USB adapter
This should be a hell of a lot easier than manualy soldering up 0603 SMT boards at my last job.
I'm just a little worried about starting the engine for the first time (still a long way away), the motor will be fresh and will need to be broken in under proper running conditions. I guess I'll have to be really patient and make sure I do everything right the first time.
I am slowly working on my EE degree so this is right up my alley

 

Sounds like you got most of it covered.

Since you mentioned the CAS, I guess you are doing ignition also. Any reason you aren't logging EGT? I think it's only like $15 more for the EGT IC and another $50 for a good probe. I've been pretty happy with mine and glad to have a little more data to look at, it gives you a little more insight into what is going on with the tuning process.

Then again, if you know exactly what to set the timing to you may not need it--especially for an NA.

Good luck on the MS and the EE degree.

Scott

p.s. I'm an AAE (Aero/AstroE) and really liked the few EE courses I took.

 

Rex is right. You can save the 8.00 as the 02 bung comes with the LC-1 already. Also the daughter board is purely a option as all you need with the V3 board is 1 additional lm1815 circuit..totally your call. If you can position the 02 sensor bung a foot away from the exhaust outlet to keep it from overheating and going into error moode or buy the 02 sensor heat sink innovative offers on the diyautotune.com site but its pricy 89.00 I believe. If your creative you can make a heat sink just copy the basic idea. The thread is 18mm by1.0 pitch. I made one as a experiment. Good luck.

 

My WBO2 sensor is at the end of a Corksport downpipe. Not using any heat sink at all and no heat problems--yet. Probably should have put one on as the egt temp easily gets up in the 1400-1500 f range.

 

Hacking up the CAS: There are two ways I've successfully done this. First was to leave just 4 teeth at 90 degrees - this will run leading only spark via a GM HEI module; you could use a VB921 just as easily to switch the coil current. I'm currently running muy's trail and lead code but am not running the second VR circuit. Instead, I've removed 2 teeth @ 180 on the CAS wheel so as to emulate a 12-1 crank wheel. The 24-2 trigger wheel in the CAS running at 1/2 engine speed works well. Also, don't get too carried away with a TPS if it's a lot of work; I implemented and have been running MAPdot enrichment only for a couple of years quite happily. Good luck, keep us apprised of your progress.

-Mike

 

I'd suggest going Mike's route (option 2 that is). If you knock off opposing teeth from the 24-tooth reluctor, then you can remove the top one completely. The V3.0 board includes the signal conditioning for one VR circuit, so you are all set to run fuel/spark from that board with no daughterboard needed.

The daughterboard is nice, in that it adds a bunch of extra features, but for a someone new to MS it will be quicker to get running/tuned using the method above. Once the base install is debugged and tuned, then the daughterboard can be added to allow for extra outputs, water injection, NOS control, EGT logging, etc.

That's my .02 anywho...

Roger.

 

Awesome info guys, I'll have to consider the egt, more info is always good. Guessing and luck are not my strengths, murpheys law kicks my *** every time.
Thanks for the heads up on the o2 bung with the LC-1. I'm not too worried about heat, I'm making my own header (none out there for to fit a beetle of course) out of 304-SS and I have a machine shop to work out of to make a heat sink if necessary. The machine shop should make the TPS mod a bit easier.
So what is the disadvantage of only running leading plugs? Aren't the trailing plugs there to get a more complete burn? or does this only help with emmisions?

 

I booked some dyno quality time a couple of years ago in an attempt to see what trailing contributed to performance, if any. I was unable to find any performance change at high power levels dependent on whether trailing was firing or not. Unfortunately, the dyno's gas analyzer was broken so we did not get that info. There is some interesting (from an engineering standpoint) info on plug number, placement, flame kernel growth and speed, etc., in the "Rotary Engine" books. One of them is at http://smrmicro.com/re-ky.pdf , I have the other if you are interested. The only difference is the publish date but they're quite different. The end conclusion is that trailing helps emissions under some operating regimes. All this data is on NA peripheral exhaust port engines. I hear from those in the know that trailing timing is important on boosted intake rotaries. The side exhaust Renesis does some very strange things with the spark at idle and low speed operation - it fires trailing first! Go figure...

-Mike

 

Second RE book up at http://smrmicro.com/re2.pdf .

-Mike

 

Thanks sooo much for the book links, I won't be going to bed tonight.

 

Quick question on EGT probes, I see some on ebay that look like regular old industrail K type thermocouples. Any reason not to use one? I don't know about the quality of the ebay ones but companies like omega give tollerances and can be had new for $34

http://www.omega.com/ppt/pptsc.asp?ref=TC-NPT

 

The issue is probably mounting. I normally see the probe inserted in a small (3/16) hole drilled in the header and fastened with a hose clamp:
http://www.pegasusautoracing.com/big...asp?RecId=5136

 

im gonna be ordering the megasquirt for my car this weekend too.. so i am using this sort of as my shopping list too.. just one question.. is there a reason for goin without the current limit protection.. ?

 

Im cheap and I plan on bench testing everything first with a fuse in there. I'll put an ampmeter in line as well.

 

I see no reason to go without it. It'll protect you from shooting yourself in the foot.

 

It is only a $15 difference.
Me:
At least I can admit when I am wrong. Current limit board it is.

 

yeah i noticed it was 15 bux more. so i think its worth it.. wideband O2 is not necessary right? can it be added later? im gonna pretest the ecu on my vert to learn it then transfer it over to my 75 Repu which has a T2 engine in it.. just so i'll know what im doin..

Sorry for hijackin the thread Rxbeetle..

 

]
No sweat, glad people are getting something out of the thread.

wideband is not necessary but it makes tuning much easier (not first hand experience but from what I have read here and elsewhere)

Has anyone had thier injectors sonicly cleaned? is it worth it? A place out here will do 4 for around $50 including flow testing.
http://www.cruzinperformance.com/fuelinj.html
The engine I am rebuilding has been sittng for a while and I just don't know what shape the injectors are in which makes some cleaning and testing very tempting.

 

Thanks for the injector cleaning link. Just what I've been looking for. Very reasonable cost, and local too.

 

Wideband is worth buying. Even for an NA it makes tuning so much easier... it's nice to be sure to within .1 AFR what AFR your engine is running at... With a narrowband you can never be sure of anything other than 14.7:1, lean, or rich. And you can't even be sure of that unless the sensor is hot enough.

I recommend wideband to anyone who can afford it (I've used a techedge, which works very nicely... I've heard good things about others though).

 

on my Repu, which originally had a carbed 4 port 13b engine, i replaced all the wires with a painless wiring 18 circuit harness.. that has for all the body and lighting and fuel pump wiring.. so would adding the relay board to the shopping list be a good option? the same would sorta apply for the beetle since it was carbed originally.

 

I wired the whole car from scratch. I'm a little ainal about wiring, I did everything on its own circuit with its own fuse and relay if necessary. I highly recomend using nissan relay and fuse blocks. They are very modular, They have a holder with 4-6 openings where a relay or tripple fuse block snaps in. You can make really nice fuse/relay blocks for just a few bucks. I think I got 48 relays and 2 full fuse blocks for $48 at "u-wrench"
The relays have the schematic on the top of the case. They are available in single pole, double pole, normaly open, normaly closed, and combined NO/NC. I cut up some sheet metal to make tools to remove the contacts from the plugs, I then solder and heat shrink my wiring to the contacts. I wish I could some pics, they are all 600KB+
http://cgi.ebay.com/ebaymotors/1993-...spagenameZWD1V
there we go, ebay duuuh...

 

Thanks for the help guys. I still need to pick up errors daughter board for egt but the motor is still in pieces so I have some time to get that all sorted out.