Initial Map on a VW Bug

jestes · Post by **jestes** » Sun Jan 20, 2013 7:55 pm

I have a moderate sized engine being built and plan to run a MegaJolt. Below are how I will be driving the car, the specs for the motor and the map I plan on starting with. Let me start by saying I know very little about ignition maps and I got this from the map library. Suggestions?

I'll be driving the car both around town and on the freeway up to about 75MPH but only on nice days. I live in the inland northwest where temps range from 40F to 90F. It gets much cooler and sometimes hotter, but I won't drive the car when it does. Altitude will be between 1900 and 2500 feet above sea level. I will also take the occasional long trip, up to about 250 miles but only once or twice a year. I do love to accelerate but I will keep the top speed at or below 75MPH. I will also take it to the strip and run it in a 1/4 mile once or twice, but I don't think it will happen with any regularity.

Engine:
2110cc (82mm stroke x 90.5mm bore)
044 heads (40mm intake 35.5mm exhaust)
Engle 120 cam
Dual 44mm Weber carbs
1-1/2 sidewinder exhaust

Mario · Post by **Mario** » Tue Jan 22, 2013 5:43 am

Hey Jestes,

What are your tranny ratio's?

jestes · Post by **jestes** » Tue Jan 22, 2013 5:50 am

Mario wrote:Hey Jestes,

What are your tranny ratio's?

I have a stock tranny right now. It has a 388 RP and all stock gears. It came from a 69 originally. When I get my good one built, I'm thinking 412 RP likely with stock gearing as well but I have not decided on that yet. I'm running 205/60 15s on the rear end.

Mario · Post by **Mario** » Tue Jan 22, 2013 6:09 am

When you get a little closer I can help you build up a new ignition map. I don't think that is very optimal for your combo and is under timed in most of the areas you will be using.

Your cruising RPM should be around 3200 with those rear tires this map isn't even all in yet. And with that cam you should be able to pull upto 7k at the track.

jestes · Post by **jestes** » Tue Jan 22, 2013 6:12 am

Mario wrote:When you get a little closer I can help you build up a new ignition map. I don't think that is very optimal for your combo and is under timed in most of the areas you will be using.

Your cruising RPM should be around 3200 with those rear tires this map isn't even all in yet. And with that can you should be able to pull upto 7k at the track.

That would be great. Thanks.

Post by **brentp** » Wed Jan 30, 2013 8:20 pm

Thanks Mario for the help!

jestes · Post by **jestes** » Tue Apr 02, 2013 3:30 am

jestes wrote:
Mario wrote:When you get a little closer I can help you build up a new ignition map. I don't think that is very optimal for your combo and is under timed in most of the areas you will be using.

Your cruising RPM should be around 3200 with those rear tires this map isn't even all in yet. And with that can you should be able to pull upto 7k at the track.
That would be great. Thanks.

OK, I think I'm ready to start on the map. The engine has come back from the balance shop and is being assembled this week. I have the exhaust on order and should be here next week. I have all the ignition components except the controller. I expect to order that really soon. The carbs are sitting in my office and all the tin is in the shop ready to be blasted and painted. The trans has a 411 R&P, the rear tires are the same circumference as a 165R15, I don't remember the exact size, but I did keep it as close to stock height as possible. The cam is good for well past 6800, but the exhaust will stop me about there. What other tid bits do we need to create a good starting point for a map? I am considering wiring in the switch to use 2 maps, one for the street and one for the strip but I don't know if that is really necessary. Thoughts?

jestes · Post by **jestes** » Tue Jul 16, 2013 4:51 pm

OK, I'm hoping to start the engine this weekend. I have the shielded cable as well as some other parts showing up on Friday. As long as I get the time and it's not too hot, I should be able to get it started. There were a couple changes on the engine specs, but nothing too big.

Engine:
2110cc (82mm stroke x 90.5mm bore)
044 heads (40mm intake 35.5mm exhaust)
Engle FK-8 cam
Dual 44mm Weber carbs
1-1/2 sidewinder exhaust

I'll be running at 3200 RPM at 70MPH with my tranny and tire size.

This is the map I plan on using. I'm shooting in the dark here, so any help would be appreciated. Better yet, is there any info on how to go about creating a map?

Lazeum · Post by **Lazeum** » Fri Jul 19, 2013 12:43 pm

You could check my topic with my Z where I've shown map evolution.
I've started with timing similar for a given load to reproduce distributor curve with no vacuum correction until power was good at WOT.
I then looked at map zone were I was cruizing under low load (3200rpm & low load), I increased timing until I can feel no more difference. I've got almost 15° difference at same engine speed between low load & high load.

I've got a wideband O2 sensor & DIY detcan to track knock.

I'm processing map in MS excel after road adjustment to make the map smooth on cells I haven't touched.

jestes · Post by **jestes** » Fri Jul 19, 2013 4:45 pm

Lazeum wrote:You could check my topic with my Z where I've shown map evolution.
I've started with timing similar for a given load to reproduce distributor curve with no vacuum correction until power was good at WOT.
I then looked at map zone were I was cruizing under low load (3200rpm & low load), I increased timing until I can feel no more difference. I've got almost 15° difference at same engine speed between low load & high load.

I've got a wideband O2 sensor & DIY detcan to track knock.

I'm processing map in MS excel after road adjustment to make the map smooth on cells I haven't touched.

Nice write-up. I'm going to get the stuff to make one of these DIY detcans next week. Which style do you use? Because my engine is in the back of the car, I think it will be easier to run a couple small wires rather than a hose. I'm going to try this one.
http://www.d-series.org/forums/diy-foru ... llars.html

I'll also try to find someone with a running VW Type1 engine that I can take some timing readings from. My engine was built with MegaJolt in mind. As a result, I don't have a distributor drive gear and the hole in the block has been plugged.

Here is a link to the blog I have been keeping on the car. You have to go back to 2012 to see a picture of it. The last year has been all about getting some of the bits and pieces worked out.
http://57bugbuild.blogspot.com/

Lazeum · Post by **Lazeum** » Fri Jul 19, 2013 5:44 pm

To start, try with conservative timing.
Let say 15° at idle and 30° at 3500rpm and up.
Make a linear plot from those 2 points and get you first map. This is how I've done mine and it is not finished yet but I've always been on the safe side.

jestes · Post by **jestes** » Fri Jul 19, 2013 9:10 pm

Lazeum wrote:To start, try with conservative timing.
Let say 15° at idle and 30° at 3500rpm and up.
Make a linear plot from those 2 points and get you first map. This is how I've done mine and it is not finished yet but I've always been on the safe side.

Something like this? At 70 MPH, I should be around 3200, so I set that as my target for 30°. I too will be doing this on a brand new motor so the soft rev limiter is set to 5000.

Lazeum · Post by **Lazeum** » Fri Jul 19, 2013 9:56 pm

That's exactly that!
With low rev limit and only soft rev limiter, my exhaust used to experience loud Bang when hitting max rpm so don't be surprised if it happens.

jestes · Post by **jestes** » Fri Jul 19, 2013 10:14 pm

Yeah, I read about the bang. I'll try to keep it low without hitting the rev limiter.