Building a 16V to run on bike carbs

[Dr.Steels]

Hello This is my first post here hopefully I can get some help.

Ive decided to build a 16V to run on R1 bike carbs. The carbs themselfs arent what I am scared of However taking care of the spark is scaring me ****less.

I have deccided to use a MSD 6AL-2 Programmable ignition box (which will be wired in according the the manual).

I know I need to use the 7 Pin ICM to convert the 5V hall sender signal to a usable 12V signal for the box. And all this sort of thing.

I know that under load the amount of vacuum in the runner will change which will throw out my timing causing a re-adjust to become necessary. As such I have done some reading and found the following Timing advance table (found here)



I then entered these values into an excel spread sheet and plottted them on a scatter plot with lines. I was expecting this to yeild faily smooth lines with a common (or fairly common) shape and advance at idle. However this is not the case. In fact My lines very significantly before the 2600 RPM Range. Should I adjust the lines to make the shape more alike or is this a bad idea?


Fig2.0 Graph I have generated based on numbers from previous table

Also, Is anybody running this Box already? Can the map sensor be used to adjust the timing based on vacuum or does this only work for boost?

Thanks for anything you have to say

[cubanvr6jetta]

if the box give u the option u can use a map is better in this case im gonna rum map on my megajolt jr just make sure to build a good vacuum source get a vacuum line from each runner into the map and u can use that as a reference is ok

[Dr.Steels]

if the box give u the option u can use a map is better in this case im gonna rum map on my megajolt jr just make sure to build a good vacuum source get a vacuum line from each runner into the map and u can use that as a reference is ok

Um not all that worried with installing the map sensor. The MSD instructions (please remember I havent bough the box yet) say I can use a map sensor, But some of the reading I have done is suggesting that the map can only be used for boost not for increased vacuum DOes anybody have any experiance with this?

Also Does anyone have any feedback on the timing curve(s) I have generated...?

[cubanvr6jetta]

Y don't u go with megajolt is a lot cheaper eaxy to tune and is map sensor integrated and give u the tps option too the u can use with bike carbs

Sent from my SCH-R910 using Tapatalk

[Dr.Steels]

Y don't u go with megajolt is a lot cheaper eaxy to tune and is map sensor integrated and give u the tps option too the u can use with bike carbs

Sent from my SCH-R910 using Tapatalk

Where can I find info on megajolt? Google has shown me allot about lights nothing about an ignition box.

[Dr.Steels]

Where can I find info on megajolt? Google has shown me allot about lights nothing about an ignition box.

I have done some reading and searching, Information has been found on megajolt.. Seems like a better solution compared to the programable 6AL-2 i was looking at earlier.

Does anybody have a map I could use as a base point for my motor?

Its an ABF clone, 11:1 compression ratio, 3 angle valve job on stock sized valves, and a TT 276 cam?

[cubanvr6jetta]

Check the forum on the megajolt website the have a base tuning for any engine and a few other ones around

Sent from my SCH-R910 using Tapatalk

[ps2375]

To me, that looks like a very optimistic range for your vacuum, especially with a slightly hotter than stock cam. Most of the ITB builds I have seen(and the one we did) were with MS and run on alpha-n (tps/rpm) based maps due to the very small vacuum range. We never had a chance to see what the vacuum range was on our build. But with 288* cams, I doubt it would have been much.

[Dr.Steels]

To me, that looks like a very optimistic range for your vacuum, especially with a slightly hotter than stock cam. Most of the ITB builds I have seen(and the one we did) were with MS and run on alpha-n (tps/rpm) based maps due to the very small vacuum range. We never had a chance to see what the vacuum range was on our build. But with 288* cams, I doubt it would have been much.

Sounds like a good idea, I have been Debating between the two methods. Initially with the MSD I was planning on Using No TPS was available so I opted for a MAP sensor, i feel like the TPS is the better option.

[vwcrackerjack]

Post pics of the build please!!! I want to try the same with my 16 but have no clue where to even start and my car runs great so I basically just want more power. Anyone know how much more you can get from a setup like this?

[Dr.Steels]

wiring diagram for Megajolt