Martin and Walker replica of the 1955 Porsche 550.
Alfa Romeo engine and 5 speed gearbox from Alfa 33. 1.7L, 8v, 118bhp
(featured on Fifth Gear a few years ago)
http://video.google.com/videoplay?docid ... 2830802986#
Car built by myself between 2001 and 2004, Megajolt added in 2010.
MJLJ 4, TPS
Coil pack can just be seen tucked under the air box between the carbs.
Porsche 550 Spyder Replica
Moderators: JeffC, rdoherty, stieg, brentp
Porsche 550 Spyder Replica
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Martin & Walker Porsche 550 Spyder replica with Alfa 1.7 8valve boxer engine. MJLJ V4 / TPS
One dyno run in isolation isn't much use. If Troy@NMS has tuned it for you then I am sure he has already done what is needed.
The way I generally suggest for the WOT row on the map is to get a baseline run using your "best guess/current setting". Then take 2 degrees out and repeat. If the power increased take another two degrees out at those points, at any points it stayed the same leave it with the 2 degrees backed out.
Now if some/all of the speed sites lost power when you took out 2 degrees then you know you weren't on the ragged edge and that those sites were at best than "Minimum Best Timing", more likely some way short of MBT. (MBT is what you are aiming for, it is the minimum advance that gives you the best power for any given site. As it is the minimum it also means that it is nicely safe but without being so safe that it costs you power. For all these sites that you have just identified add 2 degrees and do another run. If power is no better or worse at those sites then back out the advance you put in at those sites, if however you have more power at some sites then add another 2 degrees to those and repeat.
Within a very small number of runs you should be homed in nicely. I am sure that someone will ask why 2 degrees at a time rather than 1. The answer is simply that 1 degree generally yields such small differences that it is usually impossible to reliably tell if it is better or worse when you compare the runs.
The observant may have noticed that I've only discussed the wide open throttle row of the map, well the principle is the same for all the other rows, you just have to work a little harder as under WOT the load is by definition constant so all results are in the same row. For all the other load sites you just have to do your best to maintain the load constant - it's easier with a TPS setup here as you just have to keep your foot steady, with a MAP setup you just have to accept that the load sites are likely to be moving so graph MAP as well as RPM on the dyno plot.
The way I generally suggest for the WOT row on the map is to get a baseline run using your "best guess/current setting". Then take 2 degrees out and repeat. If the power increased take another two degrees out at those points, at any points it stayed the same leave it with the 2 degrees backed out.
Now if some/all of the speed sites lost power when you took out 2 degrees then you know you weren't on the ragged edge and that those sites were at best than "Minimum Best Timing", more likely some way short of MBT. (MBT is what you are aiming for, it is the minimum advance that gives you the best power for any given site. As it is the minimum it also means that it is nicely safe but without being so safe that it costs you power. For all these sites that you have just identified add 2 degrees and do another run. If power is no better or worse at those sites then back out the advance you put in at those sites, if however you have more power at some sites then add another 2 degrees to those and repeat.
Within a very small number of runs you should be homed in nicely. I am sure that someone will ask why 2 degrees at a time rather than 1. The answer is simply that 1 degree generally yields such small differences that it is usually impossible to reliably tell if it is better or worse when you compare the runs.
The observant may have noticed that I've only discussed the wide open throttle row of the map, well the principle is the same for all the other rows, you just have to work a little harder as under WOT the load is by definition constant so all results are in the same row. For all the other load sites you just have to do your best to maintain the load constant - it's easier with a TPS setup here as you just have to keep your foot steady, with a MAP setup you just have to accept that the load sites are likely to be moving so graph MAP as well as RPM on the dyno plot.
Official Megajolt distributor for UK and Europe.
Complete Megajolt packages, EDIS kits, Trigger wheels and everything else you need for your megajolt install
www.trigger-wheels.com
Complete Megajolt packages, EDIS kits, Trigger wheels and everything else you need for your megajolt install
www.trigger-wheels.com