Tuning with a 123 ignition distributor.

This is the spec but it won’t be in the bus until February next year.
KB 96mm hypereutectic pistons, AA Biral cylinders, DRD forged and counterbalanced 80mm crank, H-beam con rods. 2316cc
VW 1800 heads, CSP 41mm x 34mm valves, Stateside single HD springs, TP swivel foot adjusters.
Scat C25 cam with Scat lube-a-lobe lifters
CSP HD Alumimum pushrods
Weber 40 IDF’s 30 vents (I might change to 32 vents once the engine has a few miles on it)
CSP 42mm Python exhaust with heat exchangers
CB 26mm Type 1 oil pump
123 Distributor currently set on curve 9 but I might change it to 2.

 

I have bought down the vacuum to 7 deg and raised the mechanical advance at 800 to 10 deg.

 

Here is what the dashboard screen looks like,I like that it has a temp sensor built into the dizzy.

 

Try nearer 1,000 bhp

https://www.telegraph.co.uk/cars/news/mercedes-amg-reveals-1000bhp-217mph-project-one-road-legal-f1/

 

When I had a 123 I just used the default curve. Worked fine for my needs.

 

Ok,was your motor stock?

 

Its using four electric motors as well as a 1.6 litre engine. There are electric only insanities in that space too with over 1000HP .. I think Mercedes had a 4WD chassis they showed a while back.
So it has massive power for a short distance and then backs off to a fraction of that for realistic cruising. But by then you have left everything in the rear view mirror.

 

@Clive Neilands I think you'll end up with close to the Bosch stock curve .

The programmable 123s are fine things, but unless you've got a dyno or rolling road to verify changes, how will you know if tweaks have made any difference?

 

I will do a rolling road session at JPM Motorsports.
I am tweaking the stock curve i found but really just learning about all this for the time being.
The bus is in a million pieces but heard from the welder he is almost done.Will most probably be delivered for paint around new years.

 

The problem with a rolling road is that you are working towards acceleration and power not cruising efficiently. Fine if all the time you are at WOT so the RR makes sense. But given your bus will do silly speeds at WOT then looking at what happens at cruise may be interesting too.
So an ignition curve for an engine that accelerates hard and fast through dangerous ignition timings may turn out to be close to detonation when you gently put your foot down at 60km/h in 4th gear, and maybe the MAP based load estimate diverges from what a ported vacuum on a stock carburettor would be saying...

At least you can start at the RR for a good ballpark then tweak it after driving for a while.

 

Seems an expensive waste to just end up with standard Bosch curve

 

I bet most folk with the programmable 123s end up with the stock curve. I can’t really see the point of the programmable ones.

 

I will have a map for dyno runs and a map for cruising...
Tweaking is the fun bit...

 

I wont end up with a stock curve..Motor is not stock

 

It will be fun getting to the new curve, an interesting learning experience.

You will probably need some CHT gauges and an AFR meter too, so you can try and tweak the carburettors to match the other improvements, as all carburettors are compromises mismatched to real engines, solving for either choking off the engine (stock) or delivering loads of flow at WOT to a high-revving Beetle or sportscar engine.

Even my progressive carburettor is really intended for 2.8L Ford Granada engines, so what its doing on a tiny 1641 is being a bit wasted - every time I open the second butterfly I dare not let the engine RPM rise to match what it can deliver.. the first 32 mm barrel is good to 70mph, adding another 36mm does .. scary RPM.. Like about 5700 under load in second gear...
Please note in case my wife is watching, that since she paid for a new engine, I have been very careful in staying under 4500rpm.