So, As mentioned in my last update..... larger injectors now installed and scaled to suit by Rick @ Unicorn once that was done it was onto tuning the top end.
This proved to be more complicated than first thought as we was plagued with a boost cut at around 6.2k, No error codes and no signs in the data to say what wasn't happy, all we knew was the power to the N75 would cut and engine would continue up the revs with just wastegate spring pressure.....so not ideal!
After some trial and error data logging testing different wastegate springs and preloads although the ea111 twincharger doesn't have a MAF sensor instead uses 3 MAP sensors we found that having more preload or using a stronger spring was passing enough air mass through the throttle sensor in the mid range revs to max out the engines air flow capacity that it dropped into a soft limp mode which cut the N75, Took a lot of scratching heads and few weeks of back and forth but that's part of fine tuning a tune.
At this point I was no longer interested in hp figures I just wanted my setup to work correctly and reliably, So once we figured that out the engine finally settled on the yellow 9psi spring in the forge actuator with 4 and half turns of preload, Boost Actual Vs Requested match each other from a peak of 1.65bar @3.8K and tapers off from 6.2K into the redline whilst still making 1.35bar but most importantly it holds boost to 7K with no cuts!!
Compromise is what's key when tuning most engines and with mine on the forge blue spring (13psi) I'd previously ran 1.7bar peak boost, holding 1.6 but had to heavily taper the boost off @ 5.4k down to 1.2bar to avoid the boost cut plus stock injectors couldn't flow anymore fuel which left the top end lacking in power. Now with the larger injectors I'm able to hold my peak HP upto the redline, I think we finished around 240hp/260ft lb as the ecu was pulling timing between 6/7k when increasing boost so it became knock limited due to cylinder heat/99ron fuel.
Not massive numbers on paper but a completely different animal on the road.
The compromise to the tune would be to run less boost as the turbo comes on which gives less mid range torque and push it further up the rev range which will give higher peak HP but then the car won't be as quick on acceleration but have a faster high speed (A drag strip tune) which is pointless for anywhere else but a drag strip, especially on a circuit track, then further on from this would be water/meth to be able to increase timing which I just can not be bothered with.
Considering at the time of this update it's the ONLY stock engine Bocanegra on a Venom Hybrid turbo to be actually Taxed, Running, Driving & being abused on the UK roads & Circuits today.... plus I believe it's the only Bocanegra to be tuned by Rick also.
so a TRUE UNICORN in every sense of it's name and still a very quick and capable little motor!! Anglesey Track day booked, Cadwell and Oulton coming soon!!
7 year's of ownership this June from stock to now and still under 90K