After getting Project VE
into the 12's it was time to relook at the exhaust and try
and find a system that satisfied both the power and noise
requirements as well as having the potential to go further
as more engine mods are done . We plan to slot a cam and
maybe more in the near future.
Since last issue we have
tested 6 different 3" combo's from Difillipo ,Xforce ,Manta
,D&T ,Sureflow and KPM and all have made similar power
but each and every system has droned badly .The drone is aggravated by Holden equipping the auto's with 2.92
diff ratios so when cruising the car is loaded at low rpm
and the boot area acting as a big sub box creating the
booming drone. . some worse than
others and with the local systems we have tried different
combo's of mufflers from each manufacturer trying to come up
with a solution that worked , so far without getting a
totally acceptable solution that we could recommend to use.
We directed our attention
back to the inlet side of the engine in the search for some
more power , after having been extensively developing a 2
bar Mafless tuning solution with EFILIVE for the new
generation E38 PCM in the VE for supercharged
applications we decided to apply this same solution to
Project VE just as we did with our early development of the VT-VZ
car when we developed the first true Mafless solution for
the LS1 during
Project Monaro right here in Perth Street car .
Tuning the engine
in Speed Density mode ( Mafless) allowed us to get more
precise control of fueling and spark as there was no
reversion from the MAF sensor (maf airflow sensor ) ,
as the E38 PCM has a polynomial generated VE table rather
than a more conventional 3D VE table EFILIVE has to generate a
virtual VE table and then reverse engineer the polynomial
coefficients , this provided some unique challenges
and will really sort the tuners out from the amateurs
especially when variable valve timing and displacement on
demand are thrown into the mix .
Careful tailoring of the
virtual VE table to suit the modifications on the dyno
resulted in a fuel curve that is perfect at ever load point
( and there are 1840 load points on the E38 as compared to
the 380 load points on a LS1 ) and a engine that runs
smoother , more responsive and efficient than when it left
the factory floor.
Initial testing left
the redundant MAF in place as there was no direct intake
solutions available other than the pod air box system we
developed in last issue. With this we saw good power and
drivability gains but it was the introduction of a new
Direct Flow Induction system from Corsa Special
Vehicles that allowed us to finally unleash some more hidden
ponies in the motor.
As can be seen from the
graph power with the Maf tune was 239 rwkw , after applying a
Mafless tune power rose to x rwkw , the with the new direct
Flow induction power again rises to 249 rwkw. A added benefit
of the new induction system was the cooler air being
directly ingested into the engine has improved fuel economy
and throttle response.
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We also did the exact same mods
to a manual VE to eliminate the torque converter from the
equation to verify how much difference there was between the
manual and auto
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As can be seen the manual
version responds even better to the same modifications.
Throttle response has
increased enough where a recalibration of the automatic
transmission was required to better match the new
torque curve , this allow us to firm up the shift points and
remove some of the torque management that Holden have hidden
in the system.
It was time to go back to
the track to see if we had made any improvements , first
pass out and the car ran a
12.80@109.75mph and then did constant 12.8's all night
on the std street tyres.
Our hp increases have been
backed up by the time and also a 2mph increase which is
about right for the hp level the car is at, traction is now
becoming a issue and it will only get worse when we upgrade
the diff gears and put some more power into the car -
hopefully next issue .
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