Hey everyone. Everyone should have tracking #s now and kits are on the way.
A few folks have sent us their ECU readouts.
I'd like to take a moment to discuss lexus "premium rquired" tune vs the Tundra 87 octane tune.
Some interesting info to ponder about. All of this information is comparisons of stock tunes.
While we have tuned this calibration and did bench testing, we didn't "deep dive" into comparisons over the Tundra before. We want to share some of this information now as we do some comparisons.
Reviewing The tune on the lexus, the only thing that stands out as why it*may* require premium fuel is that under certain scenarios (when all temps are in check, oil, IAT, ECT, etc) the ECU may allow as much as 1~2psi increase around 2000 RPM vs the Tundra.
However the Tundra runs more boost overall, especially at higher RPM.
BOOST:
The Tundra and the GX550 run nearly identical boost pressure and airflow limits. The GX550 does not get any "significant improvement" in boost pressure compared to the tundra. The GX550 can, in certain scenarios only, run slightly higher boost pressure at low RPM (around 2000 rpm) and about roughly 1psi higher than the tundra.
However, the GX550 actually gets LESS allowable boost pressure above 4400 RPM than the Tundra Does. Above 4400 RPM the GX550's boost pressure is gutted.
Ignition:
Ignition timing strategies and target ignition are virtually identical, except that the Tundra actually uses more low load / low RPM ignition than the GX550 does.
Valve timing:
Nearly Identical, with the exception being the Tundra has better Valve timing targets at higher loads / moderate load / above 4400 RPM or so.
We have not received much inquiries about making an 87 octane tune for this vehicle (even though we will be providing one).. VF Tuner is quite confident we will be able to provide you guys a solid 87 octane tune that not only is safe, but will provide you more power too.
This is just our opinion, but Lexus is requiring "premium fuel" for their "premium GX550" which actually does not need it. What is more interesting are the rumors that the GX550 uses a slightly smaller turbocharger than the Tundra, and lexus makes nearly identical power figures as the tundra, but requires premium, and uses less boost at higher RPM. This is very interesting. The lexus version does use lower ignition efficiency targets which would allow but not guarantee more ignition could be given (where power can be increased or decreased pretty easily).
Our opinion of the strategy: use premium fuel, Generate similar to, or slightly higher boost psi than the tundra at very low RPM, and dramatically reduce boost pressure in the higher RPMs while using an ignition strategy that calculates as "less efficient" allowing for more ignition timing at higher RPM.
The Tundra just does this easier and doesn't require premium fuel.