Lowering The Lift Point

[ballist1x]

So, ive been looking heavily into 2zz tuning since i bought my motor, and looked into piggyback ECU, and PowerFc etc to see how they can effect the power curve when lowering the Lift point etc.

Lowering lift seems to have great benefit to the overall powercurve, im sure producing better performance ingear and 0-62 etc

So the question i have to ask, is WHY didnt Toyota set the lift rpm to like 5500rpm, for example?

the Compressor has lower lift engagement AFAIK (would a compressor ecu swap work in a corolla TS?) or is the compressor engine different internally?

is there a specific reliability/emissions reason, or lack of real foresight into drivability?

all the mods for the car attempt to smooth out the difference so its obvious that the scope for lowering lift/get more power earlier is a favourite move for car owners, why didnt toyota revise and lower the lift?!

anyone?

[borodaz]

they will have done hundreds of hours testing with different lift points and came to a conclusion, maybe for reliability or economy reasons that 6200rpm is most suitable. but the reason we will never know.

personally i think the car would be awesome if the lift was lowerd to 5200rpm, we would hit lift a lot earlier and im sure a lot of hot hatches out there wouldnt stand a chance with us anymore, maybe the gears cant handle going an extra 1000rpm in lift.

one thing i have thaught about it lowering the lift to 5200rpm and also lowering the limiter to 7200rpm therefore the car still hits lift a lot earlier but u arnt putting as much stress on the gears by staying in lift for so long, yes this may afect your top end slightly , but how often do you hit top end ? not much if never.

[stoneyfordni]

compressor map would be useless as it expects to see manifold pressure being above 1000mbar ,

its not only top end in 6th thats affected , its top speed in every gear if you drop the rev limit , vvtli engines make power right on the limiter as it is , so whats the point of moving up a gear at 7200 if its still going to be making power at 8200 , your losing power doing that and making a slower car

and the reason the compressors lift point was lowered is the charger moves enough air at low revs to create torque at 5200 on the high cam , if you made a TS lift at 5200 , id say thered be a big gap in your rev range where nothing happened , im sure toyota researched the time to engage the 2nd set of lobes

[Ryan SA]

The same issue has been debated here in S.A

Conclusion was bringing lift in before 6000rpm would result in your car running slower, as Top-End will be badly affected.

[ballist1x]

The same issue has been debated here in S.A

Conclusion was bringing lift in before 6000rpm would result in your car running slower, as Top-End will be badly affected.

maybe but if that was true, why does PowerFC give good gains mid/high end by shifting this point down?

also, note that i think XRS owners get "detuned" 180bhp instead of 190 for a better mid end?

[slarti54]

I thought it was something to do with emissions restrictions being tightly controlled between idle and 6000rpm. But I could be wrong.

[Jock Fran]

A cam profile can only really be perfect at one engine speed - so it works well over a range of engine speeds. Maybe the high lift cam wouldn't have the right profile for engine speeds under 6k rpm.

Lowering the rev limit is a pretty silly idea - you'd effectively reduce your car to about 165bhp!

[stoneyfordni]

raising the rev limit is the way to go :D

[nrgizerbunny]

if you increased the intake pressure you could get away with lowering the lift point.

The lift is there because at higher speeds the engine chokes and the valve needs to stay open for longer to get the air/fuel in. by pressurising the intake, that sorts that issue.

[GTForbes]

was jus thinking that, the charger ensures the engine is getting enough air to get the benifits, i'm sure there is a little room to improve on power by lowering it, but it would be marginal, i know a few pwople using e-manage ultimates and charging their corollas and getting good gains