Is It Possible To Disable A Turbo?

[mad082]

Accelerating hard onto the freeway will not see you use more fuel!

yes it does. if you accelerate at half throttle, but still at full boost the throttle body is only half open, so less air is going into the motor than at full throttle. when more air goes in, more fuel is dumped in to keep the AFRs right.

if i drive round town accelerating hard all the time i use much more fuel than just driving casually round.

the harder you accelerate, the more fuel goes into the motor. you sound like you think that whether at 25% throttle or 100% throttle the same amount of fuel goes into the motor. that isn't true. sure you may have got up to speed in a shorter time by accelerating hard, but you have put more load on the motor, so more fuel goes in. and generally light load mapping is leaner than heavy load, so not only is there less air going into the motor, but the air/fuel ratio is leaner. so should you get to a point where the amount of air going into the motor is the same, the light load mapping will be putting in less fual that the heavy load mapping.

[Edge]

yes it does. if you accelerate at half throttle, but still at full boost the throttle body is only half open, so less air is going into the motor than at full throttle. when more air goes in, more fuel is dumped in to keep the AFRs right.

if i drive round town accelerating hard all the time i use much more fuel than just driving casually round.

the harder you accelerate, the more fuel goes into the motor. you sound like you think that whether at 25% throttle or 100% throttle the same amount of fuel goes into the motor. that isn't true. sure you may have got up to speed in a shorter time by accelerating hard, but you have put more load on the motor, so more fuel goes in. and generally light load mapping is leaner than heavy load, so not only is there less air going into the motor, but the air/fuel ratio is leaner. so should you get to a point where the amount of air going into the motor is the same, the light load mapping will be putting in less fual that the heavy load mapping.

Maybe, but are you sure its leaner on light load on this car? Does stoichmetric cut in whenever its off boost or just when idling? I am not asking if the meter is utilised but whether it runs stoichmetric off boost as opposed to idle.

In any case it is my opinion that you make up for the the richer mixture during 100% acceleration by sitting in higher gear off boost for longer.

[psybic]

Tell ya something funny...

I'm probably the ONLY person to have actually done this!!!!

Cooler pipe kept coming off on my way from Newcastle to QLD. After a while, i went, meh, and left it off.

This was possible due to an aftermarket ecu with a map sensor. So the turbo sure did spool... and blew air onto the side of the intercooler somewhere, but not threw it.

It was an NA-T so the hi comp meant it was the same as driving a normal SR20.

To answer the question tho, this isn't something I would have done on purpose. Its just stupid. Going on a flat road, you won't go above 0psi unless you accelerate.

Oh, for those who are wondering, fuel consumption wasn't bad. Only road trip the car has been on, so can't compare to with boost, but it was just over 10L per 100kms.

[FATGTS-R]

Wouldnt doing speeds over say 130km/h on cruise possibly generate some boost due to the load against the car from the wind?

[thrtytwo]

Wouldnt doing speeds over say 130km/h on cruise possibly generate some boost due to the load against the car from the wind?

the car should only suck in enough air to replace what was used in the last combustion cycle ? wind is hardly enough force to compress air, and even if it did it would be MINUTE and not spool a turbo

[Simon-S14]

i have sat on 200kph on back straight of mallala, at a constant speed once i had accelerated up to that speed. i maintained the speed and the boost gauge was still well into the vac range... ming you boost was tiny depression away lol.

this is with a rb20 + large turbo

[saliya]

i have sat on 200kph on back straight of mallala, at a constant speed once i had accelerated up to that speed. i maintained the speed and the boost gauge was still well into the vac range... ming you boost was tiny depression away lol.

this is with a rb20 + large turbo

Hmm.

I find that with my (stock internals) RB26 cruising on the freeway at 110 +- 20km/h it's _just_ on boost at cruise.

As soon as there's a slight incline it's into +ve manifold pressure.

I guess different strokes for different folks.

As speed goes up, the amount of forward 'oomph' required to maintain that speed increases as the square of velocity -

so you must have been in a _very_ aerodynamic car.

Regards,

Saliya

[mad082]

Maybe, but are you sure its leaner on light load on this car? Does stoichmetric cut in whenever its off boost or just when idling? I am not asking if the meter is utilised but whether it runs stoichmetric off boost as opposed to idle.

i put a wideband o2 sensor on my stock ecu and it ran 11.x-1 on full load, and about 13.x-1 on light load (normal driving).

In any case it is my opinion that you make up for the the richer mixture during 100% acceleration by sitting in higher gear off boost for longer.

why would you sit longer in the higher gear? if you mean that you are at full throttle but not fully on boost, you are still running richer than you would at less throttle %. if i am driving along and accelerate from 30kmh to 60kmh, then just cruise in 2nd gear, then lean out the mixtures and do the same thing again, the second time i am going to accelerate faster due to having more power, use less fuel due to leaner mixtures, and spend less time at 100% throttle and more time at light throttle. light load at higher rpm uses a lot less fuel than full load at a lower rpm.

if you are running 5psi and if you can sit at 5% throttle at 6000rpm (off boost), you are probably going to use less fuel than 3000rpm at 100% throttle (and full boost), as the amount of air going into the motor on each stroke is probably about 10% of what it is at full boost, so about 10% of the fuel is needed to have the same afr. now those figures of 10% may not be accurate, but it would be in the ball park.