1jz builds boost

[pete05]

Can someone tell me why my 1jz builds boost when i free rev it. makes up to .5 bar at high revs

[EldarO]

is that just revving it up by stabbing the accelerator?

or it makes boost while you hold it at high revs?

if your just stabbing it, its normal to make boost, as it puts load on the motor while it spins up the crank, flywheel, clutch etc.

but if its doing it while your holding it there, somethings amiss, and i have no idea.

Elmo.

[pete05]

thanks, its more or less while im just giving it a bit of a rev, the auto must give a fair bit of load. i have had manual turbo cars before and never noticed this thats all

[EldarO]

if its still runs and boosts fine, id say it'll be ok, take it to have a dyno run if your concerned about A/F ratios.

but mine builds a bit of boost on free revs.

benefits of having two piss-ant turbos.

Elmo.

[pete05]

yeah i thought it may have been the factory pipe work is loading it up. it only has a 3inch cat back exhaust and thats it.

[brett_celicacoupe]

my 1g makes 10psi boost in neutral on the rev limiter

this is after about the second ignition cut event

[chris davey]

I have never tried revving more than 3500rpm in neutral but no boost for me with a small single.

[rogue-vl]

guys does this mean that a turbo engine doesn't generate boost in neutral? could anyone please explain the workings of that, I would have thought that the engine would build boost regardless of being loaded or not due to exhuast gas passing the turbine in both instances.

[chris davey]

Well I will give it a go in my current state. Engine being in nuetral means that there is less load on the entire driveline not only the engine. So from what I am hearing, stock turbos can build some boost with minimal load whereas my TR44 even though it is small (500hp rated) can not build boost as quickly with minimal load like the stock turbos. In the end, it doesn't really matter unless you plan on breaking auto boxes by nuetral droppin them anyway Sorry for my incoherent response.

[30psi 4agte]

Rogue VL.
It sounds like you are fairly new to turbos ??
Do a google on turbo chargers and have a read ...... There is alot of info around nd will get you started with the basics of how a turbo works and how the respond to load.

Once you have done this if you are unsure of any of it or its abit over the top give almost any of us a yell and we will be able to explain in more depth.


Im not trying to steer you away here .... Its just to explain how it works properly would take me all night !! ( i type slow )

[JZA70 R]

my 1g makes 10psi boost in neutral on the rev limiter

this is after about the second ignition cut event

if its the stock computer still you will probably find its a fuel cut rev limiter.

[renxun]

ya... mine doesnt build any boost below 4000rpm.on neautral reving. must be due to my aggresive cams.. even if there is boost on higher rpm the most i get is roughly around 0.3bar

[JZA70 R]

I can build .5 bar or 7 psi @ 3000rpm using the 2 step and only allowing 10 degrees of ignition timing doing so, so .5 bar at double that rpm wouldnt surprise me.

Building boost on unloaded motors isnt as hard as you think. probably a common misconception from the old school turbo days that you cant make boost by revving the motor in neutral. probably from the noobs that dont understand how turbos work properly.

[renxun]

haha...so how does the turbo work?

[stradlater]

I dont' get any boost free reving up to any rpm... :-)