running without intercooler plumbed?

[CHB]

i'm going to drive my 3T turbo for almost 10km to get to the nearest exhaust shop to get my intercooler fitted. so on the way, the turbo is spinning freely without plumb between turbo outlet to the intake manifold. is there any down side running as such?

[IN 05 NT]

yes you can damage the turb by overspinning it ive heard as there is no restriction...

but if you just put up there keeping it under say 3000rpm i would assume it would be fine.

[brett_celicacoupe]

you can get away with it on a MAP sensored engine but a factory 3TGTEU has a air flow meter. if you plumb the AFM to the throttle body then you will be able to drive it okay.


expect some comments like "OMG bro, you'll overspin your turbo and cause damage to teh manifloldz"

you can work out reasonably close to where the turbo rpm will reach dangerous speeds but you need a turbo map

in short, keep the revs down and you will be fine

[IN 05 NT]

you can get away with it on a MAP sensored engine but a factory 3TGTEU has a air flow meter. if you plumb the AFM to the throttle body then you will be able to drive it okay.


expect some comments like "OMG bro, you'll overspin your turbo and cause damage to teh manifloldz"

you can work out reasonably close to where the turbo rpm will reach dangerous speeds but you need a turbo map

in short, keep the revs down and you will be fine

beat you 2 it

[CHB]

i'm running Megasquirt so worrying the AFM is definately out of question.. my CT26A start to making boost around 2800RPM.. if i try to weaken the wastegate spring tension to the lowest, then keep the RPM below 2500RPM, i should be safe right?

[brett_celicacoupe]

2500rpm should be pretty safe. you can probably set a rev limit in the software to do that

you should keep an air filter on the turbo though as well

[oldcorollas]

why not just wire the wastegate fully open?

[CHB]

wire? i didn't use any external boost controller for the moment, just by adjusting the spring tension on the external wastegate and it holds 10psi pretty nicely..

[brett_celicacoupe]

why not just wire the wastegate fully open?

seems like a lot of effort

[oldcorollas]

wire? i didn't use any external boost controller for the moment, just by adjusting the spring tension on the external wastegate and it holds 10psi pretty nicely..

yes... when there is back pressure from the intake manifold, it will hold 10psi.

when the turbo is free spinning, there will be nothing to slow it down.. so the rpm will increase...

by all means try it without having the wastegate open..... it is your choice

if you hear the turbo spool up.... hope it doesn't overspin.

[thechuckster]

personally, i'd go for the fully loose waste gate - minor PITA to do but cheaper than overspun turbo.

if it's not hidden between block & turbo, remove the c-clip holding the actuator rod onto the waste gate flap and then take rod off the that small metal post - waste gate will then flop around and you wont get boost and/or turbine speeds worth worrying about (unless you rev the motor).

you can't borrow a car trailer and hilux to tow the car to the shop?

[CHB]

towing with personal vehicle is consider illegal by local cops here in Malaysia.. i won't wanna mess around with them seriously..
now wat is the conclusion here?

[CHB]

i've think an easy way.. may be i can directly plumb the turbo to the inlet with easy straight piping without intercooler first, then drive it to the shop to get the intercooler fitment done.. i think that will be safer to run without plumb right?

[mumblezzz]

I thrashed the arse out of my 1J cressida with blown intercooler pipes with no problems. You should be able to drive down the road no problems.

[brett_celicacoupe]

when the turbo is free spinning, there will be nothing to slow it down.. so the rpm will increase...

yes linearly (as linear as VE vs rpm is) but not exponentially.

i blew a rubber reducer on the 2JZ IC piping at 16psi & ~5krpm. boost went down to about 2psi while i continued to hold the throttle wide open (hey sometimes i just dont give a crap ). the wastegates would have been 95% closed and the turbo(s) would have been flowing the full amount of exhaust gas. no adverse affects have been observed yet.

if you hear the turbo spool up.... hope it doesn't overspin.

as a rough guide, 10lb/min of air is about 100hp. interpolate the rpm lines down to where the pressure ratio is 1 and you can get a rough idea of what RPM it will be at.

at its peak power output in NA form, a 1.8L 4cyl would lucky to see 200hp.

using the gt28rs map as an example, the rpm would be around 60Krpm at peak power.

above 350hp you may start to spin it pretty quick




my 2c eh