no boost in neutral? - Toyota Nation Forum : Toyota Car and Truck Forums

jesse0880 · 11-29-2006, 02:37 PM

in the second gen turbo'd mr2's, can u hear the turbo boost like u can when ur driving? cause my car runs like shit during boost (4000 rpms and on) but i can hear the turbo building up pressure, but when its neutral, i can rev it up till 7000 but the only sound i can hear is the motor without the turbo. also, when i rev it in neutral, it climbs rpms quick and smooth. whats the deal?

p.s. i bought my mr2 in none driving condition so i'm not sure if each symptom my car has is normal or not.

***MRQtwinturbo*** · 11-29-2006, 02:54 PM

in neutral..there is no load on the engine so can't build boost...how old are your ignition components??.....

jesse0880 · 11-29-2006, 06:25 PM

new plugs, new distribuator cap, used wires, and original everything else. i'v tried getting some trd wires but they keep sending me 93 wires instead of 91 so i cant use them.

no load in neutral huh??... since the engine is reving up, wouldn't there still be enough exhaust to spin the turbo? or is there some other action releasing the pressure?

Zz_005_zZ · 11-30-2006, 04:49 AM

MRQ Turbo is correct, at neutral there is no load, so although u will get a little pressure, if u have a guage, it will go up to I think - 5 vacuum. So it does buils a little, but not enough to really hear the turbo as u are still in vacuum and not in boost.
When u are revving in neutral u are only spinning on the engine, u are no longer going through the drivetrain , also u are not trying to move 2600 lbs. of car along either. Thus u will rev faster, it is completely normal, but I would chech all your ignition components as Mr2's love to eat plugs, and wires. U can get a full replacement of cap, rotor, plugs from
http://www.twosrus.com/catalog/produ...roducts_id=221
and then just purchase the wires seperately.
Hopefully this will resolve the issue with your running conditions under boost, but as you said, it might be other things to contribute as well... Good luck

Zero turbo · 11-30-2006, 08:24 AM

My car does build up 1 psi in neutral but i have to hit the redline (7,800 rpms) and you cant hear the blow off because of the noise of the engine ...but that its just my Mr2

Zz_005_zZ · 11-30-2006, 06:43 PM

lol, yeah I never went to redline... :0)

***MR2Jedi*** · 12-01-2006, 10:29 PM

The stock ignition wires are just as good and even cheaper than the TRD's. and your wastegate will not close without a load placed on the engine. So no boost...

Zero turbo · 12-04-2006, 04:02 PM

I have a external Wastegate so that its why i get boos in neutral

JekylandHyde · 12-04-2006, 08:01 PM

The second post of this thread already answered the question.
There is no boost while free-revving in neutral because there is no load on the engine.

Quote:

Originally Posted by Zero turbo

My car does build up 1 psi in neutral but i have to hit the redline (7,800 rpms) and you cant hear the blow off because of the noise of the engine ...but that its just my Mr2

You are building boost t redline because the rev limiter is kciking in which puts load on the engine.

Quote:

Originally Posted by MR2BAD

The stock ignition wires are just as good and even cheaper than the TRD's. and your wastegate will not close without a load placed on the engine. So no boost...

That is not accurate. The wastegate IS closed at idle, cruise, when the car is off and when you are building boost. The only time the wastegate is open is when it reaches full boost.

Quote:

Originally Posted by Zero turbo

I have a external Wastegate so that its why i get boos in neutral

It has nothing to do with the WG being external ... it has to do with you bouncing off the rev limiter.

***MR2Jedi*** · 12-04-2006, 09:42 PM

Thanks Doc,
I always thought it remained open at that point so boost would not build.Thanks for the corrected info..I love this site...