Boost ?
 

I just purchased a 1989 supra turbo all stock 5 speed. I was wondering what RPMS i should start seeing the stock boost guage begin to move. It seems like I really have to romp on it to get the guage to move at all, is this normal? If I really push it, it will go 4 to 5 psi. I was just wondering if I am pusing it too hard, if something is wrong with the turbo, or if it is just normal. Any info about how the stock boost and turbo should act would be appreciated.

what gear is this in? in neutral you will hardly see the boost gauge move at all. try in second and 3rd and just floor it. boost comes with load, because the more air the engine takes in and more fuel burned means more exhaust, so more turbo spin. try it out.

My 88 under normal "let's go" driving... boost kicks in at about 3200 RPM. (in 3rd and 4th gear). Fifth gear seems to be about 3000 RPM and 2nd gear can kick in at 2800 RPM (seems to sense I want to feel myself pressed into my seat a bit)

Thats without any mods or boost control or timer.

Suggestion.. if you dont have a boost timer I would get one.


And hey! Where's the pics! : )

Any suggestions in where to get a Boost timer? I tried ebay but didn't particuarly like any of the ones on there.

I found some pages with info for you... try these..

Greddy PROFEC B SPEC II - Turbo controller

Greddy Full Auto Turbo Timer|Greddy Black Turbo Timer|Greddy Japan - Turbo Timer

Those are just 2 sample areas...

Another super helpful page for you (from these forums)

http://www.toyota-supra.info/forums/...ad-thread.html - this is a "must read"

hmm.. trying to find the link that has all the other links in it... there is a post in here that has links to a lot of really good Supra sites that have a ton of info, but I can't find. When I have more time later today, I will see if I can find it and edit this post.

A good tip for this forum... when you want to find info, use the Search button at the top of the page. Just type in Turbo or Turbo timer. You will see a lot of posts similar to yours or that may have answers for the questions you have. Saves you time on waiting for replies. :dance:

Ok, my turbo is not working properly. The boost is not kicking in until about 5000rpms, in any gear, and is only reading about 3-4 psi. I checked the turbo and it spins freely and has no play. I was wondering if it could be a vaccum leak? This supra still has the origional wires on it. so I'm sure no one has ever changed or checked the vaccum lines. I'm giving it a proper tune up this weekend, if all the parts come. I guess I'll change out all the vaccum lines while I'm at it.
Any other suggestions?

The best thing you can do for your turbo past the maintenance issue (and yeah... any leaks will really play havoc with performance) is get the turbo timer. Failing that, remember that after your turbo spools up, you want to let it run non-spooled for at least 5 minutes to cool down. Otherwise, it can back the oil on it after you shut off the car. The turbo timer will run the engine after you shut off the car and lock it up for a pre-set time so that this never occurs.

If you aren't familiar with the turbo and what connects to what, i would recommend a mechanic (trusted!). Let him look it over first before you start playing with it, because in the end, its best to do it right.

all original car prob is having a gasket leak. does it sound weird or loud?

Not that I noticed, it actually sounds really good.

just to be clear i mean from the turbo, not the exhaust. Over time those bolts tend to loosen up on the turbo and the gaskets leak air.

Yes, the turbo has a nice quiet roar when it finally decides to kick in.

Were you able to get the boost situation fixed? If not send me a PM I had the same issue and resolved it.

-Ryan

why dont you post how you fixed it incase someone else has this problem... there's no point in being secretive, we all need help sometimes!

No secret really. All I was going to say is look closely at your intake to the Turbo. Mine has a crack in it, which is causing vaccume problems which was effecting my boosting. I put a rubber compound in the crack to tide me over till I can afford replacing the unit with a hardpipe model.

i think i got the same problem as u guys
i got a vacuum leak i dont know where yet and my car topped out at 118mph (it jumps at idle n when the cars cold i gotta give it gas so it can stay on)

it boosts normal but i only get about 4lbs of boost

could it be the vacuum leak?????
please help i dont wana end up buying a new motor

Could you be a little more specific? Are you referring to this being a Turbo issue? Or an idle issue? You said the Turbo was fine, but the idle seems to be off?

To answer the last question, it seems as though 4 lbs of boost is pretty standard for everyone with a stock setup. Although the gauge shows 8 psi being its max, 4 sounds about right. I myself have not messed with increasing the boost just yet, been fixing other small issues.

I had a vacuum leak that I took care of a couple of weeks ago. The issues I noticed were:

1. Actual spooling of the turbo was not consistent with the usual RPM range, such as spooling at 4,000 RPM and later.

2. As with any turbine, there is a distinct "whine" or high pitched noise when spooling happens, this sound was almost unheard because of the large volume of leaking air pressure, I did a simple test of this by driving close to a concrete wall to hear what was going on with the turbo.

The solution came by a simple replacement of the rubber tubing directly following the MAF sensor. As was stated earlier in this thread, that tube was cracked right at the inlet to the turbo, causing a massive leak of air pressure. But just to be safe I followed all the smaller vacuum lines to double check if anything else was getting too old and starting to crack. Lastly I checked the play with the compressor/turbine wheel to make sure it wasn't too lose, everything checked out ok.

Now the turbo spools just fine and at the right RPM's. Hope this helps diagnose your problems, any other questions just ask.

i really dont think its a bad turbo because as u said i was pushing 4lbs which is somewhat normal

my 0-60 speed is alright its just when i get to higher speeds is when it starts to "struggle"

plus i just noticed that the pipe from the intake to turbo is cracked on the the bolt part of it(pic below).....i should slap myself for not thinking of that.....but could that be where the leak might be?

I studied that picture you posted, and I can't tell what that clamp is there for? Is that pipe connected from the MAF to the Turbo? My second question is, is that pipe two pieces with that clamp securing the two together? I must say thats an interesting intake setup.

If I am correct in guessing that its a two piece pipe connected with that clamp then I would suggest replacing it because that clamp is broken and im sure its leaking from there.

yup thats it