eddierotary

iTrader: (7)

does theres any way to adjust a 88 turbo? im putting a 88 turbo on my gslse and i dont want to pass over 5 psi. can somebody tell me. thanks oh by the way about how much psi can produce the turbo.

VetteKiller

use a restrictive intake and exhaust, the turbo can make up to 20psi, but is only efficient to 12psi.

Ryde _Or_Die

Can't you take out something on in the wastegate(pill? or something) to keep it from going past the stock 5.5psi?

Rotorific

iTrader: (1)

boost controller that starts real low like from a volvo

Ryde _Or_Die

Boost controllers can only lower boost as far as the wastegate will allow, which on an S4 isn't very low. They are really used to raise boost and keep a more constant boost.

diabolical1

iTrader: (3)

you're probably going to have to limit it with a wastegate. i honestly don't know what type of wastegate the stock turbo on the T2 uses, but if it will allow you to change the spring in it, then that's probably all you'll have to do. however, you might have to ditch the stock wastegate for an aftermarket unit if it proves to be unworthy and insucceptible to modifications.

either way, i would strongly advise the use of some sort of boost controller for an added safety net.

eddierotary

iTrader: (7)

well im doin a n/a turbo setup for my gslse and i would like to run 5 psi. what is the stock boost of a tII?

KraftDinner

Stock 87 & 88 TII boost is 5.5 psi I'm pretty sure.
I'd just do that isntead of changing around wastegates and modifying stuff to get it to 5.0 psi.

Ryde _Or_Die

Yes stock boost is 5.5. But with different exhaust, intake or other factors it could be raised. I thought someone would chime in since it was talked about a few days ago, but I guess not. There is something you can remove that will limit the boost to the stock level of 5.5psi.

NZConvertible

Stock max boost on a S4 is 6.6psi (doesn't anyone read the FSM?) but on a stock car this drops to about 5.5psi at redline. Any performance mods that increases power (exhaust, intake) will raise boost. Even turbos with larger wastegates experience this. With a stock S4 turbo, just a cat-back and a pod filter should give ~8psi (unless the cats are clogged).

eddierotary

iTrader: (7)

i gonna use a 2.5" pipe going to the turbo to a dinomax cat and then from the cat all the way to a built for race n1 muffler. andi f it sound too loud ill gonna put the silencer that comes with it. and for the intake i think that my stock afm is smaller that a stock tII but im using a round k&n filter. do you think that enought to keep it at low boost?

diabolical1

iTrader: (3)

i still say the safest way is going to be limiting the boost yourself with a boost controller. i mean, it's been established now that the stock turbo can blow up to about 8 pounds with the right breathing upgrades, so i wouldn't keep my hopes pinned on the limited breathing of the SE's AFM ...

1- remember that the exhaust flow on the Gen II is different than the Gen I - that's going to be another factor with a question mark on keeping the boost down

2 - remember also that the higher compression of the SE motor is going spool that turbo up a lot faster (and possibly in a more erratic fashion, also) than the T2's motor.

i'm just saying it would be better to take the precaution of using some sort of boost control (manual or electronic) to give you an added cushion for error, instead of hoping that you won't get a serious boost spike and blow a rotor through the hood! just my 2 cents ...

also, which injectors are you gonna use?

Barwick

With a boost controller, it'll still be ABLE to boost up to like HUGE amounts of pressure, but the boost controller can limit it to as low as the factory wastegate thinks is good. The wastegate is sprung at 5.5psi I believe, and if you set the boost controller @ 5.5psi, it shouldn't boost over that.

NZConvertible

It seems every now and then, this reminder needs to be posted:

BOOST CONTROLLERS CANNOT LOWER BOOST!

Any mods that increase the airflow through the engine will raise boost from the factory setting, even with a boost controller. The only way to keep boost stock is to leave the engine stock. Please stop suggesting boost controllers as a safety device, they're anything but!
Sorry for the rant...

Aaron Cake

iTrader: (1)

Will people get this through their heads: A BOOST CONTROLLER CANNOT LOWER BOOST, ONLY INCREASE IT.

BlackFC

You know, instead of a turbo you could get one of those new air pump superchargers.


Please mommy make the bad man stop.

At no point during any of this rambling have you made a valid inquery. Had you taken the time to use the search button you could have found the answer to this and many more questions! I don't know about everyone else but I feel that I lost a few braincells here (not for any peticular reason to directed towards any certain person.)

Barwick

The factory wastegate is MECHANICALLY sprung at 5.5psi correct? If the boost controller tells it to open exactly at 5.5psi (and DOESN'T allow it to reach the 8 psi allowable on S5 T2's because of the Duty Solenoid Valve) then with the wastegate fully open @ 5.5psi, assuming the wastegate can keep up, why wouldn't it just KEEP the boost right at 5.5psi like it mechanically is set to?

NZConvertible

No, it doesn’t work like that. Even on cars with bigger internal wastegates than ours, and increase in airflow (exhaust, intake, etc) will increase the boost level without any changes to the wastegate or its control. This is always the case, there’s nothing you can do about it (except for using a much bigger external wastegate).
As an example, the turbo on my 12AT had a much smaller exhaust housing than the 13BT, but a much bigger wastegate. A full 3” exhaust and intake mods saw boost rise from 5psi to 8psi. Replacing the compressor wheel and housing with slightly bigger 13BT items saw this go to 10psi. This is all with no boost controller! My FC has only a pod filter and a 3” cat-back exhaust, yet runs 8psi.
It’s just the way turbos work.

BTW, stock max boost for a S4 is 6.6psi.

HAILERS

Sooooooooooo......does anybody know what the stock boost is for a 87 turboII??????? Ooops, did I hear a blood vessel just pop? humor.

I do wish I had access to a forum like this when I just had my 82 model. I was clueless that there was a turbo for that year model. Just in Japan I reckon. NZ, can you give me a idea of what kind of power you were getting with the turbo???? Sorry, I know its off the subject of this thread. I still have that 82. Emotional attachment since it was my first rebuild and has virtually brand new housings etc.

NZConvertible

Stock power for the 12AT was a typically optimistic 165hp; completely stock (including a 12yo cat and dirty air filter) it made ~135hp. That’s with no factory intercooler and a very primative fuel-only EFI system. By the time I next dyno’d it, it had a full 3” exhaust with one muffler (no cat), a custom TID and AFM adaptor, K&N pod filter, heat shield, cold air ducting, no emission controls, electric fans, plus some other bits, but still no IC. This was worth ~ 210hp on a warm day (it felt a lot stronger at night because of the lack of IC). When the turbo blew I rebuilt it with a 13BT compressor wheel and housing, and while I didn’t get it dyno’d again, it was definitely faster, with boost going from 8psi to 10psi. This was all good for high 14’s in a 2650lb 84 Comso. A mate had a genuine 84 Series 3 RX-7 Turbo, with the same engine. His mods were identical except for a FMIC; his made ~240hp, was 200lb lighter and was much faster!

eddierotary

iTrader: (7)

diabolical1 im gonna use the stock 670s plus another pair of 460s, but im not sure if ill use those 460s or find another pair of 670s. another thing should or should not use a boost controller

diabolical1

iTrader: (3)

I DON'T RECALL SEEING ANYONE, AND ESPECIALLY NOT ME, SAY THAT A BOOST CONTROLLER WILL "LOWER" THE BOOST!!!!!

I KNOW IT WON'T LOWER IT ... BUT ... IT "WILL" KEEP HIM FROM EXCEEDING THE SETTING THAT HE PUTS IN!!!!!

All he has to do is find one that can function at the lower levels, hell, he might have to build one, but it WILL keep the boost in check (as long as it's working) and it's extra insurance!

diabolical1

iTrader: (3)

well, i don't know what the stock size injectors on a T2 are ... but what i would advise is to get injectors that are capable of maintaining a fairly "rich" environment. that will help out since your compression is so high. i'm only saying that so that you can give yourself another little cushion ... that's my logic. i wouldn't be able to tell you how to control them without the use of some other computer, and i'm not sure how much adjustment is in the stock ECU's program to keep it from flooding if the T2's injectors are WAAAY bigger!
anyone that has these specs, feel free to chime in and help him out ...

as for the boost control issue ... i was saying that you should get one to help out. i already stated my reasoning, so i won't repeat it here ... but yeah, i was saying to get one.

just to clarify, it's not a way to turn boost down, it's just a way to keep it limited to the setting you choose. and if YOU got that impression from what i said, then i apologize. they are mostly used to turn boost up (by manipulating the wastegate) when it's set it will "help" to keep you from exceeding a certain boost level. it is VERY true that you might still be able to "spike," but i believe it is certainly better to have a controller than to not have one.
now, i'm clarifying that because of the individual that chose to extrapolate the wrong idea from what i said in the earlier response.
obviously there is some disagreement on this point, and i don't claim to know EVERYTHING there is about cars, so rather than telling you the wrong thing, i'll advise this:

do the research for yourself and make the decision that's best for you.

wish you the best on the car and the turbo setup!

NZConvertible

Diabolical1, please don't take this personally, but I think you should stop giving out turbo-related advice, because there are some pretty big holes in your knowledge.

Boost controllers cannot lower boost, and they cannot limit boost. What ever boost conditions existed before the controller is fitted is the absolute minimum you can achieve. If boost creeped to a certain level before, it still will, no matter how low it's set. Boost controllers can only raise boost! That's it!

Running excessively rich because of higher compression is just bad tuning. If detonation is occuring with suitable mixtures then boost needs to be lowered or ignition retarded. Rich mixtures just kill power, increase fuel consumption and increase engine wear.

I'm sure you're going to get upset and go off at me, but I'd much rather upset one person than hear of an engine failing because of poor modification or tuning.

jspecracer7

Go get 'em Jason!