Safe boost level on 91?

[MyXsPtLk]

Hey all, I drive a 91 GT4, ST185, and I'm installing my boost controller tomorrow. Due to petrol costs, I've been feeding her 91 for the past couple months. How much boost would be safe to run on this? I've got my intake done, exhaust + dp, and I'm only planning to set it to 12psi. I have a boost gauge. This sound ok? Thanks all

[Alex B]

Its prety harsh even running it on factory boost on 91, if you can afford boost controler bov etc, why can you afford an extra $4 to put decent fuel in it

[MyXsPtLk]

Boost controller was given to me, its a cheap ball and spring one. All other mods were done ages and ages ago when money was good and gas was (relatively) cheap. I'm just asking if its safe to run 12psi on 91 octane. If it's not safe, hey I just won't do it

[EVL GSXR]

WHY!!!!!!!!!!!!!!!!!!!!!! You know if you were to put 20lt of 96 in your car you'll only be paying an extra $1 do you really think it's worth it

[ATAl]

You'll probably find that it uses the same amount (in money) of either 91, 96 or 98 per km if you drive the same with the higher octane stuff.

This is because the car will run more efficiently on the higher octane stuff and use less of it.

At least that's what i find with my car.

[MyXsPtLk]

nm sorry forget i asked...

[1598cc]

it should be ok, but theres always a chance of it detonating etc.. i used to run my 4agte levin on 91 heaps when i was poor at 18psi and never missed a beat.. it isnt the best thing tho as it risks detonation, and it seemed to chew through the gas faster on 91.

[mr pad]

nm sorry forget i asked...

Dont cry. People are just trying to be helpful. You will probably find your car gets just as many kms/per tank as it currently does if you run it on 98.

[Lanius]

nm sorry forget i asked...

Dont cry. People are just trying to be helpful. You will probably find your car gets just as many kms/per tank as it currently does if you run it on 98.

And less likely to detonate itself to bits.

In answer to the original question, no, don't run it at 12psi on 91. It'll work, but it'll kill your engine.

[blackie]

0 psi.

$&#$% 91

[Lunchie]

Yeah seriously mate.... sometimes we may seem a little harsh but the people around here have seen what happens when u try and take a cheap route using nasty parts or bad fuel...... but they do have your best interests at heart. .... but to sum up I would suggest that YES... you COULD run your st185 on 91... BUT...it is highly recommended that you dont....

To put it simply just think... if you do run it on 91 and u blow your engine up or damage something your going to be looking at a couple 100 bucks minimum most likely.... BUT if you used 96 ... or even 98 you would only be payed around 1-2 dollars more everytime you fill up plus you will get peace of mind that your engine is safe and.... shell love you for ... rewarding you with smooth power and distinct lack of pinging..... good times for one and all

[MyXsPtLk]

Nah I know the risks and all that but not to what extent, which is why I came here and asked first. Its no big deal for me, I mean having the boost controller on or not. That was all I wanted to know, if it was safe or not. Seems its not, so I won't do it. I'm not one who thinks doing sth cheapo is ok and coming on to ask for advice when all they really want is approval of what they're doing. 12psi + 91 octane = no good, so no boost controller for now, cheers guys

[blackie]

nah run the boost controller..
just use 96/98 !!

[mr pad]

nah run the boost controller..
just use 96/98 !!

Doooo iiiiiiiitttt.

[Punter]

Nah I know the risks and all that but not to what extent, which is why I came here and asked first. Its no big deal for me, I mean having the boost controller on or not. That was all I wanted to know, if it was safe or not. Seems its not, so I won't do it. I'm not one who thinks doing sth cheapo is ok and coming on to ask for advice when all they really want is approval of what they're doing. 12psi + 91 octane = no good, so no boost controller for now, cheers guys

I would have said 3sgte + 91 octane = BAD.

But hey its your car, if you wanna save $4 a week and risk it detonating its self to death, thats your call.

If you can't afford $4-$5 dollars a tank can you really afford to drive an old heavy 2L turbo.

Sorry if that came across harsh but i don't really understand why people see 96/98 as sooooo expensive.

[MyXsPtLk]

But hey its your car, if you wanna save $4 a week and risk it detonating its self to death, thats your call.

I just said I won't put it on, its no big deal for me, I'm happy with the way my car is now, I've had this boost controller for ages and ages just I've never been bothered putting it on. I had a day off today so thought I'd put it on and see how it goes but since everyone tells me its bad I'll just wait till i fill up with 96 or 98 next time.

[Santa'sBoostinSleigh]

But hey its your car, if you wanna save $4 a week and risk it detonating its self to death, thats your call.

I just said I won't put it on, its no big deal for me, I'm happy with the way my car is now, I've had this boost controller for ages and ages just I've never been bothered putting it on. I had a day off today so thought I'd put it on and see how it goes but since everyone tells me its bad I'll just wait till i fill up with 96 or 98 next time.

why njot put it on but just leave the boost down low...for now

[MyXsPtLk]

why njot put it on but just leave the boost down low...for now

I actually did think of that, say if my stock boost was 7psi, and I put the boost controller on and set it at 7, it would still feel slightly more "aggressive" wouldn't it? Because the ball and spring boost controllers keep the wastegate closed until the boost limit's been reach instead of letting the wastegate open gradually until max boost. That make any sense?

[flygt4]

use the search function up the top to research boost control on st185's. i ran mine at up to 14-15psi without using any form of boost controler. theres a couple of little tricks you can do to up the boost a little. then sell the boost controller and use it on gas. you can only go up to 12.5psi b4 you hit fuel cut anyway , and 12 psi is easily achievable. try searching for turbo vsv.

[Adydas]

I run 91 with about . 8 bar ( area ) = 11 or 12 psi on my stock
Gt-4 how ever its not a daily driver as i have a company car and If i blew up the 20 year old motor its just motivation to seek a Higher gen motor

but ive done Fineeeee on it for the past 5 months no visble issues ( other than Engine Mounts )