Max safe boost? [Merged 10-6]

[Turbolaser]

Is it safe to do the boost contol solenoid mod on a stock 1G?

 

[GsX2Nv]

pte scm 1

 

[GVR4592]

I forget the exact equation but its something like (inducer/exducer)squared x 100. Usually the higher the trim the more efficiency loss. Some of the really high output turbochargers (1500+hp) are somewhere between 42 and 56 trim. Ever notice that the real big pump gas horsepower numbers are coming from 50 trims? Like Dre with his 504 whp with an agp 50 trim and 93 octane.

So like I said before there is only one way to know what the safest level of boost is for your vehicle. Datalogging and tuning.

 

[Sbeing1]

Right now i have all my belts, water pump, wires, radiator, thermostat.. evrything tune up is done. My mods are....
255 walbro pump
greddy evo catback
injen intake
super 16g turbo
boost gauge and fuel temp gauge
MBC
and i think thats pretty much it. I was wondering if i can up the boost? Right now im running at stock boost level, i havent even TOUCHED the boost controller yet (playing it safe) but i was wondering, with my current mods how much psi can i up the boost to? If anyone could help itd be appreciated. thank you.

 

[Andrew415]

You could run safe all day on 16psi , next step would be getting larger injectors and some sort of fuel tuning device... I run 16 psi and I dont have all those mods you have

 

[Sbeing1]

Great, so how would 700 somthing cc injectors be? and a safc? and after that would i beable to tweak the boost up a little again?

 

[dsmsucks]

Great, so how would 700 somthing cc injectors be? and a safc? and after that would i beable to tweak the boost up a little again?

Just remeber, once you up the boost you will be putting more stress on the engine and you would be demanding more fuel. Just finish the rest of the exhaust. I dont see a clutch in your list of mods. I would suggest looking for one, trust me the stocker wont hold . You might want to look into a better intercooler for the 16g.

Ps I wouldnt turn the boost past 16psi
later

 

[Sbeing1]

Yea i didnt put clutch cause im strickin with the auto buts thats getting swapped out soon. Yea, i was looking at a greddy 24v intercooler, i heard people have had some pretty good gains with those. Thanks for your help guys

 

[91Bomb]

Can someone help clarify this. I've read that to be 'safe' you should't go above 14 lbs and then I read somewhere else that 15 lbs is completly safe. Are the 450's 'maxing out' at about 15 lbs or is it more like 16 lbs? This is with a FP re-wire (if that makes a difference)

Will the 450's max out sooner with a s16g than a 14b? At 15 lbs the air charge should be cooler/denser with a s16g (more efficient turbo pushes cooler air) So a cooler/denser charge will call for more fuel -OR- does a cooler/denser charge = a higher boost level If not, does the ecu know and adjust the fuel for the cooler air? If it does that would mean the injectors would max out sooner with the upgraded turbo or when outside air temop is cooler? -OR- is 15 lbs always 'the same' 15 lbs -- ie., on a hot day the turbo has to spin faster to push a ?higher volume/lower density? charge to get to the 15 lbs and on a cold day the air charge will have ?less volume but be higher in density? so the same turbo won't have to spin quite as fast to reach the same 15 lbs?

Anyhow, I ask because if I put a s16g on a turbo motor it would have the FP re-wire and the other stuff done that's necessary to up the boost and although I would have a real boost gauge and egt gauge I don't plan on gatting a datalogger or a fuel controller. So I want to find out in advance what the max is on the 450's so I could set the boost at exactly 1 lb lower than that and whether the 'max' boost level for 450's is going to be the same irregardless of turbo choice.

 

[project_tsi]

Maxing out your injectors may couse you nothing but problems. Don't max them out, just because you can. W/ a stock fuel pump rewire, lets just say 15 psi max, just to be on the safe side. And although it may be more, thats what I would run to be safe.

 

[Thomas91169]

15psi is 15psi........

however.

15psi on the S16g will flow a wee bit more air than 15psi in the 14b.

i would go no higher than 15psi on the s16g with a fp rewire.

you should also invest in some sort of logging equipment, such as a palm/pocketlogger to be able to keep track of such things.

 

[94Jettameowpsst]

When i had a walbro 255, stock injectors & turbo, fmic, and exaust i was getting away w/ 94%idc and no knock on 23psi. If you wanna be safe, buy yourself a pump cause ## gonna need it w/ that turbo. Im sure if you atleast had that, you could probably squeeze 16-17psi outta that turbo w/ stock injectors...wouldnt recommend it but eh, w/ever works

 

[91Bomb]

Maxing out your injectors may couse you nothing but problems. Don't max them out, just because you can. W/ a stock fuel pump rewire, lets just say 15 psi max, just to be on the safe side. And although it may be more, thats what I would run to be safe.

I definately wouldn't want to max out those injectors. Like I mentioned I've read that at 15 they're maxed and I read that they max at 16 lbs.
Since I'd be going the 'cheap upgrade' route that wouldn't include a logger I would need to know what the max is so I could set boost level at 1 lb below that to be safe. I'm hoping 15 lbs with a s16g will be far enough below where it won't ever be a concern.

 

[Sbeing1]

Alright :sigh:, my car was running kinda weird and boost went to what i set my MBC at (16spsi) and kept changing from 15-16-15-16-15 ovver and over everytime it shifted. Now i was told to do a boost leak and itd be fixed. So i did and fixed 5 boost leaks. took it out and it got to 16psi and held (i have auto) and right b4 it shifts it flys to 21psi! then hsifts then goes to 16psi then BWOOOOOOOOO 21psi AGAIN. i dont know what to do, maybe my mbc it ####ed up. :dunno: if anyone could help me thatd be great. i bought the car about 2 months ago and havent messed with the mbc (came with it) and now i fix the boost leak and its at 21psi. maybe the previous owner set it to that? i dunno, but it goes to 21pi and holds. i forgot, is it turn to right or left to lessin boost on mbc? thanks guys

 

[Sbeing1]

now that i think about it, maybe it was supposed to be set there. it has walbro pump and maybe injectors (im going to check now, i find upgraded stuff on the car everyday.) is it safe to run 21psi with all the mods in my profile and injectors? im thinking i do have some kind of upgraded injectors because i didnt reach any fuel cut, it got to 21psi and held and kept getting faster and faster till it shifted and kept going faster. But i let off because im afraid because i never had it at 21psi b4 and i was scared the car was just gonna brake somthing

 

[oldman]

I'm not familiar with gearing on an AT but sounds like boost creep which was covered up by boost leaks you just fixed. Time to port away.

 

[Sbeing1]

Or i was thinking it might have been set at 21psi. Is it safe to run 21psi?

 

[oldman]

Or i was thinking it might have been set at 21psi. Is it safe to run 21psi?

No. To be safe, 16psi is more like it until you have larger injectors and all necessary supporting mods like afpr for your 255. Disconnect the mbc and run the pressure source directly to the actuator. If problem persists, it's most likely boost leaks. If you're boosting solid 12 psi, problem is related to your mbc or the installation of it.

 

[Sbeing1]

No. To be safe, 16psi is more like it until you have larger injectors and all necessary supporting mods like afpr for your 255. Disconnect the mbc and run the pressure source directly to the actuator. If problem persists, it's most likely boost leaks. If you're boosting solid 12 psi, problem is related to your mbc or the installation of it.

Im not sure if i have stock injectors or not, i looked at them and they have a metal ring around them, looks stock to me so your probably right on that. And i know its not boost leaks cause i did a full check, i even fixed the throttle body o ring thing. Well im not riding the car for another month starting today. Going to drive my dads car. But what if i bought injectors and a afpr during that time and installed them on the car. Could i leave it the way its been running at 21psi? Sorry for all the questions but it was really fast today at 21psi and id like to keep it there. thanks for your help

btw, yeah im at a solid 21 psi with no changes of pressure when it hits 21psi. thats why i think it might have been set there or maybe the previous owner didnt know it had boost leaks and set it to where the mbc was at 21psi but it was only pushing out 16psi because of the leaks (5 total leaks)

 

[oldman]

But what if i bought injectors and a afpr during that time and installed them on the car. Could i leave it the way its been running at 21psi?

You'll still need a tuning device to compensate for the larger injectors, safc or the likes, and a logger for tuning the safc with. After that, you will need to upgrade from the stock IC. The best option you have is to pick up a die grinder and a carbide burr, use the time you have to remove the exhaust manifold, turbine housing and o2 housing then port them like the link I posted above. Improved spool, flow, knowledge gained and solid boost control all for less then $30 plus time. Here's another link that covers all three pieces. Make your car runs properly first, the 21psi will come later.

thanks for your help

You're welcome, good luck.

 

[oldman]

btw, yeah im at a solid 21 psi with no changes of pressure when it hits 21psi. thats why i think it might have been set there or maybe the previous owner didnt know it had boost leaks and set it to where the mbc was at 21psi but it was only pushing out 16psi because of the leaks (5 total leaks)

I didn't see this part that you added while I was posting. If this is the case, the problem is mbc/actuator related. What brand mbc and how is it hooked up?

 

[Sbeing1]

The MBC is a no name bronze boost controller hooked up the way they say to hook it up in the tech section. Yea i guess im doing some porting today and this weekend. thanks alot for your help

 

[oldman]

The MBC is a no name bronze boost controller hooked up the way they say to hook it up in the tech section. Yea i guess im doing some porting today and this weekend. thanks alot for your help

Sounds like an Ebay ball and spring type, did you test run following my instructions earlier?

No. To be safe, 16psi is more like it until you have larger injectors and all necessary supporting mods like afpr for your 255. Disconnect the mbc and run the pressure source directly to the actuator. If problem persists, it's most likely boost leaks. If you're boosting solid 12 psi, problem is related to your mbc or the installation of it.

This test will tell you whether you need to port or a new mbc.

 

[Sbeing1]

no sorry to say i didnt, because i couldnt figure out how to do it when I tried, is there a write up on how to install the mbc the way you said to? im sorry, i bet its the easiest thing to do but i couldnt figure it out. thank you again

 

[oldman]

no sorry to say i didnt, because i couldnt figure out how to do it when I tried, is there a write up on how to install the mbc the way you said to? im sorry, i bet its the easiest thing to do but i couldnt figure it out. thank you again

It's alright, it can get confusing easily.

1. Unplug the hose going into the nipple on the mbc that is inline but opposite to the adjustment knob.

2. Unplug the hose connected the actuator nipple (the thing mounted under the turbo.).

3. Take the hose you removed from step 1 and connect it directly to the actuator nipple.

4. Take the dangling hose attached to the bottom nipple on the mbc and tug it some where safe.

5. Test run, you should get solid boost of 10-12psi. If boost again goes beyond 20+psi, tell us if it pauses at 10-12 then slowly increases with rpm or does it hit 20+psi immediately.

Read them carefully and think about it then post well informed questions if need be.

 

[Sbeing1]

Thanks alot, ill try to do that today and post back. again, thank you