Stock Boost [Merged 5-7]

[Gs-tHaVoC]

hehe kinda dumb question but whats stock boost on my car? just wondering if its worth it to install a boost controller and gauge without bov thats all. thanx

 

[nightstocker99]

I want to run 20 Psi what mods do I need in order to run that much boost safely.

 

[Ultimatedsm]

20 psi is a lot of boost man . Well it all depends on your goals and the size of the turbo. The bigger the turbo the more supporting mods you need to run 20 psi. For example:

EVOIII16g you need 550cc, walbro 190 LPH and some kind of fuel controller and logger.

T3/T4 60 trim you probably need at least 720cc injectors, walbro 255LPH with an AFPR and again some kind of fuel controller and logger.

You should slowly gradually turn up the boost and log your runs. Don't ever just crank it up to 20 psi without some kind of tuning and logging. You will blow your motor bottomline.

Anyway there are tons of information on this stuff all over DSMTUNERS, just search what you are looking for and most likely it will be here. I hope that helps.

Jesse

 

[Ultimatedsm]

Forgot to mention you will be needing a bigger intercooler with 20 psi.

 

[1992awdlaser]

I think only one of you have actually answered the question. I only want about 14 psi, not 243524 psi. I know my 1g bov will hold 14 psi. I'm just asking if there are any other necessary supporting mods for raising it to 14 psi.

The only things that you need for 14psi are a boost controller and boost Gauge (don't pay attention to the stock Gauge it is inaccurate).
Oh and the 1g bov will hold about 18psi before it leaks. Crushed it will hold over 20. Now stop hijacking the thread.

 

[Pitman99505]

Hey 1992AWDLaser, glad that you answered his question, I agree with everything you said. But before you go accusing someone of hijacking the thread you may want to make sure that the person you are accusing is not the one who started the thread

 

[1992awdlaser]

Hey 1992AWDLaser, glad that you answered his question, I agree with everything you said. But before you go accusing someone of hijacking the thread you may want to make sure that the person you are accusing is not the one who started the thread

I was talking to the guys that were talking about what a 1g bov could hold.

 

[Deadly BlaZe]

The only things that you need for 14psi are a boost controller and boost Gauge (don't pay attention to the stock Gauge it is inaccurate).
Oh and the 1g bov will hold about 18psi before it leaks. Crushed it will hold over 20. Now stop hijacking the thread.

thanks for the answer. time to get an mbc

 

[1992awdlaser]

Make sure you get the boost gauge also.

 

[AntiZeroTrip]

Make sure you get the boost gauge also.

Ya an aftermarket boost gauge is one of the first mods I would suggest on any turbo car. I installed mine and you wouldn't believe just how slow and inaccurate the stock one is. When your boosting the engine, you want to make sure you know just how much boost your pushing. It can be the difference between a fun night at the track, or a not so fun night at home in the garage.

 

[Pitman99505]

I understand 1992AWD...right on

 

[nightstocker99]

Whats the stock boost on a 2g eclipse and after you remove the BCS Restrictor what could your boost be?

 

[greytalon26]

I'm running 17 psi of boost with minimal modifications, and so far I haven't seen any problems . Am I going to see any reliability problems in the future for running this much boost on a stock engine, or does it depend on the mileage (46,XXX and no, it's not 146,000) and condition of the engine?

 

[TRBOBLU]

As long as you have an upgraded fuel pump you will be fine. I ran 22psi on my 7bolt 2g for close to 30k miles before I toasted a rod bearing(not due to the boost) . I a friend that runs about 16-17 psi on his 1g with the stock FP. He has had no problems but I told him to stop being cheap and buy a 100 Fuel pump just to be safe. My answer to you, get a Walbro 255 and go have fun worry free.

 

[Ultimatedsm]

No its not just the pump or fuel, its about tuning. If you have a datalogger log your runs and see how much knock or timing is pulled back. Running high boost in general stresses your motor. The stock motor with the right supporting mods and tuning can run 23-24 psi. After that either your stock head bolts will stretch too far and blow the headgasket, or your pump gas can't handle extra compression (Higher the boost, the higher the compression ratio) and you will have to switch to race gas. Bottomline is without proper tuning you can blow your engine at even 15 psi depending on the size of the turbo.

 

[dr1ftx3]

I'm running 17 on my car right now and I still have my stock fuel pump and whatnot, but then again I do have some other mods so I dunno, but no problems here so far.

 

[Ultimatedsm]

The relability problem of running 17 psi without many mods is that it will eat away on your piston rings. Do a compression test now, and do one in a few months, let me know the results.

 

[exile]

You can't ask a question and then ignore the response and say "well I'm doing it now and it works" You came here to ask the question so listen to what we have to say.

The aren't any APPARENT problems happening that you can see or feel NOW, buy a logger and it'll be very obvious to the techies here what will happen soon enough.

 

[stirpicult]

(Higher the boost, the higher the compression ratio) and you will have to switch to race gas. Bottomline is without proper tuning you can blow your engine at even 15 psi depending on the size of the turbo.

uh, how does higher boost change the volume of the combustion chamber at bottom dead center vs. the volume of the combustion chamber at top dead center (compression ratio)??? serious question, because i always thought compression ratio was a constant. if it was 7.8:1, then it will stay there until you actually do something to change it (pistons, bore, stroke, thicker head gasket, etc.)

and you cannot say that its not about fuel? the fuel and timing IS THE TUNING! so yes, you could blow your engine at 15psi....by not having enough fuel.

point is, 17psi...you need more fuel, and not just larger injectors or a larger pump, but the management of those. the difference between 14 or 15 psi and 17psi is not enough of a horsepower difference to justify taking the chance of blowing up your engine, now or eventually.

 

[greytalon26]

If I do get a 255 fuel pump, is it hard to install? (I'm not to good at complicated modifications) Does it involve any major work that would make more sense to have done at a shop, or is it something that someone who is somewhat inexperienced like me can do? By the way, in my car the difference between 14 psi and 17 psi is very noticeable.

(this question is directed at UltimateDSM)

 

[98BlueBeast]

Dude, a pump and injectors are EASY to install. Then get a SAFC and logger and you can run so many different turbos. Your choice. I'm pretty dumb and i installed them all myself.
98BLUEBEAST

 

[Ultimatedsm]

uh, how does higher boost change the volume of the combustion chamber at bottom dead center vs. the volume of the combustion chamber at top dead center (compression ratio)??? serious question, because i always thought compression ratio was a constant. if it was 7.8:1, then it will stay there until you actually do something to change it (pistons, bore, stroke, thicker head gasket, etc.)

and you cannot say that its not about fuel? the fuel and timing IS THE TUNING! so yes, you could blow your engine at 15psi....by not having enough fuel.

point is, 17psi...you need more fuel, and not just larger injectors or a larger pump, but the management of those. the difference between 14 or 15 psi and 17psi is not enough of a horsepower difference to justify taking the chance of blowing up your engine, now or eventually.

Alright if compression doesn't change on boost than why the hell are we using 7:8:1, 8:5:1, or 9:1 compression in our engines? Why don't we just get 12:1 pistons and run 20 PSI? Try that and let me know what happens

 

[Ultimatedsm]

If I do get a 255 fuel pump, is it hard to install? (I'm not to good at complicated modifications) Does it involve any major work that would make more sense to have done at a shop, or is it something that someone who is somewhat inexperienced like me can do? By the way, in my car the difference between 14 psi and 17 psi is very noticeable.

(this question is directed at UltimateDSM)

Its not very difficult, however, it is dangerous to do a fuel pump install if you don't know what you are doing. When you buy the walbro 190 or 255LPH for pump, it is usually a kit for your car and just follow the instructions. If you decide to get a walbro 255LPH, I HIGHLY recommend you getting an Adjustable Fuel Pressure Regulater or AFPR(Appreviation). The 255 will over run the stock FPR(Fuel Pressure Regulator), however, if you get the walbro 190LPH you don't need to change the FPR. You can easily make 400WHP with a 190, if you plan to make over 500 WHP, than go with the 255LPH. Anyway, I hope that helps and good luck with the car

 

[paranoidTSi]

I'm not going to post a million theories about what you should run, I'll just say this..the general consensus of this board is that 15PSI (maybe 16) is the safe limit of boost on a completely stock system.

 

[pnishr]

As was said, tuning is the tool. AND the turbo efficiency. running the T25 at 17psi is more dangerous (due to hot air) than running a more efficient wheel on more PSI could be. The tuning is about ensuring you have the proper A/F to avoid detonation. if the air is SUPER hot (aka a T25 over 16~17psi) it's gonna take more fuel to saturate it to avoid detonation. get some nice big injectors, something to control them with, and an efficient turbo, and the internals of that block can (and have) held over 28psi and 500whp. but nice racing blocks are always better!

J

 

[92GSXBaltimore]

All I can say is wow.....
Boost does NOT change the compression of an engine. Let me say that again, boost does NOT change the compression of an engine! In a 1g turbo, if you run 11.5psi as opposed to 30psi, your piston will still compress the air/fuel charge 7.8:1. Compression is how many times the piston compresses the volume present in your cylinder from BDC to TDC. A turbo will only make the volume of air entering that cylinder more dense to start with.

To answer the original question of the thread, our stock turbo(4g63t) engines can handle ~23-24psi before you have to start worrying about the head lifting.