what boost levels for 14b on stock 2g fuel system???

[ILLiCliPSE]

just wondering what is safe boost for running a 14b on the stock 2g fuel system and the stock smic? i searched, but oddly enough, if you search even for "14b" in the search (titles only), nothing shows up for me i hear 13-14psi is fine.

thanks for the help

 

[FWD98GST]

If I were you, I would get a fuel pump and rewire the fuel pump. And you can safely run your boost higher.. Maybe around 13 to 14psi, like you stated.... Better to run rich than lean...

Now when you get the chance.. Follow up with Injectors, and some sort of fuel management.. Like AFC/Datalogger or DSM Link.. whichever..

Goodluck..

 

[MrBoxx]

I ran my 14b on the stock fuel/SMIC at around 13-14 psi for a few months before I got a 190lph pump. This was before I had DSMLink though, so I couldn't tell you what kind of injector duty cycle it was forcing or how much knock I was getting.

The reason "14b" doesn't show up is because the search doesn't recognize three-letter terms. I believe this is being looked into, since a lot of DSM terms are three letter words or acronyms. Try the google search feature and see if that helps.

 

[gorf]

I ran my 14b on the stock fuel/SMIC at around 13-14 psi for a few months before I got a 190lph pump. This was before I had DSMLink though, so I couldn't tell you what kind of injector duty cycle it was forcing or how much knock I was getting.

The reason "14b" doesn't show up is because the search doesn't recognize three-letter terms. I believe this is being looked into, since a lot of DSM terms are three letter words or acronyms. Try the google search feature and see if that helps.

With my 2g 14b, I can not run over about 14 lbs without hitting fuel cut. I had it up to close 20 lbs by accident and it Screamed, till it hit fuel cut. I am planning on going with a key chip and larger injectors - we'll see what it does then..!

 

[selmerguy]

My stock 450's were at like 143% idc at 15 psi. The AFR was pretty good but the car knocked alittle. I replaced the fuel pump with a 255 and the afrs are much richer but the IDC is still high. I have some 680's comming so I should have alot better luck with them. I would stay below 13 psi if you can. With a 3inch exhaust I creep like crazy so it would be impossable for me to stay that low.

 

[MrBoxx]

With my 2g 14b, I can not run over about 14 lbs without hitting fuel cut. I had it up to close 20 lbs by accident and it Screamed, till it hit fuel cut. I am planning on going with a key chip and larger injectors - we'll see what it does then..!

Have you checked for boost leaks? Maybe my car is weird, but I've accidentally hit 19psi a few times when dialing in my MBC on the stock fuel system and never hit fuel cut. In fact, my car has NEVER hit fuel cut. I'm pretty stumped about it since I see so many threads where people report fuel cut in all sorts of circumstances.

 

[Littlebeeper]

i hit 19 PSI + when i was messing with the boost controller too. i didn't hit fuel cut but i wasn't in the higher RPM's either. i'm sure it would have if i were closer to redline. I'm running really rich right now though. maybe i'll tune it a bit when i charge the logger.

 

[TurboAnything]

I did a 6-bolt swap for a friend. It was a JDM CYCLONE with a 14b we put a fuel pump in and he had a full 3 inch exhaust. thats it and he runs 20psi all day long with no fuel cut and it runs perfect.

 

[gorf]

Have you checked for boost leaks? Maybe my car is weird, but I've accidentally hit 19psi a few times when dialing in my MBC on the stock fuel system and never hit fuel cut. In fact, my car has NEVER hit fuel cut. I'm pretty stumped about it since I see so many threads where people report fuel cut in all sorts of circumstances.

ya checked for boost leaks, think my j pipe was leaking and fixed it. My blinky light gauge was reading rich and it started to read correctly so assumed it was fixed. Then I replaced my fuel pump and did the rewire, now I'm running rich again. I have not tried running the boost back up with the leak fixed - guess I should try that before throwing money at it eh?

 

[Kevin Jewer]

143% IDC on 450s with a 14b is not possible at any pressure, never mind 15. Doesn't mean you aren't seeing it, but I'll bet there is an uncalibrated MAFt somewhere in your mod list.

Assuming a target AFR of 11:1, pump gas with a specific gravity of .76, and 43 psi base pressure, 4 450s will support 33 lbs/min (31 lbs at 38 psi). The 14b can only move 30 lbs/min. So the 450s are enough. IDCs will be high, but that doesn't matter despite what the people that make money from selling bigger injectors will tell you and what then gets curculated endlessly on the internet. But we won't get into that. So what this means is that the 14b even completely maxed out at as much boost as it can make will not outrun 450s. And indeed this has been verifed on my own 2g way back in the day.

The pump on the otherhand is much riskier. It depends heavily on what boost pressure you run. At 15 psi the stock 2g pump is MORE than enough (assuming required of course). At 20 psi you're also still good, about 36 lbs capacity. At 25 psi it starts to get real close at just over 30 lbs. You can run injectors right up to thier max capacity, but I like to give pumps more headroom. These figures assume the same variables mentioned above for the injector calculations.

If this was my car I'd run up to 20 psi on the stock 2g fuel system rewired without thinking twice (ran a 14b for about a year, so I have also some experience with it to back up the math). That's typically all you can get on pump gas with a sidemount anyway. On race gas you can then safely go to 25 psi, which is about all the turbo will do on stock cams. Anything you do to make more airflow at the same boost (cams, intake manifold, etc) will make the pump effectively seem larger.

Hope that helps.

 

[selmerguy]

143% IDC on 450s with a 14b is not possible at any pressure, never mind 15. Doesn't mean you aren't seeing it, but I'll bet there is an uncalibrated MAFt somewhere in your mod list.

Assuming a target AFR of 11:1, pump gas with a specific gravity of .76, and 43 psi base pressure, 4 450s will support 33 lbs/min (31 lbs at 38 psi). The 14b can only move 30 lbs/min. So the 450s are enough. IDCs will be high, but that doesn't matter despite what the people that make money from selling bigger injectors will tell you and what then gets curculated endlessly on the internet. But we won't get into that. So what this means is that the 14b even completely maxed out at as much boost as it can make will not outrun 450s. And indeed this has been verifed on my own 2g way back in the day.

The pump on the otherhand is much riskier. It depends heavily on what boost pressure you run. At 15 psi the stock 2g pump is MORE than enough (assuming required of course). At 20 psi you're also still good, about 36 lbs capacity. At 25 psi it starts to get real close at just over 30 lbs. You can run injectors right up to thier max capacity, but I like to give pumps more headroom. These figures assume the same variables mentioned above for the injector calculations.

If this was my car I'd run up to 20 psi on the stock 2g fuel system rewired without thinking twice (ran a 14b for about a year, so I have also some experience with it to back up the math). That's typically all you can get on pump gas with a sidemount anyway. On race gas you can then safely go to 25 psi, which is about all the turbo will do on stock cams. Anything you do to make more airflow at the same boost (cams, intake manifold, etc) will make the pump effectively seem larger.

Hope that helps.

I thought the 14b just blew hot air after about 17psi? On my RST I ran DSM 450's and ran out of injector at 14 psi too. This was on a t3 but a small one. I was running MSNS so I am pretty sure that was my limit.

 

[Kevin Jewer]

The whole hot air thing is an internet myth IMO. When you factor in IC effciency, compressor efficiency plays a very small role until the turbo is within at least 95% of being maxed out (airflow/time). I have always ran the best time for a given turbo when it is completely maxed out. Lowering the boost has never made more power. And with the right setup knock can be avoided. So it's a non-issue in my experience. Heat may be added, but more airflow still equals more power.

You absolutely can not quote injector capacity in terms of boost pressure. A 5 liter motor at 14 psi will move a whole lot more air (and therefore fuel) at 14 psi than a 2 liter will. extreme example, but you can see the more typical effects of this looking at cars with differnet airflw enhancing mods, like cams, intake manifold, turbine side, etc.

That being said, you can certainly run out of injector prematurely, usualy when trying to run too rich, like 9.5 (stock) or 10:1 to bandaid other problems.

 

[gorf]

<snip>

So what this means is that the 14b even completely maxed out at as much boost as it can make will not outrun 450s. And indeed this has been verifed on my own 2g way back in the day.

<snip>
Hope that helps.

Thanks! I have already purchased 560 injectors and my plan was to put them on at the same time as a dsmchips ECU. I was hoping to squeeze out as much as I could from the 14b and have an upgrade path for a EVO 3.

Question - With 560's and the keychip, will the 14b be running too rich? Instead of the ECU would I be better off to get a logger and AFC and forget the 560's?

 

[Kevin Jewer]

I'm assuming the DSMchips ECU is an eprom ECU with an eprom that has injector compensation for those 560s? If so, it will run like stock, which is pretty rich. Now, it's never a bad thing to have a little extra headroom on the injectors, and if you every upgrade to an EVO type 16g, the 560s (evo8 injectors?) will support it with very high, but doable IDCs (I ran 99-102% for a long time on my EVO8). So it's a good investment. You will also want some way to control fuel, like an AFC and logger, in order to get the most out of the 14b. If the budget is so tight that you have to choose one or the other, I'm not sure which way I would go. You'll have to make that call.

If this is an EPROM ECU, I would skip the chip, AFC, and logger, and spring the extra cash for DSMlink, for obvious reasons. I'd probably skip the injectors too if it meant I could get DSMlink, for whatever that's worth.

 

[KeltonDSMer]

Just to clear things up a bit; airflow is already air/time. Airflow is a mass or volume of air changing over time.

Airflow/time would be the rate at which the airflow is increasing with respect to time.

 

[Kevin Jewer]

I use airflow/time to distinguish between airflow/rev, the only other meaningful airflow measurement we take. But thanks for showing up.