T28> 14psi> Stock fuel

[ILLiCliPSE]

I just installed my T28 and for now Im running the wastegate for boost control. At redline, Im around 13-14psi. Is this ok for a stock 2g fuel system (stock injectors, stock pump, stock fuel pressure, no s-afc, no logger..this is all temporary) Ill be getting some fuel mods and a FMIC asap.

Mods in my profile

 

[JayRolla]

You should be ok. I would get a logger to make sure your timing curve looks good.

 

[welfle18]

now i am running the stock t25 and am good till any boost over 15psi then i hit fuel cut but 12-13 psi should be fine for stock fuel setup.

 

[T is for TURBO]

I just installed my T28 and for now Im running the wastegate for boost control. At redline, Im around 13-14psi. Is this ok for a stock 2g fuel system (stock injectors, stock pump, stock fuel pressure, no s-afc, no logger..this is all temporary) Ill be getting some fuel mods and a FMIC asap.

Mods in my profile

I was running about 15 psi with my T-28, I had not fuel cut, however I was running lean... The turbo took a poo before I could get it running right... (stock fuel system)
So I would say 12-13 should be good so long as you don't have any boost leaks
-Shawn

 

[2gGSX]

15 psi was the limit for my setup. At 28 lbs/min of air the stock fuel pump could not keep up, and if I had stock 450 injectors they'd be close to 100% IDC. If you're still on stock fuel, trust that fuel cut will let you know when you're moving too much air.

 

[JayRolla]

You should not hit fuel cut with the 2g maf that early. You guys most likely have a boost leak.

 

[welfle18]

i dont know if its a boost leak but it only does it when its cold out does that make any sense???

 

[oldman]

now i am running the stock t25 and am good till any boost over 15psi then i hit fuel cut but 12-13 psi should be fine for stock fuel setup.

Boost leak test, hitting fuel cut implies sky rocketing maf readings, fuel cut is triggered because ECU thinks your wastegate isn't opening causing infinite boost. Boost leaks are the number one cause of fuel cut because it produces the same effects as a defective ewastegate (sky rocketing maf reading). In a leak free with a functioning maf system, you will run lean before you hit fuel cut because fuel cut was not designed to guard against fuel starvation as the name implies, this is why tuning is crucial.

I was running about 15 psi with my T-28, I had not fuel cut, however I was running lean... The turbo took a poo before I could get it running right... (stock fuel system)

A perfect example.

and if I had stock 450 injectors they'd be close to 100% IDC. If you're still on stock fuel, trust that fuel cut will let you know when you're moving too much air.

A very dangerous assumption, many motors are blown with user's assumption that slightly below fuel cut is where the boost level should be set.

 

[ILLiCliPSE]

K im gonna put the stock t25 wastegate on my t28 so I can control boost with a boost controller...ill set it to 12-13psi

 

[AuntiesTSI]

I ran 16 psi on mine with an AFC and don't believe I was close to 100% DC at all.

Also why wouldn you have to change to the T25 wastegate to control boost???

 

[2gGSX]

A very dangerous assumption, many motors are blown with user's assumption that slightly below fuel cut is where the boost level should be set.

Duly noted. I was ASSuming that the fuel cut point was fairly conservative, but that's not something I'd want anyone to bet a new motor on.

As far as running it at 16 psi on an AFC, what size injectors were you using and what were you using to log IDC?

 

[Splitpi]

A stock 2G fuel pump will deliver ~130.60 lph @ 12.5V or ~156.47 lph @ 14V according to RRE. That equates to 2176.7 cc/min @ 12.5V or 2607.8 cc/min @ 14V. Meaning that the pump can max and exceed the stock 450 cc/min injectors and with rewire satisfy (barely) 650 cc/min injectors. It should be noted that the injectors are rated for 80% duty cycle.

For the record, assuming a BSFC of 63% and 80% duty cycle, 450 cc/min injectors max out at 217.7 hp and 650 cc/min injectors max out at 314.4 hp. Or...

hp = ((Injector Size/10.5) * 4 * (Duty Cycle))/ BSFC

 

[nightspeed87]

i have a 190lph walbro on stock 450s on a 14b and havent gotten my logger yet, does 15lbs sound ok?

 

[SRT This]

^^^^^^ ^^^^^^
Im running the same..

 

[nightspeed87]

^^^^^^ ^^^^^^
Im running the same..

The same what, the same set up?
Your boostin 15lbs with no problems? ( Do you have a logger )

Also quick thought
I have a keydiver chip with 30 % expanded 2g timing maps
would that give me more room to run more boost than that on these 450s
or will the timing have nothing to do with this matter ?

 

[andymoraitis]

Timing and adequate fueling are not related. The lower timing simply raises the knock threshold, but if there's insuffiicient fueling the motor will still run lean regardless of whether you're running 8 degrees or 24.

I'm amazed at how many of you guys just guess that you can run "x" amount of boost without a logger or some other means to read knock. No wonder there's so many "my motor blew" threads going around.

Irrespective of identical setups each motor, and what it will tolerate, is different. Set your turbos to stock boost levels unless you have the means to verify that the tune is healthy above those levels as noted above. Anything less is asking for trouble.

 

[T is for TURBO]

I'm amazed at how many of you guys just guess that you can run "x" amount of boost without a logger or some other means to read knock. No wonder there's so many "my motor blew" threads going around.

I agree. However, for a 2G, is there any software (other than DSMlink) that you read knock count with? I run palm'n'stien and OBD Gauge, and neither of those two will give knock count (pstein will, but only for a 1G).

-Shawn

 

[oldman]

With a 2G logger, you have to estimate knock count by looking at your timing.

 

[andymoraitis]

With a 2G logger, you have to estimate knock count by looking at your timing.

Correct and here's how it would work:

The 2G ECU doesn't touch timing below 7 counts of knock. Once it sees 7 it will hold timing to the next RPM data point. If it doesn't see any more, it will try to advance and if it does see knock, it will continue to hold it. In general, for every 3 counts of knock above 7, it will pull 1 degree of timing. So:

7 counts = timing held
10 counts = 1 degree pulled
13 counts = 2 degrees pulled etc, etc all the way up to 43 knock counts.

Most people look for dips in timing to indicate knock, however the hold points are just as important. If I see 5-6 RPM data points where the timing is held and it hasn't reached a max ECU level of 16 degrees above 2.1 g/rev, I know the car is knocking at least 7 counts. One of the reasons I love using a Keydiver chip is that I can see physical knock counts on the stock boost gauge since they correspond perfectly to what the logger tells me.

Keep in mind that most of you running stock boost levels are NOT on the top map since there's not enough airflow to force the ECU to switch to it. Therefore you may see more than 16 degrees of timing which is fine as long as the motor isn't knocking. To keep it simple, look for a smooth curve without excessive hold points or any dips in timing. Post a log in the log file section if you're not sure and we'll take a look at it.

Let me know if that makes sense,

Andy

 

[oldman]

Wait a minute Andy, you have a logger now? Good post, too bad the rep point button doesn't work for us anymore.

 

[andymoraitis]

Nope, I didn't buy one Bruce. I just met up with a friend to log the 50 trim to see how much air it was moving on the current tune (51.2 lbs/min at 27 psi on pump). What was great is that Jeff's chip was showing a steady 7 counts of knock from 5000 and up and it corresponded to what the logger showed exactly.

If you want to give credit for my post above that should go to Jeff from DSM Chips since he taught me what little I know about ECU functions. He really does know his stuff though and talking to him can make your head spin. I've learned a bunch about g/rev function and timing vs. airflow from Kevin Jewer so he deserves credit as well.

 

[nightspeed87]

Timing and adequate fueling are not related. The lower timing simply raises the knock threshold, but if there's insuffiicient fueling the motor will still run lean regardless of whether you're running 8 degrees or 24.

I'm amazed at how many of you guys just guess that you can run "x" amount of boost without a logger or some other means to read knock. No wonder there's so many "my motor blew" threads going around.

Irrespective of identical setups each motor, and what it will tolerate, is different. Set your turbos to stock boost levels unless you have the means to verify that the tune is healthy above those levels as noted above. Anything less is asking for trouble.

Yea but I understand that less timing means less heat, so since im on a smic maybe it would still help if I was getting unwanted knock from heat as well. I mean im not maxing out the 450s or nothing; just simply implying would I have a less chance to knock on those timing maps.

Andy as you know my issue is boost creep i never touched by boost, its just my dilema till I can get my w.g. ported or till I get my exhaust ran ( open dp )
I just want to make sure the week or so I run open dp that if it ever creeps to 15/16lbs ( like it was doing) that im still safe basically because before ive never ever touched my boost but was on a stock exhaust so didnt worry about it. Also by the way I have no money to get the rest of my open dp ran back yet since Im paying 1300 all my rebuild work.
Oh by the way I got my 6bolt rebuilt done, the guys I went to are dsm gurus there really good, and they had everything done in a week with some other problems fixed.
( HOPEFULLY THIS REBUILD IS FOR THE LAST TIME ) since my last rebuild spun a bearing for someone screwing up, and the cam caps freezing up before that one .
Im suppose to pick it up tommorow, i guess i finally have good news for you but perhaps lets not jynx it.

But im borrowing a friends logger the day I start driving my car.

 

[oldman]

and the cam caps freezing up before that one .
Im suppose to pick it up tommorow, i guess i finally have good news for you but perhaps lets not jynx it.

Did you not use the original cam caps from the same head? Pretty much the number 1 cause aside from being out of order.

 

[nightspeed87]

Did you not use the original cam caps from the same head? Pretty much the number 1 cause aside from being out of order.

something had wedged in between the journals like sand or something,
something crazy like that. At least thats what they said, couldve been the wrong
cam caps though, seems more likely. It wasnt my fault though but an incompetient builder.

 

[oldman]

It wasnt my fault though but an incompetient builder.

And those are the worst kind of mistakes.