low boost til 5k...?

[Jammin'Trey]

Hey guys, my 99 gsx makes 10psi at 2800, then when my car gets to 5k it moves up to 17psi and books. I was wondering why it isn't making 17psi at 2800.... I have a mbc and it does nothing.... Just makes the 17psi at 5k into 20psi at 5k. Its a 4$ ebay mbc..... My afr (innovate wb02) is 11.1:1 wot 17psi and 10 psi... Car has a 14b, 3in exhaust, 2.5in ss 02 housing, 4in core fmic, 2.5in hardpiping, walbro 255, B&M command flow stock injectors are at 85% duty cycle wot
. I have dsmlink
Why would my boost suddenly jump up to 17psi at 5k?

I did a boost leak test and my system will not hold pressure at all. it leaks a little from the tb and a nice amount from my bov flange weld. I am getting these fixed tomorrow.

 

[95'RS-T]

Hey guys, my 99 gsx makes 10psi at 2800, then when my car gets to 5k it moves up to 17psi and books. I was wondering why it isn't making 17psi at 2800.... I have a mbc and it does nothing.... Just makes the 17psi at 5k into 20psi at 5k. Its a 4$ ebay mbc..... My afr (innovate wb02) is 11.1:1 wot 17psi and 10 psi... Car has a 14b, 3in exhaust, 2.5in ss 02 housing, 4in core fmic, 2.5in hardpiping, walbro 255, B&M command flow stock injectors are at 85% duty cycle wot
. I have dsmlink
Why would my boost suddenly jump up to 17psi at 5k?

I did a boost leak test and my system will not hold pressure at all. it leaks a little from the tb and a nice amount from my bov flange weld. I am getting these fixed tomorrow.

after you get them fixed you shouldn't have any problems also this jumping of boost you speak of is from your leaks and is also referred to as turbo lag

 

[joshs1074]

also lose the cheap ebay mbc i had one and it leaked and sucked. i got a hallman you can also get an attachment so you can control it from inside the cab! i think they are about 80.00

 

[LandoAWD]

Your post is confusing, but it could be boost creep. Does it steadily rise, or spike at 5k? Is your target boost 10 psi?

Please clarify; both the issue/symptoms and your posting.

 

[Jammin'Trey]

target is 17psi, it is a solid 10-11psi until 5k its not a spike I would say, but it moves to 17psi around 5k.... And holds 17psi to redline.

I can run with direct boost from my jpipe to w/g and it does the same thing..(w/g sees all boost thats made...)

I want to make full 17psi boost at 3000, is this possible with a 14b?

 

[LandoAWD]

I make a full 22psi at 5k....on a MUCH larger snail. Check to see that your WG is operating properly.

 

[Jammin'Trey]

I will have to get a good mbc aswell, I have an ebay bleeder. It sucks nuts. I think I am going to order a hallman, but I hate spending 100$ on it..... But I guess I got to.

I need to get this boost leak fixed then most of my problems will go away. I need to get a good mbc, afpr, and bigger injectors. This sucks! Then I got to get it profesionally tuned, I have a innovate wideband and ECM link, so I can tune close but I think there is stuff with airflow metering that needs to be done by a professional/ I just can't seem to get a lot of timing without knock. I can hook my w/g actuator to straight boost (jpipe) and still get 19psi. Like the waiste gate isn't opening properly.

I dont think it is boost creep considering I have a 2.5in ss 02, 3in dp, 3in thermal (no cat)...

there was a few boost leaks that are getting re welded today, could that cause knock issues and a 7psi increase in boost after 4900 rpm? It feels like vtec kicks in when it creeps to 17...

 

[LandoAWD]

Let's review:

You have creeping boost, but don't think it is boost creep despite a stock 14b flapper and big exhaust.

You have no reliable boost control.

You have a 255 with no AFPR.

You have Link but don't post logs and ask about a lot of timing and knock.

Mods done improperly? Check

Verify the actuator opens at the right PSI. There is a tech article here on this. We'll go from there.

 

[Jammin'Trey]

I have a B&M command flow afpr, I find it inadequate.

I don't think it is boost creep because I have yet to find anyone creeping 7psi? I can post up a idle and 3rd gear pull if you would like??

I think I am just going to order a A1000 and install kit and Hallman mbc...

 

[LandoAWD]

I have a B&M command flow afpr, I find it inadequate.

http://www.dsmtuners.com/forums/fre...ommand-flo-fuel-modifier-other-afpr-faqs.html

You should.

I don't think it is boost creep because I have yet to find anyone creeping 7psi?

I hit 23-24psi on "WG pressure" on a 16g before the flapper mod.

I think I am just going to order a A1000 and install kit and Hallman mbc...

Good call.

You'll still creep.

 

[Jammin'Trey]

Ok, so are you suggesting I port my w/g housing? Would a evo 3 big 16g fix my boost creep issues? Money isn't an issue...

I bought the car with the command flow and a 255, stock injectors....

I have some shit to buy.

 

[Dsmj89]

I am running a evo3 16g and have boost creep and this is on a 3" downpipe with 2.5" cat-back and a resonator ! So no it will not fix it, what made you think that ?
Get an external wastegate and say goodbye to boost creep forever.

 

[LandoAWD]

A 34mm flapper and a porting will do wonders, but there's only so much you can do on an internal.

FWIW, I still run an internal WG on my current turbo, and it holds fine, but it isn't a teeny flapper.

 

[gofer]

im with landoawd on this...
your boost creeping to 17psi, its not your mbc or your wga either... at 5k RPM your wg flapper isn't efficient enough to redirect that much exhaust gas around the turbine to control the 10-12psi your wga is trying to hold. the reason why your creeping to 17psi and landoawd was seeing 22-24psi is simple, he was running a bigger more efficient turbo... the 16g.
it seems to me like you want to be running right around 17psi correct? if you can safely tune your car with the fuel setup that you have to 17lbs of boost then why fix the creep, tune for it and turn up the boost so your at 17psi @ 3k. if you want to run less boost its not going to happen until you change something on the exhaust side of things. your big exhaust setup is whats causing your turbo to creep where its efficient, not where you want it if you don't have the supporting mods. it says 3" exhaust in your mods, if that includes a dp then id say your easiest way to control boost right now is reverting back to the stock dp for the time being. if you are running a stock dp then its back to the old o2 to housing you go or start porting everything which can be a PITA unless you were planning on doing it anyway?

heres an example of what i was dealing with... i put on a small 16g, an evo 3 o2 housing, and exhaust 3" from the dp back (no cat). if i went WOT i would be at 24psi by 2600 rpm and controlling boost from my wga. i ported everything according to the "how to" threads on the site and did nothing... put on a BEP hotside for a TDO5 turbo, still creeped! put on the stock o2 housing and stock dp and i can control boost from my cheapo $60 hallman mbc all day long.

fix those boost leaks and put something on your exhaust side of the turbo back to stock or that 14b will creep all day long... and NO! NO! NO! an evo III 16g will significantly INCREASE your creep!!!

and btw, GO BIG RED!

 

[Jammin'Trey]

I want to run the 17psi, I wish I made it at 3k instead of 5k, so I got to get a good mbc, I am buying a aeromotive afpr tomorrow, fixing the boost leaks and getting my car professionally tuned. Hopefully it all works out good.

 

[Dsmj89]

You can run 17 psi without a afpr. I have a friend with a 98 gst, he now has all his fuel mods, but a month ago, he was running 17 psi with his evo3 16g with bolt ons on stock fuel system with a 255 and safc2 tuned nothing else, all this of course along with a tial 38mm external wastegate and the car ran the 17 psi pretty good. No need for a afpr injectors and all that stuff. His a/f ratios were also good, never ran rich or lean.

 

[Jammin'Trey]

You can run 17 psi without a afpr. I have a friend with a 98 gst, he now has all his fuel mods, but a month ago, he was running 17 psi with his evo3 16g with bolt ons on stock fuel system with a 255 and safc2 tuned nothing else, all this of course along with a tial 38mm external wastegate and the car ran the 17 psi pretty good. No need for a afpr injectors and all that stuff. His a/f ratios were also good, never ran rich or lean.

See thats the thing, my inj duty is like 88%, my fuel pressure is good, My afr is good, I can run 9.9 afr if I wanted too.... But I need to get a better afpr... Maybe not injectors though...

 

[Dsmj89]

I was just saying you could hold off on the setup he was running till you get EVERYTHING, meaning the injectors AND afpr and slap it all on at once instead of one by one.
I'm sure it'll be ok holding off for a bit and do it all at once. Just my opinion.

 

[Jammin'Trey]

good point, but the afpr is somewhat of a must, this B&M afpr really sucks..... Where can I get a good cheap mbc, that I can set for 17-20psi?

 

[LandoAWD]

Honestly, though lots of people have had success with cheapo MBCs, I trust my Hallman like no other. I've had both the under-hood model, and now the one with the cockpit boost-twister. (bonus points if OGs read and know the source of that term)

They hold solid, have tight adjustment ranges, etc.

As for running a stock fuel system with a 255, you WILL have overrun, but you can squeeze more out of the 450s you have by bumping up the base FP...which your B&M will do.

Log. Log. Log.