sluggish on top end in boost

[918dsm]

well ive done some searching and no luck. so my issue is when im a WOT in third or higher. i get up around 6k and my car just seems like it's not making anymore power, it feels like i feel it in the pedal just not wanting to go. it doesn't make any weird noises and i dont show any knock on my safc II. my setup is

16g on 18lbs no boost leaks
stock 450's
3" gm maf with translator
apexi safc II
hks evc
forced performance ex mani
3 1/2 inch turbo back apexi exhaust
apexi racing bov vented to atmosphere
eagle rods and pistons
fierra valves, crower springs and retainers
big greddy fmic

im not sure exactly on my maft settings but i know my safc is set to 0 across the board because of the stock injectors. i know i really need a wide band and im thinking it may just need to be tuned right. i was told it was tuned, and it runs fine except at wot in high rpm's and boost. let me know what you think

 

[stroked_AWD]

What Kind of 16g is it?

 

[918dsm]

its a tdo5 h

 

[Gasolinebaptism]

Well, from the factory the cars peak power comes at 6 grand. and as far as I'm concerned the only way to change where the peak power is made, would be with a head job, valves, cams, valve springs, ect.
Also, the 2g IM is more restrictive at high rpm than the 1g.
So from what you're describing I'm not sold that there is an issue.

 

[stroked_AWD]

is it a small 16g, big 16g or evo3 16g? If its a big or an evo3 you might want to get bigger injectors are you hitting fuel cut?

 

[918dsm]

so its just a turd after 6k. it pulls really hard to 7 in second but in then into third it's like i need to pull out a whip and start beating it!!

no fuel cut and it's just a standard 16g off a 1g

i know i cant pull anymore then 18lbs out of my stock injectors without going lean

 

[stroked_AWD]

If it came off a 1g than its a 14b man.

 

[918dsm]

its a 16g the compressor wheel is different from a 14b. the 14b has alot more fans then the 16g does. it was on the car when i got it guys said it was from a 1g but maybe he was wrong. he was an idiot anyway

 

[Gasolinebaptism]

tell us you have a fuel pump, and yes, it likely is a bit of a turn after 6 grand, especially on a 14b.

I feel like I want you to take a quick picture of the turbo where it sits and post it. That way we can all be sure. because you said "it's a 16g off of a 1g," no offense, but that tells me that you don't know much about these turbo's, or these cars yet for that matter. so snag a snapshot, we'll go from there.

 

[redrockergsx]

That is just how it is with the 16g it make it power fast and then drop off. that a big thing with turbos in general they dont plateau like v8 do it jump up to its max HP and start to drop down .

 

[Gasolinebaptism]

That is just how it is with the 16g it make it power fast and then drop off. that a big thing with turbos in general they dont plateau like v8 do it jump up to its max HP and start to drop down .

This isn't quite right. the turbo isn't going to cause a loss in power at high rpm, that doesn't make sense. but it you make you peak boost around 3 grand, then there isn't going to be a huge amount of power gain past 3 grand. and power will begin to drop off in these cars with a stock head at around 6300revs. this is because the stock valve springs aren't strong enough to push the valves down fast enough, and ensure a perfect close at such high operating speeds. this is called "valve float" the only remedy if you want to keep revving is stronger springs, cams would also be a good idea.

 

[Rob10_99]

18psi and no fuel cut? I don't see how thats possible unless something is holding you back. You sure you dont have a fuel cut eliminator on the car? The misfire or whatnot could be from it being lean.

 

[Gasolinebaptism]

18psi and no fuel cut? I don't see how thats possible unless something is holding you back. You sure you dont have a fuel cut eliminator on the car? The misfire or whatnot could be from it being lean.

This to is likely, since he hasn't been around the car that long he just wouldn't know. and because of that we can't necessarily be sure that he has stock injectors and pump.

 

[Calan]

...and power will begin to drop off in these cars with a stock head at around 6300revs. this is because the stock valve springs aren't strong enough to push the valves down fast enough, and ensure a perfect close at such high operating speeds. this is called "valve float" the only remedy if you want to keep revving is stronger springs, cams would also be a good idea.

Power does drop off a bit due to volumetric efficiency. But I'm pretty sure that the 4g63 doesn't suffer greatly from valve float at 6300 rpms. Besides that, the OP says in his first post that he has Crower springs and retainers...not exactly stock.

The OP said he has stock 450 injectors. If that is the case, I agree with Rob. At 18 psi on a 16g, he should be hitting fuel cut. And if he hits fuel cut, he'll know it.

BTW - OP; why are you running both a MAF translator and an SAFC?

 

[Gasolinebaptism]

^yoiu're right calan, I'm still halfway new to the 4g63, and I'm a biker, been around float all my life.

So mr OP, and updates or photos?

 

[918dsm]

Like I said in my original post the car has a maft translator with a 3" gm maf so the fuel cut is turned off. So no I'm not hitting fuel cut on 18psi, also like I said the car has fierra valves with crower retainers so I know I'm not losing power due to that. Also I went to the speed shop earlier and they told me I am running a 16g not a 14b lime I stated but they said it was off a evo 1 or 2

 

[Calan]

Like I said in my original post the car has a maft translator with a 3" gm maf so the fuel cut is turned off. So no I'm not hitting fuel cut on 18psi, also like I said the car has fierra valves with crower retainers so I know I'm not losing power due to that. Also I went to the speed shop earlier and they told me I am running a 16g not a 14b lime I stated but they said it was off a evo 1 or 2

Well, just because you have a MAFT doesn't mean that fuel cut magically disappears. But it doesn't sound like that is your problem anyway (I was just surprised you aren't seeing it).

Do you have any logs? You may be knocking like crazy and the ECU is pulling a lot of timing.

 

[Gasolinebaptism]

Okay, well you still havn't told us whether or not you have the stock fuel pump. you said stock injectors.
So I will imagine you are on the stock fuel system, which can handle up to 16psi. 15 is the most you should be running safely. At higher rpm, there isn't enough fuel for the oxygen, so there is unburnt oxygen going into the exhaust which has been superheated by the explosion, the O2 is much hotter than the rest of the gases. this will raise combustion temps, running temps, and cause detonation.
Please turn your boost down to 15 before the car explodes.

 

[black_gst]

you have stock cam too right.. stock cams dont make much power after 6k a friend of mine with a 1g was boosting 27 psi on race gas all supporting mods, stock cams and his power would just drop off after 6k so its time for some cams.

and you have to be running lean @ 18 psi you just dont know it

before i put my fuel system in, on my built motor with 280's and a stock fuel pump and 1600cc injectors i would lean out on anything over 10 psi and this was with a 20g

 

[2gawdtsi]

The stock fuel system does not magically handle anything exactly to 16psi.
everything is based off of load(airflow) in the ecu, not psi.
sometimes the stock fuel system is good for more, sometimes less.
thats why gauges and dataloggers are so important.

 

[Calan]

In your first post, you said you didn't know what the MAFT was set at; you need to find out.

If it isn't set for the injectors you have, that could explain how you are flowing that much air and not hitting fuel cut. It could also mean that you are running lean and knocking, causing a lot of pulled timing.

Unless there is something you aren't telling us (like you have an AFPR and base fuel pressure is adjusted higher than stock) and without any logs to look at, my guess is that your MAFT is set incorrectly, your injector IDC's are maxed to the hilt, and you're running lean...and your motor is knocking like crazy. Because of this, the ECU is pulling a bunch of timing causing the sluggish feeling.

You seriously need to lower your boost and get some datalogs.

 

[918dsm]

im not sure on the fuel pump i havent pulled the tank yet, and the translator, the setting where set when i got the car and the reason for it was so it can vent to atmosphere and also remove the fuel cut. my plugs look good not looking rich or lean but this is the least of my worries at the moment i was just driving down the highway and passed a car and when i tried to accelerate i didnt move. i have no 3rd fourth or 5th gears so im guessing i broke something. i still have second and 1st and reverse but thats it

maft trans setting aux=4 base=2 idle=2 mid=0 wot=E and all mode switches are down

 

[Red97Eclipseboy]

im not sure on the fuel pump i havent pulled the tank yet, and the translator, the setting where set when i got the car and the reason for it was so it can vent to atmosphere and also remove the fuel cut. my plugs look good not looking rich or lean but this is the least of my worries at the moment i was just driving down the highway and passed a car and when i tried to accelerate i didnt move. i have no 3rd fourth or 5th gears so im guessing i broke something. i still have second and 1st and reverse but thats it

A GM MAF doesn't remove fuel-cut, for the second time. You really don't understand fuel-cut at all. Maybe you should read up on it before you keep talking about it. And if power is falling-off at 6k, welcome to the world of a 16g with stock cams. But in all honesty, you don't even know what turbo you actually have.

 

[black_gst]

just turn the boost up! no one on this site knows what they are talking about anyway you just need more boost!

 

[918dsm]

just turn the boost up! no one on this site knows what they are talking about anyway you just need more boost!

Ya that sounds like a great idea...... Wow come on now dude

A GM MAF doesn't remove fuel-cut, for the second time. You really don't understand fuel-cut at all. Maybe you should read up on it before you keep talking about it. And if power is falling-off at 6k, welcome to the world of a 16g with stock cams. But in all honesty, you don't even know what turbo you actually have.

Yes I do know what turbo I have if you read the post earlier it says I went and had a tuner shop look at it and they said it is a 16g off a evo1 or 2 and also there are settings for fuel cut eliminator on the maft translator... So hmmm I wonder if u have read about it or used one before....