WiseAssJester

My favorite thing EVER is when people come to me for help.


Then argue with the suggestions I give them.

"Try a better fuel pump/injectors."
"Noooo! Its not that! I know its not that!"
"How?"
"Because..."

Seems a bit ridiculous. You keep argueing with advice saying that they're wrong. Well, you've already shown you're stumped, why not listen to outside input?

And getting upset because people keep telling the owner to buy new stuff is kind of... well, for lack of a better word, retarded. We see that something isn't right. Why get upset when someone tells you money might be needed to make things roll smoothly?

I hope we get some positive "Fixed it!" swiftly followed by "Dynoed at..." posts very soonlike.

Zombie

iTrader: (2)

P.S. Stock valvesprings are no good on even 5psi.

LionsDen21$$

1. New Valve Springs
2. New Injectors
3. Fuel Pump
4. FMIC
5. New Tune

Sure its going to get costly, but with sum patients and saving, theres no doubt your get the numbers your looking for. I found out the hard way, two blown motors. Funny thing is sumthing that might have cost an extra $700-1000 dollars would have saved $5000 and countless headaches and inconviences to myself and people around me. If it were me, i would take this whole thread in like a sponge, man up, saves some money and get the job done right. Even if other people run fine just getting by, why be like that. Especially on a DD

darkhorizon

HOLY CRAP someone answered the problem at hand here!!

So, what would cause this backpressure? the exhaust housing is very large according to some people here, and I would think that would only help with the backpressure issue?

I can solve the knock in 10 mins, atm I am more worried about finding the answer to the actual problem.

any insight into why the o2's are different on either side of the motor? are they normally that far off?

darkhorizon

We can see on the scan that the injectors are fine, and the wideband says we are not leaning out, what more do you want on the fuel side of things???

Pooping out things you read on other parts of this forum are not what is needed right now, we know what is the problem, and we know what is not the problem, so please leave the fuel system out of this.. I know, and knew from the start that the current fuel system will not support more than 400whp, but I do know that it would easily support what we wanted it to support. There is absolutely no question if the fuel system is failing, so please dont say I am ignoring it or somthing.

98turbls1

iTrader: (17)

That may be the case but if it is cutting out at 4000rpm then how do you KNOW that the injectors aren't going to crap out in the upper rpm range when you actually start to build boost?? My buddy had one (JD_Z28, that did really well actually, 650rwhp on a mustang dyno) and it barely started to come into boost until somewhere around 3500rpm... If you're saying the injectors are GOOD (which they may be until you get into some serious boost) how do you really KNOW that they're not going to crap out and have one good knock which is going to completely shell out your buddies motor... People are only STRONGLY SUGGESTING 60lbers because they have been there and done that... I mean look at Zombie, that guy is running 10's up in LV with a butt turbo... If that's not impressive I don't know what is... Good luck and I hope that you find the problem too...


P.S. I don't think that it's back pressure... If you're running a .96 AR on a stock cube and others are running a .81 and aren't having a problem I really don't see why you would... Just my .02..Take it as you will

2000TurboVert

iTrader: (17)

This is the weirdest thread I have ever seen...

There are a TON of people all giving ideas, and horizon wont getoff his holy horse to listen to people.. You say you know NOTHING aout turbo cars etc.. and then people start giving you info, and you dont want to listen to any of it..

It makes people almost NOT want to help you..

Your IATS ARE YOUR BIGGEST PROBLEM..

Its pulling so much timing above 4k with that high of IAT's if KILLING your power...

Get an intercooler or meth kit... If you wont do either of those ,then I am done here!

Thanks

darkhorizon

timing at 4krpms = 12 degrees , iat's = 160 , 350HP

timing at 6krpms = 12 degrees , iat's = 160 , 290HP

How does timing have an effect like that? last time I checked rpms=power gains, not power losses.

2000TurboVert

iTrader: (17)

RPM do equal power gains, until you have 160* IAT's...

Your playing with a time bomb there as well with IAT's like that..

You can pretty much say goodbye to piston 7 running those IATs alot

darkhorizon

Just a reference so you guys can see where I am coming from.

My friend dave, put down 333 hp using 6 of these very injectors in this car, out of a 3800, with an automatic frontwheel drive transmission (24-25% drive loss), running 13psi of boost, 16 degrees of timing, and IAT's around 200 degrees out of a roots blower sucking power away from the motor, all on pump gas.

So your saying, that 160iat's 5.7L of displacment, 4 degrees less timing, 2 more cylinders,2 more injectors, better flowing heads and exhaust, and a turbo should make less WHP than a 3.8L v6?

Zombie

iTrader: (2)

What brand/seat pressure valve springs is this car running again?

darkhorizon

stock everything, 50k miles.

gametech

iTrader: (1)

Yeah, Zombie, you are probably right, but the other times you suggested valve float were ignored, why should this time be any different?

2000TurboVert

iTrader: (17)

160 IATS will DEF cause problems..

What is the timing when the IAT's get that high?

Theres no way its 16* unless hes runing like 24 overall.....

The computer is pulling timing....

FI is NOT cheap.. You have to have all these components to make it run right..

ValveSprings
Intercooler/Meth
Right AR Housing
etc
etc
etc
etc
etc

darkhorizon

I am not ignoring valve problems, I dont know any direct ways to detect valve issues in these ls1's. I know that in 3800's valve float is more like a rev limiter than anything, it is usually a very noticeable power killer.

mattraypharbor

iTrader: (2)

+2 on the valve springs not holding past 5psi.

98Z28MASS

iTrader: (6)

Usually valve float is noticeable in a wavy break-up in the lines of the dyno curve. Why not just pull the heads and check for a broken valvespring and while in there install some comp 918's?

2000TurboVert

iTrader: (17)

THERE YA GO!

And get an intercooler.....

Frost

iTrader: (45)

If I were the owner of this car and was reading this thread I'd take the car away from you darkhorizon. Are you ready to buy him a shortblock when you tear this one up by making pulls on what is clearly an incomplete setup (not ready for tuning!) ?

Zombie

iTrader: (2)

There is a very easy way to detect valve float on a turbo LS1. Put it on a dyno. If you are running stock springs and the power starts falling off drastically after 5000 rpms you almost certainly have valve float issues.

Now that you know that the problem is stock valve springs, go change them, upgrade the fuel system as suggested,install and intercooler, then fix the tune and you should be in good shape. You WILL need the fuel system once you fix the floating.