Ok guys, i spared no expense on my car, what gives?

[Booost]

I have an 87' GN with 39k miles. Here is my mod list:

K&N air filter
LS1 Maf
PT-61 BB Turbo
Stock Intercooler
RJC Powerplate & Boost Controller
60 lb. injectors
Stock engine with 100 lb. valve springs
New coil pack & Ingnition module
New plugs & wires
New Cam & Crank Sensors
Turbotweak Race Chip
110 Race Fuel
3" Downpipe
Vigilante 3200 stall converter
Trans Cooler
MT ET Street Slicks
24 lbs. Boost
40 lbs. Fuel Pressure


This is what everyone told me I needed to run consistent 11 sec. 1/4 mile times. Problem is, I have only run a best of 12.5 @ 106. My O2 readings are super low at 144 idle, and 475 at WOT. O2 cross counts at WOT are 166?! What is up with that? My 60 ft. times are good at 1.67, but once the boost goes over 20 psi. the car just nose dives and sputters out? No knock whatsoever?

Any help is greatly appreciated! I'm sure you guys are sick of questions like this all the time, but I've tried everything I know to do.

Thanks!

 

[Rebel]

Do you have a Powerlogger?

 

[83ttypecooled]

HI,
Your log doesn't show fuel pump mods. Did you upgrade to a better pump? A hotwire kit will be necessary, also.

 

[1987gndave]

o2 At 475 ?????? Should be 780 to 820 WOT ... that's LEAN at 475 ...

 

[Booost]

i dont have powerlogger, i just use a scanmaster. I have the walbro upgraded in-tank fuel pump and hotwire kit. Fuel pressure comes up to 65 psi at 24# boost. I just can't figure out why i have no knock with that low of an o2 readings?!

 

[ES1]

Sure your knock sensor is working correctly?

 

[chris mccord]

With an O2 that low he may not be able to generate enough fire to knock.

 

[jdsgnx]

Get a new o2 sensor!!!!

had a car 2 weeks ago have real low o2's no knock with alky pulled o2 and was TOAST!!!!!

make sure its a purple wire ac delco!!!

JD

 

[Booost]

To be honest, I haven't changed the knock sensor or the o2 sensor. Is that what you guys think I should try next? What brand o2 is the best for race gas?

 

[Booost]

If I do get the o2's in the 770 range, will I be able to run 11's pretty easy?

 

[TurboBob]

if its not making the MPH (and ET) it "should", its time for some verification.

Fuel pressure at WOT (done)
Compression and leakdown
crank sensor index
boost gauge accuracy
fuel pressure accuracy
converter slip?
time for a better intercooler?

I had a car with all the right stuff, and it would MPH at 105, no matter what. Turned out to be a burnt piston....

Bob

 

[jasjamz]

Did you change the fuel filter?
What are the settings inside your translator?

 

[Pronto]

Is the knock sensor plugged in?
I wouldn't go WOT or in boost for that matter until you figure out why your O2s are so low!
BTW what are you using to read the O2s with? Scanmaster??
Your base fuelpressure at 40 line off is low. TT should be set at 43. Why do you have a race chip? You don't have enough mods to warrant one. You could do just fine with a street chip and alky, no race gas.

 

[SPOOLFOOL2]

Question of the day.

What plugs are you running, and what are they gapped at?

 

[Booost]

I hope its not an internal engine problem! The fuel filter is stock. But, would the engine be able to pull 65# of fuel pressure if the filter was bad? My translator is set at on, on, on, off. and set for ls1 maf and no fuel added.

 

[Booost]

Yes the knock sensor is hooked up and i can run lots of boost without any knock. I run the NGK UR5 plugs if i remember right. Gapped at .035

 

[ES1]

The reason your not in the 11s is because you stated the car falls on it's face after 20psi.

Not you have to figure out why it falls on it's face.

I would replace O2 and just go into boost in second gear.
This would tell me if this corrected the lack of power after 20psi.
If corrected OK.
If not, you need a recording scantool to see what is causing the problem.

 

[Booost]

I think your right, im gonna try a new o2 sensor first and see what that does for it. What is the best brand to run with race gas?

 

[ES1]

Denso and since your running race gas, buy several.

 

[cruzn57]

what are you gaping the plugs at?

if its anywhere near .035, its blowing the spark out!
I run mine .026-.028