data logs from test and tune 10-20-13

[TurboCajun]

I ran better at 18 psi 11.37@118 in april i think i was but is was alot cooler.
I noticed on pass three that my tps was over 4.8 at some point which it should not be , I will have to adjust it.

[TurboCajun]

I MPH are way off from the time slip

[Steve Wood]

You need to tell us if you are running a wideband, and what kinda maf plus if this is an alky car, straight race gas, or what....

Looks rich in first gear which slowed the power some and was too lean on top end which was causing timing retard and dinging the head gaskets

Do you have a fuel pressure gauge on the car so you can tell if the pump is keeping up with boost properly

[Scoobum]

All kinds of KR...possibly because your volts are low.

[TurboCajun]

no wide band, translator w/ impala SS maf, 93oct with alky, I dont have a FP gauge on the car but I did check it line off before i made my first pass

[Steve Wood]

sometimes, you all make me want to cry

[TurboCajun]

why is that Steve?

[Steve Wood]

Because one of the most basic things required to know that the car is working properly is the fuel pressure at wot at the top of third gear.  If it is dropping, or staying constant, instead of tracking boost, you are going to blow something up sooner, rather than later.

A rail mounted gauge is useless.  First they usually quit reading properly very quickly-if they ever read right.  Second, they do nothing to tell you how the pump performs under load or if there may be a problem with the pump, the wiring, the hoses, or the fuel pressure regulator.

I can set fuel pressure looking at the O2s with the hose on but I cannot know what the pressure is when it counts.  Guys usually learn when they blow the hgs or toss a rod thru the side

[TurboCajun]

I dont have a gauge on the rail, I checked it with a know good hand held gauge. but yes I know I really need to have on to read constantly. Steve what is your opinion on the difference in MPH from the power logger and the time slip, Do I need to change my speed sensor, on regular drive with a GPS I am only off by 2 MPH (slower than GPS)

[TurboCajun]

Question -- is a electronic fuel pressure gauge trustworthy, I really don't want to put a gauge on my hood?

[Steve Wood]

well the pl mph and the time slip mph are apples and oranges.  Time slip mph is calculated from the time that it takes to go from one light to another light at the finish line so it is not an instantaneous time.  The PL mph is an interpolated, calculated time derived from the ecm's take on the vss input.  It has nothing to do with performance in this case.

I never trust the electronic senders when it comes to diagnosing a problem.  I just use it as a guide rather than for precise accuracy.  I never understood why people want to mount a gauge on the hood like some ricer.  It just invites someone to rip it off.  Instead, you put the gauge on a hose long enuf to reach the windshield where you tuck it under the wiper arm when you are racing, or want to verify that it is behaving properly.  Some use both..they log a sender and tee off the rail to a quality mechanical gauge to be used when needed.

I prefer a large, 1/2 % accuracy gauge about 3" in diameter to use on the windshield and I put a piece of tape on the face marking where I expect the the pressure to rise to and stay thru out the run.  That way I don't have to focus on the reading numbers

I suspect your pressure is okay because the chip is dropping the pulse width toward the end of the run.  If this is an alky chip, I think it should do that but I would have to double check with Eric.  In theory, I would not think it was all that lean ( I have seen 740-750 with no retard), but something is causing it to pull timing.

On the second run, it seemed to be jerking timing on the shifts so it would seem the knock sensor was hearing something bang on the shifts.

My point is that you cannot assume anything.  You have to know.  Otherwise you are assuming and that always bites you at some time.

It's definitely fat in first and second which reduces off the line power.

The voltage is low as Brad said.  You need to see if it is really low or if it is the typical ecm reported voltage low that often happens.

I would probably add 2% to the 3-4 fuel and see what happens

[TurboCajun]

on the second run I was late on the shift from 2 to 3 and it had started to fall on its face before I shift, that is where I thought the Knock came from.
The 3" fuel gauge is what I use to check for runs around the house taped to the winsheild but was wondering if the electronic would work for a permanent mount in the car.

[Steve Wood]

I think I answered that above.  they are often not precise.  Therefore I don't trust them to always give the right answer.  If they change the reading, I use a good gauge to find out if the pressure really changed, or if the sender decided to report something else.  I have one on one of my cars because I like to log a trend but I only use it for relative changes.

A 7k or more engine is a bit much to risk because I don't want to use a gauge when I think it is required.

Why are you shifting manually?  If you need to modify the governor to make it shift where you want to...do so and put it in third gear and concentrate on driving the car.  Much more consistency and much less chance of being late or missing the shift

[Steve Wood]

http://www.motorsportsinnovations.com/wide_band_o2_files/WB_Pressure.htm

wb 762 is what I use

When you are at the track, you cannot watch PL and see what is happening...yo u can look at it later which might be too late.  The gauge on the windshield tells you real time to quit

[motorhead]

Get a pressure transducer on the fuel rail and run it into the PL.