jstang,
A lean mixture will burn faster because there is not as much to burn. Because carbon is carbon I'll give this example. Take a piece of bulsa wood and a piece of oak of the same size. Light them both on fire. The bulsa will go up much quicker because it has less density.
About the t-bird.
302 .030 over
GT40 heads and intake
70 mm mass air flow and throttle body and egr plate
30# injectors with 55 lbs of fuel pressure
tubbed, no power seats, no power windows, no rear seat fiberglass hood easy up front struts and 373 gears.

 

Rhody,
Let the computer do it's work. It has a long term fuel trim learning curve built into it. It will learn what your engine needs. The bigger throttle body would just make you lean again. As far as the pressure regulater. A manual one is nice if you are drag racing. Unfortunately your car has to idle from time to time. Without the lower fuel pressure at an idle your computer will not be able to lean your injectors enough for a smooth clean idle. You will end up fouling out your plugs from over richness.

 

If the truck made it to 190,000 miles i think the factory set-up is working fine with 19 # injectors. why not keep it simple go to a 160 thermostat, retard the timing a little, change the oxygen sensor and maybe run a higher octain gas.
No more tha $100 worth of stuff, it couldnt hurt.

jstang, how may mustang and thunderbirds, with no power adders, have you seen with gt-40 heads,intake and a larger throttle body running 11's?

 

Brother Dave, UH.....None. with a blower pushing 11 psi Edelbrock heads,yata, yata yata.....I've only gone 12.5. I know my AOD(performance automatic built) is killing my trap speed, but nothings faster out of the hole(1.7-1.8 60' times)with only a 2400 stall.

to go 11.9 with 3500lbs is about 400 hp, do-able, I guess. however probally not streetable.so maybe its light!!

My 67 yr old nextdoor neighbor has a 71 Monte with a Pro-charger, 21psi of boost, he spent over $100.000.00 on the car, it was tuned at Larocca's in Jersey, right around 800 at the flywheel with a small block. He wasn't happy, he wants 1000hp, so it went back for a new blower, My 2 yr old calls it Thunder when he starts it, and it breathes out that dual 3" exhaust. He plans on low 10's high 9's when hes done.

Anyone can go fast, not everyone can use pump gas, pass our states emmission testing, enjoy a awesome sound system while cruising to the track thats 100 miles away, rip off some passes and drive it home.thats what impresses me.

 

jstang,
Light is right. No A/C, no fan or fan clutch, Aluminum dash with the bare necesseties, I have a five speed manual trans. 50 lbs right there. I already told you about most of the interior mods. Car is registered in Oregon. No annual smog tests. guess it weighs about 28 or 2900.

 

Well, today it got done. I'll find out if bumping the fuel psi up to 47 will help the pinging/detonation problem.

I'll post up wether the difference is noticible.

 

I'm not a rocket sciencetist(sp),,but why dont you just retard the base timing until the pinging stops???

Or a better grade of fuel will take the ping out...

Also I believe you spell engine---engine not engin....

 

I can't let this go. On the track larger injectors will give you a richer mixture if you leave the same MAF and calibration. Because you are at WOT where the injection is calculated directly from the MAF. Warmed up not at WOT, the O2 sensors will adjust the trim until the larger injectors inject the same amount that the 19# injectors do (up to 25% correction, then it'll set a rich code). As for the larger throttle body leaning, the MAF measures the air that goes through the throttle body regardless of its size.

Low octane, advanced timing, lean mixtures, high compression and high temperatures cause pinging. Higher octane, richer mixtures, retarded timing, lower compression, and lower temperatures reduce pinging. If you have good O2 sensors, when warmed up and not over 80% throttle, you have the right mixture. If you only ping at over 80% throttle, the mixture might be off or at least you can 'adjust' it at >80% throttle.

You can't adjust the base timing on these motors, but the knock sensor should do that automatically. It is a microphone (literally) that bolts to the engine. When it detects pinging, it retards the spark hoping to kill pinging. After several seconds it adds the advance back in until it's where it should be or until it pings again. Overtorque, very slightly, the knock sensor and it may resist pinging better.

Finally, adding EGR increases gas milage, cools the cylinder, and resists pinging. Make sure the EGR ports are clear and you get good EGR flow. To test, if you open the EGR valve at idle, it should almost kill the engine before it can recover. If not, plugged lines. The DPFE can indicate more flow than you're getting, check it too. EGR doesn't get added at WOT, so if you're not pinging until WOT, don't worry about EGR.

Finally, I assume we don't have to worry about carbon buildup in your cylinders, you're lean enough and apparently don't baby your engine. Good, you shouldn't.

As to it being worse in the #8 cylinder, there is a thread somewhere about a coolant bypass. Memory serves, it was for the rearmost cylinder. It may be your cylinder wasn't lean, just hotter than the rest. Good luck and drive safe.

 

Just saw the '90 5.0L again. Scratch the base timing and knock sensor stuff. You can adjust the base timing and retard it 5 degrees or so to reduce pinging. And no, you don't have a knock sensor. Everything else still holds. Sorry, but still drive safe.

 

cantrma,
boy, I havn't been to this forum in just about 4 years.

But, here's what happened, the egr ducts had plugged up unbeknownst to me at the time. It continued to get bad and cracked a head. So I had to replace a head. So, I replaced most of the sensors at that time. Truck pretty much ran well from that point on till a recent development.....

Wrist pin in a piston is knocking...... BAD

I'll be pulling the engine, trans, T/C and going through everything again..... soon.... ah well....

I like the new trucks out there, but, I can get this one back on the road for under 3k vs. 30k for a new one. And this one is like a comfortable glove.....