Like the title says. I installed a 3 piece BBK underdrive pulley set and SLP runners and an AFPR. I port matched the plenum to the TPIS large tube gaskets and polished the plenum didnt port the runners couldnt resist trying them out. I recently replaced all ignition stuff. As in all i mean Cap, Rotor, Accel Coil, Module, Rapid Fire Plugs, Wires also have new 02 sensor. I had a best 1/8th of 8.98 at 76 mph with a 1.98 60ft. Friday I only ran only a 8.94 at 77 with a 1.94 60 ft. What in the world is going on. I should have dropped at least a few tenths but it did nothing. Any idea what could be the problem. I pumped fuel pressure up to 50 and timing up to 10 base to get the best run. Any clue what could be the problem. I also noticed that the fuel pressure doesnt stay after I cut it the motor off. It drops steadily as soon as it is cut off.

Air temp. difference? Any PROM retuning to make use of the new stuff?

I agree, you shoulda seen SOMETHING, but if you are comparing a 60 degree night to a 90 degree day...a cold motor vs a off-the-street hot motor....You could be losing the upgrades to a hot day/ hot engine.

Also forgot to mention. I redid the cooling system. New hoses, water pump, radiator, full flush of system, and hypertech fan switch. Coolant temps where way lower on this pass then the old. Only hit about 170-180 currently and used to sit at 200-220 before. The outside temp was in the 50's both times and I did probably 10 passes all night both times. Approximately the same amount of fuel. At half a tank. I still have a ADS superchip in there from before. And on my car the ADS dropped my times my .2 all by it self. I just received my AUP1 in the mail and will start messin, but still the pulleys themselves should be worth a few tenths.

Going tomorrow for a dyno pull to see. I figure with my mods I should have about 220-230 to the wheels. We will see. What do you guys think?

fuel pressure should not drop off immediately after shutoff... you have a bad regulator, bad fuel pump or bad injectors, you'll have to test for each of those

fuel pressure should slowly go down over a period of time like 15-30 minutes, not go down quickly in a few minutes

50 psi and 10 degrees base may be abit too much timing.. i know my motor liked 8 degrees base on a stock chip and 44-46 psi when i went with the HSR. you should have seen more gains than that, although 1 mph shows power increase

try playing with the timing, back it off 2 degrees and drop fuel pressure down, you dont need to run that high since your leaking off bad anyway. find out why your not holding pressure then run it again

The pressure starts dropping immediately and in ten minutes it is at zero. The AFPR is a new accel unit and the fuel pressure dropped fast before the install. This all leads me to believe it is the injectors.

Would a leaking injector cause performance problems? I think the Air Fuel ratio is going to give me a huge clue as to what is going on.

I will post results tonight after the dyno runs.

Thanks

Jason

I think you will be at around 230-240 tire power.

I think playing with timing and fuel hurt you.

Yes a leaky/stuck/plugged injector could hurt performance.

What coil did you have before? Accel is the least voltage I found of any "performance" coil. Hypertech is highest, then MSD.

Plug gap? Maybe change it. I forget which way, but gapping one way adds more power, other way gets better mpg.

Most of all, yes, you need to change the prom chip out.

Not to bust bubbles, but I only have headers, exhaust, msd coil, ecm tune, on worse heads and ran a best of 8.902 @ 74.13 this weekend in 80deg weather. No porting, no runners, no airfoil.

Yeah dale. That is the problem I ran a 8.9 at 76mph with just hooker headers and catback and the ADS Superchip. With runners, pulleys, ported plenum, and a CAI. I should be at at least 8.7.

I think I gaped them to .045 or maybe .040 I used Ac Delco rapidfires, with summit brand cut to fit wires. I just had the orginal 150,000mile coil on there now I have the Accel Coil. I did have an accel module but it crapped out on me so I put in a new OEM replacement ignition module.

I didnt have luck with the Accel module either.

Ive used just basic delco plugs. No rapids or nothing.

Since your already set for a dyno run. See what the AFR is. Also test each part of your fuel system to find the leak.

Mainly, I think you need to adjust the prom. I'm still learning that stuff and its quite annoying. But atleast I can usually feel the difference in what Im doing. Then go again.

leaking injector or bad fuel pump checkvalve i think it is will cause the pressure to bleed down.

Does the car have hard time on restarts?

fix that problem and you should definately improve

Most of the time she fires right up no problem. I went to the dyno shop and they said it would be a waste of money to just get a dyno pull now since I am going to install the Autoprom this weekend. He said he will give me a discount on some dyno tuning so I rescheduled for next tuesday afternoon. In the mean time I also got a LC-1 wideband and gauge kit I will install since I had them go ahead and weld in another o2 bung. I will post my info when I get it installed.

Also on timing dont you just advance it as high as it will go with out knock. I had it all the way up to 12 base once and only had a few knocks in the midrange. According to ALDL and Tunerpro RT.

Thanks
Jason

yeah usually that will work, just run the least amount of timing that gives max power. 10 should be ok, thats 4 degrees advanced over stock. my car just liked 2-3 over stock which was around 8 degrees base timing

I would pull the timing back to 6*BTDC and drop the fuel pressure down to around 43-45 PSI. I bet the performance picks up tremendously. The timing curves in the stock ECM are already pretty decent and there is plenty of fuel.

I could definately feel a difference in how my 305 breathed up top when I put SLP runners on it. With the stall and bumping the shift points to 6K, I didn't lose any low end to speak of either. It has a hotter cam than stock, headers, dual exhaust, ported 305 vortec heads, and custom tuning by me though.

I tried pulling timing down to 8 and pressure to 47. And according to G-tech (which is usually .2 tenths off actually time) I ran a 8.78(this is the 8.94 at the track) before then after I pulled out timing I was at 9.01. So it hurt allot. I put timing up to 12 had a few knocks and ran 8.98 same FP. Then put time to 10 and FP to 52 and ran an 8.89. According to G-tech before all this install I peaked HP at 4100 then after everything I peaked at 4480 with same HP and torque numbers.

Now that I think of at before at the track I used to have to baby it out of the hole. Now I just floored it and it hooks and goes. So I think I am losing my low end torque. Because I have done nothing to the suspension. To allow it to just hook.


What would cause the loss of lowend?

My laptop just died on me so I have to purchase another one to do programing so that will take me a while.

Also plan on install LC-1 on monday hopefully.

I can also try playing with shift points. In drive it shifts out of first at 4700-4800. Then out of second at 5100. I can hold it in any gear as long as I want.
What do you guys recommend I shift at now.

Put stock chip in and installed my LC-1. Showed my A/F ratio at 10.9-11.2 at wide open throttle. I tried the ARAP bin and my A/F is still rich at 11.5-11.8.

I dont think being at little rich will hurt performance that much but it might. I am going to continue to play with the BINs tonight and try and get my A/F ratio up to 12.8 or close at WOT.

Also will hit dyno tomorrow.

Thanks

Jason

ARAP has too much timing for me with any of the iron small block heads. Try to get your WOT timing to 30* and tune the fuel around that. 30* is very likely where you will find peak power. I would also suggest an AFR in the neighberhood of 12.7:1, unless you have E10 which has 10% ethanol, in which case it will like 12.2-12.3:1 better.

You have two tables that add togather to modify the PE AFR from the normal stoichiometric ratio. No matter what that is these modifiers modify it.

Here are the stock tables for your car.

PE AFR Modifier vs Coolant

Coolant--LambdaC
-40-------0.52
-16-------0.46
8---------0.41
32--------0.31
56--------0.09
80--------0.12
104-------0.12
128-------0.34
152-------0.34

PE AFR Modifier vs RPM

RPM----LambdaW
0---------1.03
400-------1.03
800-------1.04
1200------1.04
1600------1.13
2000------1.16
2400------1.15
2800------1.23
3200------1.32
3600------1.26
4000------1.2
4400------1.17
4800------1.13
5200------1.19
5600------1.19
6000------1.19
6400------1.19


Here is what the stock PE settings calculate out to provide for your stock car.

RPM------40-------16--------8--------32------56-------80------104------128------152
0--------9.48-----9.86-----10.20----10.97----13.12----12.78----12.78----10.72----10.72
400------9.48-----9.86-----10.20----10.97----13.12----12.78----12.78----10.72----10.72
800------9.42-----9.8------10.13----10.88----13.00----12.67----12.67----10.65----10.65
1200-----9.42-----9.8------10.13----10.88----13.00----12.67----12.67----10.65----10.65
1600-----8.90-----9.24-----9.54-----10.20----12.04----11.76----11.76----10-------10
2000-----8.75-----9.07-----9.36-----10-------11.76----11.48----11.48----9.8------9.8
2400-----8.80-----9.13-----9.42-----10.06----11.85----11.57----11.57----9.86-----9.86
2800-----8.4------8.6------8.96-----9.54-----11.13-----10.88----10.88---9.36-----9.36
3200-----7.98-----8.25-----8.49-----9.01-----10.42----10.20-----10.20---8.85-----8.855
3600-----8.25-----8.54-----8.80-----9.36-----10.88----10.65-----10.65---9.18-----9.18
4000-----8.54-----8.85-----9.13-----9.73-----11.39----11.13-----11.13---9.54-----9.54
4400-----8.69-----9.01-----9.30-----9.93-----11.66----11.39-----11.39---9.73-----9.73
4800-----8.90-----9.24-----9.54-----10.20----12.04----11.76----11.76----10------10
5200-----8.59-----8.90-----9.18------9.8-----11.48----11.22----11.22----9.60-----9.60
5600-----8.59-----8.90-----9.18------9.8-----11.48----11.22----11.22----9.60-----9.60
6000-----8.59-----8.90-----9.18------9.8-----11.48----11.22----11.22----9.60-----9.60
6400-----8.59-----8.90-----9.18------9.8-----11.48----11.22----11.22----9.60-----9.60

Now here is what my TPI 305 runs.

PE AFR Modifier vs Coolant

Coolant--LambdaC
-40-------0.47
-16-------0.4
8---------0.32
32--------0.25
56--------0.2
80--------0.16
104-------0.16
128-------0.16
152-------0.16

PE AFR Modifier vs RPM

RPM----LambdaW
0--------1
400------1
800------1
1200-----1
1600-----1
2000-----1
2400-----1
2800-----1
3200-----1
3600-----1
4000-----1
4400-----1
4800-----1
5200-----1
5600-----1
6000-----1
6400-----1

RPM----(-40)-----(-16)------8--------32-------56-------80------104------128-----152
0--------10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67
400------10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67
800------10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67
1200-----10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67
1600-----10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67
2000-----10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67
2400-----10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67
2800-----10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67
3200-----10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67
3600-----10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67
4000-----10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67
4400-----10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67
4800-----10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67
5200-----10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67
5600-----10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67
6000-----10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67
6400-----10-------10.5-----11.13----11.76----12.25----12.67----12.67----12.67---12.67

first thing tomorrow I will play with programming and check to see how close it is.

thanks for the post

Fast355. So your saying timing after 30deg is pointless? I still need to work on the timing on my car and just wondering where the to much of a good thing hurts.

he has vortec heads i believe so they like less total timing anyway. My stock L98 loved 34 degrees in early

What I am saying is to go to 30* and get the fueling corrected. He can always try more timing later on, but you get too much timing on an air/fuel ratio that is too rich and you can knock the ring lands off the pistons.

One other idea that will help. I would push the fuel pressure up to 50 psi and change the injector flow constant in the .bin to match what the injectors can push out. This will help clean up the spray pattern of the injectors, giving a finer mist. This will make the mixture quality better and give more hp and better fuel mileage with less timing.

oh i got yah. My car picked up 15lbft by going to 34 degrees in early by 3000 rpms over stock tables which was like 26 or something like that and 32 degree total advance. But i was also lean so i probly had more in it

I know this is old but I will update anyway. I did have the car dynoed with where I tuned the fuel to get around 12.4-9 throughtout pull.

The car put down 211 hp and 268.13 trq.

Graph

Somethings not right. My old stock auto Lb9 put down 187/270. It was 5.0 cuz I removed the heads to find the bore size, 3.75 inches. So with 45 cubes less, stock 2-1/4 exhaust, and no mods, my car was only 20hp less and had 3+tq than your car.

I have since added large port runners to my setup. I learned REAL quick, that unless you port the base to match. You will actually have LESS power. The ridge between the runners and base create turbulance.

Might want to look into that.