100+ octane gas ?

[Canadian1968]

I have mild build 440

750 Holley
RPM performer intake
ported 906 heads
icon pistons
1 3/4 headman headers
2 1/2 with x pipe
xe274 cam

would running some 101 avation fule give any real gains ?

[cdr]

The lowest octane you can run without ping[detonation] will make the most power.

[c00nhunterjoe]

What is the part number of the pistons used, what thickness head gasket, what were the heads milled to cc-wise. Need to determine compression before you determine fuel.
   Like cdr said, changing gas doesnt add horsepower. The most it would do is allow you to potentially run more total timing and pick up a mph and a tenth.

[INTMD8]

Same car that went 81 in the 1/8th to 88 in the 1/4?

No, fuel change will not help anything there, you could run that with 80 octane.

I would say your tune seems a bit off regardless, or you're at 8-1 compression.

Aside from that, only picking up 7mph from 1/8 to 1/4 it is laying over hard.  My first guess would be fuel delivery.

[Canadian1968]

I'm hoping to get alot more info next time I am out. I wasn't paying attention to the wideband I have hooked up at all . I know I typically run rich at WOT .. 11.8 to 10.5 range ... I need to lean that out

[John_Kunkel]

Running leaded avgas will shorten your spark plug life, no sense in running it if you're not experiencing detonation.

[BSB67]

Same car that went 81 in the 1/8th to 88 in the 1/4?

......... only picking up 7mph from 1/8 to 1/4 it is laying over hard.  My first guess would be fuel delivery.

He said he lifted, and maybe tapped the brakes

[c00nhunterjoe]

Run it all out and reassess. Change nothing until then

[Challenger340]

I have mild build 440

750 Holley
RPM performer intake
ported 906 heads
icon pistons
1 3/4 headman headers
2 1/2 with x pipe
xe274 cam

would running some 101 avation fule give any real gains ?

No gains av gas on that.

Bur far more info is req'd to assess the 88 mph in the 1/4 if that's true ? seems quite low ? Hussein Bolt can run faster than that ?

What 750 Holley, Vac Secondary ?
Torque Converter ? gearing ? Tire Diameter ?
Which ICON Piston ?
and most importantly...
can you elaborate at all on the "ported' 906 Heads ?

[Canadian1968]

yes 3310 vac. secondary carb. currently running second lightest spring .  Choke horn has been removed and barrel inlets smoothed. Butteryfly screws shaved , 4.5 powe valve .

2500 Torqe converter stock 3.23 posie , 26" tire

I did a lot of reading and research on the head porting and valve angles . I ported them myself paying a lot off attention to bowl blend and blending in the material arouND the valve guide . I followed some information you gave in one of your other post about valve seat angles and had a 3 angle job done with a 75 throat cut.  Valve are back cut , but factory size .

head and intake were also gasket matched  intake side of the head was blended in as well.

pump is carter HV . with 3/8 right from the tank to carb.

http://www.dodgecharger.com/forum/index.php/topic,121570.msg1511385.html#msg1511385

Like I said .... I did lift

[c00nhunterjoe]

Something is amiss. Your 1/8 mile mph should still be higher assuming the head flow is correct.

[BSB67]

So to make clear, this is where I think the key pieces to the puzzle are:

1) Your compression ratio is probably between 9.2:1 to 10:1, depending on CD, gasket thickness and final head volume.  Unless you have detonation, av gas will not help, if you do have detonation, it will help a lot.  Do you know your actual CR, and cranking cylinder pressure?

2) Your heads should flow 230 to 235 cfm, IMO.  Do you know actual flow?

3) Race weight is probably 4000 lbs.  Do you know for sure?

4) the DA during track time was probably 2500.  Do you know what the DA was?  If you give us the track name, dates and time, we can check that.

If those things above are generally true, and we take the leap that if you kept your foot in it through the traps, the car would have gone 13.85 @ 101.5 mph, I think I can make some general conclusions.

1) Changing nothing, and practice driving to achieve a 2.05 sec. 60 ft should put you in the 13.50s at 102 ish.

2) My experience indicates that folks that are relatively new to running at the track can find another 0.1 or 0.2 in et and 1 mph in driving technique even after the 60 ft is down to 2.050.  Shift points matter especially on a tight converter

3) My experience also indicates that getting real serious about your tune will find another 0.1 or 0.2 in et and 1-1.5 mph.

With that, I would guess that there is a 13.3 @104 in the car, maybe a little more.  If number 2 and 3 above don't get you to 104 mph, I would say some horsepower is missing somewhere based on the parts you have.

A Holley 4779 or a 4781 would pick up the car a little bit more too.

Me and 4 friends probably have 500 time slips during a time when we were taking our cars from 14.0 to 12.8.  True pump gas, small hydraulic FT cam, full exhaust street cars just like your's.  No slicks, no "gears", no "converters", no real suspension work.  A couple guys had 1 3/4" headers.   

[c00nhunterjoe]

So to make clear, this is where I think the key pieces to the puzzle are:

1) Your compression ratio is probably between 9.2:1 to 10:1, depending on CD, gasket thickness and final head volume.  Unless you have detonation, av gas will not help, if you do have detonation, it will help a lot.  Do you know your actual CR, and cranking cylinder pressure?

2) Your heads should flow 230 to 235 cfm, IMO.  Do you know actual flow?

3) Race weight is probably 4000 lbs.  Do you know for sure?

4) the DA during track time was probably 2500.  Do you know what the DA was?  If you give us the track name, dates and time, we can check that.

If those things above are generally true, and we take the leap that if you kept your foot in it through the traps, the car would have gone 13.85 @ 101.5 mph, I think I can make some general conclusions.

1) Changing nothing, and practice driving to achieve a 2.05 sec. 60 ft should put you in the 13.50s at 102 ish.

2) My experience indicates that folks that are relatively new to running at the track can find another 0.1 or 0.2 in et and 1 mph in driving technique even after the 60 ft is down to 2.050.  Shift points matter especially on a tight converter

3) My experience also indicates that getting real serious about your tune will find another 0.1 or 0.2 in et and 1-1.5 mph.

With that, I would guess that there is a 13.3 @104 in the car, maybe a little more.  If number 2 and 3 above don't get you to 104 mph, I would say some horsepower is missing somewhere based on the parts you have.

A Holley 4779 or a 4781 would pick up the car a little bit more too.

Me and 4 friends probably have 500 time slips during a time when we were taking our cars from 14.0 to 12.8.  True pump gas, small hydraulic FT cam, full exhaust street cars just like your's.  No slicks, no "gears", no "converters", no real suspension work.  A couple guys had 1 3/4" headers.   

also-depending on tire height, i have achieved 1.9 60' times in b body mopars on legitimate, non race, street tires.
I still feel "ported" 906s should get a mild-properly- built pump gas 440 into the 12s on 3.23 gears. Depending on the above stated weather factors. Mtns of Colorado vs sea level in maryland can be a 4 mph and .6 second difference in the same car easily.

[BSB67]

So to make clear, this is where I think the key pieces to the puzzle are:

1) Your compression ratio is probably between 9.2:1 to 10:1, depending on CD, gasket thickness and final head volume.  Unless you have detonation, av gas will not help, if you do have detonation, it will help a lot.  Do you know your actual CR, and cranking cylinder pressure?

2) Your heads should flow 230 to 235 cfm, IMO.  Do you know actual flow?

3) Race weight is probably 4000 lbs.  Do you know for sure?

4) the DA during track time was probably 2500.  Do you know what the DA was?  If you give us the track name, dates and time, we can check that.

If those things above are generally true, and we take the leap that if you kept your foot in it through the traps, the car would have gone 13.85 @ 101.5 mph, I think I can make some general conclusions.

1) Changing nothing, and practice driving to achieve a 2.05 sec. 60 ft should put you in the 13.50s at 102 ish.

2) My experience indicates that folks that are relatively new to running at the track can find another 0.1 or 0.2 in et and 1 mph in driving technique even after the 60 ft is down to 2.050.  Shift points matter especially on a tight converter

3) My experience also indicates that getting real serious about your tune will find another 0.1 or 0.2 in et and 1-1.5 mph.

With that, I would guess that there is a 13.3 @104 in the car, maybe a little more.  If number 2 and 3 above don't get you to 104 mph, I would say some horsepower is missing somewhere based on the parts you have.

A Holley 4779 or a 4781 would pick up the car a little bit more too.

Me and 4 friends probably have 500 time slips during a time when we were taking our cars from 14.0 to 12.8.  True pump gas, small hydraulic FT cam, full exhaust street cars just like your's.  No slicks, no "gears", no "converters", no real suspension work.  A couple guys had 1 3/4" headers.    

also-depending on tire height, i have achieved 1.9 60' times in b body mopars on legitimate, non race, street tires.
I still feel "ported" 906s should get a mild-properly- built pump gas 440 into the 12s on 3.23 gears. Depending on the above stated weather factors. Mtns of Colorado vs sea level in maryland can be a 4 mph and .6 second difference in the same car easily.

Yup.  Of the five of us, one guy was in the 1.90 - 1.95 range pretty consistently.  The rest of us in the 2.0 to 2.1  range.  He did have 275-15s where as the rest us were usually on 235s and his car was a couple hundred pounds lighter.  I went a best of 1.98 at National Trail which was a better prepped track than my local tracks on T&T nights.

If it were my car, I'd be targeting a 13.1 -13.2 @ 106 in really good air. (1000 - 1500 DA) if it is 4000 lbs race weight.   At one point, my car was very similar to his, mine probably 200 lbs heavier, a smaller cam, exhaust manifolds and no port work at all and went 13.40s @ 103.5.

[INTMD8]

Same car that went 81 in the 1/8th to 88 in the 1/4?

......... only picking up 7mph from 1/8 to 1/4 it is laying over hard.  My first guess would be fuel delivery.

He said he lifted, and maybe tapped the brakes

Yes. I edited my post right after hitting -post- and apparently it didn't save.

[c00nhunterjoe]

In reply to bsb67- my 1.9 60' was on 275/15 as well with a sure grip rear. My home track of cecil county dragway in rising sun md is usually top notch track prep.

[BSB67]

 

Same car that went 81 in the 1/8th to 88 in the 1/4?

......... only picking up 7mph from 1/8 to 1/4 it is laying over hard.  My first guess would be fuel delivery.

He said he lifted, and maybe tapped the brakes

Yes. I edited my post right after hitting -post- and apparently it didn't save.

[Canadian1968]

looks like Oct 4th will be my last chance to race this year.

Do you guys do a burnout with the "real" street tires ?  Tire pressure?

I don't have actual weight. Another thing on my to do list .
No flow numbers sorry.
Load up the converter at all on launch ?

[Q5XX29]

If running regular street tires, just clean them off with a quick spin, and try to avoid the water in the burnout box. If running "drag radial" DOT-approved tires which are basically slicks with just enough tread pattern to qualify as street-legal (Hoosier DR2s, Nitto NTO5Rs, Mickey Thompson ET streets, etc), then try lowering the pressure to about 18 psi, roll through the water and do a nice smoky burnout to heat them up. Not sure what tire pressure you would try if actual "normal" street tires, but probably around 25 psi? in the rears and at least 40-45 in the fronts (decrease rolling resistance). If your engine doesn't stumble with a stab of the gas off-idle, you might find that doing just that (stabbing the throttle, rather than loading up against the converter) might work best, as it sometimes allows the engine/trans to spin up a bit faster and "flash" the converter at a little higher rpm. A lot will depend on your track conditions, of course (ambient temperature, quality of track prep, etc).

[c00nhunterjoe]

Legit street radial tire on correct width rim (not a 11 inch tire on a 7 inch rim) run 30 psi, drive around the water, spin enough to clean and barely haze, almost no smoke at all.

Dot drag radial on correct width rim- 2 ton b body, start at 25psi. Mine in a stick car performed best at 30.

Bias slick- start at 15 and work up, i usually run my 30x9 at 28 psi and can cut a 1.4 60' on stock suspension.

As far as building up on the converter goes, you will have to practice and see how your car performs. With a 2500 flash, its essentially stock so there isnt much room. I would say with your combo, a 2k launch rpm with a hard roll into wideopen should work well if track prep is there. A stab will probably just spin.

[BSB67]

Pick a pressure and don't change it, ever.  Pick the low side of acceptable for the street, 26 to 30.

Drive around the water.

I do smoke the tire.

I load the converter pretty hard, brake off on last yellow, half throttle at green, roll into the rest of it quickly after that.  The goal is to find a way to put the tire on the edge of traction without spin. 

[c00nhunterjoe]

ECHO echo.....echooooo.    seems to be a pattern.