I'm having similar isues with me car with E85 Al, it is intermittent though, not all th etime It made three time trial runs the last time out and didn't miss or hestitate, first round it stutter and missed the first hundred feet after letting go of the trans brake button, same thing the next day I let it idle on the starting line with the trans brake on until the top light comes on and I then floor it and let go of the trans brake button, the Biondo 400 Mega box releases the trans brake in the time I set in it to not red light. I've been fighting this problem on and off for the last year, it is not consitent so I'm not real sure if it is the ignition( the MSD 7AL2 failed last year and I had them repair it before racing started this year), carb or tranny or converter
I would verify TDC now before doing anything else with a brass TDC tool in the #1 spark plug hole
Edited, I may have a power valve issue,it is three years old now using E85 I'll check it next week when it warms up outside.

Back your idle/air screws out a turn and try it...
Good Luck

That's exactly what I was thinking.
I've dynoed a couple of moderate CR 440's with -1 heads and slightly too big of a cam, and they were pretty darn weak in that rpm range.
My feeling is in a combo like that if the cranking compression isn't absolutely high enough for the duration of the cam, that hole in the TQ curve will be pretty deep.

I don't know the specifics of your converter(or cam for that matter), but assuming the cam is close to 280@ .050, and I were looking to help this situation without digging into the motor, I'd try having the converter set of for more free speed and a flash stall speed of about 56-5800 and run the two step at 5000-5200.

I am not so sure I wouldn't try another ignition box. 48* is a ton, and that may be caused by a bad msd as well. seems like most everything else that makes sense has been mentioned. HTH, Beep

FWIW the converter is an 8" that is 6000 stall behind an 800hp motor. We now it was way tight for the combo so tried another one, no change other than a lot more RPM up top and 14% slip. We may have found an issue today with my son working on it as I was home most the day today. He is still working on it now and hopefully found something. Will report back and let you know if it is better tomorrow.

This is a very thrown together piece with parts we had lying around. We have a 511 on the stand but kinda want to get this deal sorted out first. It is a very compromised combo, I considered more compression but not wanting to dump a bunch of money in it used what was here. As for the cam I will have to find the card, I don't recall it being to crazy on duration and it is in 2 advanced and is on a typical mopar 108lsa. Not my favorite but once again was here and had it forever.

FWIW I saw a couple comments about not using a 2 step. Not sure that will help any here as the car seems to stumble and stop about 3600 or so, then after a short duration will jump up on the chip. I am sure if we unplugged it it would still "Stall" at 3600 before pushing through and going to converter stall?!? The issue is the temporary "Stall" at 3600 that will not go away, but we may have found an issue and will let you al know.

If its carb related then its in the main jetting, because when you see this happen you are on the floor, and I'm sure that at 3600 the main circuit is already flowing.

If the car has headers that are more suited towards the 800hp motor, like what is typical on a dragster these days(big tubes, short primary length, short collectors or mufflers), then that would reinforce my belief that it's the shape of the power curve, and the motors unwillingness to pull itself out of the big dip in TQ when the converter starts to put up a fight.
If it were a typical street/strip type chassis, I'd say add about 18"-24" of collector length and see what affect that had.

All of this assumes that in the end you rule out the carb & ignition as being the problem.

What plugs r u running. I would remove the int. Bleeds and try a 7 ngk to start but as I said inVegas, a 2 circuit conversion could be your friend.......

Electrical or ignition, does not explain why is seems to stall in the 3600 rpm range, struggling to get on the chip, but when it does get through it comes on up to 4600rpm. Nor is it likely the converter. People run super tight converters all the time with not huge HP motors, if they are heavy nitrous motors or similar. Struggling to get on the brake is nearly always a carb calibration issue. Doesn't matter that he tried two carbs. If both have similar calibrations, they will have similar issues.

I recently worked on an EFI nitrous car with a 865in motor. He said when you put it on the brake, it struggled to get there, but when you turned it loose, the motor stayed at 3600 and would come no further. Sounded like it was on a rev limiter. He was convinced it was the ignition box, ECU, plug wires, broken converter, whatever..........with me telling him the whole time, that is was the fuel tune. He messed with this thing for 3 months and changed everything on the car. When I finally saw it in person, it did EXACTLY as he said. When he turned the button loose, it sounded like it was on a limiter and the rpm flat lined on the graph at 3600 and would go no further. He could step off a little and get back in it and it came up fine. I told him again it was the tune........NO WAY was the response.....OK. I finally went over there and snatched the laptop out of his hands and put 25% fuel in it, at THAT rpm range and told him to try it. Did the same thing and "SEE" was his response........Hold on a damn minute, I told him........LOL! So then I removed THAT 25% fuel in that range, plus another 25% more and told him to try it. Came up like a champ and revved to the moon when he cut it loose. Handed him the laptop and told him to now go "fix" the Tune in that area. So why did I relate that story.........because to me, Al's issue seems fuel related. Too much or not enough in that rpm range, for the combo of air flow, converter and other parts he has

Well hang on to your hats we have figured out what this issue was, now we are working on some others that we created trying to fix this one. Anyway long story short as I have to be out there again tomorrow here is what we found. The starting line enhancer had a small leak at the cylinder. It was fluctuating the cylinder in and out causing the throttle to move and open at different increments. Crazy deal that was found late last night.

It is much better now but now, but not 100% still. We are now chasing the carb to get it right again. Just wish it was not at a big dollar bracket race.

Dom we have a -7 plug in the car. We played around with the car tonight on stands trying to get it on the chip cleaner. We have had to RICHEN the carb up a fair amount. Intermediate bleed is much smaller than where we started as is the squirter size. Also have smaller idle bleed in it now too and it is getting much better and gets up quicker and cleaner now. But we are still not happy and will keep working on it. Just feel bad for the driver, as it is a friend of my sons and we have given him a car with issues. FWIW it did run it's best ever as well, we will find those .20's eventually I am confident.

Dwayne you are dead on, to much header. I also feel a looser converter will help a ton. But that's a story for later.

Do what?

I'm confused....lol....not that that is abnormal, but....

So, you have tried three different carburetors and two different fuel sources and the one thing that helped was bumping the timing to 48º plus, correct?

Now you think that you have fixed/helped the issue with correcting a SLE problem and fattening up the mid range circuit, Correct?

If so....I don't know how the timing had any influence with a SLE problem and if it was lean, advancing the timing would have hurt, not helped...

I would assume you have returned the timing to a normal range after you fattened up the mixture and all is good?

If nothing else, makes for a good campfire story....

Al i would think a number 7 plug is board line cold for e85 and 11 to 1 compression just my 2 cents but when i made the switch over to e85 albeit a boosted motor but the car ran better with a set of normal temp range plugs then a set of colder ones like most suggested thats proably why you could get away with so much timing
I asked the question on page one about your afr and plug gap if you dont have a Wideband id suggest getting one
Good luck

Hey Al, is Hunter Walker in the drivers sat?

I always ran an NGK -8 plug in my deal.

I to run e-85 has been a learning curve over 2 years, as stated it will like 1 -2 more degrees of timing you can play with squirts and cams ,but one of the huge gains I found was changing plug heat range (ngk)from 8 to 7s just a thought. Mark sullens worked with me on the tune. I don't know if you recall I was trying to get the 1250 in tune finally switched to a 1050 went from 9.90 135 -137 to 2 weeks ago 9.63 142 mph I still have a convertor issue.as my 60ft is terrible 1.41- 1.46 just my issue check your plug heat range AL... I stage at 170 cross the stripe @ 180

We have been watching the plugs very closely BECAUSE of the number the timing tab is showing. I only gave that number to show how ludicrous it was. I do not believe it is anywhere near the number mentioned. But have not bothered to check any of it at the track as it is a pain to get to most the stuff in the dragster. Will worry about that at home. Needless to say the plugs look good. The plugs show no sign of detonation and heat range and timing look good. So that number is just a number nothing more. Will get that sorted out later as car is still at track this weekend.

No Hunter is not driving the car this weekend. He did at SCSN for us while we tried to sort out the deal. He has also driven it before. I don't fit in the car and my son still has not had the opportunity to get his license yet, that will happen in January. Hunter is a great driver and good friend. Been helping him with his Chevelle this weekend as well. And no doubt he will be wheelin the car again. Unless I feel like figuring out how to get my legs in the car but since I am not a dragster guy not likely to happen. I got it for the kid just cannot find the time to get him licensed.

The SLE was just not holding ANY certain RPM. It just was leaking air and moving wherever it wanted to. So full throttle was rarely that especailly at lower RPM's where it was really affecting things. Was also causing our 60's to move around run to run. All that is now gone, car is 60 footing consistently now and repeating numbers like it did the weak before.

We also had an issue with the delay box, TB switch or TB solenoid. Not sure which yet as we just swapped out all three at once. That came about from HUGE swings in reaction times, as in starting with crooked numbers. The person driving the car this weekend drives a blown altered normally and is generally pretty darn good on the tree side of things so we knew it was not him. Since the change he has averaged .009 on the tree.

In the end the major issue on the not coming up clean deal was the SLE not holding, when you would go to hit the throttle it would not always open fully, certainly never the same amount each time and made it very unhappy. Once we took the SLE off and the car got up on the chip easily. Adding fuel to the intermediate circuit just made it get up that much quicker and cleaner.

In the end I have learned enough about what E85 wants to feel much more comfortable with the stuff. Learned it don't like the cold for sure But we overcame that by just squirting gas in it in the morning to fire it and that was enough to overcome that. The fuel definitely like engine temp for sure. We have been 180 in the beams and it likes that for sure, not easy to keep heat in it in the dragster. It sure cools down quick. And lastly you gotta put some fuel to it. We are inching closer and closer to the .20's now and I am happy with this hodge podge combo of bits and pieces. Learn something new all the time. Also learned going to the gas station and paying a couple bucks for fuel aint so bad either

Al, Im not sure how it is over your way but E85 from the pump here in Australia apparently varies too much, you might E75 or 90 ?? I was told to buy it in drums for consistency, cost is a little more but still cheap.

My 2cents (only about 1.4 US)

Glad to hear you found the problem. It wasn't anything to do with using E-85 as fuel.

Let us know what was going on with the timing mark when you get it back to the garage and have time to work on it.

OK, I am just brain dead this a.m., what is SLE?


Steve

Starting Line Enhancer.