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DRR Pro |
I have a 598 12* with profiler heads in a 2025 lb RaceTech dragster. I run 410 gears with MT big bubbas. I normally run 28* of timing. Was just wondering if I ran 34* to get it out of the hole quicker then set it back to 28 after about 1.5 seconds. At 28* of timing I have been 4.57 @150.3 Just wondering it it might help a little Thx in advance Brian Mollison 2013 American Dragster 2020 Sumerduck Dragway VA Top ET Champion 2017 Sumerduck Top ET & SSS Track Champion 2017 MAC Top ET Track Champion 2009 Sumerduck Dragway Va Top ET & IHRA SSS Track Champion 2008 IHRA Division 1 Top ET Bracket Final Runner-up 2007 Colonial Beach Dragway Top ET Track Champion | ||
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DRR Sportsman |
Have the exact combo albeit in a slightly lighter dragster. I run 31* per Reher Morrison's dyno. 28 seems too low to me. You want it to move out of hole quicker put the little bubbas on it, a 4.30 gear or 1.80 trans. It'll move then. Been there done that. It'll go low 40's Mike Greene  | |||
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DRR Trophy |
Best thing to do is creep up on it.. Try going up 2* at a time and see how it acts and what the timeslip says. Slip won't lie. I can't say I've heard more than 32* in a spread port type motor though.. Nick Craig 1971 Camaro Split Bumper 376ci LS3 | |||
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DRR Pro |
Time your engine by what the spark plugs show you. Then if you want to add tricks, figure out what works. "Despite the high cost of living, it remains popular." Dave Cook N375 | |||
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DRR Sportsman |
Do you have a terminator on it? If so, try putting 2 degrees of timing IN the engine, about 100 rpm before the converter grabs the engine. We know that Rons stuff gets fatter the more you turn it, or, put a high speed lean out on it. Jeremiah Hall | |||
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DRR Pro |
we've had 4 different Big Chief big blocks and all of them ran the fastest at 34-35 degrees ...even made more power on the dynos ... thats 18* stuff .could just be our combo of compression, camshaft timing , chamber size etc ... I can't comment on any other spreadport heads though ... | |||
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| DRR S/Pro |
Read the plugs, it's the safest way to make sure you are not hurting anything. There are too many variables to make a safe suggestion. Bob | |||
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| DRR Pro |
I am running a Terminator. #1 pump 40 nozzles and a 82 return pill Brian Mollison 2013 American Dragster 2020 Sumerduck Dragway VA Top ET Champion 2017 Sumerduck Top ET & SSS Track Champion 2017 MAC Top ET Track Champion 2009 Sumerduck Dragway Va Top ET & IHRA SSS Track Champion 2008 IHRA Division 1 Top ET Bracket Final Runner-up 2007 Colonial Beach Dragway Top ET Track Champion | |||
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| DRR Sportsman |
That is A LOT of fuel!!! A friends 12 degree 615 only had 39/102. I run 40/108 in my conventional headed 632. Jeremiah Hall | |||
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| DRR Pro |
The more fuel I give it the better it runs. My pump might be down on output compared to others maybe Brian Mollison 2013 American Dragster 2020 Sumerduck Dragway VA Top ET Champion 2017 Sumerduck Top ET & SSS Track Champion 2017 MAC Top ET Track Champion 2009 Sumerduck Dragway Va Top ET & IHRA SSS Track Champion 2008 IHRA Division 1 Top ET Bracket Final Runner-up 2007 Colonial Beach Dragway Top ET Track Champion | |||
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| DRR Pro |
I got a friend that has a alum 632 with 14* heads and it made the most ho on the dyno at 36* of timing. He runs a terminator and has run 4.41 Brian Mollison 2013 American Dragster 2020 Sumerduck Dragway VA Top ET Champion 2017 Sumerduck Top ET & SSS Track Champion 2017 MAC Top ET Track Champion 2009 Sumerduck Dragway Va Top ET & IHRA SSS Track Champion 2008 IHRA Division 1 Top ET Bracket Final Runner-up 2007 Colonial Beach Dragway Top ET Track Champion | |||
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DRR Top Comp |
A couple of things to note. 1. I think many people run too much timing. 2. If you are running too much timing you can run more fuel but it is not optimum. https://postimg.cc/gallery/np3zpruo/ "Dunning-Kruger Effect" -a type of Cognitive bias where people with little expertise or ability assume they have superior expertise or ability. This overestimation occurs as a result of the fact that they do not have enough knowledge to know they don't have enough knowledge. Before you argue with someone ask yourself, "Is this person mentally mature enough to grasp the concept of a different perspective?" If not there is no point to argue. 4X NE2 CHAMPION. 2020 TDRA NE2 Champion | |||
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| DRR Sportsman |
If this is what you are finding, timing is NOT going to help. Sounds like your pump needs to be sent back during the off season and checked. Honestly, that tune up should be .1 slow. Rock and Roll injected stuff is usually in the 90s and 40 pill. With the tune you have, it SHOULD need a high speed to get that fuel out of the motor. Jeremiah Hall | |||
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| DRR Sportsman |
How many teeth are on the crank gear and pump gear? If its not 50% that could be your problem. And would also explain the tune up you need to make it work Jeremiah Hall | |||
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| DRR S/Pro |
First thing you need to know when it comes to timing amounts no matter what the combo is! Is the pointer correct with actual TDC??? Many assume that it is when it's not! So forget what anyone tells you they run unless they know the pointer has been checked with TDC. Now for your combo, those heads on gas run between 29 to 31 degrees. Never ran them on alky so I can't say if there is any real difference. With regards to your injection system, you should have the pump flowed to get a base line. Then talk to James Monroe, he ran this deal many years ago. I am pretty sure he used 39 nozzles too. If you have or can added a data logger with O2, it would be very helpful! and allow you to tune it quickly. It will also tell you if a high speed lean out is required. If you got your system used from someone, 329L has a great point, check your pump and drive teeth to get the ratio! This matters big time. 329L Can't compare conventional head tune ups to this combo. the 12 degree stuff needs less fuel for a given HP level vs the conventional headed stuff. | |||
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| DRR Sportsman |
Correct, but it is a starting point. And what i will say, on engines between 1150 and 1300, those tune ups will go down the track really well if the combo is right. James has been a really good teacher to me  Jeremiah Hall | |||
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| DRR Sportsman |
What ignition do you run? I assume since you say you take timing back out at 1.5 that you have a grid. If so you can set up a gear curve instead of using a number. The load on the engine in first gear is much smaller than in high gear. The engine will tolerate alot more timing in low gear than it can in high gear under full load. We add timing in first to burn off excess fuel from being on the two step, to compensate for the air, more water=more timing, etc. In the heads up car we actually run more than base timing in both 1st and second gears. Sometimes it is as much as 11 degrees over base, and yes it shows on the slip. We do the same in our dragster add +4-6in low gear to help. We typically run 1.04-1.05 60'sherein Vegas in our Diamond. Car runs low 4.50's to.60's here depending on what time of year. "I am not ashamed to confess I am ignorant of what I do not know." Marcus Tullius Cicero | |||
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| DRR Pro |
36/18 teeth. 50% Brian Mollison 2013 American Dragster 2020 Sumerduck Dragway VA Top ET Champion 2017 Sumerduck Top ET & SSS Track Champion 2017 MAC Top ET Track Champion 2009 Sumerduck Dragway Va Top ET & IHRA SSS Track Champion 2008 IHRA Division 1 Top ET Bracket Final Runner-up 2007 Colonial Beach Dragway Top ET Track Champion | |||
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| DRR S/Pro |
So no data logger, no fuel pressure etc? Get the pump flowed.... either way, I would listen to the time slips regarding fuel and be careful with timing. | |||
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| DRR Sportsman |
X2. **edit** While the pump is at Rons, might be a good idea to pull intake and make sure it isnt turning the intake gaskets to jelly around the ports. When mine starts messing up the intake gaskets, i have to start throwing fuel at it until i have a chance to pull the intake. Switching to steel insert gaskets this year to try and stop this stuff. Jeremiah Hall | |||
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