Hemirunner
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I spun my 572 7000rpm and I shift my 540 7600... granted they’re hemi’s
440 How would you build for 700hp
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I hadn't thought I would be turning those kind of RPMs, but our forum friend's math is probably right. Add nitrous to reach a goal, and the gears and tire size complete the ET/MPH equation...
Reaching for OD 5th in a 1/4 mile seems silly, but then again, going back to my 3.54 would seem silly too.
Look, I'm going to have my hands full just trying to keep her beautiful, as in straight and off the railings/walls. I haven't even had the time to do almost anything in my Roadrunner since a HOST of upgrades over a year and a half ago, but I have to keep moving forward with the 572 build or it won't happen, and I AM going to make time for the things I want and need to do with my Roadrunner, starting real soon, as the "vacation camp" we've struggled with for 3 years is almost done.
66Satellite47
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Bio, I expect the big motor you are planning will be capable of handling high RPM, but be sure you make the combination match what you intend to do with it.
A few thought's. Wide ring gap wouldn't bother me in the least. My 572 with -1"s and a fairly large cam (285/[email protected]", .800", 112LCA) doesn't care if you shift anywhere between 6800-7100. Shifting at 7300 slows it down.
Doug
Doug
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I will have another chat with the builder when we get to the time to spec the cam. I expect the solid rollers will give tremendous flexibility in the ultimate design.
66Satellite47
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The roller cam combo does get expensive. But I expect you can make some power. Back in the day my mushroom cam made about the same or more power as my roller cams. Actually it made much more than my Comp 276/720 roller, same as the 280/660 and very slightly less than the 284/690 Lunati. But cam design has progressed a lot since then. Those were 12.2+ CR drag race motors at 7000+ RPM. Choose your cam carefully.
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I texted my builder today. Here's the gist of it:
"With 29" diameter tires (larger than I have now) and the 4.10 gears, if I'm going to run with my long time friend in his 9.5 second 140 mph vette, say on some nitrous, that is around 6,900-7,000 RPMs across the finish line. I wouldn't think that any of the parts would be a problem, but my desire for fat, wide torque around 700 ft lbs may mean "outta steam" by the upper 6k range."
He replied with a clip on a recently delivered 572 Mopar he built for a guy in Finland! (Anyone know the Finlander or his car??)
"look at my facebook as to latest
dyno on 572 in Finland we did"
(For my forum friends, it's the dark maroon Dart)
From his Facebook post:
"Marko T. in Finland took his Dodge Dart and RB440 / 572 to the dyno and pulled 752 RWHP with 749 FT LB Torque!! Taking into consideration a 15% driveline loss puts engine HP around 865HP. Not to shabby."
https://www.facebook.com/southeastrt
Scroll down a little and you can hear the 572 "singing in the snow".
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440rb
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That 865hp? 572 is not a 10.5:1-ish .650" street roller cammed 572 motor with 270's Bio, your not going to get near that hp so build it for street/show, cam it mild with not much more than 600lbs open spring pressure I would say not being a guru on that and let the N20 do its job at the track, it'll rpm ok and you'll have a long lasting unstressed street motor with low maintenance.
If we can make almost 700hp with our puny roller cam and just 10:1 I'm sure 750hp won't be that hard to do with a bit more cam and comp than us and your 6pk not our single old 950 carb, the 270's are as good if not better (albeit getting a bit small for 572ci) and more suited to a hot street build with good low lift cfm than our 572-13 heads which are a race head and have poor low lift flow and really require 12.5:1+ and .750+ lift to perform for what they were designed for.
If we can make almost 700hp with our puny roller cam and just 10:1 I'm sure 750hp won't be that hard to do with a bit more cam and comp than us and your 6pk not our single old 950 carb, the 270's are as good if not better (albeit getting a bit small for 572ci) and more suited to a hot street build with good low lift cfm than our 572-13 heads which are a race head and have poor low lift flow and really require 12.5:1+ and .750+ lift to perform for what they were designed for.
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"you'll have a long lasting unstressed street motor with low maintenance" THAT is exactly what I want above all else. No level of track performance is more important than the bolded summation above.
I paused reading your post right at the quoted paragraph because I am in full agreement with your quoted post. It is his "way" of addressing my concern about RPM capabilities in the motor he is building for me, as if to say "Hey, I've built motors with the same rotating assembly as yours and they're exceeding the capabilities you're concerned about"
Also, I see it was a fresh post he had broadcast, so I'm sure there was some prideful "showing off" going on there.
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Since the nitrous was mentioned, and IF I was working with a factory 440, I think nitrous would be a "very high on the list" option to reach that 700 HP goal, especially since nitrous only affects the engine when it's being used. Instead of dealing with the constant stresses, wear, and "roughness" of a NA 700 HP 440, use the right components to handle the effects of nitrous, and build the engine to output the difference between 700HP and the HP estimate of the shot. Say 500 HP NA and a 200 shot, or a 550 HP and a 150 shot, and so on...
Just the musings of a shadetree mechanic, not ever having used nitrous, but I have always had that view of N²O that as long as your parts are up to the heat and stress imparted during the seconds of time the spray is on, you enjoy the benefits of the extra power without the burdens of the HP gain, so a smoother cam, maybe less lift required, "gentler" springs, than would be needed w/out N²O to make up the HP difference. The cam lift, profile, and so on are always at work, and any other "more race oriented" things that would always be in play in a 700HP NA engine can be "milder" w/nitrous added on a less radical 500 or 550 HP car.
Here's the Nitrous Express 6bbl system, and I bought just the 2bbl spray plate a few years ago to test fit, and it's perfect for the Holley 2bbl and I like the design concept of their spray plate vs the spray "bar" too.
I'm all in on their FAST auxiliary one gallon fuel cell and pump system, and it's especially a great match when using carbs (vs some elaborate fuel and spark management setup) and a "premium pump gas" motor, by using readily available AVGAS or higher octane race fuel in the cell, at a time when the timing to prevent detonation is a factor, having that high octane fuel being used exclusively with the nitrous adds a level of safety and could even "buy" you a degree or 2 of timing that wouldn't have to be backed out if only pump premium was in the nitrous mix.
Just the musings of a shadetree mechanic, not ever having used nitrous, but I have always had that view of N²O that as long as your parts are up to the heat and stress imparted during the seconds of time the spray is on, you enjoy the benefits of the extra power without the burdens of the HP gain, so a smoother cam, maybe less lift required, "gentler" springs, than would be needed w/out N²O to make up the HP difference. The cam lift, profile, and so on are always at work, and any other "more race oriented" things that would always be in play in a 700HP NA engine can be "milder" w/nitrous added on a less radical 500 or 550 HP car.
Here's the Nitrous Express 6bbl system, and I bought just the 2bbl spray plate a few years ago to test fit, and it's perfect for the Holley 2bbl and I like the design concept of their spray plate vs the spray "bar" too.
I'm all in on their FAST auxiliary one gallon fuel cell and pump system, and it's especially a great match when using carbs (vs some elaborate fuel and spark management setup) and a "premium pump gas" motor, by using readily available AVGAS or higher octane race fuel in the cell, at a time when the timing to prevent detonation is a factor, having that high octane fuel being used exclusively with the nitrous adds a level of safety and could even "buy" you a degree or 2 of timing that wouldn't have to be backed out if only pump premium was in the nitrous mix.
440rb
Well-Known Member
Regarding your last post re N20, timing etc., this is something I have kept for a while, some of it may not be currently up to date with innovation today but have a read>
Nitrous doesn't care what octane rating the fuel is. The TIMING is what matters. The lower the fuel octane, the lower the timing you run.
Nitrous drastically increases the efficiency of the motor, by creating a quicker and cleaner burn. The quicker and cleaner the burn, the less spark lead the motor needs. No different than a motor with poor heads needing 40* of timing to run hard and when you put a better head on it, then it only needs 32* to run hard. You have made the motor more efficient. Timing does NOT make power.
Timing is only when you light the fire in the hole in an attempt to have a complete burn by about 15* ATDC. When you think about it, advanced timing is fighting what you are trying to do. The sooner you light it, the more the motor has to overcome in the increasing cylinder pressure of lighting the fire early. In a perfect world, the closer to TDC you could light the fire and burn it completely by 15 after, the more power you could make by freeing the motor up.
Unfortunately engines are just not THAT efficient yet. Don't put timing in until it slows down and run the max you can. Pull timing OUT until it slows down. If it runs the same at 36* as it does at 40*, the latter is doing you no good and only increases your chances of pre-ignition.
TIMING is what destroys nitrous motors NOT lean. With enough timing out, you can't get one lean enough to hurt it. It will just be down on power, like any other vehicle that is lean. No fuel, no power.
Too many are under the impression that timing MAKES power, it does not. Timing, or spark lead is just where you light the fire based on the efficiency of your engine to get a complete burn. The combination is what makes power, NOT how much timing you run in it.
The "old school" way rich tunes seemed to stand more timing, simply because you were not making near the power you thought you were, because it was dead rich. Way rich, with big loads of nitrous this will beat ring lands off pistons faster than you can replace them.
A nitrous motor of any kind always responds to plenum volume
A piston with the top half burned is strictly too much timing
Take plenty of timing out to be safe enough. If you are not detonating its harder to hurt it. Rich tunes are not safer tunes. It's nearly impossible to hurt something running too lean. If you are detonating like crazy and stuff is about to melt, well you might hurt it. But, lack of fuel didn't do this. Detonation got it.
On new stuff start with a really lean hit. Run engine timing as low as possible and with a nice lean tune in carb. Pull plenty of timing. 2 per 50hp and some extra. Another 4 if you have a small quench, less than .040”
To tune from here. Trim fuel pressure to see if you pick up mph. If not put it back. Take another degree of timing out. If it don't pick up put it back.
Add a degree of timing, try again. Key thing is if the mph quits picking up put it back. New plugs pushed in the lanes and cut off at end of pass will give you the best reading.
You could run a full 33 deg. say timing for the burn out and then have a retard come in when the N20 is activated adjusted for the amount used without the need for an extra cell with race gas, many ways to go about doing things.
Nitrous doesn't care what octane rating the fuel is. The TIMING is what matters. The lower the fuel octane, the lower the timing you run.
Nitrous drastically increases the efficiency of the motor, by creating a quicker and cleaner burn. The quicker and cleaner the burn, the less spark lead the motor needs. No different than a motor with poor heads needing 40* of timing to run hard and when you put a better head on it, then it only needs 32* to run hard. You have made the motor more efficient. Timing does NOT make power.
Timing is only when you light the fire in the hole in an attempt to have a complete burn by about 15* ATDC. When you think about it, advanced timing is fighting what you are trying to do. The sooner you light it, the more the motor has to overcome in the increasing cylinder pressure of lighting the fire early. In a perfect world, the closer to TDC you could light the fire and burn it completely by 15 after, the more power you could make by freeing the motor up.
Unfortunately engines are just not THAT efficient yet. Don't put timing in until it slows down and run the max you can. Pull timing OUT until it slows down. If it runs the same at 36* as it does at 40*, the latter is doing you no good and only increases your chances of pre-ignition.
TIMING is what destroys nitrous motors NOT lean. With enough timing out, you can't get one lean enough to hurt it. It will just be down on power, like any other vehicle that is lean. No fuel, no power.
Too many are under the impression that timing MAKES power, it does not. Timing, or spark lead is just where you light the fire based on the efficiency of your engine to get a complete burn. The combination is what makes power, NOT how much timing you run in it.
The "old school" way rich tunes seemed to stand more timing, simply because you were not making near the power you thought you were, because it was dead rich. Way rich, with big loads of nitrous this will beat ring lands off pistons faster than you can replace them.
A nitrous motor of any kind always responds to plenum volume
A piston with the top half burned is strictly too much timing
Take plenty of timing out to be safe enough. If you are not detonating its harder to hurt it. Rich tunes are not safer tunes. It's nearly impossible to hurt something running too lean. If you are detonating like crazy and stuff is about to melt, well you might hurt it. But, lack of fuel didn't do this. Detonation got it.
On new stuff start with a really lean hit. Run engine timing as low as possible and with a nice lean tune in carb. Pull plenty of timing. 2 per 50hp and some extra. Another 4 if you have a small quench, less than .040”
To tune from here. Trim fuel pressure to see if you pick up mph. If not put it back. Take another degree of timing out. If it don't pick up put it back.
Add a degree of timing, try again. Key thing is if the mph quits picking up put it back. New plugs pushed in the lanes and cut off at end of pass will give you the best reading.
You could run a full 33 deg. say timing for the burn out and then have a retard come in when the N20 is activated adjusted for the amount used without the need for an extra cell with race gas, many ways to go about doing things.
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Thank you very much. It wasn't that long ago when the epiphany regarding timing advance and it's relationship to nitrous was clear in my mind, that it is the improved burn efficiency (because of the O in N²O) was the reason for reducing advance. The first paragraph is a little confusing though, so let me see if I understand.
Is that sentence referring to timing of a gasoline powered engine and the standard knowledge of "lower octane demands less advance" to prevent detonation (pinging)?
OR
Is it saying you "run lower timing when using N²O and lower octane fuel"?
Also, even if I run the same fuel in the fuel cell as the gas tank, and I don't get any "timing bonus", I like the separate fuel pump and regulator the FAST system provides, because it can be dialed in for the specific needs (volume/pressure) of the fuel+N²O "event" and I am using a Carter M6903 high volume, but "low" pressure fuel pump. I may find the 120 GPM flow rate isn't high enough with the new motor, but even if I have to go to a higher volume pump, without the FAST setup, I would need one fuel pump to provide both the appx 4-6 pounds of pressure for the carbs, and the much higher pressure for the nitrous system.
It's the bolded part that I am unsure of.
Is that sentence referring to timing of a gasoline powered engine and the standard knowledge of "lower octane demands less advance" to prevent detonation (pinging)?
OR
Is it saying you "run lower timing when using N²O and lower octane fuel"?
Also, even if I run the same fuel in the fuel cell as the gas tank, and I don't get any "timing bonus", I like the separate fuel pump and regulator the FAST system provides, because it can be dialed in for the specific needs (volume/pressure) of the fuel+N²O "event" and I am using a Carter M6903 high volume, but "low" pressure fuel pump. I may find the 120 GPM flow rate isn't high enough with the new motor, but even if I have to go to a higher volume pump, without the FAST setup, I would need one fuel pump to provide both the appx 4-6 pounds of pressure for the carbs, and the much higher pressure for the nitrous system.
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440rb
Well-Known Member
To answer your question as I see it running race fuel gets you a bit more advance but that extra advance doesn't necessarily give you a gain in anything, its the combo itself that has the properties in it as to how much timing you NEED to make the most power because of how efficient it is or not. Our 589 made its max power at only 33 total and lost some with more, how many times do you see dyno pulls where they reduce the timing and make more hp. On a large motor less is more generally.
So if you use premium pump in yours NA you'll hit the sweet spot for total on the dyno say at 33 deg. Add N20 and you'll need to come back an amount that makes the most power (mph), wherever that is will be down to the combo itself, how much N20 used and quality of fuel. Fuel supply being very important of course. Adding race fuel will enable you to use more timing to get the max hp as before only, there is no real gain in more timing to achieve the same level of hp just because the fuel is better if you see. You need to forget the more timing makes more hp theory, sometimes it does and sometimes it doesn't, again all combo dependent.
Thats why they say N20 doesn't care what fuel you use, you can use either, race or pump, its ALL down to the timing, the efficiency of your combo will dictate that primarily, use pump and you'll need less, use race and you can run more but it won't get you any more hp generally and its not safer. Marketing tells you it is!!
Reducing timing NA to stop detonation is used but not the way to go about stopping it, lots more involved in this that can give a headache to understand properly, like quench, cam timing events, altitude etc. Thumper carbs 470 Dart runs 12.1:1cr on premium fine with an old Isky 660 s/roller as an example.
Back in my days of using N20, I didn't come back with timing much at all, the kits were way rich is why I got away with it without even tipping a plug BUT I didn't make anywhere near the hp from the jets I should have, 175 from a 250 cheater shot, and 130 from a 175 big shot.
So if you use premium pump in yours NA you'll hit the sweet spot for total on the dyno say at 33 deg. Add N20 and you'll need to come back an amount that makes the most power (mph), wherever that is will be down to the combo itself, how much N20 used and quality of fuel. Fuel supply being very important of course. Adding race fuel will enable you to use more timing to get the max hp as before only, there is no real gain in more timing to achieve the same level of hp just because the fuel is better if you see. You need to forget the more timing makes more hp theory, sometimes it does and sometimes it doesn't, again all combo dependent.
Thats why they say N20 doesn't care what fuel you use, you can use either, race or pump, its ALL down to the timing, the efficiency of your combo will dictate that primarily, use pump and you'll need less, use race and you can run more but it won't get you any more hp generally and its not safer. Marketing tells you it is!!
Reducing timing NA to stop detonation is used but not the way to go about stopping it, lots more involved in this that can give a headache to understand properly, like quench, cam timing events, altitude etc. Thumper carbs 470 Dart runs 12.1:1cr on premium fine with an old Isky 660 s/roller as an example.
Back in my days of using N20, I didn't come back with timing much at all, the kits were way rich is why I got away with it without even tipping a plug BUT I didn't make anywhere near the hp from the jets I should have, 175 from a 250 cheater shot, and 130 from a 175 big shot.
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I am going to be using the amazing Progression Ignition system, so timing is going to be more tunable than any other system, IMO. By the time I'm ready for N²O I will probably have a timing adjustment for nitrous available through Ted's brilliant mind and work on his ignition system, or I'll use another kind of spark advance adjustment for the shot.
Thanks a lot to ALL for your patience and replies!
Thanks a lot to ALL for your patience and replies!
Hemirunner
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Sounds like a circus act. “The Amazing Progression Ignition system”... Never even heard of it. Where do you guys find this stuff? Got a link to this thing?
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It's awesome, and proven tech. I'm "practicing" with the app offline.
Pay no attention to the numbers, that is what comes up, then you enter the values you want. New phone, so no saved tables for me right now.
https://progressionignition.com/
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OE Iron block ? or aftermarket ?
I didn't have very good luck with RB OE blocks (or cranks)
lasting at high RPM
not for long anyway
no matter the caps or crank materials, studs or not
alum. rods & light pistons or not
let alone boosted/blown (on methanol) or N2O
@ 713 hp
Impressive for any era
how did it last/hold up ?
I didn't have very good luck with RB OE blocks (or cranks)
lasting at high RPM
not for long anyway
no matter the caps or crank materials, studs or not
alum. rods & light pistons or not
let alone boosted/blown (on methanol) or N2O
& still climbing at the end of 7,000 rpm
@ 713 hpImpressive for any era
how did it last/hold up ?
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Hemirunner
Well-Known Member
As far as I know, it still runs. Car was sold.OE Iron block ? or aftermarket ?
I didn't have very good luck with RB OE blocks (or cranks)
lasting at high RPM
not for long anyway
no matter the caps or crank materials, studs or not
alum. rods & light pistons or not
let alone boosted/blown (on methanol) or N2O
& still climbing at the end of 7,000 rpm
Impressive for any era
how did it last/hold up ?
Hemirunner
Well-Known Member
Well.... I’ll be.... what they won’t think of next lol
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Since this post wound up long, I am putting this at the top. The Progression Ignition has a GREAT feature that accommodates BOOSTed engines!! Here's the link to their channel featuring the "tuning for BOOST" details:
I saw a guy at a big out of state MOPAR show I had taken my Roadrunner to, and I think it was Chattanooga, but it may have been another "a couple of states away from Louisiana" venue..The important thing is he had a cheap tablet/laptop device, and several components that made up his homemade "ignition control system". Being as I am a VERY strong proponent of the critical role (IMO) the ignition system plays in a performance application especially, I took a great interest in his description and "demo" of the setup. The tablet was "glitchy" and slow, the components being strung together with one item on the fender, one under the dash, in the trunk, zip tied to the steering column...you get the picture. NOT the most reliable setup, and I don't recall his name...
BUT
The concept was FASCINATING and damn near what I had been dreaming of someone bringing into existence.
Time passes, and one of my forum friends directs my attention to the GENIUS of Ted at Progression and by then Progression had videos to demonstrate the product and the great app used to setup, tune, control, AND give live real time feedback on what the timing, manifold vacuum, RPMs, and so on were doing.
When I entered some baseline numbers (on the opening page of the app) and it self-generated a starting point, the graphic of that timing map hurtled my mind back to the day, the LONG 8 hour day, when I had my 2011 Harley-Davidson V-Rod tuned for more performance and the 2 simple mods I had done simultaneously. It ran on the lean edge from the factory by design, but the Delphi module in the EFI control unit is fairly powerful, and I had selected the TTS MasterTune software solution for my choice in product to take it to this one small step up. I contacted the guy who is the trainer of the motorcycle shop techs/mechanics who are certified in using this particular technology, and he directed me to H&D Cycles in Lillian, Alabama as the BEST tech for the TTS system and relatively close to me.
The MAP that was displayed for tuning all of the aspects the computer controlled system affected looked a LOT like the one the Progression Ignition system app generates..
LOOK AT THE VIDEOS on the Progression Ignition YouTube channel and WITNESS the GENIUS of this system!!
There is NO ignition system that I know of for carbureated engines that offers the kind of FINE TUNING that the Progression system does, AND it can also just pop out a basic "map" and some people could run that and get better performance without ever touching it vs a crappy setup or worse, a good ignition system that is too difficult to understand how to tune for their particular "best purposes".
One feature I may use is to compensate for when I turn on my AC system. Unless I decide to use the factory 6bbl electronic idle solenoid to increase the idle RPMs to compensate for the draw down in RPMs when I turn the AC compressor on (for what the idle solenoids are selling for, I may sell mine and take the CASH to finance my build LOL), the Progression system can slightly increase the ignition advance in the very narrow RPM range it slows to when the compressor engages. They feature the "same concept" in a video on their channel, but the "event" is the drop in RPMs for automatic transmission equipped cars, especially those with low vacuum, high performance cams that want to keep their idle speed low, but at that setting when they shift into "D" and are idling, like sitting at a light etc, the engine slows enough to drop oil pressure, not do a great job of charging the battery or spinning the AC compressor to get that great cold, dry air blowing around, and the fan speed drops too.
So without any compensation for either case (AC on, or N or P into Drive) about the only other choice is to always have the idle HIGHER than it needs to be, so it won't be too SLOW when the AC comes on or it's put into gear.
It's an interesting scenario because it really highlights the precise tuning that only this kind of setup can provide.
If you want a 850 RPM idle speed, and AC off or in neutral that is what you have, then just add however many degrees of advance you find you need to compensate for the additional load of the torque converter, or in my case, the AC compressor. If the idle drops from 850 to 725 when I turn on the AC, I would just add, say 2° of advance from 800 down to 600 RPMs. That way whatever makes the RPMs drop below my desired 850 will be overcome by the extra advance, but when it's idling at 850, the "extra" advance goes back down to whatever I had it set at.
CAPICHÉ??
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