FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: FE Jonny on December 08, 2015, 02:55:26 PM
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How can I make the most torque at the lowest RPM? I know the basic small tube header with long primary and long runner injected intake stuff but what about cam timing and other goodies? I want to make the most as low as possible and wondering what could be done. I have Performer heads with a Stage II prep and one of Jays intake adapters that I am going to use for a Injected intake. I am looking at the Trick Flow R series but should I get the Box R due to the intake is designed for 350 cubes or the R series long runner. I already have the lower and a 90mm throttle body, I haven't decided on the upper yet.
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Big inches, low camshaft duration, good head flow.
I've built lots of FE engine packages, but have no experience with the hybrid type of build that you're dealing with.
Look through the dyno results here on Jay's forum and you can get an idea of what does what. What do you consider "ultimate"?
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I lifted this blurb from the Comp site.
EFFECTS OF CHANGING LOBE SEPERATION ANGLE (LSA)
Tighten (smaller LSA number) Widen (larger LSA number)
Moves Torque to Lower RPM Raise Torque to Higher RPM
Increases Maximum Torque Reduces Maximum Torque
Narrow Power band Broadens Power Band
Builds Higher Cylinder Pressure Reduce Maximum Cylinder Pressure
Increase Chance of Engine Knock Decrease Chance of Engine Knock
Increase Cranking Compression Decrease Cranking Compression
Increase Effective Compression Decrease Effective Compression
Idle Vacuum is Reduced Idle Vacuum is Increased
Idle Quality Suffers Idle Quality Improves
Open Valve-Overlap Increases Open Valve-Overlap Decreases
Closed Valve-Overlap Increases Closed Valve-Overlap Decreases
Natural EGR Effect Increases Natural EGR Effect is Reduced
Decreases Piston-to-Valve Clearance Increases Piston-to-Valve Clearance
http://www.compcams.com/Pages/413/cam-timing-lobe-separation-angle.aspx
Judging from this comparo I can't see any benefit of moving the torque to the basement.
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Well I started with a Survival 445 stroker kit, then had Barry do a stage II prep with T&D race rockers. I have a roller cam but will more than likely change the cam from what I have now to something more low end oriented. I know moving the cam will change the torque curve but I am not sure where and how much to maximize low end torque. My pistons are 10:1 survival coated flat tops with Molly rings. I am just wondering mostly cam wise and intake wise which direction to go? The long runner R series is rated for lower RPM but is also designed for smaller cubic inches, the Box R is rated for higher RPM but has larger and more acessable ports for porting should I need to open it up. Another member used the R series intake with one of Jays adapters a while back but I never saw the finished project?
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What cam do you have now?
And you want to put a smaller cam in correct?
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What I am after is low speed power for negotiating steep terrain and and crawling. Spinning the engine to 6000 RPM is not really going to help me much, I need all the low end I can get as I am moving a big truck with a lift and big tires with 3.70 gears. I am also kinda hindered for low range gearing as I am using a NP 205 transfer case, it is a bullet proof gear driven case but has an anemic 2:1 low range.
Yes I am going to change the cam, it has a power band of 4000-6000 RPM right now so has to go.
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I would aim for something in the 210-215 range at .050". With that low duration you can go tight center without adding a ton of overlap. I would do a 107-108 LSA. Need a lazy lobe to help with the cylinder pressure and depending on the valve job, prob around .550" lift.
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I got an awesome flowing head for lower lift, the valves are back cut and seats are all done up by Barry over at Survival. Also he replaced the guides and installed 11/32 stem valves instead of the original Edelbrock 7/16 stem. The bowls and guides were smoothed over also. I was thinking somewhere around .500 to .600 lift but honestly I never have built an engine for low RPM, I was always going for top end. Right now my cam is just under .700 intake/exhaust.
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I find it hard to believe your power band is from 4000 to 6000 rpm.
Probably somewhere around 2000 to 6000 and probably pretty flat cause most 390
strokers are torque monsters.
You would need to lay out your gear sets.
That's were you will make huge gains in using your torque.
What trans and gear set?
If auto what kind of converter?
Tire size?
It's all in the gears.
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6.00 first, 1:1 fourth T19, 3:70 gears, NP 205 transfer case 2:1 low range , 33/12.50 tires or maybe 35s. 2800-3000 cruising speed. I would like my power band from idle to 5500 but like a 2000 sweet spot. I am injecting so duration can't be too high, and l am looking for about 550 lift. I am thinking about 110 separation to keep idle smooth and have vacuume. Any closes I would have a crappy idle and no throttle response. I was looking at some cams that Barry has but nothing quite like I am looking for, maybe I'll give him a call next week and run some ideas past him.
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At these numbers you have a low gear ratio of 44.4 to 1.
At 2000 rpm you would be traveling at about 4.4 MPH.
Some of those crawlers like to get down to 60 to 1.
One issue with lugging the engine down, especially a bigger engine is detonation.
That will beat the engine up more than anything.
The 10 to 1 comp at low speed under heavy load will detonate.
I would recommend a steeper rear gear, keep the rpm up a bit
and use the gobs' of torque you have to your advantage.
A 4.56 rear gear will get you to 54.72 and put you into some serious stump pulling giddy up.
At 2000 RPM you would be zipping along at 3.6 MPH.
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Take a look at the other thread about the hydraulic roller camshaft. The 482 that I built for "TJ" will lug around a 10000 lb trailer at idle, but yet peaked at 5200 rpm on the dyno. Now granted, that was a 482 inch motor, but the characteristics could be applied to a 445.
Also, keep in mind that a 110 LSA sounds like it would be more mild, have more vacuum, etc., but you need to look at the overall picture of the cam. I could probably spec a grind that at 107 or 108 LSA, would have more vacuum and a smoother idle than another cam at 110 LSA. You look at total amounts of duration and overlap...not just focus in on LSA.
Howie, you have a good point about lugging a higher compression engine, but I think this is the guy wanting to run E85.
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Yup going E85 with 13:1 compression and SN95 PCM with a tuner. Detonation will not be an issue at all, I will have full controll of my timing and fuel curve.
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Seems like a compromise engine.......
*cough* get a diesel *coughcough*
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Seems like a compromise engine.......
*cough* get a diesel *coughcough*
:)
High compression, deep breathing heads, small cam, low engine speed, high gear ratio.
Yup should run great. ::)
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I would aim for something in the 210-215 range at .050". With that low duration you can go tight center without adding a ton of overlap. I would do a 107-108 LSA. Need a lazy lobe to help with the cylinder pressure and depending on the valve job, prob around .550" lift.
On the EMC entry of Kaase, the camshaft was in the 184ish degree for low end torque for the dyno pulls. It was weird to listen to how he had different cam lobes cut for different lifts, different base circle all on the same camshaft. He had custom machined, lengthened lifters all on the same camshaft just to clear the 4.250" stroke in a block that normally cannot accept more than a 3.9" stroke without a girdle/spacer. The reversion in the exhaust ports and intake ports was terrible, but it made torque at low rpm, and peaked just over 5400 rpm. On top of all the rules, the fuel requirement was also a player in the competition. Joe-JDC
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Kaase "ain't right" when it comes to creativity.
Nobody else comes close..
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Hate diesels, we got three and not going there. I am looking at specs for truck towing EFI roller cams and think if I get a custom grind for more cubes I'll get what I am looking for. Also playing with the cam timing will give me more grunt. I do have the advantage of a low geared trans in first.
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Diesels are my bread and butter so can't complain about them. I find them very boring on a whole, but they certainly serve a purpose.
I meant moreso, it seems like you bought a lot of cool parts, and are now trying to make them fit together with a camshaft that will have to make sacrifices to work.
But I'm certainly no expert on the whole thing. I'll be interested to see how your "no detonation" thing pans out.
Best of luck, please keep us all posted on how it works out.
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I did spend a lot, I was going to use the engine for high RPM HP. I had to clean house and sold my Comet, two Jeeps, my 68 Ranger Pickup, a Ranger mini that I ended up putting a 402 cube Cleavor in with a C6. 6 farm tractors and a bunch of implements. I sold a lot of stuff from a previous estimate marriage like furniture and tools. I gave my collection of Power King tractors to my nephew that consists of a 52 foot semi trailer of stuff. Now I have my 83 Jeep Cj7 and a 91 Bronco left. I really wanted to use my FE for something so I decided to keep it and put it in my Bronco. I think if I can get the cam and tuning right it could be a good engine for it. The heads are not overly modified, I was going to do a 325 CFM port but never got that far so they will still work. The intake adaptor is still in the box untouched as is the lower Trick flow intake. The only part that will hurt me at this point is the cam, I also have a set of Jays water pump adapters and the water pump to go with it. A plastic fuel cell to go with E85, regulator, fuel pump and Ford fuel sender to work with my gauge. I have a 90mm Wilson throttle body, EGR spacer that needs to be bored and sleeved but have the sleeve, Fiveology mass air flow kit with Moeat's Quarterhorse and Jaybird. Also have a Moroso road race pan, windage diamond scraper and baffle kit. Forged crank, H beam rods, a set of Barry's forged coated 10:1 pistons and T&D race rockers. I have all the gaskets including Cometic steel .027 multi layer gaskets, roller lifters, a double roller timing chain and ati three ring damper. I guess I may as well use it if I got it.
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The 3.70 is nowhere near enough gear! Not for 33" or bigger tires and really those tires should be bigger yet.
I ran 4.88's with a 39" tire on my Bronco and it's highway cruise RPM was way under 3000. You must want to drive really fast.
I would use tires more like 37" and gears more like 4.56.
I didn't think the T19 had a 6 to 1 gear? I have the 4.0 first diesel mid 80's Ford T19 in my ramp truck and I think the gas engine ones were 5. - something.
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I had the trans built up with an international gear cluster @ 6.5:1, they actually lad a 7.1:1 in the Fords. I have a 68 Ranger trans with that gear. Maybe I will go with a 4:00, I run my calculations again? I used the Summit ratio calculator and came up with 3000 RPM @ 78 MPH on a 33 tire. I could go 4.00 and that gets me to 70 which is highway cruising speed around here. Some places are 75 up north but most people drive 80 in general. Around here if you drive under 70 the semi trucks run you off the road and people drive past giving you the one finger solute so you had better stay off the highway under 75.
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You are confusing me, you mention the T19 in your truck has 6.0/6.5/or 6.7 ratio, what is it? Per Novak's web site, the lowest T19 1st gear is 6.32. The NP435 has 6.68 1st with the older SM420 (GM) having the lowest 1st of all the common pickup trannys at 7.05.
30 mpg with an FE in a pickup truck? Is that a typo?
Nick
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I look at torque as the product of displacement, volumetric efficiency (at the rpm you want), and compression ratio. That's pretty much the same as has already been said.
Only thing I might add is this sounds like a good engine to use aggressive cam lobes. Two reasons for that.
One is that you want low duration to keep the power band at low rpm, but you'll want a lot of area under the curve to maximize the volumetric efficiency (and torque).
Second, since this is to be a lower rpm engine, it will be easier to control the valvetrain with aggressive cam lobes, without using crazy spring pressure.
JMO,
paulie
edit: This is predicated on the use of E85 and no detonation issues.
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Thanks for all the input, it has given me a lot of stuff to mull over. I definetly agree that the 3:70 should probably go and maybe something I the range of 4:00 is more in line. The first gear cluster I can't remember exactly what he put in there but it was the gas IH low range gearing use in the large trucks, I want to say about 6:50 or so.I'll have to find the receipt but it in the higher 6:00s as I recall. My main concern is what I end up with in 1:1 as I need to make a driver out of it and do not want to have it running 5000 RPM at 75 MPH. Night wise I am going with 4" of lift to keep a stable platform riding on 33/12.50 tires. I have just been throwing ideas out there just to get some feed back on some of you who have had experience with trial and error and found what works and what doesn't. I may later add a gear vendor between the t19 and the transfer case which would effectively not change the overall drivetrain length as I have a pretty big adaptor on there nor as it is that is a factory part. I am also not going to do the E85 right away as it would require more modifications and machine work I do not have the funds for now.
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Re: Drew's "Seems like a compromise engine.......
*cough* get a diesel *coughcough*
How about *Psst*, *Psst*, *Psst* never forget Jay Leno when he was going over his Stanley Steamer stated a steam engine produces Maximum Torque at Zero RPM. He mentioned you had to be gentle on the steam valve to avoid spinning the rims in the tires. Kind of neat when you think about the steam pressure from an external source displaces the piston..........vs internal combustion