I'd like more HP ... without Turbo

[ecomike]

I have enjoyed reading this thread (This is The Bomb) ... but for now at least, this is way beyond my ambitions (I know hard to believe eh?). But I would not mind getting a few more HP out of my Jeep/Nissan hybrid at the top end, WOT with the A/C running and a lot of people an heavy stuff onboard, especially going up hill.

I was thinking, and wondering about things like ram air and / or a small low pressure low power blower on the air intake inlet. Also wondering about the small exhaust pipe at WOT as far as restrictions go.

My thinking is that at WOT the system is starved for air (it is under a strong vacuum reducing the air mass flow rate) and the exhaust is maybe a bit small at that point too. What if you just boosted the air pressure at the throttle body inlet back to or closer to atmospheric pressure and added 1/2" to the diameter of the exhaust system, do you think we could squeeze something like an extra 5 hp out of these mean machines!!!!?? If so would it require any other adjustments like to the fuel injector pump system?

Would the naturally aspirated ....... pneumatic governor control system compensate for those small changes automatically???????

If this is worthy of extended (continued) discussion I might start a separate thread, but this seemed like the place to ask first, and it offers the opportunity for contrast and comparisons to the really cool (I mean HOT) stuff you guys are doing here!

[TooManyIdeas]

Before you go all out to make more ponies, why not try and free up some of the wasted power already generated by the engine.

One thing I did was switch over to complete synthetic from Royal Purple (they claim at least 5 extra) When I did it I noticed the truck ran easier. I didn't need to use the throttle as much. The truck started easier. And it increased my fuel economy a smidge to boot.

I'm also running the FS2500 bypass oil system. It may not increase HP, but it gets rid off a lot more oil contaminants which reduces friction. That will make the truck run even easier.

Another mod I've had my eye on is the BULLYDOG propane injection kit. They have a universal application that we could make work on the truck. Yes, it says for turbo diesels, but I called the guys at BULLYDOG and they said it can be run by oil pressure rather than boost. The Big 3 applications say 80 extra hp over stock and better fuel economy. Even if the 720's only get half that, it is still a significant improvement.

I'd also love to run a turbo on the beast, but that requires too much down time for the truck to be feasible right now. It’s a daily driver. Once the IP situation is resolved you’re looking at 33% more power over stock at the least (when done properly).

I'm not claiming to be an expert I'm just relaying what I've done and what I've read. I don't know if any of this info helped, but any time I hear about horsepower or modifications I get all hot and bothered

[Knucklehead]

Where to start? Lots of considerations.

I guess if turbocharging were not an option I'd look at the propane deal, which I have no experience with, but one thing raises a red flag. Propane needs oxygen to burn and I don't think there's enough as it is. Will it help if you're already at the smoke point? If the motor had a TC then the propane would push the turbo harder and give more air, but n/a that is not the case. Dunno.

In any case, first concern is to get more air in. I think you can get noticeably more power, even without turning up the IP. You have to understand that a turbo in itself does not add power. It only allows you to add more fuel, that's where the power comes from, so theoretically you have to turn up the IP to get more HP. Now, to contradict myself, mine ran significantly better after the turbo even though I didn't turn up the fuel. A little extra air really increased efficiency of the burn. An electric blower might do it, but knowing what I know and have measured now, the biggest problem with the SD22 is the throttle body. It needs to go. First question I asked years ago on the MSN board was if anyone knew how to make the IP manual so I could get rid of the TB. I have come full circle and am back at that point. More power? Need more air. Turbo or not, TB needs to go. I don't really think there's much you can do beyond proper tuning (and that will do a lot) unless you turbo charge, and even if you do that, you can see what problem we are still dealing with.

Forget about exhaust improvements unless you can get more air in.

Not satisfied? Do this -


Install a pyrometer. You'll never want to drive without one again. Then, run a tap off the exhaust manifold into the cab and put a pressure gauge on it. I didn't do this when mine was n/a so I can't tell you what the pressure is (or is not). If you think you can do something to make an improvement, go for it. Also, run a pressure/vacuum gauge off the intake manifold so that you can see what improvements are made with the leaf blower or whatever. I think 2 or 3 lbs would be enough. (Incidentally, someone once suggested that the alternator drain [with an electric blower] would rob whatever power was gained but I completely disagree and moreover, you could put a switch on it so that it only came on at WOT or whenever.) You should also tee a gauge into the air horn line just to see if you have an air filter drop.

I would save all your ideas until after you put the gauges on. If the propane won't take any air from your already air starved engine, it might help.

[asavage]

I was thinking, and wondering about things like ram air . . .

Maybe. Depends on how much ram you can get.

. . . and / or a small low pressure low power blower on the air intake inlet.

No. While there is such a thing as an electric turbocharger, and it does work rather well, it does not recover waste energy like an exhaust-driven TC does. IOW, you can get more power -- temporarily, not continuously -- but you then have to recharge the battery that's driving the electric blower. People do it (not with those damned muffin fans on eBay!) but you do need a very good alternator to recharge the blower batteries. You can't take HP and feed the alternator to feed the electric blower and get continuously more power -- TANSTAAFL ("There Ain't No Such Thing As A Free Lunch"). Galen & I will have to agree to disagree on this one.

Also wondering about the small exhaust pipe at WOT as far as restrictions go.

It's plenty large enough unless you are running continuously near redline It's only a 2.2l that runs 4k. Waste of money to enlarge it, unless you are adding more air (back to a turbo).

My thinking is that at WOT the system is starved for air (it is under a strong vacuum reducing the air mass flow rate) . . .

IIRC, the SD throttle body doesn't have much of a venturi, so at WOT it isn't a restriction. It's definitely a restriction at part throttle, but that's not what you're asking about.

[I've drilled/tapped the exhaust manifold on my '82 Wagon, installed the Type K thermocouple, but now I have to do the hard work of routing the leads and installing the gauge. This weekend was a pick-up-and-diagnose a 20Kw genset for Dad weekend, instead of play-with-LD28s weekend.]

[Knucklehead]

I agree that the gain may not be a gain in efficiency, like the turbocharger is, but it is a gain in net HP. Yes, there is an electrical drain, and I agree that you should plan for the load on the alternator (another story), but the x horsepower investment required to drive the fan does not remain x horsepower at the crankshaft any more than the crankshaft HP to drive a roots blower yields no net gain. One form of powering the blower (belt, electric, hydraulic) may be more efficient than another form (yet another story), but they all will give you more HP if they allow you to burn more fuel. In that you pay for the fuel, there is no free lunch. But, if you have 5 potential horses going out the pipe in unburned fuel and (say) 3 to pump in the air to burn that fuel, you even have gain in efficiency. Not free, but reclaimed.

I'm a Stranger In A Strange Land man myself.

[ecomike]

Al,

First off thanks for setting this up as new thread!

On the ram air option it would be at 60 to 70 mph, so I would consider it signifcant, but I have not back calculated the effective pressure of a 60 mph air speed feeding the intake.

I disagree with the energy analysis that the electric blower MUST use more electrical energy than the additonal HP can produce. It is not the additional air alone that is producing the extra HP, you must figure in the fuel burned due to the extra air and the net HP produced and compare that to the energy (electrical) consumed by the blower and the HP needed to produce it. The extra fuel burned as a result of the additional air could exceed the electrical energy consumed if the blower pressure (boost) is low enough like 10 to 20 " of water pressure. Also keep in mind that the engine consumes energy (HP) trying to suck air in. If it does less work to suck the air in, it takes less HP, so in other words there may be a trade off point where it uses less NET HP to push some extra air in with a minimal blower, that in takes for the engine to suck it in at high vacuum. No I have not done the math on this example, but I worked similar problems in my Chem eng classes.

You are probably right for a high pressure supercharger blower, but a small vacuum cleaner sized blower capable of overcoming some of the the throttle body air pressure losses, enough to increase the air pressure back to say atmospheric at the throttle body inlet or outlet (?) at WOT (and thus increase the mass air flow) by say 30 %, might be worth the effort and might produce a net engine HP increase after the additonal alternator load was figured in. The trick would be to use a limited amount of electric blower energy, maybe by combing a ram air supply with a small low pressure blower.

My thought would be to shop (spec out) for a small blower that uses less than 10 amps max at 14 volts and run it off the alternator, then place it in line with the ram air and air filter. Something similar to an A/C blower or small vacuum cleaner blower.

First question is what CFM would it need to handle a WOT air demand?

The part I am wonder is discussed in part by knuckleheads response, which is the need for delta P sensor data as to where the main, primary choke point is, i.e. pressure drop test data. I was hoping you guys had a good enough feel, or data by now to make some educated guesses on this.

On the exhaust pipe issue, I think (but I am not sure) I have an OEM exhaust system that was designed for the 2.5 liter 4 cyl gas OEM engine, that was adapted to the SD22. It could be an SD22 exhaust system.

So what was stock for the SD22 exhaust system???

I do note that at idle, the SD22 exhaust gas velocity coming out of the pipe on mine is about 5 times higher than the exhaust velocity exiting my 4.0 liter gas Jeep exhaust pipe at idle,making me think it must be undersized for WOT on the SD22 diesel engine???

Al, I am not sure I get your point or understand your comment that "the throttle body does not have much of a venturi and thus does not cause much of a restriction at WOT", can you elaborate please?

So where is the restriction at WOT? Air filter? Air pipe between the filter and throttle body? I would think the throttle body ID is the choke point. Dirty air filter next.

I have read that some of the 4.0 liter gas engine owners have simply bored out their throtle bodies to get more hp (via more air flow).

On the 4K max speed, I think I must be topping out at 2500 rpm in fifth gear when I am under heavy load, which is part of why I am looking into this topic. Maybe the two are unrelated, but my thinking is I have room under heavy load to increase the engine RPM in fifth gear, it would just take more HP. I can hit the top rpms in all the other gears, and down hill with no A/C and extra passengers I might be getting to 3500 at best in 5th gear. I know I can reach higher rpms in 1-4th gears than I can in 5th.

What is the 720 KC stock weight? Wondering how it compares to the XJ jeeps 4,500 lbs.

[ecomike]

My thoughts on TANSTAAFL!

There are three rules to thermodynamics.

Rule number one, you can't win.

Rule number two, you can't break even.

Rule number three, You can't get out of the game!

LOL.

Courtesy of a Rice University Professor.

[philip]

Al,

First off thanks for setting this up as new thread!

Ahem

First question is what CFM would it need to handle a WOT air demand?

Cubic Feet per Minute restriction is ... in the SD ... limited to the intake valve diameter. There is only ONE intake valve in each cylinder and are only 1.6" (42mm) diameter (smaller at the valve face diameter). The air intake runner is smaller yet!

On the exhaust pipe issue, I think (but I am not sure) I have an OEM exhaust system that was designed for the 2.5 liter 4 cyl gas OEM engine, that was adapted to the SD22. It could be an SD22 exhaust system.

So what was stock for the SD22 exhaust system???

In my 1982 Datsun, it's 2" from the exhaust manifold to the muffler. It's 1-3/4" leaving the muffler to the end.

So where is the restriction at WOT?

1. Small diameter valves (in/ex) and air intake runners through the cylinder.
2. Intake manifold. There are several different intake manifolds used on the SD fours depending on which injection pumps are used.

The "automotive" ...

...comparing to Fork Lift engines (SD22 with Bosch inline pump) ....

...and marine (SD22 with VE and CAV Bosch pumps)


3. The air plenum' are not restrictive except when the air filter is choked with dirt.

Another consideration is the strange cam timing. The intake valves are set to close VERY late (compared to gasoline engines) and the exhaust valve are set to open very EARLY (comp to gas engines). Ask Galen.

On the 4K max speed, I think I must be topping out at 2500 rpm in fifth gear when I am under heavy load, which is part of why I am looking into this topic.

Max 61 HP is 3800-4000 rpm. Max torque is 102(or less) torque @ 1900-2400 rpm. It's a DIESEL ... Mike! Good grief. Diesels like this thing LOSE torque well before HP top.
Torque Chart

Maybe the two are unrelated, but my thinking is I have room under heavy load to increase the engine RPM in fifth gear, it would just take more HP. I can hit the top rpms in all the other gears, and down hill with no A/C and extra passengers I might be getting to 3500 at best in 5th gear. I know I can reach higher rpms in 1-4th gears than I can in 5th.

What is the 720 KC stock weight? Wondering how it compares to the XJ jeeps 4,500 lbs.

Look Mike. It's time you trade for a new vehicle. Bring MONEY. Yours is ONLY 61 HP four cylinder in a FAT 4,500 truck. The Datsun 720 truck is just under 3,000 lbs.

[Knucklehead]

Is it that heavy? Wow! I had a '57 Dodge p/u that I put a 392 hemi into and it only weighed 3500 lbs (I think the motor alone was near 500).

So where is the restriction at WOT?

I was hoping you guys had a good enough feel, or data by now to make some educated guesses on this.

Phil's point is solid about valve and port size being the smallest restrictions at WOT (and remember that only one valve is drawing air at a time); if WOT is your only concern Al is right in that the TB is probably not the problem. On the other hand, it appears that if the TB were completely removed part throttle operation would have 2-3 lbs more air and therefore a better burn - better mileage.

Al, I am not sure I get your point or understand your comment that "the throttle body does not have much of a venturi and thus does not cause much of a restriction at WOT", can you elaborate please?

Al, if I may?
On a carburetor the venturi restriction is significant because the intent is to draw out and atomize gasoline (or nitro or whathaveyou). There is no restriction at all on a gas fuel injection TB. The venturi restriction on the SD TB exists to provide just enough pressure differential to control the IP, which is not very much, but enough to cause significant turbo lag. If the area of the wide open TB is more than the port, the TB shouldn't be the problem at WOT. Theoretically.

You could do head work, but a turbo would be easier, so you're back to a fan. I think it would work ok and give you a little extra at the top end.

Probably doesn't need to be said to you (Mike, Al, Phil) but it should be said, more power at the top doesn't necessarily mean cruising at 3500, but being able to get to 2500 quicker and hold it on a hill. If you are cruising out of the peak torque range you are losing efficiency. My International used to be governed at 1850 rpm which was 63 mph in 9th (Phil knows). I regoverned the pump to 2200 and I put maybe 200,000 miles on running 2000-2100. Mileage was about 6.3. Then I redid the tranny so that I could run 65 mph @1400 (600 rpm drop) and my mileage picked up to over 7 mpg. Not that you can't cruise high, but it's sure not the best. Besides, there is less than 4 mm clearance between the valves and the pistons, depending on how deep your valves sit, and less than two mm between the head and the pistons. Do you have a tach, and do you trust your valve springs?

First question is what CFM would it need to handle a WOT air demand?

CFM @ 3000rpm would be 1500 x 2.2 liters converted to cubic feet. No?

Would the naturally aspirated ....... pneumatic governor control system compensate for those small changes automatically???????

As long as you have an IP diaphragm control hose going to the TB and an IP vent hose going to the plenum it will "compensate", but at WOT it won't matter about the plenum hose. There really isn't any compensating to do because diesel fuel does not have to be metered with air the way gasoline does.

Again, theory is a good starting place but gauges are where it's at. Next step is to get them on and tell us what the numbers are.

Rule number one, you can't win.

Rule number two, you can't break even.

Rule number three, You can't get out of the game!

My favorite Ginsburg quote!

[philip]

First question is what CFM would it need to handle a WOT air demand?

CFM @ 3000rpm would be 1500 x 2.2 liters converted to cubic feet. No?

Staying about naturally air engines, if rounding in easy terms...

CFM (amount of air the engine needs) = Displacement (in cubic inches) X Maximum RPM / 3,456
reviews.ebay.com/Correct-Carburetor-CFM-Size

But if you add for a volumetric %...

The math formula is: CARB CFM = Cubic Inches x Max RPM's / 3456 x VE%
www.musclecarclub.com

As an example, if you have a stock 350 cubic inch engine and want it to turn 6000 RBM maximum and it had an estimated Volumetric Efficiency (VE%) of 75 then your maximum required carb size would be 456 CFM. 350ci x 6000 / 3456 x 75% = 456 CFM

For my SD22:

132 cu/in x 4000 rpm / 3,456 = 152 CFM
132 cu/in x 2500 rpm / 3456 x 90% = 86 CFM (just guessing the Volumetric Efficiency %)

Cummins M11
661 cu/in x 1650 rpm / 3456 = 315 CFM
661 cu/in x 2100 rpm / 3456 = 401 CFM

(Just for the heck)
Honda CB1-400 (400cc)
24 cu/in x 13,500 / 3456 = 93 CFM

[asavage]

[I may have broke my L thumb -- will have x-ray'd t'morrow. Can't type.]

The Datsun 720 truck is just under 3,000 lbs.

1981 non-KC GVW = 4250
OM says payload = 1100

Ballpark curb weight = 3150

I'm astounded at Mike's expectations for a 61 HP forklift engine!

[ecomike]

Well no, its not that heavy. My 73 Ford LTD is the one that weighs 4300 lbs.
and that is with a 351 Ford V8 gas guzzzllller. I was recalling the wrong tax title/registration form data. I checked and the title says the 2WD Cherokee Pioneer is 3000 lbs., but that was with a 2.5 l OEM gas engine. So the current weight is close to 3000 lbs, but wait, one of my 87 Jeeps, with a 4.0 L, straight 6, and the title lists it as only 2900 lbs. Hmmmm... The other 87 Jeep is a 4WD, 4.0 L, and it is listed as 3,200 lbs. Maybe the 85 had more steel in the body and frame? Don't know, but lets say its 2900 to 3100 lbs, guessing the SD22 might be a bit heavier that the 2.5 L gasser was.

OK you guys got me on that one. Maybe thats why I like hanging around here, somebody to keep me honest, LOL.

[ecomike]

Al,

First off thanks for setting this up as new thread!

Ahem

Ahem, seems I made another mistake? Thanks! And thanks for the feedback, glad to see you back in style here!!!!

On the exhaust pipe issue, I think (but I am not sure) I have an OEM exhaust system that was designed for the 2.5 liter 4 cyl gas OEM engine, that was adapted to the SD22. It could be an SD22 exhaust system.

So what was stock for the SD22 exhaust system???

In my 1982 Datsun, it's 2" from the exhaust manifold to the muffler. It's 1-3/4" leaving the muffler to the end.

That sounds like exactly what I have. I will check and verify it.

On the 4K max speed, I think I must be topping out at 2500 rpm in fifth gear when I am under heavy load, which is part of why I am looking into this topic.

Max 61 HP is 3800-4000 rpm. Max torque is 102(or less) torque @ 1900-2400 rpm. It's a DIESEL ... Mike! Good grief. Diesels like this thing LOSE torque well before HP top.
Torque Chart

I seem to be noticing that! but in fifth gear I am trying to maintain a steady speed. That becomes a problem when I encounter a hill, climb, so are you saying more HP alone wont cut it, that it needs more torque as well to maintain a constant speed when I go up and overpass?

Maybe the two are unrelated, but my thinking is I have room under heavy load to increase the engine RPM in fifth gear, it would just take more HP. I can hit the top rpms in all the other gears, and down hill with no A/C and extra passengers I might be getting to 3500 at best in 5th gear. I know I can reach higher rpms in 1-4th gears than I can in 5th.

What is the 720 KC stock weight? Wondering how it compares to the XJ jeeps 4,500 lbs.

Look Mike. It's time you trade for a new vehicle. Bring MONEY. Yours is ONLY 61 HP four cylinder in a FAT 4,500 truck. The Datsun 720 truck is just under 3,000 lbs.

NEVER! I will take this SD22 to my grave with me!

[ecomike]

I'm astounded at Mike's expectations for a 61 HP forklift engine!

Hay, Its already far exceeded my expectations, its a keeper, but we always want MORE!

[philip]

I'm astounded at Mike's expectations for a 61 HP forklift engine!

Hay, Its already far exceeded my expectations, its a keeper, but we always want MORE!

Automotive (in Calif) is 61 HP. You're lucky you don't have an Industrial or Marine spec which is quite a bit less in both RPM and HP.