What are the best hp improvers?

[oak4000]

Want to start a post on what people have done on their truck to add performance ie, exhaust, air filter, etc etc and which they feel gave the best results. What about modifications that resulted in worse performance, ie a 4" exhaust,

[Dave S]

Although a new air filter probably doesn't count as a performance upgrade, a good clean one really helps.

I opted for a K&N oiled gauze element, bolts right in. I've way too many hours logged with K&N's both street driving and various racing applications.

The have always worked exceptionally well for me, and I've been in some gaud awful dusty couldn't see 50 feet for the airborn silt conditions. (Baja 500, 1974,75,76)

I think a good open exaust would help, but 4" might be a bit much. I'm headed toward a 2.5" system when I get the injectors and rocker arms changed out on my 82 sd22 KC. (291K, and still going!)

I've a BAAAD injector or two, mileage down 5-7 mpg, performance down, oil useage up noticeably.

So, just having the engine up to specs helps quite a bit.

[zen]

a turbo..

[philip]

First, it needs to be understood and accepted that diesels ... especically two valve diesels are NOT about horsepower up near the governor limit. Diesels are about TORQUE ... twisting power. Typically diesels are "undersquare" (longer stroke than bore dimension) which gives the piston more leverage against the crankshaft at the expense of increasing piston speed for any given RPM compared to a shorter stroke. All rotating and reciprocating components weigh more than comparable displacement gasoline engines to survive the greater stresses brought about by higher compression ratios (22:1 in the case of our SD fours vs. 10:1 for typical gasoline engines). These things reduce the physical "redline" of diesels.

So focus on improvements that improve torque such as air delivery, exhaust extraction, and optimized fuel delivery.

There is an Australian company that used to make a header for the SD22 but alas ... no more.

SD22 Header

Here locally, we have Galen's homebuilt SD22 turbo.

Galen's Turbo SD22

Quite frankly, a good thorough tune up can do wonders.

[philip]

(Dragged from the "other" forum )

From: flannelman19

Phillip thanks for the info. I do have more questions. I would like to know why the exhaust is so small on the 82 Diesel powered pickup trucks? Most of the guys with the Ford powerstrokes and the Dodge with the Cummins etc. always remove the original exhaust for something larger to gain more power. Does the Datsun Diesel need back pressure? If not could I go with a 3 inch unmuffled exhust?

Why is the exhaust so small?

Is it?

1) The SD22 is only 2.2 liters .... your comparisons are 6 liters.
2) The SD fours are NOT turbocharged while your comparisons are turboed.
3) The SD diesels have only two smallish valves (IN=42mm, EX=38mm) per cylinder.
4) The SD fours are usually fitted with an AIR THROTTLE so ... at anything less than full throttle, the SD'd air supply is restricted a bit. (bosch inline pump)
5) The cam profile is cut and timed to produce max torque in the 1900-2400 rpm range. Max HP is just below 4,000 and no electronic interventions.

You have not investigated the stock exhaust manifold and available space between the starter, frame, and torsion bar for such a monster (unnecessary) pipe starting at the exhaust manifold. Things like replacing a sooted up muffler with a "straight thru" could be money better spent.

These days, turbos are much more about exhaust emissions. Here's the new Caterpillar engine with 2 turbos, afterburner, and soot trap.

[oak4000]

Has anyone put a full exhaust system on there truck? I was considering putting a 2 or 2.5 inch exhaust tubing but wasn't sure if that 2.5 would be too large. I am playing with the idea of a turbo and have planned out the oil intake and drain and sorta thought about the water, but havn't planned out how to stab into the exhaust without alot of welding and cutting.

[philip]

SNIP I am playing with the idea of a turbo and have planned out the oil intake and drain and sorta thought about the water, but havn't planned out how to stab into the exhaust without alot of welding and cutting.

Are you up to adapting this setup to an SD / 720 pickup?

Why is liquid cooling necessary? With 22:1 compression, the engine isn't likely to tolerate high & continuous boost pressures.

[TheDieseliminator]

Has anyone put a full exhaust system on there truck? I was considering putting a 2 or 2.5 inch exhaust tubing but wasn't sure if that 2.5 would be too large.

I haven't installed an exhaust system on a Datsun/Nissan 720 diesel, but I do have a 2.25" stainless system installed on my 82 Chevy LUV diesel. It also has a 2.2 liter sized diesel engine like the 720s do. Factory the truck came with 1.625" diameter pipe, which in my opinion is just too small looking at it. I think if you were going to decide to install a system on a 720 diesel going in the range of 2-2.25" is fine and do remember to include a free-flowing muffler (a straight-thru design is fine) so the diesel has no restrictions. I wouldn't go any bigger than 2.25" also because anything larger then that is overkill.

Salvy

[philip]

I haven't installed an exhaust system on a Datsun/Nissan 720 diesel, but I do have a 2.25" stainless system installed on my 82 Chevy LUV diesel. It also has a 2.2 liter sized diesel engine like the 720s do. Factory the truck came with 1.625" diameter pipe, which in my opinion is just too small looking at it. SNIP-
Salvy

The LUV is also naturally aspirated(?) What measureable engine performance difference came about with the new exhaust system? Was this 1.6" diameter starting at the exhaust manifold or just the section after the muffler ... where exhaust temperatures are lower? Any difference in top speed?

[Knucklehead]

Those are good questions. I'd like to see some data. Meantime, I hope I won't make anyone feel bad if I disagree on larger pipes. I might be wrong, but here's my reasoning:

A four cylinder is a bit easier to plan the exhaust for, unlike a V8, because there are 4 exhaust strokes spaced evenly. At any time, one and only one of the cylinders will be on an exhaust stroke, with no overlap. That means that as far as the headpipe and tailpipe (the muffler is a slightly different matter) it might as well be a one cylinder motor. In fact it is even better than one, because the even exhaust flow of four keeps the mass moving evenly (kind of like drafting the car in front of you). And what is the port size that I am matching my pipe to? The exhaust port at the manifold is less than 1-7/16". At the valve it is 1-1/5" at best. If the moving mass of exhaust loses velocity somewhere down the pipe, pressure at the valve will increase (just imagine the backup in the chapel as everyone who is leaving congregates in the foyer to chat). As the exhaust travels, it cools and contracts, requiring less volume.

If I make the pipe larger than the port, I assure that there will be no restriction, but I also lose the benefit of the exit velocity. Out at the end of the pipe it should actually be smaller, not larger, and the pipe should be wrapped to keep it from losing heat and becoming more dense. The pipe should be long enough to contain no more than 4 exhaust pulses.

The reason I don't have to worry about CFM's or RPM's or stuff like that is because I'm not worried about delivery at the tailpipe, I'm concerned about pressure at the valve.

So there's the theory, which I think is a good place to start. Now put some gauges in the pipe at the beginning and at the end. Doesn't matter whether it's an absolute measurement or static (the way it's plumbed), as long as they both are the same. I have not been able to see a difference on a 15 lb gauge, that is, no reading at all at either end, done while driving WOT at near peak RPM.

Nor can I get up my favorite onramp any quicker with or without the muffler. While you may enjoy a change of tone, I doubt you'll see anything else. Now I might be able to turn the boost up to a point where the stock muffler WILL impede flow, but on a N/A motor it ain't gonna happen.

Other than a good tune up (which is likely needed) there is not really much that can be done to this motor without major headwork to get more power out of it unless you...

I am playing with the idea of a turbo and have planned out the oil intake and drain and sorta thought about the water, but havn't planned out how to stab into the exhaust without alot load of welding and cutting.

I have always wondered why anyone would make an N/A diesel. A diesel was made to be turbocharged, even if you're not looking for more power. Like the line from the glowplug thread says

Even at equal power, a forced-air diesel engine has an advantage over a naturally aspirated engine.

I wouldn't worry about a watercooled turbo unless shutting down hot is something you insist on doing.

Have you looked at the This is the Bomb! thread?

[oak4000]

Yeah I’ve read the "the bomb" thread, and if by my choice I would go without the water cooled turbo, but I purchased a turbo that was off a dodge Daytona. I did the research to put it on a Ford Escort 2.0 liter diesel and seemed a good fit, but unfortunately I had hot wired the glow plug to start because of a failed temp switch and while driving home, the make shift switch got turned ON and soon complete cylinder implosion ;( bad.

Anyways, I also have the intercooler that is ready to go, but I’ve just been lazy. Now that I bought this truck, I'm trying to visualize how to get -this- turbo. How would you guys recommend I splice into the water lines? Oil I figure I could splice into the vacuum pump in and out lines.

Next, would you recommend 2 or 2.5 in pipe for turbo? I have picked those two diameters because they are the most common in the Summit catalog and would more likely to get bends and hardware. Installing the turbo at all is still a waffler though. (lol).

Ok another question. Do you think it is completly necessary to have the turbo right on the exhaust flange, because I was thinking of putting a turn directly on the manifold and routing it in that fashion to gain clearance. Also, how much boost are you putting out, i was hoping to be in the 7-10 range.

thanks a bunch

[Knucklehead]

How would you guys recommend how to splice into the water lines?

I don't know much about the water requirements of that turbo. If it can take a hot supply then right off the heater hoses would be easiest. If not then you will have to add an auxiliary pump for cold water because there are no post-pump pre-engine sources. Don't know if a draw-through would work, maybe.

Oil I figure I could splice into the vacuum pump in and out lines.

Yes, but you may need to enlarge the drain hose bib in the bottom of the block. Most turbos don't like any backup in the oil drain, and not knowing the exact flow of the two drains, I chose to overengineer. Also, there are two other oil pressure ports, but they are access holes to drill oil passages to the crank. Like you, I chose to tee off the vacuum pump supply line.

On a side note would you recommend 2 or 2.5 in pipe for turbo?

I would use whatever matches the turbo.

do you think it is completly nessary to have the turbo right on the exhaust flange, cause i was thinking of putting a turn directly on the manifold

I don't think it matters where you put the turbo, as long as the oil drain is above the pan and less than 45 degrees. I guess that doesn't even matter, but I still don't know how the guys are doing it. Anyway, mine's where it's at just because I couldn't find a better place. The only conflict is with the parking brake cable.

what kinda of boost are you putting out

I got 7 lbs without any changes to the IP. I plan to see how high it will go.

also have the intercooler that is ready to go

Please note that unless your intercooler has very good efficiency it may be counterproductive at boosts under 10 lbs.

[oak4000]

what do you mean by counterproductive on boost under 10lbs? as in the amount of heat it would produce at less then 10lbs wouldn't be enough for the intercooler to cool the air much more then it is at the point and not adding much hp performance, i always figured at any amount of boost that the turbo would require a intercooler, but at the time i was studying to put a big turbo or twin set up on a 6.9 ford, so wansn't paying attention to the low side of the boost chart lol,
do you recall the AR of the turbo you put in? and when you have 7 lbs is it floored or can i produce that under normal conditions? thanks
on a side note how do i go about using the quote process lol

[philip]

SNIP- I have always wondered why anyone would make an N/A diesel. A diesel was made to be turbocharged, even if you're not looking for more power. -SNIP

Application (context) is everything. Lots of stationary diesel applications don't justify a turbo on a four cycle diesel (which has a positve displacement intake stroke).

BUT ... in two cycle diesels, a pressurized air source is pretty much mandatory because there is nearly no positve displacement intake stroke.

[Knucklehead]

what do you mean by counterproductive on boost under 10lbs?

Let me clarify that when I say 10 lbs, I mean a system set to max at 10. Let's assume that you're motoring down the street at 2000 rpm and your boost is about 2 lbs. You floor it and boost jumps up to 5 climbing til it peaks at 10 when the motor's wound up. If your system is like that, your average boost will be around 5 lbs. I'm not saying that is the optimum system, just a very possible scenario. Now add an intercooler that isn't placed very well, has a lot bends in long plumbing, and doesn't get the best air flow, and you could end up with more pressure drop than temperature drop. I'm just saying it's not just a gimme. I used to think that an intercooler was a no brainer but I learned that at low boost it may not be worth the effort. (Newtons law of cooling - a body warmer than its surroundings cools at a rate proportional to delta T.)

do you recall the AR of the turbo you put in? and when you have 7 lbs is it floored or can i produce that under normal conditions?

It is pointless to use maps and ratios unless you are fine tuning your setup, which means you have lots of gauges, time, and money to be trying different turbos and/or turbo parts. There are so many variables on different engines even of the same displacement that it is impossible for an automotive engineer to choose a perfect turbo match purely by calculation even if such a thing as a perfect match existed. How do you use your motor and where do you want the peak? Not to discourage you; perfection is hard to achieve, but good is easy. A good estimate will usually work well, and in the absence of baseline turbo data on the SD22, it will have to do.

how do i go about using the quote process

The way I do it is to copy what I want to quote to clipboard, click the quote button, paste, then click the quote button again. Doesn't Al have this set up nicely for us illiterates? Kudos to Al.