What are the best hp improvers?

[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 of 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 only 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. Which is a good argument for starting with a cheap turbo.

Mine produced boost up to 7 just about like the hypothetical system I described above. A tighter turbine housing would bring the peak down in the RPM range, but may not be so good at 20 lbs. Still, smaller is better than too large.

how do i go about using the quote process

You should see the FAQs. 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.

Lots of stationary diesel applications don't justify a turbo

Yea, I have seen them, but aside from things phallic, why go with something large when something smaller and cheaper will do the job just as well?

[philip]

Lots of stationary diesel applications don't justify a turbo

Yea, I have seen them, but aside from things phallic, why go with something large when something smaller and cheaper will do the job just as well?

Tis a question owners of large SUVs should ask themselves!

[TheDieseliminator]

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?

I'm not really sure what performance gain I may have received, if any at all to tell you the truth. I wish I would have got the truck dyno tested to see what it made with the stock diameter exhaust pipe and then with this newer, larger diameter pipe. I'm not sure I noticed any upgrades when driving it, but I do believe it would rev a little higher RPM in each gear (not to say that makes it have a good HP/torque gain). The 1.6" diameter pipe does actually start right at the exhaust manifold (or right at the flange of the exhaust manifold where the physical pipe bolts to it). And top speed I do think may have been better as far as 3rd-5th gears go. I've never really thought the factory mufflers were restrictive, but always looking at that small diameter pipe I'd think it's just undersized right outta the factory. I haven't driven the truck in over a year due to body damage, but if I remember it seemed like it got up and went down the road better than it did with the stock exhaust pipe. What made me change to the bigger exhaust system was not so much that I wanted to increase performance or to get it to sound a certain way, but actually because I had a break of my stock exhaust pipe about 2-3 feet down the system and it was falling apart. Not much else could be done to save it and plus it had seen plenty years of use as it was. I felt great about having the opportunity to install a newer, more updated system. As far as the exhaust temperatures go I couldn't tell you what they were when I was driving it with this 2.25" system. I didn't have a pyrometer installed like a turbo vehicle and I didn't notice any change in the engine's full operating temperature either (or what the temp guage read). This is some great debating and intelligent information being posted too. Galen, you bring up some really good points too when bringing up valve pressure and all. I never did really think about that. On my LUV I went with a MagnaFlow performance (straight-thru) muffler and I do admit I love the sound of the truck going through the gears while driving down the road. If I didn't gain any performance figures going with this diameter pipe I sure do at least love the exhaust sound from it. And with a turbo I'm sure it would be that much cooler.

Salvy

[gimmy51]

First thing I did was loose the factory muffler and tail pipe. After making sure there wern't any warrenty issues. At the cab bed joint a 2 inch system was run through the bed floor to a Y then a pair of 2 1/2 x 48 pipes cut at 45%. Now it sounded great, the power band was now 1600 to 3200. It gained a whole gear across the board, and downgrades were kinda loud, sounded like a jakebrake. after a few too many noise violations I tryed a Turbo muffler. No good it pluged so now have a short glasspac. Have taken a lot of grief over the look and sound but the thought of putting a "normal" pipe won't fly. I am playing around with how much power it can make n.a. By the way the head can be shaved. Don't know the CR but it cranked like a bigblock with 12 1/2 to 1. Last fun run toped 6% grade at 54 mph 4th. gear. For the record stock trim was only good for 35 or so on the same hill. The summit is around 7500 feet. The SD stands for Super Diesel. I would be glad to share tips or advice. These are great trucks wish they still had them in the states.
Jim

[philip]

-SNIP-.... I would be glad to share tips or advice. -SNIP
Jim

Here's my tip. Photos, verified data, and undetectable blarney.

[philip]

Here's my tip. Photos, verified data, and undetectable blarney.

OK you want proof this is the real deal.
Due to age and other circumstances some records have been lost or destroyed. dyno runs cost. the proof is when you hook to a load and see if the last tweak was good or bad. The truck has had a hard life but I'll see about posting some pics. Please understand that some things are sensitive.
Jim