This is The Bomb ... with Turbo!

SD diesels were widely available in the US in the 1981-86 Datsun/Nissan 720 pickups, and in Canada through '87 in the D21 pickup.

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Zarghareth
Posts: 19
Joined: 8 years ago
Location: Sisters, OR

#181

Post by Zarghareth » 6 years ago

Wow! I'm super impressed with your mileage larrynsr! I'm not anywhere near that. I only get about 28 MPG. I think that the main reason why your getting such good mileage is that tiny turbo. It spools much more than my honkin big T3 on average and therefore gives you much more constant boost. For comparison, when I'm at top cruzing speed (70mph) on the freeway, I get a minimum boost of 4 psi (during the warmer months) and I have to constantly feather the peddle to keep it from jumping up to 8-12psi and pulling like an angry pitbull! At 55 mph, and not accelerating, I only have about half a psi. If your goal is driveability and efficiency, definitely go the route Larry did. In fact, I would strongly discourage anyone from using a T3 unless you can lay hands on a AR .48 turbine scroll. Unless you want to bust $1300 on a Turbonetics GT-K, the AR .48 scroll will be very difficult to find.

Larry, Do you find that you have to feather the peddle to stay at a constant speed?

larrynsr
Posts: 25
Joined: 9 years ago
Location: portland oregon

#182

Post by larrynsr » 6 years ago

Zarghareth wrote:Wow! I'm super impressed with your mileage larrynsr! I'm not anywhere near that. I only get about 28 MPG. I think that the main reason why your getting such good mileage is that tiny turbo. It spools much more than my honkin big T3 on average and therefore gives you much more constant boost. For comparison, when I'm at top cruzing speed (70mph) on the freeway, I get a minimum boost of 4 psi (during the warmer months) and I have to constantly feather the peddle to keep it from jumping up to 8-12psi and pulling like an angry pitbull! At 55 mph, and not accelerating, I only have about half a psi. If your goal is driveability and efficiency, definitely go the route Larry did. In fact, I would strongly discourage anyone from using a T3 unless you can lay hands on a AR .48 turbine scroll. Unless you want to bust $1300 on a Turbonetics GT-K, the AR .48 scroll will be very difficult to find.

Larry, Do you find that you have to feather the peddle to stay at a constant speed?
Yes this small turbo spools up very quickly but the negative is the exhaust restriction. I do also have a t03 from a Saab. Its a larger housing also. I have toyed with the idea of making a twin turbo set up using both the k03 and the t03 but there is not enough room under the hood due to all the extra plumbing involved. If i were to start over again, i would go with a vgt turbo....and have the best of all worlds.

The engine has very good road manners and doesnt need to be feathered at all. it drives like pre turbo but just with more power

Zarghareth
Posts: 19
Joined: 8 years ago
Location: Sisters, OR

#183

Post by Zarghareth » 6 years ago

I agree with you about the VGT for sure. I must say I'm quite surprised that you can still drive it like you did pre-turbo! You said that you routed the IP regulation lines the same as I did so I wonder if it is entirely due to the smaller turbo then.
I've got a few of questions for you if you don't mind:
1. What did you do for you exhaust manifold?
2. Where are you getting the oil for the turbo?
3. Are you running a BOV? (I didn't see one in the picture.)
4. Are you using the stock intake manifold? (It looks like your TB is pretty far forward for the stock intake manifold)
5. Do you have an oil pressure gauge? If so what pressure are you getting?

Sorry, I guess that's more than a few. I'm just trying to ascertain all of the differences between our builds.

larrynsr
Posts: 25
Joined: 9 years ago
Location: portland oregon

#184

Post by larrynsr » 6 years ago

Zarghareth wrote:I agree with you about the VGT for sure. I must say I'm quite surprised that you can still drive it like you did pre-turbo! You said that you routed the IP regulation lines the same as I did so I wonder if it is entirely due to the smaller turbo then.
I've got a few of questions for you if you don't mind:
1. What did you do for you exhaust manifold?
2. Where are you getting the oil for the turbo?
3. Are you running a BOV? (I didn't see one in the picture.)
4. Are you using the stock intake manifold? (It looks like your TB is pretty far forward for the stock intake manifold)
5. Do you have an oil pressure gauge? If so what pressure are you getting?

Sorry, I guess that's more than a few. I'm just trying to ascertain all of the differences between our builds.
yes I did route the MV govenor front hose like you did in the beginning of this project ...vent it out into the atmosphere.....but it was very touchy like you described. it was hard to drive...kind of like a on/off switch. this was happening because once there is positive pressure inside the intake manifold, the rear side of the diaphram is pushed forward,,,meaning full throttle. opening the front side of the diaphram into the atmosphe like you described does not work well. I plugged the front diaphram hose back in to the intake horn (like factory nissan did) and built an adjustable restrictor to restrict flow to the front of the diaphram. this way boost is also present (but not as much as the rear side) on the front side of the diaphram..therefore dampening the diaphram from going full throttle but still allowing the rack to go forward. so in theory the diaphram turns into boost actuated rather than vacuum actuated once the turbo kicks in.
1. the exhaust manifold is stock. I just ran a mandrel bent pipe from the manifold to the turbo.
2. I put a t on the vacuum pump oil supply and also another t for turbo return.
3. yes a bov is present. its that aluminum piece between the turbo and intake horn. the valve itself is just facing down.
4. yes I am using the stock intake manifold and throttle body.
5. no oil pressure gauge. the turbo uses such a small amount of oil that I didnt bother.

Zarghareth
Posts: 19
Joined: 8 years ago
Location: Sisters, OR

#185

Post by Zarghareth » 6 years ago

Hmmmm... I find it very perplexing that you are getting good results with that set-up. I have experimented with similar set-ups in attempt to regulate the throttle response but I never tried what you have just described. The primary reason why I did not is that with the in-line Bosch Kiki IP, more fuel is delivered the further the control rack (the rod actuated by the diaphragm) is moved toward the rear of the pump. This is why the venturi generator in the TB is plumbed to the rear chamber of the diaphragm. Subsequently, applying pressure to the front chamber should push the control rack even further out and dump in the fuel. Are you positive that you are not somehow applying vacuum to the front chamber?

Also, I would suggest installing an oil pressure gauge.

Zarghareth
Posts: 19
Joined: 8 years ago
Location: Sisters, OR

#186

Post by Zarghareth » 6 years ago

Hmmm... I find that very perplexing. Before I go any further, I would like to note that none of the following is intended to degrade you or your build in any way whatsoever. Simply put, the way you have described the behavior of your build, it sounds like the most successful and practical build that has been introduced to this forum and I am merely trying to figure out exactly why that is for the benefit of other builders.

I know for a fact that the Kiki inline pump as well as almost all of the other inline injection pumps made by Bosch actually works in reverse of what you just described. The control rack actually delivers more fuel the further it is pulled out of the pump (moved toward the rear of the engine) I have verified this by looking at schematics of the IP produced by Bosch. If you think carefully about the way the system was originally designed you can ascertain this as well. I will now explain my logic.
When the throttle is all the way closed, that is when the maximum amount of air-flow is forced through the venturi generator. Subsequently the maximum vacuum is applied to the diaphragm

Zarghareth
Posts: 19
Joined: 8 years ago
Location: Sisters, OR

#187

Post by Zarghareth » 6 years ago

Very interesting... I will implement the same system on my engine and get back to you on the results.

One thing I would suggest would be to install a pressure gauge. I think you would be surprises how much the turbo drops the oil pressure. On mine, I lost over 10 psi to the turbo. That's why installed the auxiliary pump.

dn29626
Posts: 249
Joined: 10 years ago
Location: Anderson, SC

#188

Post by dn29626 » 6 years ago

Do either of you, larrynsr or Zarghareth, anticipate (more) head gasket issues?

I do not consider myself to be a good metal fabricator, so the turbo mount would be my initial challenge.
82 King Cab 2wd (nice)
82 Reg Cab (body damage)
Anderson , SC
Since Fall 2009

Zarghareth
Posts: 19
Joined: 8 years ago
Location: Sisters, OR

#189

Post by Zarghareth » 6 years ago

dn29626,
No, I have not ever had any head gasket issues and I do not anticipate having any until I install an inter-cooler, electronic IP control, and that turbonetics GT-K I mentioned previously. Right now, I have put over 12,000 miles on my engine since the turbo with absolutely no head-gasket problems or loss of compression from piston ring wear and I drive it really hard. The only gasket problem I have had due to the turbo was blowing out exhaust manifold gaskets whenever I broke 10 psi but that was simply because I was using really low quality gaskets at the time. About 6,000 miles ago, I installed a triple layer metal gasket and haven't had any problems since despite frequently breaking 12 psi this winter. In short, I don't think you need to worry about the head-gasket unless your engine has been rebuilt before by someone who used a low quality aftermarket head gasket.

About mounting the turbo, I'm pretty sure the easiest way to mount the turbo is what Larry did. Though it is not the best for power performance, it would appear that it is a good configuration for efficiency and drivability. The main limitation on implementing that solution is the size of the turbo. However, I would say, if the turbo is too big to use Larry's solution, the turbo is too big period and you should find a smaller one.
What I did was to drill a 3/4" thick plate of steel in the stud pattern of the manifolds, cut the flanges off the stock exhaust manifold, bolted the flanges and the intake manifold down to the plate, and fabricated a log-style manifold from forged steam pipe bends. That approach was pretty tricky, lots of mitered cuts and you should be a very good welder before attempting to weld to the cast steel flanges of the original manifold or you will end up having the welds crack. I had to do it this way because of the over-sized turbo I used as well as my goal of maximum power performance.

larrynsr
Posts: 25
Joined: 9 years ago
Location: portland oregon

#190

Post by larrynsr » 6 years ago

dn29626 wrote:Do either of you, larrynsr or Zarghareth, anticipate (more) head gasket issues?

I do not consider myself to be a good metal fabricator, so the turbo mount would be my initial challenge.

I really believe that the sd25 is built turbo ready. it comes factory with an all metal headgasket. I havent had any problems so far.

dn29626
Posts: 249
Joined: 10 years ago
Location: Anderson, SC

#191

Post by dn29626 » 6 years ago

Guys
That is good to hear.

The gentleman (elboss) that does drifting with a SD22 turbo charged (mine is SD22) went through several head gaskets before getting a beefed up gasket that holds.
Last edited by dn29626 6 years ago, edited 2 times in total.
82 King Cab 2wd (nice)
82 Reg Cab (body damage)
Anderson , SC
Since Fall 2009

elboss
Posts: 59
Joined: 8 years ago
Location: Portugal

#192

Post by elboss » 6 years ago

Yes, i have... the stock, blow.... the sd22 steel headgasket (1,60mm i think), make a "explosion" with 3hours running with 2 bar bosst... i change to a custom dobble layer of Copper metal, with steel combution rings, (2,20mm) i think... i run now with almost 3 bar boost, and never have problems again
:D

Zarghareth
Posts: 19
Joined: 8 years ago
Location: Sisters, OR

#193

Post by Zarghareth » 6 years ago

Larry,
I just installed a needle valve in a line from between the turbo and TB to the front of the diaphragm. It doesn't seem to have had much effect in the lower rpm but due to the large amount of snow and ice on the roads, I was unable to really put the truck through its paces on my test drive. I think it probably will stabilized the power delivery at high speeds under load and can't wait to truly see if it has decreased the slope of my power delivery curve.

Zarghareth
Posts: 19
Joined: 8 years ago
Location: Sisters, OR

#194

Post by Zarghareth » 6 years ago

Hi elboss! Good to hear from you again! Where did you get that head gasket?!

dn29626,
Elboss is running a pretty mental setup and on top of that running it hard as hell! Unless you do some seriously radical stuff to your IP you should be fine.

elboss
Posts: 59
Joined: 8 years ago
Location: Portugal

#195

Post by elboss » 6 years ago

I buy from a portuguese company, who made them
http://www.torresvedrasnegocios.com/e/?id=1345

eurojuntas@gmail.com

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