The 2LT Diesel Dyno Panga

[wasifali89]

this is good fun

[qwertypoiu]

Wouldnt overboosting decrease the reliability? and eventually result in more wear and tear

[sami_voodoo]

Please correct me if I am wrong, but the 2.4l 2LT engine was rated at 96 bhp at 4000 RPM with 139 lb-ft of torque at 2200 RPM.

Isn't 171 lbs/ft @ 2389 RPM pretty good for this engine already? Considering at 20% loss for a 4WD drivetrain, horsepower at the wheels should be around 77 bhp, and he is getting about that., although at a much lower rpm.

Considering that it is a non-standard drivetrain and the dyno may not be correctly calibrated, what am I missing here?

If the 2L-T's injection pump is a Bosch VE, he should have a limit of 189 lb-ft at the wheels (assuming the 20% loss). For me, the greater danger is exhaust gas temperatures. I'm not sure, it seems that you guys are living on the edge here...

[VCheng]

If the 2L-T's injection pump is a Bosch VE, he should have a limit of 189 lb-ft at the wheels (assuming the 20% loss). For me, the greater danger is exhaust gas temperatures. I'm not sure, it seems that you guys are living on the edge here...

That is a very good point. The addition of an EGT guage would be helpful if that level of tuning is being considered.

[Ghuncha]

what i am confused is the dip in torque, and as the op said turbo is shot, is there a possibility that as the revs increase the turbo is not capable of giving enough volume. a simple boost gauge would have disclosed a lot i guess.

[sami_voodoo]

Its a huge dip actually.. like if the IP was fuel starved

Are you ready to play with the IP ?? lets tweak it a bit

I don't think it's fuel starved, either the turbo is losing boost at high RPM, or the injection pump is pulling back fueling at high RPM. Also, it's not that rare of a trait of diesels, see below:

Prado Power-Up

[VCheng]

I don't think it's fuel starved, either the turbo is losing boost at high RPM, or the injection pump is pulling back fueling at high RPM. Also, it's not that rare of a trait of diesels, see below:

Prado Power-Up

Like I said before, the curves and the numbers look pretty good for a small diesel.

[Xulfiqar]

If the 2L-T's injection pump is a Bosch VE, he should have a limit of 189 lb-ft at the wheels (assuming the 20% loss). For me, the greater danger is exhaust gas temperatures. I'm not sure, it seems that you guys are living on the edge here...

Yes its a vertilier - how did you land at 189 lb/ft -

the Cummins 4BT uses a VE and twists out 355 lb/ft easily

[sami_voodoo]

Yes its a vertilier - how did you land at 189 lb/ft -

the Cummins 4BT uses a VE and twists out 355 lb/ft easily

It's the diameter of the plunger and the stroke on the swash plate that dictates the fuel flow to each injector. Going by the Bosch Diesel Engine Management book, we'll try to decipher the pump codes. Look for the model number on the injection pump, it should look like this:

V E 4 / 9 F 2200 L 12

V = Distributor Injection Pump
E/R = Axial Piston / Radial Piston high pressure pump
4 = Number of high pressure outlets
9 = Pump plunger diameter
F/E/M = Mechanical Governor / Electric Actuator Mechanism / High Pressure Solenoid Valve
2200 = Upper nominal pump speed (half engine speed for 4 stroke engine)
L/R = Counterclockwise / Clockwise rotation (viewed toward pump drive)
12 = Type code

I think the VE pumps on the Cummins are of the 11 or 12 mm variety. In addition, they've got a longer stroke, from memory it was 5.5 mm instead of 4.5. Doing a bit of math:

Area increase of plunger wrt 9mm plunger is = (12/9)^2 = 1.78
Stroke increase of plunger wrt 9mm plunger is = (5.5/4.5) = 1.22

Multiply the two increases and you've got a net fuel flow increase wrt the "smaller" injection pump = 2.17

189 * 2.17 = 410 lb-ft

There's your increase in torque.

As for my original guesstimation of 189 lb-ft, that was based on the basic specification (9 mm plungers - 4.5 mm stroke) VE pump producing 30kW per cylinder at 4000 RPM. That corresponds to more or less 236 lb-ft at the crank. I deducted (rightly or wrongly, you decide) 20% to fall at a wheel torque figure of 189 lb-ft.

p.s. I'm still a bit foggy about the plunger stroke figure. I suppose you'll have a better measured value?

[Xulfiqar]

the pump code decipher is correct Thats how I select a pump for purchase - and when doing up a pump - you also have to consider the internal pump advance - metering sleeve and surely very surely the pump stroke..

What you are considering is near max engine speed, thats why the LDA is on the pump, the max torque comes in strong at low revs and keeps it there by increasing fuelling on boost and keeping the rev cut governor at bay - the max allowed engine speed is dictated by the fuelling governor which will proceed to reduce fuelling gradually till it dies at max revs. unless you have a solid shimmed governor - (heat problem)

but anyway - you are nearly there - but considering boost compensation on the pump pushing the full load screw farther away - it will literally flow double the stock fuelling.. But the pump is usually a hybrid or custom job.

You are on the dead right track on the VE fuelling technique - just peer into it further, - btw the stroke of any certain VE pump is different across different pumps

[sami_voodoo]

the pump code decipher is correct Thats how I select a pump for purchase - and when doing up a pump - you also have to consider the internal pump advance - metering sleeve and surely very surely the pump stroke..

What you are considering is near max engine speed, thats why the LDA is on the pump, the max torque comes in strong at low revs and keeps it there by increasing fuelling on boost and keeping the rev cut governor at bay - the max allowed engine speed is dictated by the fuelling governor which will proceed to reduce fuelling gradually till it dies at max revs. unless you have a solid shimmed governor - (heat problem)

but anyway - you are nearly there - but considering boost compensation on the pump pushing the full load screw farther away - it will literally flow double the stock fuelling.. But the pump is usually a hybrid or custom job.

You are on the dead right track on the VE fuelling technique - just peer into it further, - btw the stroke of any certain VE pump is different across different pumps

It is impossible for a mechanical governor to cut fuel off sharply at the maximum RPM. It has to start cutting off fuel quite early in RPM range. This would explain the Torque curve that we see posted by the OP. In common-rail systems, you can stay on max torque almost till the end of the RPM range where you can cut it off sharply. You can actually feel it as you're driving along. I've driven quite a few common rail diesel powered cars of diffeirng power and displacements, and all of them pull well until around the redline, then in 500 RPM, they go dead, like they hit a brick wall.

Also, one has to remember that without the supporting airflow, the power increase by just changing fueling will be limited. Limited by EGTs mostly. If you're not willing to change your turbo, you can try N2O. In diesel applications, it's not as dangerous as in petrol applications, since the aim of the nitrous is to lean out the mixture, or reduce the EGTs to a safe level wehn running at full power. This is in comparison to petrol applications (or more correctly, spark ignition applications), where the air/fuel mixture ratio has to be in the correct range, or you'll either burn out your engine due to lean mixtures, or belch black smoke if you're too rich.

[Xulfiqar]

im not arguing that the you did wrong or anything, BUT the fuelling lever is spring loaded and forced to compress by the flyweights - now you can stiffen the spring(s) to overcome the flyweight push - but the push is there.. and still can hit 90% safe engine rpm till the time the fly will literally shove the governor to close out the metering sleeve..

about chopping fuel supply - (I said that it will decrease fuel gradually - gradually being 500 to 800 revs before max engine speed) - the factory calibrates pumps to reduce fuelling at about half engine speed (to keep the feds and the likes happy)

No doubt electrical control on the pump is good and precise but if youre stuck with oldschool technology you can exercise the manual pump to push out a good quantity of fuel - only if you have a turbo to feed the engine.

[Xulfiqar]

anyways - NICE to see this thread is going good, - when Im back in Pak Im gonna pull my VW GTD (with K24) on the dyno to see what it prints out

[sherwan_88]

Nice info on Diesels Injection Pumps....
Does anybody have an idea if in Pak somebody can modify a TD42's inline pump to incorporate 12mm plunger?

[sami_voodoo]

im not arguing that the you did wrong or anything, BUT the fuelling lever is spring loaded and forced to compress by the flyweights - now you can stiffen the spring(s) to overcome the flyweight push - but the push is there.. and still can hit 90% safe engine rpm till the time the fly will literally shove the governor to close out the metering sleeve..

about chopping fuel supply - (I said that it will decrease fuel gradually - gradually being 500 to 800 revs before max engine speed) - the factory calibrates pumps to reduce fuelling at about half engine speed (to keep the feds and the likes happy)

No doubt electrical control on the pump is good and precise but if youre stuck with oldschool technology you can exercise the manual pump to push out a good quantity of fuel - only if you have a turbo to feed the engine.

Hmmm, I missed something here, I think we aren't on the same page. Rest assured, I never thought for a minute that we were in disagreement, It was just that I was elaborating the nature of mechanical diesel injection pumps to state a few facts that I had learnt (of which we are in agreement I hasten to add). As for the reduction of torque at high RPM, I agree that one can limit the fueling in the mid range with the LDA, and then let it rip at high RPM. Although, you have to be careful as the engine can be made to run away if the pump has been modified and it does not cut fueling enough, result, valve float, broken cambelts, pistons, thrown rods etc...

About the reduction in fueling at high RPM, in addition to the reduction in emissions, I think it will also reduce thermal loads on the engine.

[sami_voodoo]

Nice info on Diesels Injection Pumps....
Does anybody have an idea if in Pak somebody can modify a TD42's inline pump to incorporate 12mm plunger?

I suppose you could if you could source a rotary pump head from a truck. I'm not sure if Nissan or Hino trucks ever used rotary pumps. I think they were in-line type - I may be mistaken though. Have you tried stationary engines?

There are a couple of things to add to your shopping list as well, bigger injectors, and a thicker driveshaft for the injection pump. The bigger area of the plunger will require more torque to run it. Around 78% more if we do a quick calculation (ratio of diameters squared - (12/9)^2=1.78). Without the thicker shaft, you run the risk of breakage. At the very least, reliability will be compromised.

[sherwan_88]

I suppose you could if you could source a rotary pump head from a truck. I'm not sure if Nissan or Hino trucks ever used rotary pumps. I think they were in-line type - I may be mistaken though. Have you tried stationary engines?

There are a couple of things to add to your shopping list as well, bigger injectors, and a thicker driveshaft for the injection pump. The bigger area of the plunger will require more torque to run it. Around 78% more if we do a quick calculation (ratio of diameters squared - (12/9)^2=1.78). Without the thicker shaft, you run the risk of breakage. At the very least, reliability will be compromised.

Early Td42's were with an inline pump and in Nissan Medium Buses all Td42's were with inline pumps. The later versions mid 90's and later were with rotary pumps and all TD42T were with rotary pumps. The later versions were prone to many malfunctions and were basically a hunk a junk. The early ones though survived but with pristine care administered.

I am collecting and researching data for my future project to turbocharge my Patrol which is powered by a early TD42-2. Now these engines are really gutless in terms of acceleration but the torque is substantial enough to tow a 2 ton trailer. What i am hoping for is to up the torque by 100%, which at this moment would be around 160-180 ft-lbs. A small turbo would only increase the torque by 25-30% only in the low range and start to run out of puff in the mid range and finally have no boost vice versa with a big turbo.

If i am able to get the pump to deliver the torque in the low revs, a big turbo can cover the mid range and thus covering the whole rpm range.
To avoid the pump i have to build a compound turbo setup which is very tricky and is impractical in daily applications. To this date the turbo i deem the most feasible is a Toyota CT-26 off a 1HD-FTE or a 3S-GTE not sure which one to go for as I've heard the trim and the compressor wheel is different in both.

Do you have any opinions on this particular aspect? am i correct on the small turbo, big turbo thing or have i got it all wrong?
I think your feedback and advice can help me come to a solution.

P.S... Sorry SK for hijacking the thread...

[sami_voodoo]

If i am able to get the pump to deliver the torque in the low revs, a big turbo can cover the mid range and thus covering the whole rpm range.
To avoid the pump i have to build a compound turbo setup which is very tricky and is impractical in daily applications. To this date the turbo i deem the most feasible is a Toyota CT-26 off a 1HD-FTE or a 3S-GTE not sure which one to go for as I've heard the trim and the compressor wheel is different in both.

Do you have any opinions on this particular aspect? am i correct on the small turbo, big turbo thing or have i got it all wrong?
I think your feedback and advice can help me come to a solution.

P.S... Sorry SK for hijacking the thread...

I'm not sure if this is the case for your engine, but many turbo variants have some modified parts, most notably the pistons with thicker top ring lands, uprated oil pumps etc. It would probably by good to verify if the only differences between the N/A and turbo versions of your engine are the injection pump and turbo hardware.

As for the choice of turbos, I'd go for the one off of a 1HD-TE. It's roughly the same engine size, it's diesel, and the power ratings are within reasonable limits. The only thing that bugs me about Toyota turbos is that you can't find compressor and turbine maps, so it's a bit of a guessing game unless you've got a turbo test bench...

[sherwan_88]

I'm not sure if this is the case for your engine, but many turbo variants have some modified parts, most notably the pistons with thicker top ring lands, uprated oil pumps etc. It would probably by good to verify if the only differences between the N/A and turbo versions of your engine are the injection pump and turbo hardware.

As for the choice of turbos, I'd go for the one off of a 1HD-TE. It's roughly the same engine size, it's diesel, and the power ratings are within reasonable limits. The only thing that bugs me about Toyota turbos is that you can't find compressor and turbine maps, so it's a bit of a guessing game unless you've got a turbo test bench...

Well, yes there are some differences in terms of parts. There is only one drawback to turbocharging a standard TD42 is that it should not be boosted above 15 PSI or it simply dies of heat, and TD42's are already infamous for the heat they produce. Otherwise T'ing a stock TD42 is fairly simple.

I will go with the CT26, but there would be one problem which is the internal waste gate configured at 8 PSI. having an adjustable waste gate would be nice though for one. I agree there are no maps out there, but with a boost gauge and some trial error some performance can be achieved. And i have yet to see a turbo test bench yet, i think the Toyota folks have got it but they will only entertain you are holding a sack full of cash. :P:)

It will be sometime before i start this project, as i have to bring down the Cr on the engine and the only way to do it is to just drive it for now, maybe put 10-15k on it.

If you've got spare time on your hands check out the info available on how the Aussie's do it. Some quite nice info on the net.

[SuhaibKiani]

@Sami_Voodoo and Xulfiqar: Many thanks for your feedback on the thread and your continued interest.

@Sherwan: No problems on discussion any side topics as long as they remain relevant. All turbo charged diesels generally have similar issues and considerations from what I understand.

I have been away with IJC on the whirlwind Summer Camp 2010 tour and will get around to putting down some points, though I must admit that the discussion on IP dynamics and metrics is way beyong my level at thyis stage. I had thought that I had posted a few things regarding the boost compensator but I think the post got lost somewhere in the prepartions when I was leaving.

BTW: the 2LT performed very well on the trip, touch wood, and the overfuelled IP and high boost enabled the engine to keep up with the big boys running them TEs and FZs where required. By the end however, I was getting complaints of a huge smoke trail at the back on full acceleration but I guess that is somewhat expected with these games. The engine was smoking the most when the boost and the turbo had not kicked in at full acceleration. No smoke if I managed the accelerator at the low end and no issues once the boost kicked in.