More tech from the d40 on the dyno

Hey guys just thought I would post up for the education of all about a few things we have been up to at work lately.

First up exhaust systems.

Well my nav has had a 2.5" system installed for a while now and I have been happy but due to pressure from the public our supplier has asked to put a 3" system on for testing. He has also developed his dump pipe with cat to bolt in and this includes the factory rear heat shield bolting up COOL
At the moment he has just installed the dump to my existing 2.5 system.

While I cannot feel any difference in the seat the results did show up on the dyno. A very slight increase in power in the middle to top of rev range over just the 2.5 system alone.

Next week we will be installing the full 3" system to test also just to compare.

3" systems are the buzz at the moment but on paper they seem overkill for this size motor. We have undergone this experiment to test the pros and cons for both with dyno results on the same car for all to see. All the systems we are testing have a straight thru exhaust and noise on the 2.5 is on par with factory but good power gain. Will see what the 3" one is like next week.

Will keep you all posted anyway.

Also on a side note while my new dump was installed I got him to weld in a bung for my e.g.t pyro gauge to fit up. I would highly recommend if you have a weak heart to not install one of these!!! ha ha

Bear in mind I have not added ANY fuel to my car but have increased airflow by about as much as possible with exhaust, filter, upgraded intercooler and pipe work. I have still not taken it up any big hills or anything yet but on the dyno and even with a very short but full throttle strap up the road it is very easy to see 500 deg c!!!! I reckon 650 to 700 will be easily doable!

So to all of you running chips with no other breathing mods.... Be careful!

Hope this is informative
Regards
Brian

Hey Great Thread,

Love seeing the proof of dyno's but can't afford to make all the changes back and forth myself.

Any Chance of Posting some graphs ??

I am just waiting for one of the guys at work to scan them for me and then I can post em.

Bit hit and miss taking pictures of em so bear with me.

Top thread, those 2.5's run bloody hot.

I ain't adding any extra fuel to my ZD30, intercooler coming soon once the bloody tax office stops asking for money and that will do as I have the exhaust already.

Dave.

you said you put on a 2.5 inch exhaust already.. isnt that stock size?

Yeah the factory one is pretty good actually but once you iron out some bends and run a straight thru muffler the gains are there.

In theory 2.5" has enough flow for more power than the 2.5 nav motor could make.

End of the day that is why we are doing this little experiment to see if there is any major difference in power between the two.

If the gains are not substantial then there are benefits for running the smaller exhaust not least of all cost.

I agree 2.5 " is more than enough for exhaust flow rates, however I installed a 3" to allow for the EGT's to dissipate as quickly as possible.

Cheers.

I should be able to comment on this theory soon too xray as I have had my egt gauge in for a while now and have been watching it closely.

The dump pipe I have is actually using a 3" cat and then reduces down to the 2.5" exhaust from there.

Unfortunately the exhaust guy has been a bit busy to do the 3" this last week so will probably have to wait a bit longer. He is taking the dump out tomorrow so he can jig it up and then it will go back in and the 3" exhaust will mate up to the same place. Hopefully next week.

keep up the good work

oh and fyi i over adjusted my actuator and hit 1.8bar with no boost cut (i turned it back down to 1.5bar)

Yeah I am not sure how smart these motors and there systems are really as they don't seem to really use any safegaurds etc.
That could be a good thing in that they have built em tough so they will handle abuse or a bad thing like they have been a bit lapse in there control systems.

I have heard of a couple of hilux d4d motors with 3" exhaust boost cutting which is interesting.

Keen to hear about how this is going. Update?

I am really sorry guys my computer crashed the other day and I lost everything. Had to get a new hard drive and all.

First night back on the net tonight and my wireless is not working now either!!! I hate computers.

Anyway I have not had a chance to get the truck down and get the 3" exhaust put on yet but the truck is going real well anyway.

Last trip to hervey bay from caboolture and back with some town driving thrown in netted me 8.4L/100km so I am stoked with this. Last tank of fuel that was all suburban with some very spirited throttle use netted 9.7l/100km.

This is with roof bars on too.

BTW the Navara cruises on the highway at between 350 400 deg c!!!!!
Funny thing is though when ya get to a big hill if you just let the torque pull you up it does not go up much at all. When I was cruising at 400 I fully expected to see 6-700 deg when going up a hill but it didn't happen. I think boost is the key here. At 100km/hour no load boost sits between 0 and say 6psi (very touchy so hard to narrow down) but as soon as you hit a hill or even the slightest touch on the throttle boost jumps to 15 plus therefore keeping egts under control

I think that is why the nav is so good between say 80-100km/hour as I think they must keep the vanes in the turbo closed to maintain torque/throttle response at cruise speeds.

Anyway once I get the 3" done I will post a dyno graph of all the different outcomes.

Regards
Brian

Mate a couple of questions.

I'm new to diesels and egt's. I understand that high egt's are bad. But I'm also thinking that high is a relative word. What is normal for the Nav 2.5 and what is dangerous?

Also did you find that putting on the dump and 2.5" exhaust make the max boost go up? By how much? And interesting to see what a 3" does to the boost.

Of interest, what kind of boost does the nav run standard? I admit that I haven't searched for this, but figured it would be relevant.

Cheers.

from my understanding anything past 650*C keep is wise to keep to a short time frame

the navara runs around 18psi from factory

Sirnixalot said:

the navara runs around 18psi from factory

Click to expand...

Yeah interesting this....I notice on my Scangauge when cruising on 100km (highway) the MAP can show 28psi - so subtracting the 14.7psi which it reads at idle/off (being 1 Atmosphere or thereabouts) it would seem that I'm running 13.3psi (or thereabouts) of boost. I would've crapped bricks if the boost gauge in my old patrol showed that level of boost at any time let alone for highway cruising. Guess this is the difference between engines being designed to run high boost like the Nav and those not.