Adjustable rev limiter for 2.8 CRD engines ?

Waltsu · **Joined:** Sat Feb 23, 2019 12:41 pm **Posts:** 9

Hi guys!

Have you come across a way how to limit or adjust the top revs of the 2.8 CRD?
My engine is running at approx 4480-4490rpm tops when the MOT guys are performing their emissions tests.
At this speed, my emission levels are too high and I fail in my MOT test.
Sometimes the engine won't rev up to 4490 but stay at approx 4000 rpm, don't know the reason for that, but the emissions are just below the limits and the car would pass in theory.
So my question is: Can the top revs be adjusted electronically somehow?
If not then I will consider putting a LEGO-brick between the pedal and the metal

flash7210 · **Posted:** Thu May 23, 2019 1:10 pm

WTF are these guys doing?
Do they know its a diesel engine?
4000 rpm is the redline and 5000 rpm is the absolute max.
In the real world, your engine should never have to rev past 3000.

No, there is no rev limiter that can be added. The rev limiter is your right foot.
Maybe GDE can write a tune with such a limiter.

Things you can do to prepare for the emissions test:
1. have a properly functioning thermostat
2. have your engine warmed up to at least 190F
3. fill up with biodiesel if available
4. change your air filter
5. check all the intake hoses from the air filter, to the turbo, to the intercooler, and to the engine and make double sure there are no tears, splits, or leaks

Waltsu · **Joined:** Sat Feb 23, 2019 12:41 pm **Posts:** 9

Thanks Flash,

Yes you are right - this is nuts... these MOT guys in Finland has to slam the pedal to the floor and then they measure the emissions. I feel sad for the engine ;-(

Thanks for the list of topics to check - I have done them all except the biodiesel. I have just rebuilt the cylinder head, ported it and also disabled the EGR.
Would be nice to know if someone has had the same issue and managed to reduce the rpm's in a way that is not too obvious for the MOT
Cheers

GordnadoCRD · **Posted:** Thu May 23, 2019 11:00 pm

A fresh oil change also helps.

This procedure sounds very much as if there is some personal or institutional bias at work here. There is nothing meaningful that can be learned from an emissions viewpoint by subjecting any engine to that abuse, whether gas, diesel, propane, or other.

Is there another place you can have your MOT done?

WWDiesel · **Posted:** Thu May 23, 2019 11:08 pm

This is totally "NUTS"! :shock:

These engines are not really designed to run at those very high RPM's. :banghead:

They are very lucky they have not blown up your poor engine by slinging a rod out the side of the block.

Adjustable rev limiter for 2.8 CRD engines ?

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