Thread: Td5 Boost Pressure

Mine under similar conditions (assuming a lot I know)
MAF would peak at about 520
Boost would be 230

These are peak values and they may not be exact for your conditions

You should be getting airflow figures of 6-650 with a healthy MAF (on a d2 anyway).

The manifold pressure shown in Nanocom is absolute, not boost. You need to subtract ambient pressure to find boost. Ambient is usually around 100kpa at sea level so you are getting about 100kpa/14psi boost which sounds fairly normal.

Originally Posted by OffTrack

You should be getting airflow figures of 6-650 with a healthy MAF (on a d2 anyway).

The manifold pressure shown in Nanocom is absolute, not boost. You need to subtract ambient pressure to find boost. Ambient is usually around 100kpa at sea level so you are getting about 100kpa/14psi boost which sounds fairly normal.

Thanks 'Offtrack' - that explains the boost pressure reading which I thought was unreasonably high.
Will keep searching for reason behind sluggish performance on highway - maybe I should check what's in the monster box on the back of the ute, maybe there's a couple of ton of gear holding it back a tad.

Originally Posted by Xtreme

Thanks 'Offtrack' - that explains the boost pressure reading which I thought was unreasonably high.
Will keep searching for reason behind sluggish performance on highway - maybe I should check what's in the monster box on the back of the ute, maybe there's a couple of ton of gear holding it back a tad.

The MAF does look like it's reading low. If you have access to a known good unit it would be worth swapping it out to repeat the test run.

cheers
Paul

Paul
I have read this before even though I had fitted a brand new genuine MAF I was still getting up to 500 .
A bit annoyed that I wasnt getting the 600-650 I went to Alive Tuning and bought a genuine Siemens unit put it on and tested it last week to discover the best I could get was 522.
After more research it appears that only cheap aftermarket units go that high.

Duane

Originally Posted by OffTrack

You should be getting airflow figures of 6-650 with a healthy MAF (on a d2 anyway).

The manifold pressure shown in Nanocom is absolute, not boost. You need to subtract ambient pressure to find boost. Ambient is usually around 100kpa at sea level so you are getting about 100kpa/14psi boost which sounds fairly normal.

Thanks Paul, will do as suggested and if readings are same then maybe it needs an intercooler flush.

Am I correct in assuming that the Air Flow readings are taken from the MAF unit and there isn't another sensor somewhere else such as the inlet manifold?

BTW, fuel and air filters have been replaced recently so don't suspect any restrictions there.

Oops - Just read your reply 'djam1' - interesting results, thanks,

Roger
If you put the Nanocom in instrument mode you will probably only be seeing 1 bar boost max.
With a Defender that is in good condition it would be 1.1 bar you can adjust the boost pressure up to 1.3 without going into overboost.

Originally Posted by djam1

Paul
I have read this before even though I had fitted a brand new genuine MAF I was still getting up to 500 .
A bit annoyed that I wasnt getting the 600-650 I went to Alive Tuning and bought a genuine Siemens unit put it on and tested it last week to discover the best I could get was 522.
After more research it appears that only cheap aftermarket units go that high.

Duane

Duane,

It's more likely case that the 600-650 is a D2 reading because I regularly see over 600 with a Siemens/VDO unit purchased from Alive Tuning. It's possible, but very unlikely, you got one from a bad batch. It seems more likely the defender Td5 is a wheezy asthmatic compared with the Disco 2 Td5 in this regard.

Even so, and factoring in that you see 522 peak, a peak reading of 420 maximum is what I'd call "a bit low" - by 20% compared with your figure. A Siemens/VDO MAF in good condition is definitely a good reference for what a Defender Td5 should be reading.

cheers
Paul