Thread: Wastegate actuator bypass mod

Originally Posted by AussieAub

Thoughts on by-passing the turbo wastegate actuator on the Td5 D2? The Td5 Defender doesn’t even have one, so why the D2?

Runs WAY better by-passed, but could it cause potential future damage?
Pros and cons??

Cheers

What do U mean by runs better? Higher boost?

It is there to stop wastegate creep. Sounds like yours might be starting to fail. Peirburg were the manufacturers of this for Land Rover, don’t use a cheap pattern part. PMK100130 | VALVE WASTE GATE CONTROL TD5 TURBO - DEFENDER - DISCOVERY 2 | Eurospare | Defender 1983 To 2006 | Britcar (UK) Ltd

Also check for splits in the three hoses connected to the modulator for splits. If they are split replace them.

Thoughts on by-passing the turbo wastegate actuator on the Td5 D2? The Td5 Defender doesn’t even have one, so why the D2?

Runs WAY better by-passed, but could it cause potential future damage?
Pros and cons??

It stops wastegate creep up to 15PSI, but then opens so if you are running more boost by shortening the rod to 7-8 turns then the shortening of the wastegate rod means the wastegate is not opening enough to prevent boost from going to 20PSI or whatever.

I tried to bypass using a cheap boost controller and was astounded at the difference in boost above 15PSI but because I had not shortened the rod I was getting up to 28PSI.

I have now bought a Turbosmart controller and when I have time will wind back the rod to 10-12 turns and test it again.
This reduces EGTs by up to 100C when mine was running at about 22PSI .

The agreement from others more expert than me is that high boost is better than high EGTs , so hopefully I will be able to run 22-24 PSI and benefit from the lower EGTs. ( my ECU has been altered to allow higher boost and higher MAF numbers)
It doesn't seem to go much or any faster at the higher boost so I guess it is running into a fueling limit and running cooler because of a leaner AF ratio.
Regards Philip A
BTW I should qualify all this by advising that this is just my conclusions from empirical testing, and I do not for sure know that the results are correct or why they happen.

Actually I have noticed slightly cooler EGT running 1.3 bar (18.8 psi) on the nanocom then when it was standard. (Just under 1.2 bar by memory)

Originally Posted by AussieAub

Thoughts on by-passing the turbo wastegate actuator on the Td5 D2? The Td5 Defender doesn’t even have one, so why the D2?

Runs WAY better by-passed, but could it cause potential future damage?
Pros and cons??

Cheers

If it's running better bypassed, you have a faulty Wastegate modulator, or a leak in a hose you are now not using with it bypassed.

Cheers James
Edit:
Just to clarify, if it's running better disconnected, the modulator wasn't letting the Wastegate operate at all, then you get an overboost situation, then fuel gets cut until you restart, but the car would go "better" in this scenario UNTIL you hit overboost.

Plenty of us running without them but usually because we have upgraded the turbo to a VNT/VGT so it's redundant.

The Td5 Defender's don't have them as they weren't as refined, and I think made less power. On a stock Td5 you're going backwards by bypassing it. If your finding it's better without it then you have an issue that you're better off resolving properly.

Curious, are the VNT/VGT turbos worth the extra money?

Originally Posted by twr7cx

Plenty of us running without them but usually because we have upgraded the turbo to a VNT/VGT so it's redundant.

The Td5 Defender's don't have them as they weren't as refined, and I think made less power. On a stock Td5 you're going backwards by bypassing it. If your finding it's better without it then you have an issue that you're better off resolving properly.

I think you are spot on about the power difference.
Disco td5 is 101 kw iirc and Defender td5 90 kw with the difference due to the modulator on the Disco allowing higher boost.

If that is the case then it would obviously be better to fix it than bypass.

I am pretty sure that is how it works but someone else could either confirm it or not.

Paul.