If you want a modern, fast, and reliable VW Van, the T4 ticks all the boxes right off the bat. But that doesn’t mean there isn’t room for improvement, and the deletion of the EGR (Exhaust Gas Recirculation) valve has become one of the most common upgrades in recent times for 2.5-litre TDi engines.
Over time, the valves become bunged up with a mixture of oil sludge, carbon deposits and generally awful stuff and, if left unchecked, can restrict airflow and lead to major power loss. This will be particularly noticeable if you’ve already fitted a de-cat exhaust system, uprated your intercooler (102 engine and above), changed your injectors or even treated your ECU to a re-map.
Using a T4 EGR valve delete kit is said to give a 10% power increase (possibly more if your engine is really choked up) and to improve your fuel economy by 3-4mpg.
But just what is the EGR valve, and what does it do? The theory is it helps your engine run more efficiently by re-circulating some of its exhaust emissions back into the inlet side of the engine and running it through the combustion process once again. This results in a more complete ‘burn’ of the fuel in the system, which both helps cool the engine down and decreases its production of nitrogen oxides. Although it’s better for the environment, which we all agree is very important, the downside is it increases carbon build up and leads to the horrible tar-like substance in the intake system that, left unchecked, will ultimately block up your inlet manifold and EGR pipe altogether.
Bypassing the EGR valve cures this issue, but is only possible on diesel engines, as a petrol motor will fail its emissions test come MoT time without all the smog gear in place. The EGR power pipe kit we fitted here came from Bluebird Type 2, but Allard Aluminium Products and Darkside Developments also offer similar items.
While we were at it, we also slotted a free-flowing Pipercross air filter into position to make the path of the inlet air as clean as possible. As these fit in the factory airbox, there’s really no reason not to fit one.
Combine this upgrade with an ECU re-map on an 88bhp (ABL / AJT) engine and you should be looking at around 120bhp, at which point the injectors are essentially maxed out from a smoke and safety perspective.
If you choose instead to have a go at cleaning your inlet manifold of any carbon sludge, we recommend removing it from the engine altogether (entirely a more complex job). If you do this, try not to drop any sediment into your inlet manifold, as combusting solid objects is not a good idea and could lead to a big bang and lots of smoke.
Whichever route you choose, enjoy the work, be careful and take your time.
- Tools: Basic hand tools, including a socket set and a pair of large pliers / VW spring clip removal tool
- Costs: £82.50 for EGR delete; £35.99 for panel filter
- Who from: www.bluebird-type2.co.uk
Install a T4 EGR delete kit: Step 1
Unplug and remove
We’ve started with a non-intercooled T4 here, which makes the job far simpler. You’ll have to remove the MAF sensor wiring from its housing on the airbox and the cold air feed pipework in order to wiggle the top free of it.
Install a T4 EGR delete kit: Step 2
Start by removing the top of your airbox in order to slot the Pipercross item into place. Look to the left of your engine bay and prise open the fiddly cover top clips.
Install a T4 EGR delete kit: Step 3
Remove the old filter and replace with the posh new offering from Pipercross.
Install a T4 EGR delete kit: Step 4
Refit airbox lid
Slot the top of the airbox back into place and then secure the inlet air feed, MAF Sensor and clips back into position. A screwdriver is often vital for pinging the final clip back into position.
Install a T4 EGR delete kit: Step 5
Remove EGR pipework
Locate the EGR valve that lives directly on top of the engine. Disconnect the pipework and vacuum feed that run to it using a big pair of moles grips or the specialist VW spring clip tool. It will be a swine to riggle off because those clips are tough blighters.
Install a T4 EGR delete kit: Step 6
Remove the two braided vacuum hoses that run to the top and bottom of the valve using some nifty cutters / pliers.
Install a T4 EGR delete kit: Step 7
Undo Allen bolts
Undo the two 6mm Allen-head bolts that secure the bronze pipe to the exhaust system and the four 5mm Allen-head bolts that hold the EGR valve and inlet pipe to the exhaust and inlet manifold. Note: if you’re only cleaning, and not blanking your EGR, just loosen the bronze pipe at the EGR end.
Install a T4 EGR delete kit: Step 8
Fit blanking plate
The key to whole process is blanking off the EGR inlet pipe using the plate that comes as part of the kit. Always use a new gasket as well (one should come as part of the kit). This is a bit fiddly, but be patient and try not to drop the bolts, especially not into your exhaust manifold.
Install a T4 EGR delete kit: Step 9
It’s best not to dig around too much in your inlet manifold to avoid pushing any crud into your inlet / cylinder head. If you want, remove the inlet altogether and clean it thoroughly. Clean the mating surface, fit the new gasket (also supplied) and bolt the EGR bypass back into place with the Allen-head bolts.
Install a T4 EGR delete kit: Step 10
Re-fit vacuum hoses
Don’t forget your vacuum hoses, as the new bypass pipe has the required bronze take offs.
Install a T4 EGR delete kit: Step 11
Re-attach and enjoy!
Re-attach the existing pipework and you can do away with the bronze inlet pipe altogether. Voila! Jobs a good ’un. If your EGR valve was bunged up before, we guarantee you’ll feel a difference in driveability and throttle response, as well as a reduction in smoke and improved economy. What you might call a win win situation.
For more technical guides on fixing problems or making modifications to your Volkswagen T4 or T5 Transporter, have a gander at our: VW Transporter technical guides