Thread: Raising boost on a td5

Matt .... remerbering that my tires are 4% oversize, and I have a full length (2m) Rhino alloy tray on the roof (which is a bit of a parachute) .... and they vary depending on load carried, headwind, etc ... these are as per my GPS for road speed.

AT 80kmhr ... 1800rpm ... 0.32-0.38 BAR (0.36 = 5.22psi) - speedo says 75
AT 90kmhr ... 2050rpm ... 0.58-0.62 BAR (0.60 = 8.70psi) - speedo says 85
AT 100kmhr ... 2200rpm ... 0.76-0.80 BAR (0.78 = 11.31psi) - speedo says 95

... as best as I can remember.

Your boost doubles from 80kmph to go only 20kmph faster Wow, that must be an effective parachute up there.

If I am not completely wrong any increase in boost pressure/air volume is useless from the point of performance gain if you don't increase the amount of fuel accordingly. This will involve remapping of the ECU. Please correct me if I am in error.

Originally Posted by Jojo

If I am not completely wrong any increase in boost pressure/air volume is useless from the point of performance gain if you don't increase the amount of fuel accordingly. This will involve remapping of the ECU. Please correct me if I am in error.

Yep you are in error in part. An increase in boost will drop EGTs and provide a performance increase. In the case of the TD5 ensuring boost is optimum is noticeable. However big increases in boost without corresponding increases in fuel and changes to intercoolers will be noticeable but limited in effect.

Cheers

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At times like this I'm glad to be just a fossicker

It becomes more of a case of a bit more boost, sooner .... ie:more boost down low.

Originally Posted by strangy

. However big increases in boost without corresponding increases in fuel and changes to intercoolers will be noticeable but limited in effect.

Cheers

Sent from my iPhone using Forum Runner

I've heard that in somecases,you can't get very high boost,unless you add extra fuel..

Once a TD5 is highly tuned, the standard M8 Exhaust Manifold studs can have problems, some times even if the manifold webbing has been removed. The higher tensile and longer 10.9 / 12.9 M8 studs with spacers from JE Engineering UK are an improvement, and are basically cut-down and re-threaded High-Tensile M8 Allen Bolts.

For some, even these mods have not worked, so up-sizing the studs to M10 have finally brought the Exhaust Manifold under control. The problem with this is, even though the drilling and re-threading can be done with the cylinder head still on the engine block, it really is better done with the head off.