Tale of the 82mm Throttle body upgrade

[alexthom1]

I thought i would document the story so far so that i do not need to store it in memory and it may be benefit to others.
Got myself an 82mm bosch throttle body and plenum connection flange. Made my own plenum as I did not have the dosh for the IPD solution.

Removed standard airbox / filter which is a job in itself and made a new filter housing that sits between the inner and outer wing. Plumbed in using 3.5 inch 89mm alloy pipe and silicone hose.
Also fitted oil catch tank to try and stop AOS residue from lining the inlet and TB.

Thing goes like a rocket. Much free'er revving and pulls much better through the rev range
Kept getting 1126 and 1133 codes indicating an air leak after the MAF causing lean running. Made blanking plate with holes i could tape off so i could do a soap test to find the leak.

Well that was a mistake as i t caused flashing CEL, multiple P codes and misfire. Reverted to stock plenum and TB and all is good again for now.
Points of note.
1. Do not use silicone hose between TB and plenum as it is not strong enough and collapses under suction.
2. Any time you disconnect or change the TB re run throttle set procedure otherwise tick over will be lumpy.
3. 89 mm pipework is excessive and makes the connection to the TB very close to the back of the engine bay.
4. To much air is not a good thing.
5. Either the TB is faulty or the air leak is now causing the O2 sensors / fuel input to go out of range
Going to get the TB checked for operation, but i do not think that's the problem as it responds to throttle input.

After Classic Le Mans trip going to re fit with alloy plenum, wiggins pipe connector and carbon airbox and re map once i have fitted the new hi flow exhaust headers and cats.

[white944]

Is the Maf sensor housing still the standard diameter or have you fitted a larger one with the standard MAF sensor in it? If so, the errors may come up because the air velocity passing the MAF sensor is lower due to the larger bore housing.

[alexthom1]

It is larger at 90mm. however since reverting the TB to stock and fitting a filter before the MAF, the errors have gone away. So i guess that may have constrained the air flow through the MAF Hsg.

This may however be a ginger fish(red herring) as i found an air leak on the oil dipstick outer sleeve. It had a crack which i think only became an issue due to the changes.

Changing back one piece at a time I have had no more CELs to date.

My inlet is now just acting as a trumpet. Have fitted carbon sealed airbox and now have K&N filter to replace the one that came with it from eBay. Will be interesting to see what happens next week.