NZ Performance Car - - Tech Guide -

When pur­chas­ing an off-the-shelf turbo man­i­fold be sure to buy one that is of good qual­ity. Many of the cheap and low-qual­ity man­i­folds that have flooded the mar­ket are worse than the stock item in terms of re­li­a­bil­ity and power out­put, of­ten fool­ing peo­ple with their shiny good looks. If you do buy one of the com­mon, cheap in­fe­rior man­i­folds, en­sure you have it checked over by a fab­ri­ca­tor be­fore it’s in­stalled. Of­ten the man­i­fold-to-block flanges are warped straight out of the box, which can be a huge has­sle, as the man­i­fold studs of­ten get pulled out due to the flex. An­other com­mon prob­lem with th­ese man­i­folds is crack­ing. In­fe­rior weld­ing qual­ity and wall thick­ness, the weight of the turbo and waste­gate are all enough to make the welds crack un­der high-heat sit­u­a­tions. We’d rec­om­mend get­ting braces welded in-be­tween the turbo flange and the man­i­fold, and the waste­gate flange and the man­i­fold, which should en­sure your flange welds won’t crack if you do choose to pur­chase one of th­ese man­i­folds. We’d also rec­om­mend en­sur­ing the down­pipe is well sup­ported, and a flexi-joint is used in con­junc­tion with the afore­men­tioned braces.

An­other thing to check with th­ese man­i­folds is the port di­am­e­ters. Quite of­ten the ports on the man­i­folds are dif­fer­ent to that of the head. A good way to check this is by pur­chas­ing a good-qual­ity OEM man­i­fold gas­ket and com­par­ing the port holes in the gas­ket to the man­i­fold ports. Do not trust the gas­ket that is sup­plied with the man­i­fold, as th­ese are of­ten made of a lower-qual­ity ma­te­rial, and the ports will be the same as the man­i­fold’s ports. Weld­ing ‘dags’ have also been known to break away un­der high-heat sit­u­a­tions, make their way through the man­i­fold and into the tur­bine hous­ing on the turbo, caus­ing costly dam­age.

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