Thread: 300tdi power boost

Originally Posted by isuzurover

The 300tdi conveniently comes with a plate in the perfect spot:
http://www.thermoguard.com.au/img2.jpg


You just need to drill and tap it for a swagelok-type fitting - the probe goes through the middle and you tighten the nut to seal.

Did u remove that plate to drill the hole or did u leave the plate intact and drill? If u left the plate on, how do u drill w/o getting metal bits from falling inside and into the turbo?

You remove the plate unless you want to kill the turbo.

Originally Posted by loanrangie

You remove the plate unless you want to kill the turbo.

Yeah, that's what I thought but what's the chances of those bolts snapping off when go to undo them?
Wouldn't post turbo be just as good providing u realise the temp drop across the turbo?

Originally Posted by Robmacca

...
Wouldn't post turbo be just as good providing u realise the temp drop across the turbo?

No. The temperature drop across the turbo is 0-300 oC depending on load.

Many a hole has been drilled with the bit tip dipped in grease, do it slowly and clean the metal filings as you go. Removing the plate is your safest option as removal of broken fasteners is still possible if you are unlucky and break one.

Excuse me for my lack of knowledge here, but what temps would you expect to see 'Pre" Turbo as to what Temps you would see "Post" Turbo ??

300 degree in temp difference seems quite a big drop considering the closeness of probes (Pre & Post) and heat transfer, etc

Originally Posted by isuzurover

No. The temperature drop across the turbo is 0-300 oC depending on load.

I've heard of using the "grease" method on the Drill Bit, but that worries me as to how would u really know that no metal pieces have not dropped down into the turbo area??

How often do these bolts snap off when u go to remove them? What can be done to minimize this from happening when undoing the bolts ??

Originally Posted by slug_burner

Many a hole has been drilled with the bit tip dipped in grease, do it slowly and clean the metal filings as you go. Removing the plate is your safest option as removal of broken fasteners is still possible if you are unlucky and break one.

Originally Posted by Robmacca

Excuse me for my lack of knowledge here, but what temps would you expect to see 'Pre" Turbo as to what Temps you would see "Post" Turbo ??

300 degree in temp difference seems quite a big drop considering the closeness of probes (Pre & Post) and heat transfer, etc

Pre turbo the highest you even want to see is 750oC. That is also the max EGT value given in the isuzu manual for the 4BD1T.

Post turbo you have no way of accurately calculating EGT, as the turbine takes variable amounts of heat out of the exhaust flow depending on how hard it is working. So as I said the numbers post turbo (lets say at 750oC pre turbo) will be anywhere between 750 and 450.

Those using post turbo EGT probes usually assume a safety factor of 250-300oC (i.e. tune to max EGT of 450-500) however they have no way of knowing what the real values are.