Mr Pointyhead replied:

Hi,

I have been doing a lot of research on fitting a turbo to my 03 lc100 1HZ.

For long term reliability, keeping the exhaust gas temperature low, at or below 500 Celsius is critical.

Apparently as small changes have been made to the 1HZ by Toyota over it lifetime to improve fuel economy and reduce emissions, it has made the 1HZ engine even more susceptible to damage from high Exhaust Gas temperatures.

These changes include changing the design of the top of the pistons to reduce the weight of the piston, but in doing so making them more susceptible to heat damage.

So, my research indicates that an intercooler is mandatory if Turbo charging a late model 1HZ engine. Not for the extra power, but to ensure reliability. Also, it is suggested that you fit an Exhaust Gas Temperature gauge (Pyrometer) with alarm to monitor the EGT. If the EGT starts to exceed 500 C, then you simply back off the accelerator until things cool down.

I was told that one of the most well known turbocharger supplier originally only released its 100 series turbo kit with an intercooler for these reasons, but was later pushed by market pressure to release it without an intercooler.

I am sure there will be others reading this that have non-intercooled 1HZ’s without any problems. However, my research is based in talking to a number of very experienced Toyota diesel people, and they all say the same thing. Also remember my comments apply to the late model 1HZ engines.

Another thing you need to be aware of is the 2003 lc100 manuals only have the R151 manual gearbox. This is the same lighter duty box fitted to Prado’s etc, not the heavy duty H151 (or H150) fitted to the 70 series. The extra power from a Turbo has the potential to shorten the life of this gear box. The advice I was give to avoid this is to ensure you do not labour the engine in 5th gear. The engine may have the torque to keep things moving, but for gear box reliability you are better off down shifting to fourth (or lower)

domlc100 replied:

Thank you Mr Pointyhead for all that info I do say that the intercooler is a must to do. Do you have a turbo on your lc at the moment. Thank you Nick for your feed back how do you find the extractors did they give you much more power.

bigaz replied:

aggree with the above comments as well. i have also done a far bit of research and while many swear balck and blue that turboing to the 1hz is a big no-no, i believe it can be done as long as it's done sensibly eg. boost below 9 pound and intercooler for added insurance against high exhaust exhaust gas temperatures.

i know people say that intercooler dont give you anymore power, but they kinda do, however not directly. i would think they allow you to run a higher boost and turn up the fuel pump a bit more and achieve the same EGT's as you would without the intercooler, if you know what i mean..

unfortunately, i have been unable to fit turbo to my 100 series, not because of fear of engine failure, due to $$$$. i got some pace maker extractors and 2.5 inch exhaust ($800). the money i saved went to other extra's like suspension, tyres, steel winch bar, snorkel, K&N filter, ect, ect.

will definately get one oneday and i'll get a safari intercooled system, however for know the extractors do the job and allows me to fit the truck out with the other goodies. there's no point in having an awesome intercooled turbo 100 if it gets bogged at the site of mud beacuse you still running raod tyres, or the standard suspension leaves you hanging, or your alloy bull bar crumples at the site a kangaroo.

cheers

aza