Safe boost numbers

[Phat Patroller]

Ok lets talk boost numbers.

I'll start by saying stick away from those dodgy electronic ebay gauges, the truck I just brought (04 TD42t) had them installed and the boost would top out at 15psi........

I just had the truck on the dyno and was slightly concerned with the results.

It peaked at 21.5 psi and producing 79KW @ Rear wheels. Cant remember the torque numbers
EGT peaked @ 475 degrees (post turbo)

Since learning this I have taken the VDO gauges off my old truck and installed them and they correspond with dyno report.

My questions to you all is what do you consider safe? and what do you consider silly?

[threedogs]

21 psi sounds a bit high for a 4.2 TD.

[the evil twin]

Wearing 2 condoms I consider safe and anything that cannot produce triple digit Killerwasps I consider silly or Korean.

Other than that I would say you could crank a fair bit more grunt out of the TD42T than the above.
What fuel economy are you getting?
Find a good Diesel Tuner and say in your best Dickens voice "I would like some more please"

[Phat Patroller]

bahahaha Korean....

The fuel consumption has been around the 15-16L per 100

I would love performance, but I also don't want to be starting the "td42 rebuild" thread

I'm looking for a dependable tourer ultimately rather than a ball tearing comp truck (ok so maybe I'd like it some where in between)

[nissannewby]

21 psi sounds a bit high for a 4.2 TD.

What do you base this assumption on?

[mudski]

21 psi sounds a bit high for a 4.2 TD.
Im running 27 in mine. Er, well was, still am, but not able too. Lol.

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[nissannewby]

Im running 27 in mine. Er, well was, still am, but not able too. Lol.

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I ran 25+psi for 3 years. Engine still sounds good at 340k.

[Phat Patroller]

Im running 27 in mine. Er, well was, still am, but not able too. Lol.

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Why are you unable to?

[tuckertrucker]

So for a NA Silvertop with after market turbo and no other mods - what would be the max?

[Phat Patroller]

Does anyone else have any thoughts on this and maybe some experience to support the high/low debate? I'm really at a loss.

I have some people telling me 12-15psi is high and others saying they can handle 27+

Would love to get more data to support my decision

Cheers peeps

[Bloodyaussie]

12-15 psi is nothing.... dont stress mate these engines love it.

[Ben-e-boy]

Why are these people saying 12-15 is too high, too much boost for the turbo? Or bad for the engine

[Rocket55]

My undersanding is that the stock HT-18 turbo is only good for about 12-14psi efficiently, after this it turns into a heat pump, but the engine is capable of holding much more. I hope so as I'm about to jam about 27psi into mine.

[Cuppa]

I too was of the understanding that 15psi was about the safe max for the stock factory turbo & stock intercooler. Clearly higher boost pressures can be successfully run, but thought that to do so you have to start spending bigger turbo, aftermarket intercoolers etc?


When I asked the dyno tuner to tune my stock GU 4.2TDi with 3” pipe & stock 8 psi, for towing & economy I got 13.5psi max, EGT maxing out around 475 deg & 90.1Kw (up from 76.5Kw & 600 deg EGT). Am very happy with it - transformed the car.

[threedogs]

What do you base this assumption on?
On OE figures