how much boost for a 3b? (1 Viewer)

[bj70cruzer]

hey I just turboed my bj70 with the 3b diesel using a td04l turbo of a wrx subaru

I think stock wastegate is at 7 psi i was wandering what a 3b can safely handle?

can it handle 15psi as long as the egts are kept normal?

also what is the max egt i should aim for?

Thanks!

forgot to mention it is not inter cooled at the moment but will be later on

Thanks!

 

[Slowerthanu]

1200-1250 is the recommended peak (pyro plumbed pre turbo) but I wouldn't stay there long.

I would stick with 10-12 psi.

The Subaru TD04 turbo doesn't run very efficiently over 14 psi, it becomes more of a heat pump at that point, it should be a great turbo for quick spool though.

Dan

 

[ToyRoverlander]

Mine uses the same turbo (very nice btw) and runs about 20psi max.
During normal driving it only just occasionally touches 14psi... I've got the fuel turned up to the max and wastegate disconnected. Max EGT I've seen is 500degree celcius.. Intercooled..

It has run like this for a year now and still runs nice and pulls great.

 

[gerg]

The tdo4l 13t compressor has a very nice high effeciency island that maps well to a 3b. It falls in the sweet spot at 2000rpm at all pressures up to 23psi. I personally think 20 psi is runing it very hard unless you have a 360 thrust bearing. It also has a very small turbine so your drive pressures will be excessive at that boost. Here is a map at 20psi. The 6th dot is 2000rpm and the 8th is 3000rpm. No hot air here that I see. Even at 3000 its still 70% effecient, but again your boost/drive pressures will be way out of wack. If you want to run that kind of boost id go for a stock td04hl-15g-6cm. Would flow much better on the hot side and still spool up pretty quick.


If you want to run boost like that I would be looking to replace your headgasket to MLS in the near future as 3Bs gaskets will blow out if they are fiber. At the very least retorque your head. It might buy you some extra time.

 

[ToyRoverlander]

Good info, thanks heaps!

Luckily mine doesn't see much boost over 14psi. Usually between 5 and 10. 7psi at cruise (90kph no headwind). 10psi with a strong headwind or going uphill. I try not to let it get past 14psi too much. Usually it only sees more than 14psi when I push it hard in 4th gear, which I have to try not to do as the clutch might slip.

When ordering a HG from the dealer, will it be MLS or fiber?

 

[BEE-JAY42]

In spite of what the large number of people think there isn't really a magic safe boost number for an engine, there are just way to many things to factor in to come up with a number. The simplest way to explain it is to say the longer your engine will spend at max boost the lower max boost should be.

If you are chasing a quick hit of power to overtake or on the trail then you can up the max boost because you won't be spending long there, if you are doing serious long up hill stints or towing something heavy then limit the max.

 

[bj70cruzer]

thanks everyone great info

my 3b is on the stock wastegate and runs stock fueling and i can say it has made a big difference

it should go alot better with the fuel and boost turned up

Thanks again

 

[gerg]

I dont think you can buy a fiber HG from Toyota for the 3B anymore. Here is the mls part number. 11115-58110

Do a search about MLS. There are a bunch of threads. Its more finiky than a fiber, but way stronger.

 

[FJn00b]

hey I just turboed my bj70 with the 3b diesel using a td04l turbo of a wrx subaru

I think stock wastegate is at 7 psi i was wandering what a 3b can safely handle?

can it handle 15psi as long as the egts are kept normal?

also what is the max egt i should aim for?

Thanks!

forgot to mention it is not inter cooled at the moment but will be later on

Thanks!

turbo PSI has a direct relation to engine power and eng temp. I run mine at 8psi max with 1100f egt in worse uphill condition but ave speed the egt is 700f. with standard bj radiator you will over heat if you boost above 7 psi for a long a time. if you want your engine to last a long time then keep the boost pressure low. there is a lot of argument over why not boosting higher and as i said, over heating engines worse enemy and all pro mechanic agree on this.Also higher engine temp effect oil pressure which again is bad for journals.

 

[ToyRoverlander]

I dont think you can buy a fiber HG from Toyota for the 3B anymore. Here is the mls part number. 11115-58110

Do a search about MLS. There are a bunch of threads. Its more finiky than a fiber, but way stronger.

Good to know, thanks! Will do a search to learn some more about them.

turbo PSI has a direct relation to engine power and eng temp. I run mine at 8psi max with 1100f egt in worse uphill condition but ave speed the egt is 700f. with standard bj radiator you will over heat if you boost above 7 psi for a long a time. if you want your engine to last a long time then keep the boost pressure low. there is a lot of argument over why not boosting higher and as i said, over heating engines worse enemy and all pro mechanic agree on this.Also higher engine temp effect oil pressure which again is bad for journals.

Luckily I run a pretty big aluminium radiator with twin 12" electric fans. During normal driving and the few hills we have around here they don't even come on. Only in traffic. It runs quite low EGT's as well. That helps keep the water temp down. Plus, I'm watching those gauges like a hawk when the engine is under load...