12H-T boost mods (1 Viewer)

[kevin in okinawa]

so I am thinking of eventually having this motor make a little more power. there isn't a lot of talk about these motors, mostly the 3b...

i have never drove a diesel before so i'm unsure of how the boost/fuel relationship works. in general, i am assuming that the boost could be increased to 10-12psi; my stock boost is .6bar.

does the fuel also have to be turned up?

i also believe that for a diesel, the EGR numbers (pyrometer guage) are more inportant than the a/f ratio, correct?

i think that this is about 8psi. I also intend to hook up a water injection kit for detonation and chenmical intercooling purposes.

currently, it looks like there is a 2 1/2" exhaust. how much help would a 3" do?

also already have a k&n filter and snorkel.

Any 12ht drivers want to chime in?

 

[crushers]

K&N filter... garbage. allows too much dirt in.
pyro is most important if modifying boost an fuel levels" will do nothing for power but might flow the exhaust gasses faster to keep the EGTs down
you can run 14 psi easily on the engine
bring the boost up to 14 psi then increase the fuel slowly unitll 1200F is reached during rapid acceleration up a long hill. you should have a bit of black out the butt.
turn the snorkel intake tip towards the windshield for max air charge (which will be minimal at best)

 

[kevin in okinawa]

thanks crushers.

so egt is the benchmark for diesels where a/f is for gas motors then?

sounds pretty simple. do you mod the wastegate or with a schrader valve-type boost controller?

anyone else mod a 12h-t lately?

i am getting the feeling that these engines are not too common outside of japan...

edit: any info on the turbo? size, max output, good replacement unit, etc?

 

[daboheme]

Crushers, in your opinion, 14psi boost is OK when non-intercooled?

 

[crushers]

sure, 14 psi on any Toyota Land Cruiser diesel is fine.
an intercooler will reduce the charge generated heat for a more effective charge.

of course just increasing the boost with out modifying the fuel will have limited results...

 

[Tapage]

Actually I thought more boost without more fuel only help cooling the EGT .. but nothing in the performance side ..

Yeah .. boost controller on that CT26 .. easy .. I use Hallmans .. cheap ( blocker type ) and nice results. Easy adjustment.

 

[Waggoner5]

I shimmed the waste gate to get 11 psi up here in Colorado and adjusted the boost fuel control to get optimum EGTs. I felt that 11 was enough since it came factory at 7 psi.

 

[Greg_B]

of course just increasing the boost with out modifying the fuel will have limited results...

Wayne

In addition to the advantage mentioned by Tapage of slowing down the pyros advance into the danger zone, there may well be enough response gain for some people by simply increasing the boost to 12-13 psi and leaving the fuel alone.

I've increased the boost on both Petra's 12HT and my 13BT and have not touched the fuel on either. Both had noticable inprovements in response. If it was simply better use of the available fuel or not I can't say for sure...but there was a noticable improvement in response. Same thing when we did Stones BJ74, and a number of others I know about or have been involved in.

With the 13BT and the stock exhaust I was able to get the pyro into the danger range on the slightest incline at freeway sppeds. After increasing the boost and no adjustment to the fuel it was much harder. That, in conjunction with a 2.5" exhaust, and ceramic coated turbo/exhaust manifold now has the set-up just about in the idiot proof range = long incline, max throttle, works hard to get to 1000F (post turbo probe). At elevation I have to watch it closer, as it will start edging over. Neither beltched a lot of black even when in stock trim.

No gauges on the 12HT yet.

There would be a crossover where no more gains are apparent and fuel is needed.

Now if you are simply talking about trying to tune it to the max...then sure.

When we have turbos rebuilt now we give option of having the shop thread the waste gate rod so the dump pressure can be adjusted on the rod.

hth's

gb

 

[kevin in okinawa]

20 yrs of gas motors has me still a little confused regarding +/- of fuel.

in a gas motor, if you increase the boost, you will usually want to increase fuel...to achieve the desired air/fuel ratio.

in a diesel motor, does the increase of fuel retard the egts?

if someone wants to expalin it Barney-style to me, I won't be upset one bit!

thanks in advance.

ps: this 12ht is one gutsy engine, i cannot wait to give it some more balls.

 

[kevin in okinawa]

Wayne



I've increased the boost on both Petra's 12HT and my 13BT and have not touched the fuel on either.

by messing with the wastegate, or an manual boost controller?

 

[jb BJ73]

don't the 13B-T and 12H-T have boost compensators on the pump? being factory turbo'd you would think so wouldn't you?

 

[daboheme]

12H-T does.

 

[crushers]

Tapage and Greg, yes, the increase of boost does drop the EGTs and does burn the fuel more efficently and as you alluded to, if you want better power then increase the fuel using the pyro as the gauge...

no debating your points...

 

[Greg_B]

by messing with the wastegate, or an manual boost controller?

By shimming the wastegate initially. Now by an adjustable wastegate rod. Boost controller (aka grainger valve) would work well too. Make sure you have gauges before taking the fuel off stock trim.

Check out all the articles in this link to get some great primers on diesel engines: Banks Power | Technical Articles

jb BJ73, yes to both the 12HT and 13BT.

hth's

gb

 

[Tapage]

here the boost controler that I use .. not shims, not cutting the rod ( that it's not adjustable in the CT26 )

Welcome to Hallman Boost Controllers

 

[The Dude]

I have a homemade boost controller like the one above. I have it at 14psi and the over boost light never comes on.

Also running an intercooler. I don't know if it adds more power but it takes a lot more time to see the high EGTs. I love it, well worth the effort.

I have the TRD filter (I don't think it's available anymore) with snorkel

3" exhaust will drop your EGTs but won't do much for power.

Soooo...after all that, get your engine breathing the best you can to get the EGTs down and then crank up the fuel to get MORE power!

 

[Greg_B]

Brad, you know anyone running water/meth?

gb

 

[jb BJ73]

Wayne

I've increased the boost on both Petra's 12HT and my 13BT and have not touched the fuel on either. Both had noticable inprovements in response. If it was simply better use of the available fuel or not I can't say for sure...but there was a noticable improvement in response. Same thing when we did Stones BJ74, and a number of others I know about or have been involved in.

gb

so wouldn't the boost compensator take into account some of the extra boost and deliver more fuel? i suppose it wouldn't have a lot of travel in it, so if you max that out thats when have to turn up the fuel. while we're on the subject, how do you adjust the fuel on a 12H-T?

 

[The Dude]

Brad, you know anyone running water/meth?

gb

There are a couple guys in town running it on their Subarus but I have never seen it on a Toyota or a diesel...

 

[Greg_B]

so wouldn't the boost compensator take into account some of the extra boost and deliver more fuel? i suppose it wouldn't have a lot of travel in it, so if you max that out thats when have to turn up the fuel. while we're on the subject, how do you adjust the fuel on a 12H-T?

Yes, it......well....compensates. What the specs or stats are is beyond my knowledge, as is where the max out point would be. I did not agree with the generalized statement "that increasing the boost without modifying the fuel would only give limited results". I agree that increasing the fuel setting above stock settings will give more results when you have looked after the air and flow side of things. And if you are aware of potential impacts and power is what your after then go for it.

Either buy or download the FSM for the 12HT. A search here will lead you to the download sites.

I know a few diesel folks here running water/meth in diesels (not Toys) and the results seem favorable. I don't know enough about it to comment fully. Some just go in and get -40 wiperfluid and fill'r up. Otherwise known as "chemical Intercooling" and was used in WW2 by planes in takeoff and dogfights.

gb