12H performance upgrades (1 Viewer)

[Talos]

Hi guys.

I´m in the midst of transplanting my HJ-61 drivetrain to (dare I say it) a cherokee ZJ, the body was completely rusted out and I have a very severe rust allergy so this was the path I chose.
Anyway.
I wanted to get some more oomph out of the 12H, I was boosting around 17psi with a big intercooler, fuel screws all but maxed out, performed quite ok, but as always there is never enough in this department

Was thinking about adding a roots supercharger (eaton m112 maybe) since the turbo isn´t doing anything special until 2000RPM and I want boost sooner, will be having the supercharger boosting about 7psi at 1000rpm and then when the turbo is up to speed, bypass the supercharger, also I will be adding water injection since EGTs seem to be limiting me at high outputs for extended intervals.
Has anyone twincharged a 12H before?

Are there any other good ideas you might have to get more power from the old girl?

 

[Tim-HJ61]

I wanted to get some more oomph out of the 12H, I was boosting around 17psi with a big intercooler, fuel screws all but maxed out, performed quite ok, but as always there is never enough in this department

Hi Talos,

It's a 12h-t is it, or an aftermarket boosted 2H?

You'll get your boost lower with a GTurbo Grunter Extreme, but not as low as you're suggesting with the supercharger. Sounds like an interesting idea.

With the extra air the GTurbo blows you will keep your EGT under control much better and I would think this would be a simpler way than twin charging.

The power limit for the 12h-t is the injection pump. There is a company in Queensland that build high capacity fuel pumps at a cost of around A$4500 that will also increase your performance, as long as you can blow enough air into the motor.

Tim

 

[Talos]

Thanks for your reply.

Yes its a 12H-t.

Just bought a rebuilt CT-26 last year so I was hoping to get more life out of it, thought about getting a turbo from gpentink at the time but was a bit pricey for me at the time.
but $4500 for an injection pump? :O
Does the company have a webpage or email?

Are the injectors them self not a bottleneck?

Also does anyone know if you can rack the barrels of a 12H-t injection pump like they do for the P7100 on the cummins?

 

[blis]

The injection pump itself should have more than enough potential since it has 9,5mm elements in the pump...

 

[Tim-HJ61]

They don't seem to have a dedicated webpage but this will give you the contact details
http://www.localdirectories.com.au/Gracemere,QLD/Diesel-Central/profile/3fy1

Re injectors. At some stage, anything along the way is going to be a bottleneck if you keep on pumping more fuel in. Adding things such as unleaded petrol injection is another way of getting more fuel into the motor. But it will need more air to control the EGT as you have found. Shame you didn't go GTurbo at the start, now in catch up.

Any chance of getting a 1HD-FTE motor in Iceland?? I suspect not :-( That would make the Cherokee move out!!
Graeme is getting 250hp at the wheels and 900nm out of them now. https://www.facebook.com/pages/Gturbo-Diesel-Performance/490891624305172?fref=ts for the dyno results

 

[Talos]

a lot of cruisers here with 1HD powerplants, but they cost an arm and a leg

Although a good CT-26 is something one could sell over here... still alot of $$, and shipping across the entire planet

 

[Tim-HJ61]

a lot of cruisers here with 1HD powerplants, but they cost an arm and a leg Although a good CT-26 is something one could sell over here... still alot of $$, and shipping across the entire planet

So an FTE motor is out if the question then. :-/

Postage will run to around a$150 to A$200

Tim

 

[Talos]

How about adding a more powerfull liftpump and run about 30-40psi of fuel pressure up to the injection pump?
maybe no huge gains, but it´s simple enough.

 

[Tim-HJ61]

I have no experience in these mods

Thinking about it though
The aim is to get more fuel onto each injection stroke of the piston in the IP, true?

The standard spec for the lift pump is 30psi

By increasing the pressure internally inside the IP (you'd have to modify the return ball and spring pressure relief valve too), how is that going to increase the volume of the fuel injected? Will the diesel compress?

It may increase the speed the piston fills and it may increase the pressure in the injector line, but the injector governs when it opens and more pressure from the IP will change the injection timing, which will affect low speed boost response.

I'm just posing the questions, I'm not an engineer of any sorts.

I'm thinking tapping into the inlet manifold and mounting a petrol engine injector, then injecting petrol triggered by boost pressure would be an easier way to get more energy into your cylinders.

Tim

 

[Talos]

It´s just something I´ve been picking up from the cummins forums, they say anything over 50 psi is not going to give any extra, mind you this is with the rotary pump not the P7100 inline one, not sure if it makes a difference.

Aren´t you worried the petrol will self ignite under such high compression?
I know that some people do this with methane, but then you loose some of the air volume going into the cylinder... more boost I guess!

Might have my pump worked on to see if it can give me more fuel, probably needs an overhaul, done 360.000 Km.

Are there any injectors available for the 12H that can flow more fuel?

 

[yotahed]

Uh, Injecting gasoline(petrol) into a diesel is a no-no. Maybe propane or Meth/alchohol/water injection.

You could upgrade the plungers to 10mm(not sure how that works on a DI, Im a IDI kinda guy.)

Going with a better turbo like a GTurbo would definitely help the low end, custom cam grind, larger volume injectors(again not sure) , fool around with the boost compensator.

Lot of guys here know more than me about the Direct injection stuff....

Love the Icelandic truck scene. You guys build some serious sh!t

 

[Tim-HJ61]

Well okay, if you don't like petrol injection, there are many diesels running around here with government subsidised LPG gas injection. Works well for more power. Injecting anything different always has an element of risk, it's a matter of being sensible about it.

The problem Talos has is getting more fuel into the engine. Yes he will need a GTurbo to manage any extra fuel he is able to pump in, but right now he's at his limits.

Talos you could try increasing the off boost fuel, screw goes IN, at the back of the governor and it might tickle along the turbo a little give more low boost, but you risk being unsociable and blowing too much smoke off boost. The engine will feel more perky low down if you get the adjustment right.

There are wild options of stroking the crank and fitting different big bore pistons, but I'm guessing this is out of your realistic range.

Tim

 

[ozwallaby]

Well okay, if you don't like petrol injection, there are many diesels running around here with government subsidised LPG gas injection. Works well for more power. Injecting anything different always has an element of risk, it's a matter of being sensible about it.

The problem Talos has is getting more fuel into the engine. Yes he will need a GTurbo to manage any extra fuel he is able to pump in, but right now he's at his limits.

Talos you could try increasing the off boost fuel, screw goes IN, at the back of the governor and it might tickle along the turbo a little give more low boost, but you risk being unsociable and blowing too much smoke off boost. The engine will feel more perky low down if you get the adjustment right.

There are wild options of stroking the crank and fitting different big bore pistons, but I'm guessing this is out of your realistic range.

Tim

On the stroking...... has there been any definitive info on whether 12ht and/or 2h cranks are nitrided or not.... since any offset grinding would remove or partially remove any factory nitriding treatment........

 

[Tapage]

but you risk being unsociable and blowing too much smoke off boost.

you can minimize with a sensitive right foot ..

 

[mattsgemmy]

Well I had my pump done out to can't remember if its 10.5 or 11.5mm plungers high mount turbo manifold gtx3071 on 35psi boost stroked to a 4.35L forged rods ported head stronger valve springs decked block and probly more can't remember at present and have 205hp ate on 35" tyres dyno sheet to prove it injectors are the hold up they don't flow enough to support the pump so they are in the process of opening them up now a lot of work for only double the power but I want to see what these engines are capable of before they self destruct

 

[ozwallaby]

I would be interested in seeing the dyno sheet with all relevant data including but not limited to, what actual size plungers, what brand rods... is the crank nitrided.... how much offset was ground into crank... who supplied himount turbo manifold.... what were original flow figures on head and what did you raise them to..... afr numbers thru the dyno test/s...... what gear were the dyno tests done in..... what are/were the boost numbers thru the rev range on the test etc etc etc.... others may be interested in this also..... basically I want to know everything

And as many pictures as you can post....

 

[Tapage]

high mount turbo manifold gtx3071 on 35psi boost

how it's your low end boost with this one .? turbo map shows 77% efficiency and impressive number up in the zone ..

 

[ForealBoreal]

you happen to buy graeme's old truck?

 

[mudbludger]

Well I had my pump done out to can't remember if its 10.5 or 11.5mm plungers high mount turbo manifold gtx3071 on 35psi boost stroked to a 4.35L forged rods ported head stronger valve springs decked block and probly more can't remember at present and have 205hp ate on 35" tyres dyno sheet to prove it injectors are the hold up they don't flow enough to support the pump so they are in the process of opening them up now a lot of work for only double the power but I want to see what these engines are capable of before they self destruct

Mattsgemmy, start a thread on this i will happily subscribe, I miss the simplicity of those old motors, they were a pleasure to work on and would love to see one fully snotted.

 

[Ravi Pannell]

Hi Talos,

It's a 12h-t is it, or an aftermarket boosted 2H?

You'll get your boost lower with a GTurbo Grunter Extreme, but not as low as you're suggesting with the supercharger. Sounds like an interesting idea.

With the extra air the GTurbo blows you will keep your EGT under control much better and I would think this would be a simpler way than twin charging.

The power limit for the 12h-t is the injection pump. There is a company in Queensland that build high capacity fuel pumps at a cost of around A$4500 that will also increase your performance, as long as you can blow enough air into the motor.

Tim

Hi Tim,
What's the name of the company?