3B N/A EGTs (1 Viewer)

[350HJ75]

late reply but have been busy

It was not full throttle as i find if i am about 3/4 throttle and sort of modulating / flaring the throttle a little bit then i get a little more power and egt's are kept under check a bit better. rather than just foot flat all the way up.

I sure wont say no to a spring just to give it a try.... might prompt me to change out the diaphragm as well but because the car runs well i dont really want to touch it but it could be torn without me knowing.

interesting to see how you go with other springs too.

 

[dare]

Yeah I find the same, a little bit less than full throttle often gets me a tiny bit more power.

We went up to perth and back the other day and I brought a spring to stick under your wiper but your car wasn't there.

The Landcruiser is out of action for a while and I'm going to be busy. TBH I'm pretty over the 'cruiser, thinking about selling it.

 

[gerg]

Same thing happens to my 3B with more power at just under WOT. I have always thought it had to do with optimized flow over the Venturi acting on the diaphragm. I've tried different orientations of the Venturi but it never worked out.

 

[dare]

I'd love to get a vacuum gauge on the venturi line.

If we had a data logger that could record vacuum, throttle position and rpm (or at a specific rpm point) we could learn a lot. Fuel rail position would be nice too. Honestly though, for all the work in it you'd probably be better off converting to a different pump/governor. The vacuum/diaphragm governor is always going to be a compromise.

Maybe tomorrow I'll go spring hunting and I'll see if I can dig up a 2H throttle body as well to compare.

 

[gerg]

I always toyed with the idea of hooking up a bleeder valve linked to the throttle that would dump pressure on the other side of the diaphragm to maximise travel. Always seemed complicated though. Could do like an electric solonoid on a button below the pedal that activated when you put it to the floor completely.

 

[dare]

I've slotted another 3B in my BJ73 and got it back on the road. It's slower than I remember, makes my Suzukis look like rocket ships!

Today I fitted a 240D governor spring that gerg sent me. It's still a stock 3B running N/A. The 240d spring is much longer but made from lighter wire. I tried to rig up something to measure how much load each spring had at certain compressed heights but I gave up on that.

The difference is pretty subtle. It's more responsive and egts are maybe 5-10% higher at low revs. At high revs it's much the same. The governor cuts in about 100rpm lower so it must have less load in the diaphragm at full extension. I recorded my 1/4 mile and 0-100 times and they were pretty much the same, a couple of tenths in favour of the 240d spring which IMO means nothing at all. The difference is in low rpms and response.

It still has the same problem of losing egts as the revs get lower.

Whilst playing with things I wound the fuel screw out 1.5 turns. This seems pretty happy for this car, I can get to 750c egts in 4th now but not really any higher, certainly not in normal driving anyway. It hazes a little when the revs are right up. I think it has about 10% more power, I'll do a 1/4 mile/0-100 run later.

Out of interest I tried disconnecting the reference vacuum line and noticed no difference. The BJ73 has a one way valve vent in the cavity on the reference side of the diaphragm, 40s have just a bung. I've not seen a reference to this before, you'd want to block that off if you turbo'd.

I gave a 240d spring to @350HJ75 , dunno if he installed it though? I think he sold his BJ73?

 

[gerg]

On my bj62 I removed the fuel screw and bent the tab connected to the arm that limits travel to allow for maximum fuel. Give that a go. It will speed it up.

 

[dare]

On my bj62 I removed the fuel screw and bent the tab that contacted the arm to allow for maximum travel. Give that a go. It will speed it up.

Might need a turbo for that much fuel!

I took the cruiser for a decent drive today and I'm really pleased with the difference. I hardly drove it after winding out the fuel screw yesterday. It has WAY more low down power, on the roads around home I can drive in 4th instead of having to be in 3rd. The throttle is far more responsive and overall, it just feels like a larger engine. Largely, the low revs = low egt problem is fixed. It's so much more drivable. I think the new spring and adjusted fuel screw have worked great together.

The high rpm difference isn't as dramatic but I did the 1/4 mile and 0-100km/h, recorded as per this thread. Ih8mud diesel drag challenge

Before and after in the 1/4 mile
25.49s
23.51

0-100km/h
36.49
31.16

Quite a reasonable improvement, how often do you knock 2 seconds off your 1/4 mile with practically free adjustments? I think I could do a bit better again if I adjusted the governor to 4100rpm like it's meant to be instead of about 3750 as it is now. The 3rd and 4th shifts take it out of its powerband and it takes a bit to recover.

Max EGT is 765c, though you can only get that high really thrashing it, certainly not in normal driving. It hazes a bit under full throttle but I live in a country area so I'm not bothered by that.

 

[gerg]

Nice improvement. It sounds like turbo time!

 

[dare]

Nice improvement. It sounds like turbo time!

Maybe, I'm a bit worried about the health of the motor. It has a quite a bit of blowby and compression is a bit low on no.4. It sat for many years before I got it and the blowby problem seems to be getting better the more I drive it so hopefully it's just a stuck ring or similar. Aside from the bits for the dump pipe I have everything I need to turbo it.

You'l have to do the 1/4 mile run to prove the value of the turbo to me.

 

[gerg]

Gahh, sold the truck. Tuff to convince anyone to turbo their truck. It's is like trying to convince some one that laughing is good when they've never done it. It's hard to explain. It just makes everything in life better......

 

[brownbear]

31 seconds 0-100? Man we drive slow bricks. and somehow love them...

I actually think mine with the turbo is quite a bit quicker but won't be able to say until spring. But I remember it pre-turbo and it was so slow on Alberta highways I thought it would get me killed.

I also remember being in the states, loaded with gear, towing a trailer at like maybe 50 mph (maxed out power) in a 75 mph road feeling like I was going to get seriously rear ended out here. These silly slow trucks. I actually really dis-like driving mine on roads that have higher speed limits. Its a great back country putt putt but I never want to merge on a freeway with it any more.

 

[dare]

Gahh, sold the truck. Tuff to convince anyone to turbo their truck. It's is like trying to convince some one that laughing is good when they've never done it. It's hard to explain. It just makes everything in life better......

Don't get me wrong, I'm sold on turbocharging. I was just trying to coax some performance stats out of you.

31 seconds 0-100? Man we drive slow bricks. and somehow love them...

I actually think mine with the turbo is quite a bit quicker but won't be able to say until spring. But I remember it pre-turbo and it was so slow on Alberta highways I thought it would get me killed.

I also remember being in the states, loaded with gear, towing a trailer at like maybe 50 mph (maxed out power) in a 75 mph road feeling like I was going to get seriously rear ended out here. These silly slow trucks. I actually really dis-like driving mine on roads that have higher speed limits. Its a great back country putt putt but I never want to merge on a freeway with it any more.

Haha my 2L powered 4Runner does it in 46 seconds from memory. I can't imagine how bad a loaded up N/A BJ60 must be, it's hard to understand why Toyota gave you guys that engine. Even though my Suzuki Sierra (Samurai) is universally considered a very slow car it does the 0-100 in 21.5s, positively flying in comparison and that's a 4wd that came out before the BJ73!

I'm still really enjoying the changes I've made. Every time I drive it I'm surprised how willing the motor feels. I can see how gerg experienced the light switch throttle effect with this spring and turbo, it's certainly less linear. Still, I think it works great N/A.

 

[gerg]

Doubling power to the wheels is very achievable, but it's greatest bennifit is tremendous ability to increase the volumetric effeciency of the engine. Up till now you can really only play with the fuel and your at the mercy of ambient air pressure.

 

[GTSSportCoupe]

Turbo's are great for all the reason's Gerg has mentioned. Only thing to be aware of, is they create a lot of extra heat for the IDI diesel's. So be prepared to also install an intercooler and possibly upgrade your cooling system. Cooling system upgrade may only be necessary if you actually work the truck by towing etc. Also, more gauges to keep on top of everything become truly necessary as well: boost/pyrometer at a minimum. Often an exhaust upgrade is require too. More air/fuel in = more exhaust out. The costs can really begin to add up.

 

[brownbear]

Certainly an intercooler and cooling system upgrades are good like said above.

But I run 10 psi roughly with no inter cooler, or changes. The power or feel of power increase was extremely noticeable once I put the turbo on.
In fact prior to getting the turbo on I installed a clamp on EGT probe just below the exhaust manifold. I wanted to see how it was doing. Cause I was pain.........fully slow. I actually found it was pretty under fuelled. I turned up the fuel and ran it and checked the egt and it was still safe temps. I literally changed the performance night and day. So proper tuning is very important. Once I put on the turbo I was able to add a little more fuel. It is very drivable lightly loaded. If I am towing or heavy, or in high winds it still is not enough. But I can hold 60 mph in fifth gear on slightly rolling (slight) hi ways. No way to be able to do that pre-turbo.

 

[dare]

Anyone else running the Mercedes spring experienced this?

At around 700rpm the revs hunt like a semi. It's like someone is rythmically nudging the throttle. Obviously the fuel rack is working its way back and forth. It's particularly bad when cold.

Out of interest I have a fordson tractor with a similar vacuum controlled Simms inline pump but it has an adjustable damper built into the fuel rack to tune out this rack movement at your chosen rpms.

 

[gerg]

I found the Mercedes spring to be hard to control. It was like an on or off switch fuel wise.

 

[Dougal]

Diesel burns at a fixed speed, so as your RPM's rise the time in cylinder gets shorter and you've got more heat into the exhaust. Even advanced timing can't keep on top of it.

That's why your EGT climbs with RPM. Your in cylinder temps aren't rising, just exhaust.

 

[GTSSportCoupe]

Diesel burns at a fixed speed, so as your RPM's rise the time in cylinder gets shorter and you've got more heat into the exhaust. Even advanced timing can't keep on top of it.

That's why your EGT climbs with RPM. Your in cylinder temps aren't rising, just exhaust.

Neat, I never thought of it that way, but totally makes sense. Thanks for sharing Dougal! I've learned a lot of the more subtle but important things about diesels/turbos by reading your posts!

Is this also why a diesel torque curve falls off so abruptly beyond a certain rpm? Not so much a volumetric efficiency thing, but rather an efficiency loss from incomplete burning of the diesel during the power stroke of the engine?