Anyone using a turbo boost tee to raise boost for lower EGTs? (2 Viewers)

[OM617YOTA]

1996 Prado 1KZTE, 152k kms, dead stock as far as I know.

EGTs are higher than I'd like. Now that spring is here and ambient temps are rising, I'm easily able to top 1200f in normal driving, and have looked down and been over 1350 a few times. I shudder to think about what temps I was getting driving around last summer with no EGT gauge, just blindly assuming Toyota engineering that lasted this long would be fine. Can't believe people drive these across Oz in 105f heat and dragging a camper trailer behind them, no wonder they pop heads.

Just got a boost gauge installed and test driven, only making ~9psi of boost. Was hoping this was a low boost problem and if fixed would lower my EGTs. Alas, FSM says 7.4-9.7psi is stock.

I have no interest in more power, just want lower EGTs and to be able to use all the power I do have without letting off the pedal due to EGTs. Hopefully extend the life of my fragile and probably inevitably doomed head. Searching was completely useless, page after page of "what's the max boost I can run?" which I don't care about. Hoping to leave the rest completely stock, factory exhaust and intake. No more fuel. Maybe the resistor mod.

So, anyone bumped up boost to lower their EGTs? Any success?

 

[AirheadNut]

You should be able to use a standard manual boost controller plumbed in to the line to your wastegate. As long as you don’t turn boost up past the fuel cut point (14psi if I remember correctly) you should be fine. My brother has been using one on his 1HD-T running 16-17psi for probably 30k miles without incident.

 

[Skter505]

I did it to my FT HDJ81. Running 15-16PSI lowered my max get by damn near 200° on factory tune and pin. Before I could spike to 1450+ in seconds.

 

[Dougal]

You'll be able to raise boost a little but will be hampered by a weak spring with not much preload. Cutting and adjusting the rod works better and doesn't leak boost.

 

[OM617YOTA]

Alrighty, manual boost controller installed. That was quite a job to do since I left the turbo water lines in place. I don't think it would have been possible without some double jointed needle nose pliers. If you have any idea that you might install a manual boost controller in the future and you have your water lines off, definitely recommend proactively hooking up a loop of silicone hose, even if all you do is zip tie it out of the way until you get to the manual boost controller in the future.

Started with the boost controller turned off, then did some test driving and tweaking adjustment a fraction of a turn at a time, I got it so that it runs 12.7-13psi at wide open throttle instead of ~9.7-10psi. I did overshoot and it had no problem hitting 14.7psi and fuel cutoff, obviously I backed it down at that point. Adjustment is tricky, wish the adjustment bolt was fine thread.

EGTs are significantly lower. Used to have to be quite careful to not top 1200 even in normal driving any time ambient temp was over 70F, now that's no concern at all. Can still top 1250F but I really have to try to do so. Will do some more tweaking and try to get closer to 14psi and see if that drops that last 50F off. I shudder to think what was happening last summer, driving with no EGT gauge and trusting all was well; no wonder these things pop heads.

I wouldn't say it has more power(which wasn't the goal) but it does seem happier to rev and seems to pull better farther through the RPM range. That might just be me able to stay in the throttle without topping 1200F now.

 

[OM617YOTA]

Got another update after a few more days of driving.

3psi more boost, particularly mid-throttle, made it an entirely different vehicle. The butt dyno is not a calibrated instrument by any means and I suspect any perceived power gains are just that I can stay on the throttle without spiking EGTs, but it really seems to pull harder mid range. Definitely spools faster due to the design of the manual boost controller. Able to pull out and pass people while floored and only see ~1270F at the absolute top for a few seconds. Took a fun curvy uphill drive home yesterday, previously had to back out of the throttle plenty to reduce EGTs, but this time I was able to give it all the throttle I wanted and never got close to 1200F. Turbo sounds better too, although I know it's working harder.

MPG might be improved as well. Usually I get ~300km per half tank, I'm at ~320km right now, about to hit half tank, and have been using the throttle a lot more than usual. MPG improvement wasn't expected and I'm skeptical, especially given the limited testing sample size.

 

[Skter505]

Sounds like my experience as well. I still need to do an exhaust but I don't really want to go front mounted intercooler unless absolutely necessary. I have a GTurbo ready to go on but need to build an exhaust first as I want to check everything in stages.

 

[OM617YOTA]

Alrighty, couple more tanks of fuel on this mod. Probably my last post on this unless something changes.

1. Overall I love it, very happy with the mod.

2. Can easily hit 10+psi while at part throttle and relatively low RPM, and even boost spike to fuel cutoff if I flat-foot it in from low RPM. Not ideal.

3. Runs out of boost on the top end, ~10psi at 3500 rpms and foot flat on the floor, topping 1270F EGT. Tiny turbo that boosts at low RPM on a small engine, may just be running out of breath at that point and this may be as good as it can ever do.

4. I wish the adjustment was a little finer, might need a softer spring. Would like to not hit 10psi while at part throttle and 2000rpms, and would also like to hit 12+psi when at high RPM and foot flat on the floor.

5. Can easily climb any hill I want, at any speed I want, at part throttle, without getting anywhere close to 1200F EGT. Bingo, objective achieved.

6. I started watching the EGT gauge obsessively as soon as I got the gauge installed. This mod has let me stop doing that.

6. Last tank of fuel was 350km to half instead of 300km. Still skeptical.