Build Isuzu 4BD1T Lexus LX450 (Land Cruiser) Build

[Polar Bear]

Dougal, you really need to change your handle to "the professor" or something similar. The knowledge you're constantly dropping is pretty prolific.

Jeremy, keep going bud- the finish line is in sight, you're almost there! It's always the last five percent that merits 95% of the sweat and pain, but that's what makes it worth it.

 

[Wheelingnoob]

Tested pre vs post intercooler boost and its the same +/- 1psi. So no issue there unfortunatly.

At 15psi boost 2500rpm 1000/1050egt's drive is 17ish psi. At low rpm say 1600rpm 10psi boost 850egt's and 20psi drive. At 2000rpm hwy cruise flat ground running 6-8psi boost at 700-750egt's and 8-10psi drive.

I decided to take a break from trying to fix things on the truck today and had a buddy help me install my snorkle. Felt good to get somthing done that is not going to fight me.

Did a 100km round trip kind of a test to see if the millage really is as bad as the last tank. Non corrected it was 19mpg with correction it was 20.9mpg. So I do not seem to have an issue like I thought last night. It must have been a combination of the head gasket and possibly the fuel leak.

Valve adjustment was done as per the manual 300kms ago so they are a non issue.

 

[gerg]

Well now that doesn't sound too bad. Pics of the snorkel!!

 

[Dougal]

300km's ago being just after the head-gasket? That's good.
I/C pressure drop is good.
Drive pressure at cruise and 2500rpm are where they should be. Drive pressure drops as EGT rises.

It might not be as bad as it was sounding. Timing and more fuel might be all it needs!

 

[Wheelingnoob]

Well now that doesn't sound too bad. Pics of the snorkel!!

No pics at the moment.

300km's ago being just after the head-gasket? That's good.
I/C pressure drop is good.
Drive pressure at cruise and 2500rpm are where they should be. Drive pressure drops as EGT rises.

It might not be as bad as it was sounding. Timing and more fuel might be all it needs!

Yep right after the head gasket. Everything looks good as far as pressures. Ill play with some settings tomorrow I hope.

 

[UCruiser]

Hmmm... 20.9mpg, sucks to be you... Just let me know if you are ready to push her off a cliff, and we can roll it into my shop instead... I can give you a ride home if required...

 

[lostih]

Sorry you're still slogging through this. You certainly have my respect! It's an amazing swap and you've stuck to it with real craftsmanship!

Looking forward to seeing your truck one of these days!

 

[scottryana]

What happens if you drop the downpipe and run open? Just to test exhaust restriction? Slow to spool and high egts sound like high back pressure?

 

[Mr Cimarron]

What happens if you drop the downpipe and run open? Just to test exhaust restriction? Slow to spool and high egts sound like high back pressure?

I was thinking the same thing.

 

[lostih]

Seems unlikely to me that is it. I have a 2.5" downpipe feeding into stock muffler and resonator...his is way more free flowing than mine as long as the exhaust brake isn't causing any restriction.

 

[warezdog]

I say turn some screws for the timing and fuel, give it more!

 

[Wheelingnoob]

I say turn some screws for the timing and fuel, give it more!

Took the advice Dougal and a few others havebeen giving me for the last 10 pages or so. Today I spent a few hours adjusting the timming. I advanced it as far as possible. I have a the slightest bit more diesel rap at idle. Once I get the reves up to 2000rpm its got noticably more rap to it, not sure what it sounds like to "nail" its not like a old mercedies. Its alot more like a 4BT sound wise at reves. I get a bit more viberation from the engine as well.

Not sure if I need to back it off a bit or should just leave if for a bit.

Plus side is EGT's are noticably reduced now. My short test hill that would net 16psi and 1120f now tops out at 15psi and 970f. So tomorrow if I have the time I will add a few more turns of max fuel. See if I can get some more boost out of it.

 

[Dougal]

Took the advice Dougal and a few others havebeen giving me for the last 10 pages or so. Today I spent a few hours adjusting the timming. I advanced it as far as possible. I have a the slightest bit more diesel rap at idle. Once I get the reves up to 2000rpm its got noticably more rap to it, not sure what it sounds like to "nail" its not like a old mercedies. Its alot more like a 4BT sound wise at reves. I get a bit more viberation from the engine as well.

Not sure if I need to back it off a bit or should just leave if for a bit.

Plus side is EGT's are noticably reduced now. My short test hill that would net 16psi and 1120f now tops out at 15psi and 970f. So tomorrow if I have the time I will add a few more turns of max fuel. See if I can get some more boost out of it.

Excellent, we're making progress. The throttle response should be a bit snappier too.

Mine sounds almost exactly like this one at idle:
Maybe a shade softer. It's idled at 1m50 and revved at 4min50.

If you advance too far the noise/vibes will start to sound wrong and the boost will come on too slowly. For me it was a big enough difference that I would lose a gear climbing one particular hill (it was twisty so speed was limited). Retarding the timing just a fraction from there increased boost enough to stay in 4th.
It's all about experimenting to find the timing that best suits your setup and driving. One specific timing number is good for passing EPA certification and that's about it.

Time to wind in some fuel. 970F is embarrassing.

 

[Wheelingnoob]

Mine sounds just like that maybe a touch harsher. Boost is coming in a bit slower but with the dop on EGT's and advanced timming I was expecting that.

I thought that 970f egt was fantastic! Ment there is still hope.

 

[warezdog]

Doug, I've never been a fan of a LR until today!

 

[Polar Bear]

Two words for you warezdog: British wiring. There's a reason that Lucas was referred to as the Prince Of Darkness by mechanics. I learned my lesson after owning a '68 English Ford Cortina with the Lotus engine and suspension. The wiring was based on a positive ground 6 volt schematic. Tore my hair out until I finally dumped it on the lawn of the guy I bought it from after the third fire. He gave me an SKS rifle to say he was sorry- I got out good lol.

Sorry for the hijack- that motor sounds great. I can't wait to see video of Jeremy tearing up through the snowshed near the pass...

 

[Dougal]

Warez, google "LR Perentie" and "LRPV" sometime. The 6x6 landrovers came stock with the 4BD1T, 4x4 with the 4BD1. You will be impressed.
Polar bear is entirely correct. Landrover didn't have the production numbers to entertain the better switchgear makers, so they got stuck with Lucas. It's all stuff that's fixable, but it's the #1 problem in any older british vehicle.

Jeremy, looking forward to updates. It takes a lot of fuel to bring in that last 400F of EGT as boost rises with it. Your power and torque may double. Leave the timing on the aggressive side until you've got the fuelling sorted.

 

[Wheelingnoob]

So today I added 4 turns of fuel to it and pre loaded the wastegate 3 more turns. Its definantly faster now by quite a bit but boost is still topping out at 17/18psi. Not sure why, drive pressure is good, about 1.5:1 drive to boost. EGT's are ok but start hitting 1250* plus with in about 10sec of having my foot to the floor. I just need more boost not sure where the issue is I was getting 27/28psi in the past (with the 7cm housing). I cant see the 6cm housing costing me that kind of boost.

Im out of town for 3 weeks starting Monday so will have really no more time before I go to tinker with it.

 

[Dougal]

So today I added 4 turns of fuel to it and pre loaded the wastegate 3 more turns. Its definantly faster now by quite a bit but boost is still topping out at 17/18psi. Not sure why, drive pressure is good, about 1.5:1 drive to boost. EGT's are ok but start hitting 1250* plus with in about 10sec of having my foot to the floor. I just need more boost not sure where the issue is I was getting 27/28psi in the past (with the 7cm housing). I cant see the 6cm housing costing me that kind of boost.

Im out of town for 3 weeks starting Monday so will have really no more time before I go to tinker with it.

You're making progress now.

Retarded timing works like anti-lag on a petrol engine. Great for building boost but rubbish for making power. 1250F is no cause for concern. More fuel and the higher egt will also deliver more boost.

Enjoy the time away, should be more relaxing now you've got some progress. Have you ever done a bench test of the wastegate to see when it wants to open?
If you have a soft wastegate spring they can require ridiculous preload to maintain boost. I currently have a 22psi actuator and it takes a lot of preload to hold 20psi.
Real boost is usually a few psi below a bench test.

 

[Wheelingnoob]

You're making progress now.

Retarded timing works like anti-lag on a petrol engine. Great for building boost but rubbish for making power. 1250F is no cause for concern. More fuel and the higher egt will also deliver more boost.

Enjoy the time away, should be more relaxing now you've got some progress. Have you ever done a bench test of the wastegate to see when it wants to open?
If you have a soft wastegate spring they can require ridiculous preload to maintain boost. I currently have a 22psi actuator and it takes a lot of preload to hold 20psi.
Real boost is usually a few psi below a bench test.

Yeah feels like it. I am watching EGT's on my test hill its a low gradient so im not getting it loaded too heavy and its only about 10sec worth of foot to the floor. My concern is a mountain pass that they will be far too hot. On the coke thwy topped 1350f after 15min of full throttle that orcouse was with old timming but at that stage on my test hill I got 1000f EGT.

I just do not want to tune it too hot to use it where its needed.

I have the same actuator as you with a 1.4bar spring. I dont have a bike pump to test it but I have about 6mm of preload. Intrestingly boost has not going up at all I had 16/18psi pre timming change after and now with more fuel. I need to get around to testing for boost leaks, usuay they are quite audible.