Restrictive Airbox

[gloverman]

I have been working on a 1978 Landcruiser with a 1uz. Well the rego says 1978 but it's made up of a few years of parts like many older cruisers these days. Fitted with an early 1uz that I wired (whole vehicle) a few years back. I finally got to take it to the dyno. Its running a link G4 with a prado auto(70 series). I dropped to some 31/10.5x15 wheels for the dyno runs. As I was reasonably happy the tune was safe I did a power run straight away and it spun up 121rwkw. I then removed the airbox as I suspected it was an issue and without making another changes it spun 144rwkw. The dyno sheets show the first and second runs.

I then continued the tune and ended up happy with 155rwkw. It drives heaps better and goes quite a bit faster then a landcruiser was designed to go.

 

[gloverman]

Final dyno sheet.

 

[melvinmelvin]

The conclusion must be that airboxes are unhealthy.

The sheets show a considerable amount of torque, 450 Nm or thereabouts.
Is that not fairly high compared to advertised specs? I thought advertised spec was in the 250-300 Nm area?

Your 144 kw is about 195 hp.
Maybe I am wrong but I seem to remember that advertised power is about 250 hp at the flywheel.
So that is 55 hp (more than 20%) vanishing between the flywheel and the rubber. Is that about as can be expected, 20%+ loss?

 

[gloverman]

I feel dyno figures should be used as a guide and when the only safe way of comparing is when two vehicles are on the same dyno.

If you look at the torque you see its highest at the beginning of the run. This is due to the multiplication effect of the torque converter before the lockup comes in. I didn't have a bypass wired in on the set up.

This is a 4x4 with big wheels, auto and transfer case so large loses power loses are expected. The comparison is starting with 125 which the owner thought went well and leaving with 155.

Not all air boxes are bad. I often measure them in this way and well designed ones can increase power by supplying cold air. Often plastic keeps temps down more than shiny stainless or alloy. This air box was off a 1300 Or 1500 starlet so wasn't up to the job but interesting enough still flowed 125rwkw which is way more than a starlet makes.

On this dyno with 2wd running smaller wheels I normally spin up around 175-180 with the best being 186rwkw and around 350nm

 

[Zuffen]

Do you put the figures down to the Link being superior to the factory ECU?

I don't think my 1UZ puts out anything with 3 figures in it.

I do think it's down on compression.

 

[gloverman]

Hello Rod

Being able to tune the ECU makes a big difference. This one has better headers so I can increase the timing a bit. Typically I see guys fitting bigger exhausts and they can feel (read hear) the increase in power. Ive done dyno runs before and after exhaust changes and measured a loss in power. Typically I see maybe 2-3% from an exhaust but often get 10-15% from an ECU upgrade. Add ECU, Exhaust and intake(a good one) and thats where the most gains are made. I did a run back to back with stock ECU and aftermarket ECU on the same dyno using an adaptor I made. It was quite interesting when everything else was the same.

Dyno figures can differ so much yet it's the real world results that matter. Ive seen 300rwhp cars walk all over 500rwhp cars so someone wasnt getting true results. I sometimes hate telling customers their power figure as they think it should be so much more as they have mates getting that amount. Best stock ECU ive run up is 155rwkw. It was the dirtiest motor Ive ever seen but it went well.

 

[melvinmelvin]

155 kW is about 208 hp, that compares reasonably well to the Toyota figure of 250-260 (hp) at the flywheel, me thinks.

 

[Zuffen]

Thanks Kelvin.

My engine suffers from the big headers and dual 3"exhaust it ran with the supercharged engine.

It would be chaper to put another type of engine in than have another set of headers built and new exhaust. last one was $5,000.00 and that was probably 8 years ago or more.

For that sort of money I could run and LS an, have it engineered.

 

[melvinmelvin]

suffer from 3"? I thought big bore pipes were healthy?

I have roughly the following setup;
the bolt on exhaust flanges are Toyota original, so are the first 2 inches of pipe from the flanges
it then goes into a 2" pipe that just behind the engine expands to 2 1/2" pipe for about 40+ cm and then finally the last stretch is about 60 cm of 3"
2 cylinders per exhaust pipe

(all wide open pipes, no silencers)

OK? or not so good?

(hmm, somewhat departed from airbox, sorry)

 

[gloverman]

Rod - I often tell guys these days if they want more power fit either the VVti engines with aftermarket ECU or fit an LS motor. I also warn them that more power means more strain on drivetrain.

Big headers won't be helping the torque and low end. I've done testing with different exhaust sizes. Young guys want their vehicles loud (hey look at me) and dont believe me the vehicle will overall be better with a smaller exhaust so I fit up 3inch systems. Old guys listen and want a V8 sound without being too noisey, They want sound when they want it so I do a 2 1/2 system. The smaller systems make just as much top end power but are far more responsive down low. Add some long tube headers and they get better again. Funny enough the stock manifolds arent as bad as many people think. I've made 170rwkw through 131 crown logs , soarer and celsior headers , all NA. Ive even played with primary pipes off the headers from 2 inch through 2 1/4 and 2 1/2 and been able to make the same top end.

In a boat if you are running at constant High RPM a open exhaust will be fine but you could make it run just as well without all the noise.

 

[Zuffen]

Kelvin,

I've thought about an LS swap for a few years.

My LS3 project was damaged a two years ago when I ran into myself and I nearly did the swap after I had recovered as I was over the vehicle.

The LS3 is putting out around 350kw and has has bulk torque. The project will wheelstand on the street!

 

[melvinmelvin]

Rod - I often tell guys these days if they want more power fit either the VVti engines with aftermarket ECU or fit an LS motor. I also warn them that more power means more strain on drivetrain.

Big headers won't be helping the torque and low end. I've done testing with different exhaust sizes. Young guys want their vehicles loud (hey look at me) and dont believe me the vehicle will overall be better with a smaller exhaust so I fit up 3inch systems. Old guys listen and want a V8 sound without being too noisey, They want sound when they want it so I do a 2 1/2 system. The smaller systems make just as much top end power but are far more responsive down low. Add some long tube headers and they get better again. Funny enough the stock manifolds arent as bad as many people think. I've made 170rwkw through 131 crown logs , soarer and celsior headers , all NA. Ive even played with primary pipes off the headers from 2 inch through 2 1/4 and 2 1/2 and been able to make the same top end.

In a boat if you are running at constant High RPM a open exhaust will be fine but you could make it run just as well without all the noise.

The noise is not so worrying as I am sitting in front of the mill when driving.
More low end response would be most welcome though.

I remember now. I asked about length/size of exhaust pipes on another forum.
The simple answer I got was; Short and Fat

 

[George_R]

Rod - I often tell guys these days if they want more power fit either the VVti engines with aftermarket ECU or fit an LS motor. I also warn them that more power means more strain on drivetrain.

What exactly an aftermarket ECU can do to stock 1uz vvti / 3uz?
You can't squeeze any more than like 285 hp at crank with regular fuel and stock internals

 

[gloverman]

George - I can squeeze more than 285 at the crank. I made 295hp(220rwkw) at the wheels on a 1uz VVti running a LINK Xtreme, 95 octane fuel and internals totally stock. It had a 90mm manual throttle body and nice headers. It was through an R154 2 wheel drive gearbox running synthetic oil .

 

[George_R]

Yes I can imagine, because you did intake and headers. I can do the same with stock 3UZ which is tuneable