STANDARD CHEV LS1 V8s
How much power can various spec LS1 V8 Commodores make at the back wheels?
A standard one - like a Gen 3 SS - makes about 210-220 horsepower at the back wheels. With HSV models - as the rule of thumb - however many kilowatts it is at the flywheel, that's roughly how many horsepower there is at the back wheels. So with a 300kW GTS it's gotta be making 280-290-300hp at the wheels.
Have there been any significant running mechanical changes to the LS1 range since its introduction in Australia?
No, nothing mechanical I'm aware of. But - according to Metro Holden's Service Department - they've had heaps of updates on the computer programs - the trans shifting rather than the engine side of things. It was the same when they went to the electronic controlled trans in the VR - they get customer feedback and they do something about it.
And what sort of engine management computer does it run?
The LS1 computer's got an all-new architecture 256k program in it. It's huge. There's stacks of spare inputs and outputs, and its a flash program too - they don't want you to get into the system. Holden spend a lot of time and money getting the thing to make power, meet emissions and get good economy - they don't want you mucking around in there.
It's a v-e-r-y sophisticated program as well - so, if you don't know exactly what you're doing, you can destroy an engine pretty easily. They also have a self-learn facility in the computer, which dials the power back to standard a short while after - say - you fit an exhaust upgrade.
And what do you think about the LS1's rumoured oil pump problem?
I don't think it's the oil pump. I saw a 300kW one blown up and all of the bearings looked like new - including from the two rods that failed on it (numbers 5 and 6)! What I could see were scuffmarks on the pistons - they've actually seized and the top has been torn off. Every one I've seen has had a seized piston. So it isn't an oil problem - it's a cooling system problem.
I think it is a combination of the crappy water pump, the all-alloy construction and a really efficient radiator. If you check the temperature differential across the radiator you'll find - hey - it's a really good radiator. But when the thermostat opens, it sends a shock of cold water through the engine. Now - because the pump is cavitating, you get more cooling in one spot of the engine than the other - the bores will actually contract a little bit. The piston comes down, seizes up and - boom - the top gets pulled off. That's what happens to 'em.
I hear the GT-P guys are running more piston to bore clearance in them to solve the problem. But it's a band-aid fix.
So, yeah, I know everybody was saying it was an oil problem to start off with - but show me an engine that's spun or damaged a bearing.
What sort of AFR numbers and ignition timing does the basic 225kW Gen 3 run at full power?
Eleven point two or 11.1:1. Yeah, rich - probably for emissions, again. And they run around 26 degrees of timing at full power. But they've all got twin knock sensors.
Are the twin knock sensors very sensitive?
Yeah, they're brilliant - you can't compare them to the one in the HSV Holden 5.0s. I mean they've got a 32-bit CPU and it does like a zillion calculations per second. It's smart - it runs two oxygen sensors and two knock sensors for each bank. That means it can pick which cylinder is firing and therefore which cylinder is knocking. It's the same with mixtures - it can tell the mixtures of each individual cylinder.
I don't know how much timing the knock sensors can pull back, but I saw on a supercharged R8 - where the knock sensors were fairly active - it was pulling off up to 18 degrees. And I think it can pull back more.
Given the excellent knock detection, will a Gen 3 engine make more power on the highest possible octane unleaded?
They recommend that you run the on premium, but - yeah - you can pick up a little bit with higher-octane fuel. On the Holden V8 there isn't enough compression, but the LS1 - with about 10.0:1 - makes a little more out of it. Depending on the octane, I'd say it might be worth up to 20hp at the wheels on a stock motor.
MODIFYING THE COMMODORE'S LS1 5.7-LITRE V8
What mods would you recommend with a budget of around $1000?
There's not much you can do with that much. They neck the exhaust down at the headers, so you can replace that section of pipe between the headers and the cats. That'd be a cheap one. But to try and find someone to do a full exhaust for under a grand you'd be pushing.
A K&N panel filter replacement is also less restrictive and - as a bonus - you can re-use them. I say K&N but you can use any gauze type oil-able filter.
And the ECU's relearning?
Yeah, there you go. As soon as you make a mod it'll just relearn and go back to stock power over a period of time. The only way around it at the moment is to pull the battery leads off to reset the memory on the computer. If you drive the car a lot, you might have to do it once a day. And - don't forget - once you pull the battery leads off, you've gotta reset your radio, this, that and the other. Who's gonna want to do that?
So, yeah, all you get with like an exhaust are temporary gains.
Does the GTS's 300kW LS1 - which runs a MAP sensor instead of an airflow meter - respond to mechanical changes in the same way as other Gen 3s? In other words, will it relearn and go back to near-standard power?
No, they've got rid of all that stuff in the 300kW - it'll respond. So, yeah, it's actually easier to modify a GTS. But, then, look at what the car's worth...
How long does it take for the airflow meter'd LS1 computers to relearn?
Well, Julian [AutoSpeed Editor] had a SS that had some stuff done and it took about 3 days - he didn't even do that many kays. That car went back to near stock - whereas it had showed a big gain initially. And I bet - had he driven it a bit longer - it would've been back to stock.
So is there no point in making mechanical changes until software has been altered?
Well, there's aftermarket people out there that say they've got a modified airflow meter that cures the self-learn. But how - how does it do that?
We've checked a so-called modified airflow meter by putting it in series with a standard airflow meter and measuring the output of both - and they were identical. And you look at a modified airflow meter - there's no honeycomb in it. That honeycomb is there to straighten the airflow past the Gen 3's sensor so that the measurement is accurate. So you get these idiots that pull it out and throw it way coz they say it's a restriction. They've just f*%&ed their airflow meter basically.
There's a lot of bullshit out there with these engines.
Is it possible to get around this engine management block?
Well, you'd have to basically bust the engine management system - and that hasn't been done by anyone that I know of. I know there's a guy in Sydney that reckons he's into the box - but that'll be the same ol' deal. They'll go - ohh, there's a timing map and there's a fuel map. That's all they'll be able to get to.
And I know for a fact there's heaps of fuel and timing maps in it - so they might not even get the right one. The program is so huge. All they'll be doing is sucking the program out of it, putting it on the bench and going hmmm, I think it could use more timing here or a leaner mixture here, dump the new program in and try it out. So it's not going to be a real-time thing either.
That's all I know of at the moment. In the 'States - on the Corvette - they've had little independent controllers that fool the computer (an interceptor) but that wont work on the LS1 here.
Does this mean - at present - the only way to get past the airflow meter'd vehicle's self-learn ability is to fit programmable aftermarket injection?
Yeah - and, really, that's going backwards. I mean you've got to tune the whole engine again - and do you really think it's going to be as good as the factory tune? It's a pretty expensive way to go too.
The only other way around it that I've heard of is what CAPA do with their supercharger kits - they pull the computers and send them to the 'States for a reprogram.
Holden are pretty clever. I mean, car companies know people will buy a car and then want to modify it. But - now - they know it'll only make X amount of power and that'll see them through to the end of the warranty period. It's good for their image of reliability as well.
If you were searching for a big power improvement, would you do a traditional engine build-up or go for a blower?
Same as the Holden engines - a blower. A lot of the blowers are really quiet now - some of the Vortechs have got specially cut gears. And - as I said before - you don't have to pull the engine apart and you can keep the blower down the track. The composite [plastic] intake manifold of the LS1 hasn't given any problems running up to 7 psi internal pressure - whatever they make it out of it seems pretty tough.
Because the factory management system is so sophisticated, I reckon - with an adequate amount of fuel - you could bolt on a 6-pound supercharger without having to touch the engine management. The supercharged R8 from the Northern Territory we did, he sits on the 255 km/h speed limiter - which we haven't been able to do anything about - and the only thing that's giving hassle is the trans and the diff. [This car had been equipped with a CAPA ECU.]
If you're using it as your weekend-only car - sure - you might want to go for a big cam and stuff and rev the guts out of it to make power. But if you're driving it everyday, you'll get pulled over and you'll get done on emissions.
You can get gains inside the engine; but if you're looking at pulling it apart for a bit of working, they're garbage. They're not designed to be pulled apart.
What sorts of things need to be done for a performance re-build?
Number 1 the conrods. The rods are not bad, but they've got cracked caps. They actually crack the big-end cap off of it so they align perfectly when you put it back together. So, if you need to resize those rods - if they aren't all exactly the same length, if you don't have the right bearing crush etcetera - how are you going to resize them? You can't, because they're cracked.
Normal resizing machines the face of the cap, so - basically - you have to throw these ones over your shoulder and buy aftermarket rods that you can resize.
So, straight away, you're up for a set of conrods.
And with the Chev being all-aluminium, all of the bolts on the block are torqued to yield. So if you're building a performance engine, the next thing you have to do is pull the engine apart is helicoil the bolt threads so you can run a decent fastener. And helicoils are not cheap.
So that's two things - straight away - that you have to do that the Holden 5.0 V8 guy doesn't.
And it gets worse. Like, the cylinder liners in them are very, very thin. I've seen that 300kW engine blown up and, I don't know what the thickness is, but it's paper thin. So, I mean, how are you going to bore it?
I reckon they're junk - they're disposable engines.
So - overall - the LS1 engine is great out-of-the-box, but it has little potential?
Yeah, well, with no access to the management system for sure - the factory's plan has worked. And - of course - in the future it's just gonna get harder for people who are into modifying. And it's largely because of emission laws - emissions tests for registration will have to come in soon. That'll make things real tough for the average guy.
The LS1 is just a taste - the beginning...
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