vr6 cams

[Kevin Bacon 5]

For example, take any engine that is incorrectly set up and put it on the dyno (baseline figure - say 125 bhp for arguments sake), put some new cams in and set up the fuelling and ignition and you have a new number (modified number - say 175 bhp) did you just get 50bhp from the cams? No you didn't, you got some gains from the cams, and some from the setup.

 

Yes we understand that, but why would a standard VR6 being incorrectly set up in the first place? And I'll pick on that engine as an example since it is the 263 cams that are being debated here.

 

Assuming the cam sensor isn't dead, the spark plugs are good, the cat isn't blocked, the air filter isn't clogged, the cylinders / head aren't worn, the lambda isn't dead/slow reacting and the uranus hasn't crossed paths with Jupiter, then it should make 190hp, right?

 

Those are just a few variables that can affect power, and that's before we move onto ambient pressure and temperature.

 

To accurately state an increase from a certain modification you need an optimised baseline figure in the original mechanical state. In this example, the original cams but with the ignition and fuelling correctly calibrated. When you have this, then change the cams and re-optimise the ignition and fuelling and you will get a true gain / loss number for a certain modification. Simple.

 

But as we've said, that is exactly what VAG-HAG did. It was dynoed before as a 100% stock car and made the expected power, so was surely optimised to begine with? 263 Cams in, optimised fuel and timing applied, redyoned, 26hp up. So what's the problem?

 

What Norman is also driving at (I think) is that the original VW mapping is not 100% optimised for a standard setup. I would like to see true gain or loss figures for individual modifications, but as with anything, it costs time and money to quantify accurately.

 

Why isn't it? It ruddy well should be for what we pay for their cars. The original VW mapping is THE baseline we are working to. Remapping before we start the comparisons is just adding another variable in the equation because Bob the Builder might map it differently to Bob's back street garage. We know the VW map is the same across all cars within that specific model year / type.

We're not dealing with Carburettor jet sizes here, it's not possible to just change one thing at a time like that on electronic management.

 

I think the real issue here is trying to discredit the 263s. For what other reason is this silly debate going on for? I've never seen such anal retentivness over a few hp. People fit them, they like them, end of story.

[andy 0]

I think the issue (possibly) is a financial one, I can see Normans point of view. I don't mind paying a couple of hundred quid for a set of cams that will release a few more horses. However, its the further (few?) hundred pounds that a remap costs that makes the whole idea less attractive. The point being, is it worth doing one without the other, I like most people, don't mind putting in a few hours under the bonnet bolting on a modified part. Its the whole hassle and expense of remapping that puts some people off. We simply are curious to know, how much is to be gained by installing cams alone. No one seems to have the answer yet unfortunately. Just my 2 penneth 8)

[Leonard 0]

Its the whole hassle and expense of remapping that puts some people off. We simply are curious to know, how much is to be gained by installing cams alone. No one seems to have the answer yet unfortunately. Just my 2 penneth 8)

 

What mods are there accross the whole spectrum of the car world, that offer better performance and driveability without a remap or ECU change?

[greasegriff 0]

Its the whole hassle and expense of remapping that puts some people off. We simply are curious to know, how much is to be gained by installing cams alone. No one seems to have the answer yet unfortunately. Just my 2 penneth 8)

 

What mods are there accross the whole spectrum of the car world, that offer better performance and driveability without a remap or ECU change?

 

Not strictly a mod and going slightly off topic but running Super Unleaded has been shown to give gains all-round hasn't it? Maybe only 1-2bhp but guess it all counts. Personally, I do a lot of motorway work and don't fancy slugging in Super at near enough £1 a litre but whatever floats your boat.

[87 Jetta 16v 0]

Yes we understand that, but why would a standard VR6 being incorrectly set up in the first place?

 

For the same reason that all these chip companies make a living - i.e there is more power to be found in the standard mechanical set-up. Perhaps if every single one of these companies is peddling BS then you are right...and all those people will shortly be signing on!!

 

Assuming the cam sensor isn't dead, the spark plugs are good, the cat isn't blocked, the air filter isn't clogged, the cylinders / head aren't worn, the lambda isn't dead/slow reacting and the uranus hasn't crossed paths with Jupiter, then it should make 190hp, right?

 

Those are just a few variables that can affect power, and that's before we move onto ambient pressure and temperature.

 

I am not disputing that, what I am saying is there could be more power in the standard set up, so all of the gains quoted cannot be attributed to the cams.

 

To accurately state an increase from a certain modification you need an optimised baseline figure in the original mechanical state. In this example, the original cams but with the ignition and fuelling correctly calibrated. When you have this, then change the cams and re-optimise the ignition and fuelling and you will get a true gain / loss number for a certain modification. Simple.

 

But as we've said, that is exactly what VAG-HAG did. It was dynoed before as a 100% stock car and made the expected power, so was surely optimised to begine with? 263 Cams in, optimised fuel and timing applied, redyoned, 26hp up. So what's the problem?

 

No no no no NO. Just because the car in question made a certain number that you would hope for does not mean it is optimised. All it means is that is is working as the manufacturer intended. Optimised. No.

 

What Norman is also driving at (I think) is that the original VW mapping is not 100% optimised for a standard setup. I would like to see true gain or loss figures for individual modifications, but as with anything, it costs time and money to quantify accurately.

 

Why isn't it? It ruddy well should be for what we pay for their cars. The original VW mapping is THE baseline we are working to.

 

Good question, budget restraints? Margin of safety? Longevity? Lack of R&D? I don't know. It's all well and good saying it should be perfect, but the reality is, is that it probably isn't. A lot of people have made a living by tuning ECU's, perhaps they ALL have random number generators attached to their dyno's to massage a few egos and loosen a few wallets?!?

 

Remapping before we start the comparisons is just adding another variable in the equation because Bob the Builder might map it differently to Bob's back street garage. We know the VW map is the same across all cars within that specific model year / type.

 

Well if you trust one person to map your car AFTER changing the cams, one would assume they are competent enough to re-map it WITH standard cams, or maybe the reputable tuner should find another profession, and the owner of the car find themselves somewhere else to look after their car. By using the same person you will be comparing apples with apples.

 

I think the real issue here is trying to discredit the 263s. For what other reason is this silly debate going on for? I've never seen such anal retentivness over a few hp. People fit them, they like them, end of story.

 

This has nothing to do with discrediting ANY type of cam, just the methods generally quoted to quantify the "gains". You can do it a right way, or you can do it wrong way. I prefer to trade in facts rather than hearsay. It must be the education.

[Leonard 0]

For the same reason that all these chip companies make a living - i.e there is more power to be found in the standard mechanical set-up. Perhaps if every single one of these companies is peddling BS then you are right...and all those people will shortly be signing on!!

 

I think the point is the VR6 engine has never been an engine that responds well to chip tuning. You cannot compare it to modern engines that have a lot of safety margin built into their maps. Be it for longevity, or because the engine is shared accross model ranges or perhaps more pertinent price ranges. I am aware of at least a couple of tuners who fudged rolling road results in the 90's early noughties to make their VR6 chip tuning appear more productive than it actually was!

 

That is why I dont really see where this thread is heading. A std VR6 mapped will maybe gain a few horses. The reason the 263 cams offer such good value is for the NA performance they offer at such a reasonable cost, even taking into account a £250 remap. The 268 cams are good but as far as I am aware they offer most of their performance gains higher in the rev range. Where as the 263's offer that but not at the expense of the mid range.

 

As I think everyone is agreeing it will be interesting to see how they fair and compare with the 268's when fitted with a VSR

 

Matt

[87 Jetta 16v 0]

As I think everyone is agreeing it will be interesting to see how they fair and compare with the 268's when fitted with a VSR

 

Matt

 

Absolutely, the same engine with the VSR mapped on 263's and mapped on 268's would be a good comparison and a good source of information. :)

[Kevin Bacon 5]

OK I give up, I'm bailing out of this one :D

 

At the end of the day, you pays your money and takes your choices. Getting embroiled in all these scientific debates and experiments, whilst interesting on one hand, is counter productive and tedious on the other (imo).

 

Besides, as soon as you get to ~ 250 hp on the VR6, naturally aspirated, you hit a flow brick wall that is the head anyway, so it's all a bit academical imo.

[Leonard 0]

 

Besides, as soon as you get to ~ 250 hp on the VR6, naturally aspirated, you hit a flow brick wall that is the head anyway, so it's all a bit academical imo.

 

Ok no need to show off :grin:

[andy 0]

Its the whole hassle and expense of remapping that puts some people off. We simply are curious to know, how much is to be gained by installing cams alone. No one seems to have the answer yet unfortunately. Just my 2 penneth 8)

 

What mods are there accross the whole spectrum of the car world, that offer better performance and driveability without a remap or ECU change?

 

Erm, most. Or would you have your car remapped after fitting a BMC CdA for instance, or perhaps we should all have our cars remapped every time we renew our spark plugs, or fill up with a different grade of fuel. I think you'll find plenty of people across the car world who have better air filters and exhausts but haven't considered a remap.

I'm not saying a car won't be better with a remap, obviously it will . I could say there's absolutely no point in modding or mapping anything unless you're going to remove avery last gram of unecessary weight from a car, or unless you're going to fit the most expensive tyres, or unless you have a quaiffe. The list goes on.

[Leonard 0]

[Erm, most. Or would you have your car remapped after fitting a BMC CdA for instance, or perhaps we should all have our cars remapped every time we renew our spark plugs, or fill up with a different grade of fuel. I think you'll find plenty of people across the car world who have better air filters and exhausts but haven't considered a remap.

I'm not saying a car won't be better with a remap, obviously it will . I could say there's absolutely no point in modding or mapping anything unless you're going to remove avery last gram of unecessary weight from a car, or unless you're going to fit the most expensive tyres, or unless you have a quaiffe. The list goes on.

 

I know what you are saying but I was talking about mods that actually give you some REAL performance gains not just 1 or two horsepower. My BMC filter probably gave me a couple of extra horses but I know I have lost some torque from fitting it also.

 

Free flowing exhausts tend to only give up there true potential when fitted as part of a mapped package. Then normally only on turbo applications. Unless you are going back to some old V8's or a nice big Chevvy block you just dont get decent performance gains without optimising all the mods with a remap. :shrug:

[Philmo 0]

As I think everyone is agreeing it will be interesting to see how they fair and compare with the 268's when fitted with a VSR

 

Matt

 

Absolutely, the same engine with the VSR mapped on 263's and mapped on 268's would be a good comparison and a good source of information. :)

 

Agreed - & I think Dukest will shortly be in best position to advise on that one. How's it goin John? :?

[Philmo 0]

Yes the cams actually make sufficient difference to the flow regime [and therefore potentially the a/f control] that you should have concerns if you DON'T have your mapping checked over after the 263's are installed.

Do you really want to risk engine damage which might ensue if the fuelling and knock control haven't been reviewed following the change?

Vince doesn't charge £X00's for the checkover if no significant map review is done - iirc £65 for mine in May '08.

[andy 0]

Do you really want to risk engine damage which might ensue if the fuelling and knock control haven't been reviewed following the change?

What do knock sensors do? :scratch:

[Leonard 0]

What do knock sensors do? :scratch:

 

The knock sensor picks up when the engine is starting to "pink" (over fuel). The ecu then receives a signal from this sensor and retards the ignition to suit.

 

Matt

[Toad 0]

What do knock sensors do? :scratch:

 

The knock sensor picks up when the engine is starting to "pink" (over fuel). The ecu then receives a signal from this sensor and retards the ignition to suit.

 

Matt

 

Yeah, basically it's a microphone.

 

Oh, and I will post the 263 data when I get a chance. Have no internet at home at the moment though.

[andy 0]

Yes I knew that :tongue: , I was questioning why Philmo was saying engine damage could result from incorrect knock control following a cam change. Doesn't make much sense to me. :scratch: By changing cams without a remap, you haven't changed knock sensors or the way they work, they hear pinking they tell the ecu to retard the ignition. Why would engine damage result....?

[dr_mat 0]

Yes I knew that :tongue: , I was questioning why Philmo was saying engine damage could result from incorrect knock control following a cam change. Doesn't make much sense to me. :scratch: By changing cams without a remap, you haven't changed knock sensors or the way they work, they hear pinking they tell the ecu to retard the ignition. Why would engine damage result....?

 

Because the ECU can only adjust to "-11 degrees" timing offset from the base map. If your base map is now 12 degrees too far advanced, no amount of knock sensor activity will prevent the engine knocking. And we all know that knocking kills engines.

[Leonard 0]

Yes I knew that :tongue: , I was questioning why Philmo was saying engine damage could result from incorrect knock control following a cam change. Doesn't make much sense to me. :scratch: By changing cams without a remap, you haven't changed knock sensors or the way they work, they hear pinking they tell the ecu to retard the ignition. Why would engine damage result....?

 

I think he may have been suggesting that if you didnt map your engine then you increase the chances of pinking.

 

Although the knock sensor will obviously still pick this up. It is not very healthy for your engine to have the ecu repeatedly retarding the ignition. In fact the knock sensor is only a mild safety device. You can still severely damage your car.

 

edited to add "Doh! beaten to it :grin: "

[Philmo 0]

Yes I knew that :tongue: , I was questioning why Philmo was saying engine damage could result from incorrect knock control following a cam change. Doesn't make much sense to me. :scratch: By changing cams without a remap, you haven't changed knock sensors or the way they work, they hear pinking they tell the ecu to retard the ignition. Why would engine damage result....?

 

When you change the cams, you modify the gas flow regime and [hopefully] increase the power / energy throughput and therefore also raise the combustion space temperatures.

The risk of premature ignition [knock] is therefore raised.

Even if the cooling system capacity has been improved its response speed is limited and will simply facilitate a generally steeper temperature gradient from combustion space to ambient air.

Given the VR's known weakness in combustion space coolant circulation/distribution - do we really want to risk stretching that weakness further?

IMHO - to modify a mechanical process significantly and then not review its control system [including general health / protective controls] is a recipe for possible mechanical failure. :shrug:

[Kevin Bacon 5]

Does a "This thread is boring" smilie exist?

[Philmo 0]

Does a "This thread is boring" smilie exist?

 

Do you mean smiley?? ! :shrug:

 

Sorry Kev - you must know I'm closely related to Marvin [cybernaut] :lol:

[Kevin Bacon 5]

Ah, yeah you're right..... I think it was because I had Carol Smilie's backside in my mind whilst typing that :D

[Philmo 0]

Can't fault yr synapse function! :lol:

[andy 0]

Does a "This thread is boring" smilie exist?

Its only boring to you Kev, if you're not interested why comment? :brickwall:

 

The fact the thread is 5 pages long shows quite a few people are very interested. :)

 

For what its worth the last few replies have made more sense, cheers for clarifying things philmo :)