Long story about fitting 262 cams, dyno, and lots of drama

[Ryan]

but it is a debate between 2 very knowledgeable club members .with more knowledge on these cars than half the club combined ,

[Kenneth]

Your setup is VERY different on the exhaust side, which is where I believe that a good percentage of the gains Brad has are. Your car is also factory manual so probably has the smaller TB, Brads was facelift Auto (converted to manual) so has the larger TB.

http://www.clubvr4.com/forum/showthr...ght=dyno+400hp

Potentially throwing the cat among the pigeons here but my car is setup very similar to Brad's and was tuned by the same man - the only thing different is that my turbos are standard and I do not have my air filters enclosed in a metal box as Brad does (where the battery is, facing down with a hole cut out of the battery support tray). My car made 198kW atw on stock turbos and fuel pump. Changedto Walbro fuel pump and increased to 205kW atw.

I'm not trying to cause an argument and certainly don't have anything to add to the above debate from a technical point of view but just thought that I'd mention it.

[Kenneth]

It is my understanding that VE is affected by intake and exhaust flow as well as porting, valve timing etc.
We have been told by others that the exhaust manifolds have been used to 500+hp (again, not necessarily proven to scientific standards, but I choose to believe that there is at least a majority of truth in it) so I don't have too many qualms in accepting that sufficient work to the exhaust housings and turbines could contribute to much better exhaust flow. There was enough done to Brads exhaust to (in 4th gear) result in max boost being achieved at ~3250RPM which is quite a bit slower than standard.

If you had a 1.4l Polo, claimed 1000bhp and provided the dyno graph to back it up (and the dyno graph wasn't totally unbelievable) then I would accept your claim. I don't really care whether or not you made 1000bhp. If you didn't then it is your lie. The only one you would be cheating is yourself. Even if it was 990hp, I don't see the point in splitting hairs over it.
Brad knows his car was tuned on a dyno which is known to be a little optimistic and he was due to lose a few KW at the wheels if he dynoed with the club dyno day, which is why he didn't. That is his choice though, he still has his claim to 400hp in the mean time.

I would like to see your flow maps etc which prove that 400hp is impossible. It would be nice if you could do it up in a spreadsheet so we can fiddle with parameters which we feel might contribute to system differences.
I am highly interested in what figures you feel WOULD be possible.

I agree that the VE could be different, but that would only be the case if there were differences in porting and valve timing, which there are not so it would be reasonable to say that they would have to be the same.
VE can be calculated from air flow, to which MAP, Lambda, IAT, Injector pulse width can help with gathering the data. It is true that this may be all a little academic, and it is certainly not a case of my car's faster than your car. What irratates me somewhat is the internet (maybe a bit broad but here we go). You can say whatever you like on it and it can become gospel. There is no true process of review. So when it comes to people who are looking for answers to questions and are using a resource I would prefer them to be given information that is factual and accurate, not hearsay and conjecture. Granted there was a power graph, I could go and run the car that is currently sitting on the dyno and give you whatever power figure you want (within reason).... it doesnt mean that it is true. These things need to be looked at with a sceptical eye, back to the reviewing process, to assess whether the information is of any use or not.

As for sour grapes, I'm not quite sure what I'd have to be sour about? I don't own a VR4 anymore, nor do I ever intend to again. My car was what it was, as was Brad's. My point is not car specific, but general in that figures that are posted up have to be reasonable... for example if I said I had a 1000bhp 1.4l Polo would you believe me? If not why not? All boils down to the same thing.

Now if you wanted to, we can go further into this and make it far more scientific and bring the flow maps into it, and physically prove that you can not flow enough air for 400bhp.... that is my point.

[Oblivion]

....I am highly interested in what figures you feel WOULD be possible.

Me too! Very curious about the limits of the stock turbines.

[swinks]

Little update.
Thanks to Paul (psbarham) who borrowed to me stock front exhaust cam gear with cam rotor blades I could investigate why in my aftermarket cam verniers rotor blade was so much misaligned.
So did few checks:
IMAG0413.jpg
Here is the answer...
Rotor blade wasn't misaligned at all! There was wrongly positioned timing mark!
There is 2 tooth misalign between both cam gears
Now adjustable cam gear has a "new" timing mark scratched by myself:
IMAG0435.jpg

[jungle]

Interesting read. Any updates?

[amsoil]

Bit late in the day this I know, but from memory no graph can be correct if the torque and power lines do not cross at 5200 rpm. Simple maths from the formula for each, please correct my dying brain cells if I am in error but I have dabbled a little and most of the rolling roads and dynos out there are, shall we say, only really useful for comparisons. Love the torque figures, beats my car (at tickover, lol)

[Sketchy_Race]

Bit late in the day this I know, but from memory no graph can be correct if the torque and power lines do not cross at 5200 rpm. Simple maths from the formula for each, please correct my dying brain cells if I am in error but I have dabbled a little and most of the rolling roads and dynos out there are, shall we say, only really useful for comparisons. Love the torque figures, beats my car (at tickover, lol)

I don't believe this is the case

Horsepower is the product of torque * RPM so if your peak torque was made at say 4000 RPM and then fell flat after due to poor fueling etc then the cross over point of power would be much earlier than 5200 RPM for example.

But yes no two dynos will read the same on any given day, there are just to many variables.

[Kenneth]

I believe Don was correct

HP = (Torque * RPM) / 5252

When RPM = 5252 they cancel each other out and you are left with just hp = torque.

However that may just be true for HP and torque in lb-ft

[swinks]

However that may just be true for HP and torque in lb-ft

I think Don just forget about this...
You can easy spot that in my dyno graph that scaling for torque is not matching power scaling, unlike typical imperial HP vs. LbFt figures.
Posted above graph is KM (PS) vs. Nm

[Adam.Findlay]

yes kenneth and swinnks are right
The internet is full of arguments with keyboard warriors saying hurr durr that dyno graph is wrong because hp doesnt cross torque at 5252 rpm. but most of the people dont take into account mostly the torque lines and hp lines are on different scales to fit them on the same page. as well as 5252rpm being the crossover point for imperial measurements. im sure it would be different when measuring in kilowatts and newton meters instead of horsepower and foot pounds.

but don is also right when the scales are the same and you measure in hp/ft-lb vs rpm it should cross at 5252rpm

[Gowf]

I don't believe this is the case

Horsepower is the product of torque * RPM so if your peak torque was made at say 4000 RPM and then fell flat after due to poor fueling etc then the cross over point of power would be much earlier than 5200 RPM for example.

But yes no two dynos will read the same on any given day, there are just to many variables.

This does irritate me. Power is NOT Torque *rpm.... it is Torque * angular velocity which is very much different from rpm (rad/s). Power is simply T*2*Pi*rpm/60. However you have to be careful of what units are used, if you are using Nm for Torque then you will get watts out. If you want HP, then you have to use a conversion factor which is then why if you are using lbFt that you then get the 5250 division.

Thus if you want it in kW (divide by 60000) and if you have the same scaling on both, you will find that they only cross at 9554rpm

[Sketchy_Race]

This does irritate me. Power is NOT Torque *rpm.... it is Torque * angular velocity which is very much different from rpm (rad/s). Power is simply T*2*Pi*rpm/60. However you have to be careful of what units are used, if you are using Nm for Torque then you will get watts out. If you want HP, then you have to use a conversion factor which is then why if you are using lbFt that you then get the 5250 division.

Thus if you want it in kW (divide by 60000) and if you have the same scaling on both, you will find that they only cross at 9554rpm

hmmm power is torque * RPM, just it has to be converted to a value to make the calculation true. They are both a measure as to how fast the engine is rotating. Just the same as Nm is the same as lbFt, just different units.

But I digress all I was wanting to illustrate is that there is no fixed point that the curves must cross.

[amsoil]

Very late at night for me now, but...... from an online converter:- 100Nm at 5252 rpm = 100HP so maybe irrespective of the scales at 5252 rpm metric torque = BHP? So that line is pegged here. The other line however moves and as Gowf says with KW the cross point is 9550.
Guess if they kept these metric scales they lines would rarely meet never mind cross. Soooooo looks like they use KgM instead to fit it all on the same piece of paper. The correct crossing point? I'll let someone else work that one out.
Gosh I hate metric, the threads arnt even right!
Guess I'll have to remain using the 2nd best system of fastners, imperial.
The best was of course Whitworth! but long gone.

[Gowf]

hmmm power is torque * RPM, just it has to be converted to a value to make the calculation true. They are both a measure as to how fast the engine is rotating. Just the same as Nm is the same as lbFt, just different units.

But I digress all I was wanting to illustrate is that there is no fixed point that the curves must cross.

I really cant be bothered to argue over unit expressions, BUT when you tell people that P=T*RPM then that is exactly what they try and calculate and get horendously confused when you then put a conversion factor in, as they don't understand where it came from, far better to explain it by stating its true formula which is angular velocity

[Adam.Findlay]

I really cant be bothered to argue over unit expressions, BUT when you tell people that P=T*RPM then that is exactly what they try and calculate and get horendously confused when you then put a conversion factor in, as they don't understand where it came from, far better to explain it by stating its true formula which is angular velocity

yep power =2*pi*(rpm/60)*T
if you put in newton meters that formula gives you killowatts out.

[AKKO]

Yes, cam gears left on stock settings, 0 degree. Can't do anything with them because the most important one with cam position sensor is temporary wrong. Once I get to UK, I need another stock front exhaust gear as sample and try to align that adjustable one.

Did you resolve this alignment issue in the end...
what adjustment was required or did the supplier address the issue somehow?

[swinks]

Did you resolve this alignment issue in the end...
what adjustment was required or did the supplier address the issue somehow?

Yes, post #45.
Anyway, rather recommend to check on tdc marks before fitting, seems that
It was only issue

[AKKO]

Thanks not sure how i missed that post *puzzled*

Just purchased a set myself