Cupra R airflow

[Scotty_b]

On my hybrid k04 i see 228g/s max and around 220 normally.
I also have the de screened MAF. The way i look at it is that the plastic mesh is there to "straighten" the air over the MAF so it works well with the stock air box and smoothing. However if you fit something like BMC induction kit this spins the air causing a cyclone effect so the screen would be counter acting what your trying to do with the "straightners". That’s how i look at it anyway, but I don’t know how this will effect the airflow readings of the MAF?

 

[ibizacupra]

the MAF is designed to see laminar flow, so the function of the screen is clear to me.
Its seeing a nett cooling effect from the mass of air passing by, but its in reality a velocity type sensor which uses its known ID to give a proportional signal related to airmass, given factory (bosch) conditions.

Would be interesting to compare results of screened from unscreened, with various induction systems on the front end. Absolute max number may not be the only thing thats going on.

ECU is expecting (requesting) a target airmass I thought.

 

[Feel]

I knew it was only a guide, but does the internal ECU scaling differ between individual cars of the same model (obviously the scaling is different for the differnt sized MAFs on different models).?

 

[martin CR]

so 225gs = 295bhp!!!

How accurate is this 1.31 rule then, I loged my old S3 as it was run on the rollers last year and it pulled 188g/s, so times that buy 1.31 = 246hp, but the car pulled 255?

 

[J@mes]

How accurate is this 1.31 rule then, I loged my old S3 as it was run on the rollers last year and it pulled 188g/s, so times that buy 1.31 = 246hp, but the car pulled 255?

not very! its a ROUGH guide!...

kinda the same thing... scaling in factory ecu's is not the same, so comparisons with x g/s = a power output can at best only be a guide...

 

[Feel]

How accurate is this 1.31 rule then, I loged my old S3 as it was run on the rollers last year and it pulled 188g/s, so times that buy 1.31 = 246hp, but the car pulled 255?

It's that far off then - with RR's the way they are the 255 might be a bit high. 188 g/sec is around about the 190 odd that Revo quote as the bottom end of the range (was this an AMK S3?)

The other way of looking at it is this:

bhp/g/sec

266/225 = 1.18

188*1.18=222bhp

Your S3 made 250odd @ 188g/sec, your LCR is supposed to make 270odd @ 225g/sec? Same engine size, same turbo size, roughly the same boost...

So, while 1.31 (it might be 1.32, thinking about it) might be rough, you can see that it's not 30bhp out.

So, you can see something's wrong. It's a rough guide, Bill says the scaling is different on different cars, but it can't be THAT different (can it)?

 

[martin CR]

It's that far off then - with RR's the way they are the 255 might be a bit high. 188 g/sec is around about the 190 odd that Revo quote as the bottom end of the range (was this an AMK S3?)

The other way of looking at it is this:

bhp/g/sec

266/225 = 1.18

188*1.18=222bhp

Your S3 made 250odd @ 188g/sec, your LCR is supposed to make 270odd @ 225g/sec? Same engine size, same turbo size, roughly the same boost...

So, while 1.31 (it might be 1.32, thinking about it) might be rough, you can see that it's not 30bhp out.

So, you can see something's wrong. It's a rough guide, Bill says the scaling is different on different cars, but it can't be THAT different (can it)?

My S3 had the earlier APY engine, it pull 188g/s when it only had Revo st 1, when I added Revo st 2, exhaust, Forge FMIC and Neuspeed P-flow it whent up to 210-215 g/s, our Leon only has a 3" DP and better intercooler (in my opinion only!!) over our S3 and pulls 10 g/s more, last night it only pulled 220 g/s but that could be down to the Tesco's fuel the misses put in this week

 

[DPJ]

It's that far off then - with RR's the way they are the 255 might be a bit high. 188 g/sec is around about the 190 odd that Revo quote as the bottom end of the range (was this an AMK S3?)

The other way of looking at it is this:

bhp/g/sec

266/225 = 1.18

188*1.18=222bhp

Your S3 made 250odd @ 188g/sec, your LCR is supposed to make 270odd @ 225g/sec? Same engine size, same turbo size, roughly the same boost...
So, while 1.31 (it might be 1.32, thinking about it) might be rough, you can see that it's not 30bhp out.

So, you can see something's wrong. It's a rough guide, Bill says the scaling is different on different cars, but it can't be THAT different (can it)?

Sorry, I know this is actually an LC thread - tell me to butt out if you want, but I find the topic very interesting.

In my case 193.08 x 1.31 = 253 bhp.
You don't really think my Revo stage 2 LC is pulling 253bhp, do you?

 

[bentaw]

to be honest the more this goes on the more i am beginnig to think the airflow equation means nothing at all

 

[martin CR]

Had car Rolling Roaded today, pulled 220g/s with perfect fueling, 267bhp and 307ibft

 

[Feel]

Sorry, I know this is actually an LC thread - tell me to butt out if you want, but I find the topic very interesting.

In my case 193.08 x 1.31 = 253 bhp.
You don't really think my Revo stage 2 LC is pulling 253bhp, do you?

That's because yours is a different setup (different Turbo, different compression ratio), different MAF tube etc.

If you did stock LC power over stock LC g/sec, you'd end up with a different ratio...

 

[ibizacupra]

I knew it was only a guide, but does the internal ECU scaling differ between individual cars of the same model (obviously the scaling is different for the differnt sized MAFs on different models).?

different ecu software revisions even on like for like 150/180/225 motors

 

[neil_f225]

i logged my lcr which has revo stage 2 last night and could only get a peak of 189g/s...most of the runs were 185g/s. Seems a bit low? Settings are b6 t8

 

[DPJ]

That's because yours is a different setup (different Turbo, different compression ratio), different MAF tube etc.

If you did stock LC power over stock LC g/sec, you'd end up with a different ratio...

Yes - but no one has ever quoted a K03S ratio in that case? Unusual as we've come from a K03S golf platform where most of the development / research has been done......

1.31 is more likely to have originated from a K03S base than anywhere else....

 

[Feel]

Nope, 1.31 came from people working it out on LCRs/k04 cars. It's not hard, assuming a linear relationship between airflow and power, on the same motor/turbo etc, with the turbo working efficiently:

210bhp / 160g/sec = 1.3125

1.3125 * 195g/sec = 256bhp
1.3125 * 210g/sec = 275bhp

So, chipped LCRs make roughly 260-275bhp. No surprises there.

Obviously if you keep turning the boost up beyond what is efficient for the turbo, it'll fall down because hotter give less power, but for like for like comaprisons it's ROUGHLY right.

 

[Feel]

From ross-tech:

Here's a good sanity check for the status of your MAF. Do a full-throttle run all the way to redline in a single gear (second works fine). Group 002 usually shows air mass in g/s. Your peak airflow should be roughly 0.80 times your horsepower. So, if you have a stock 150 hp 1.8T, expect around 120 g/s. If you see significantly less than that, you MAF may be on the way out. This still works if you are chipped, but "race" programs may make more power through timing, rather than airflow. Therefore, take all readings with a grain of salt.

150 / 120 = 1.25 Different turbo, different ratio. If that ratio works for the 180's, using your 193.08 g/sec you posted earlier gives 240 bhp.

Happy Now? No? f'off and buy Corky Bell's book (Maximum Boost)

 

[neil_f225]

i used to have a custom map on my lcr which peaked at 210g/s but got 262bhp on dyno. Now have Revo stage 2 and air flow is less but car feels stronger. Havent had it dynoed with revo on it yet. Surely that rule becomes less accurate on mapped cars as some software might rely more on timing than boost values alone?

 

[DPJ]

From ross-tech:



150 / 120 = 1.25 Different turbo, different ratio. If that ratio works for the 180's, using your 193.08 g/sec you posted earlier gives 240 bhp.

Happy Now? No? f'off and buy Corky Bell's book (Maximum Boost)

Sorry Phil

 

[ibizacupra]

one of my library...

not that i agree with everything thats in there.

 

[Feel]

I can't say whether I agree with or not (I don't know enough to disagree), I suppose it's a bit out of date nowadays- but I like the fact that it's written as guide to turbocharging a non-turbo car, so you get to see what it's all about from the ground up.

I'd be interested in any other recommended titles...