Simota Intake will be available in August

[mmm-five]

I got similar numbers for area when I worked out mine, but the result was 9% due to using 88mm (6,082mm²) rather than 88.45mm (5,542mm²) - for a 9% difference

However, the airbox/intake neck on the Simota looks to be even smaller, so wouldn't that be even more of a restriction. It's about 8mm narrower (i.e. 76mm) so 4,536mm² - so this would make it a 25% difference :?

What's the area of the standard airbox/intake neck - is it as restrictive?

Lucky that I'm only doing it for the noise

 

[pilchardthecat]

Lucky that I'm only doing it for the noise

I was only doing it for the noise...... and would have been happy with just noise..... i wasnt expecting my car to drive like it was broken though. Trust me, it's bad

 

[exdos]

I did an experiment with a commercially available "Cold Air Intake" on my Citroen C2 VTS runaround 2 years ago, so that I could datalog it and see what happens. Below is the graph produced from the information. As the graph shows, the Volumetric Efficiency was all over the place in 1st and 2nd gears and the drivability was bloody awful because the acceleration was far from linear! That was all that I needed to know about these things.

 

[pilchardthecat]

I did an experiment with a commercially available "Cold Air Intake" on my Citroen C2 VTS runaround 2 years ago, so that I could datalog it and see what happens. Below is the graph produced from the information. As the graph shows, the Volumetric Efficiency was all over the place in 1st and 2nd gears and the drivability was bloody awful because the acceleration was far from linear! That was all that I needed to know about these things.

That looks like it felt.

Now if only you'd told me your special secret about the OEM system i wouldn't have had to put myself through this So it's all your fault.

 

[exdos]

What's the area of the standard airbox/intake neck - is it as restrictive?

I measured this for you yesterday. :wink: The absolute narrowest part is inside the trumpet section just infront of the mesh screens: it was 86.75mm diameter = 5910.6 sq.mm. The screens also add to the restriction but the MAF will be calibrated to account for that.

 

[exdos]

Now if only you'd told me your special secret about the OEM system i wouldn't have had to put myself through this So it's all your fault.

I've always said that the OEM air-intake is the best deign of the lot with a bit of modification, but it seems you guys are wanting noise and not performance gains.

 

[pilchardthecat]

Now if only you'd told me your special secret about the OEM system i wouldn't have had to put myself through this So it's all your fault.

I've always said that the OEM air-intake is the best deign of the lot with a bit of modification, but it seems you guys are wanting noise and not performance gains.

You are the only person who claims that performance gains are even possible, but you wont tell us the magic ingredient to make increased ram-air work

 

[exdos]

You are the only person who claims that performance gains are even possible, but you wont tell us the magic ingredient to make increased ram-air work

That is true.

 

[pilchardthecat]

You are the only person who claims that performance gains are even possible, but you wont tell us the magic ingredient to make increased ram-air work

That is true.

Although having had the OEM system in bits now i believe i have worked it out

 

[exdos]

Although having had the OEM system in bits now i believe i have worked it out

So there are now 2 of us who claim that performance gains are possible!

 

[pilchardthecat]

Although having had the OEM system in bits now i believe i have worked it out

So there are now 2 of us who claim that performance gains are possible!

I'm not claiming anything yet, but there is one particular aspect of the OEM system that i don't understand, and which is probably why the ram air scoops (eg RPI) don't seem to do anything

 

[exdos]

I'm not claiming anything yet, but there is one particular aspect of the OEM system that i don't understand, and which is probably why the ram air scoops (eg RPI) don't seem to do anything

What bit don't you understand?

 

[pilchardthecat]

I'm not claiming anything yet, but there is one particular aspect of the OEM system that i don't understand, and which is probably why the ram air scoops (eg RPI) don't seem to do anything

What bit don't you understand?

When I have purchased some spare OEM bits to mess with i shall announce my findings publicly. I'm now glad you didn't just tell me as it's more fun this way.

 

[exdos]

I'm now glad you didn't just tell me as it's more fun this way.

It's only when you closely examine the parts, that you get into the minds of the designers and you then truly understand their thinking and the principles behind their design. You'll need to datalog your mods if you want to know for sure the effects of your changes. The 4 main parameters that you need to simultaneously record are: 1. Intake Air Temperature, 2. Airflow at MAF, 3. Engine RPM and 4. Vehicle Speed. From that data you can compute Volumetric Efficiency (VE) and if you save your data as .csv files, you can make a formula that calculates a "rolling" VE so that you can see precisely how VE changes due to "ram effect" whilst the vehicle is in movement and how it is affected by gear ratio as well as speed. Improvements in VE are the definitive proof that your mods are effective.

 

[pilchardthecat]

I'm now glad you didn't just tell me as it's more fun this way.

It's only when you closely examine the the parts, that you get into the minds of the designers and you then truly understand their thinking and the principles behind their design. You'll need to datalog your efforts if you want to know for sure the effects of your efforts.

I think the OEM component that i'm most interested in is probably the way it is for noise (more accurately resonance) reducing properties, so i am expecting a double-whammy (more noise) when i mess with it. I dont have a datalogger unfortunately, and I really need to get hold of a bigger ram-air scoop to prove out my theory so that's where my cash is probably going now (unless of course you'd like to share the dimensions/plan of your home-made scoop?)

 

[pvr]

There is one design element that works against the most optimal design, and that is cost.

Say for example, that a Gruppe M really was the most ideal design, the engineers could simply not use that as it would be too expensive for the car so they will go for an average price model and design instead.

 

[exdos]

I didn't make any templates of my scoops made in aluminium but here are a couple of photos to show the parts during fabrication and you should be able to be able to get an indication of scale from the photo showing the parts in situ. You will probably only want to make the part on the right.

mmm-five mentioned his datalogger app for his iphone a couple of weeks ago. That seems like an affordable way of accessing the ECU.

 

[exdos]

There is one design element that works against the most optimal design, and that is cost.

Say for example, that a Gruppe M really was the most ideal design, the engineers could simply not use that as it would be too expensive for the car so they will go for an average price model and design instead.

If a Gruppe M style intake were the optimal design, then it would be cheaper for BMW to make a plastic shroud or even an aluminium one like the GruppeM carbon fibre one, rather than the more complex multi-part OEM air-intake. The fact is, BMW knows that ram-effect in a closed air-intake system works and that's why they persist with the design. Look at the graph that I got from datalogging my Z4MC on the day I bought it completely OEM. In 2nd gear and above, the engine runs at 100%+ Volumetric Efficiency!

 

[Rye]

so what power gains and figures have you gained from doing your mod then exodus as against the stock figures?

 

[exdos]

so what power gains and figures have you gained from doing your mod then exodus as against the stock figures?

I posted in another thread about the gains I'd obtained on my Z3MC, with the same S54 engine here: http://www.z4-forum.com/forum/viewtopic.php?f=9&t=44687&start=29

The S54 engine in the Z3MC is set up to produce 325bhp whereas the same engine in the Z4MC is set up to produce 338bhp, so it's easier to get larger gains with the Z3MC than it is with the Z4MC. However, here's a dyno graph produced by datalogging the ECU of my Z4MC showing the before and after-modding outputs that I've achieved so far.

As the graph for my Z3MC in the other thread shows, my "ramcharger" mod had a very significant improvement on that car. I've yet to do the equivalent mod to my Z4MC because the layout of the engine bay is totally different and I'm still considering the best options.