E30 Zone

I fitted a BMC carbon airbox to my 325i yesterday. Its a very tight fit but it does fit.

Anyway, I carried out an experiment.

Using my digital thermometer (Supplied by Sercal Electronics aka forum member Brent) with dual probes I set about testing air temperature in the engine bay.

Firstly engine was brought upto operating temperature.

Then the probes were placed in exactly the same place to make sure they both read the exact same temperature which they did.

Air temperature outside of the car was a constant 21 degrees.

One probe was the placed inside the BMC and the other just outside it where a normal K&N or any other cone filter would sit.

Waited 1 min for the thermometer to settle down to a constant temperature and recorded the results.

Temperature inside the BMC airbox was a constant 23 degrees C. Temperature outside Airbox was 52 degrees C.

Thats a difference of 29 Degree C!!

This is quite alarming as all people using un sheilded cone filters are basicaly losing quite a bit of power. As a general rule 1 degree = roughly 0.3-0.5 BHP. With a difference of 29 Degree that would roughly equate to around 8.7-14.5 BHP recution in power.

The bonnet was open through out the test so with it shut the heat build up would have been even greater.

Even if the car was moving there would only be a marginal drop in under bonnet temperatures. Under bonnet ventilation is just not very good on an E30.

Conclusion:

If your not going to use a heat shielded induction kit dont bother and stick to your standard airbox.
If yo do have a standard Airbox be sure to attach the small hose which attaches to the head light cover as this will to some degree help keep temperatures down of the intake air.

The BMC is definately a much more free flowing design than the standard air box. It has shown to reflect heat very very well.

The next phase is to get a slightly shorter BMC CDA box so that the air feed pipe can be attached at the front and taken to somewhere where the air temperature is the same as the outside air and where there is the highest velocity of outside air coming in to minimise intake temperature.

The above proceedure is the exact same as what Dinan, Nowack (E39 M5 tuner) and ITG use to get proven power gains on cars. Only diffeence being is that they design their own air boxes where as I am using something which is already a very good design and which is just about affordable and maximising its effect on E30's.

This is a very worthwhile experiment. For those that think the origional Airbox is the best thing think again - Nowack reduced intake air temperature on an E39 M5 by 24 Degrees C over the standard airbox simply by carrying out a more advanced version of the above test. If a highly developed supersaloon can benefit then the E30 could also benefit.

That is really interesting Sal. Proving what we have been saying for ages now.

Thats very interesting. Just goes to show how useless the unshielded K&N cone filters are.

Is it possible to do the same test with bonnet shut?
Obviously the under bonnet temps will rocket up, but it would be interesting to see if it has an effect on the temp inside the BMC - just thinking about heat transfer or whatever its called.

Excellent test Sal Its good to have results as to what products work or dont work.

Nice one mate, did'nt really think that far into it
I've just got the k&n panel filter on mine but put some holes on the passenger side of the box which has made an improvement

Am i right in thinking that the BMC is'nt really exposed to the heat in the engine bay (other than the outside of the casing) as the BMC is an enclosed unit, so then with the pipe attached to it, it can only suck in cold air?

just put a panel filter in mine as i realised how hot it gets under the bonnet. did you wear a white lab coat to do the tests? if not they are not worth a thing

jonbuoy wrote: Am i right in thinking that the BMC is'nt really exposed to the heat in the engine bay (other than the outside of the casing) as the BMC is an enclosed unit, so then with the pipe attached to it, it can only suck in cold air?

Thats is mate. Heres a pic of Karans BMC fitted....

Sal will be doing driving tests soon. Hopefully I can get longer probs to him by friday.

Interesting stuff, any plans to get temp. readings of standard airbox for comparison?

jmc330i wrote:

jonbuoy wrote: Am i right in thinking that the BMC is'nt really exposed to the heat in the engine bay (other than the outside of the casing) as the BMC is an enclosed unit, so then with the pipe attached to it, it can only suck in cold air?

Thats is mate. Heres a pic of Karans BMC fitted....

Look's pretty good aswell, how much are they?

Sal, my K&N is shielded, but I think it's too shielded and actually restricting loads of airflow to it! I've got ducting for a cold feed but can't find anywhere suitable to run the feed from. I'll send you a pic later on MSN if you're about.

Funnily enough I do actually have a white coat but wasnt wearing it at the time! I used to do lab experiments at College and Uni and i kept the coat with the protective glasses!

The BMC is totally shielding the internals, Carbon fibre is very good at reflecting heat and thats why the likes of BMC and GruppeM use it.

Brent will be supplying 3 metre probes this week so bonnet shut and driving temp will be measured.

Karans BMC is incorrectly fitted as there is no cold feedpipe and its just sucking in hot air from next to the radiator, he might aswell have an standard airbox with his MAF.

Just fitting a BMC without a feedpipe is a waste of time, the cold air feed is crucial.

I will also carry out experiments on the standard airbox to see the internal temperature there and hoe much heat is transferred through the plastic. Again, the design would benefit from a better air feed area.

It is however quite a restrictive box so im not really going to bother too much with it.

Induction kits do work better than the standard airbox if and only if heat sheild is fitted and a cold air feed is supplied.

The price of the BMC will be around Ԛ£190 inc postage. This is not the box which is listed for the 325i on the website or other dealers as it simply doesnt fit as the intake diamater is all wrong. BMC CDA's are custom fits - they really shouldnt be saying which vehicles they fit because all kits come with the same fittings.
Also, when using an AFM an adapter needs to be used which isnt supplied with the BMC. I have sourced one though with the correct size round inlet.

Basically this will be a kit which I have put together for the 325i which will fit without a problem.

Yes, I did some temperature measurements a few years back and quickly came to the same conclusion. ie: cold air is much more significant than a slightly freer flowing hot air source. I've always preferred to put a panel filter in a modified air box over a cone filter. On my last car I cut a 4 x 4 inch hole in the box (ie: the entire base) with a similar feed hole in the inner wing. So it was 100% cold air through a big hole.

Oh yes, I've also done the maths on "ram air" and it's totally insignificant.

tomstickland wrote:
Oh yes, I've also done the maths on "ram air" and it's totally insignificant.

There are companies out there who suggest their induction systems give a ram air effect. Bunch of liars. If you were getting a ram air effect it would be at something like 170+ mph and thats if the cold air feed were in the exact right place. Even then, the effect would give less than 1 bhp gain.

Cool, I noticed a huge difference when I put a standard airbox back on my GSI Astra after the previous owner fitted a K&N.
Never bothered changing the airbox on the BMW as I know these engines dont respond too well to bolt ons.

Interesting, that seems to work very well. I look forward to reading the results of the road test.

Road test will be carried out on weekend now.

I can guarantee much lower intake temps comapared to cones unheatshielded even from my first experiment.

The BMC is fitted to the Alpina and even in heavy traffic the low end power and response is not reduced at all.

When the unshielded ITG was fiitted to it the difference in power drop was really felt in traffic. The BMC gave more torque low end after mapping aswell. INfact, it gave a much smoother torque curve altogether.

Heres a dyno result of an e36 m3:

Piper x viper's are supposed to be pretty good. About Ԛ£190 too.

They are Ԛ£250 retail.

They are a normal cone filter inside a very small plastic heat shield. Not particlularly rated by anyone thats used them.

I can supply them at 20% discount but dont bother seeing as BMC is better and cheaper and looks loads better.

I am trying to get hold of a gruppeM style induction kit aswell but its very expensive. It works on E36's very well and Honda Civic Type R's. Its made out of carbon fibre and the noise they make is just evil.
Looking at Ԛ£200+ though.

You're forgetting that with the car moving, the 'hot air' won't stay around very long, and that the temperature in the engine bay is nowhere near that high when you're doing say 50-70mph...

And this is exactly what Im going to be testing when the new probes arrive.

Ive mentioned this above.

I personally dont believe temperatures will drop by a huge amount, but they will drop. I could be totally wrong but I dont see a very well ventilated engine bay.

Point is that a cold air feed is going to bring in air from the outside which which should be alot lower than under bonnet.

The results will show everything anyway, its all an experiment.

So far its been proven that lower speed driving and no heat shield on your cone will lose you power as the temperature is very high under the bonnet.

The tests I will conduct will be on the same day and at different roads speeds.

wow, going by your temps that would mean after the engine has come up to temeratre that you are lookig at a prety much constant increase of 14bhp? that is quite something! does the car become incredibly loud? or just have a sort of whoosh sound when its drawing air lie those standard cone filters?

You could lose alot of power by not having a heat shield.

The induciton noise from a BMC isnt stupidly loud, its just right.

liam012 wrote:wow, going by your temps that would mean after the engine has come up to temeratre that you are lookig at a prety much constant increase of 14bhp? that is quite something! does the car become incredibly loud? or just have a sort of whoosh sound when its drawing air lie those standard cone filters?

You'd get an increase of 14bhp over an open kit I think is what the test is showing?
An open kit would probably lose a fair bit of power over the standard kit though.

M5pilot wrote: For those that think the origional Airbox is the best thing think again

hi
i am one of those who thinks the original is the best. my reasoning is the same as you i suppose, i dont believe in all these cone filter bussiness. i have never been convinced they help your car in the performance side but only in the sound side. This a cool tread, very interesting stuff. I was actually thinking about bying a BMC filter and installing in the original airbox.
cheers

The main reason I even started this was because I know origional stuff can be improved upon. Epecially when your dealing with a car that was designed like 20 + years ago.

Standard suspension for example is not very good, its not compliant and the car doesnt handle at all.

Same goes for the exhaust system, the intake system, the gearshift.....

Origional BBS's are super cool though and so is the sports interior.

If an E39 M5 can have major improvements done by simply changing to a super sprint Exhaust manifold and reworking of the air box to get a massive increase of around 50 bhp then an E30 should definately be looked at.

The BMC is not a noisy system unless you take the feed pipe off.

but we all knew cones were pants.

Even if the air take system is old the only real dated part of it is the air flow metre. The rest is fine. BMW spent millions developing this system and engines.

The proof in the pudding sal is a dyno of a standard e30 with, whether it be a 316 or a 325

with print outs of torque and bhp

A) standard air box
B) cone sh!te
C) cheap as chips BMC box

then i can believe whats being said. temperature this, temperature that a dyno result is what we need!

M5pilot wrote:The main reason I even started this was because I know origional stuff can be improved upon. Epecially when your dealing with a car that was designed like 20 + years ago.

good point as long as everything is discreet, wouldn't want it sounding like a nova and farting up the roads. Just scared that with all these improvements the real car is lost.

sal dude, your a true jem, a marketing jenius also

bmc box on my list of things to buy sal

get those figures up

redrobbie wrote:

M5pilot wrote:The main reason I even started this was because I know origional stuff can be improved upon. Epecially when your dealing with a car that was designed like 20 + years ago.

good point as long as everything is discreet, wouldn't want it sounding like a nova and farting up the roads. Just scared that with all these improvements the real car is lost.

no matter how much u modify your e30 it will always have it's character. (excluding streetfighter bodykits)
It's the chassis and looks which to me give them this character plus 6 pots! Most people like them too, when was the last time someone wouldn't let u out in traffic? i know in my dads e46 325 no one would let me out!

Yeh your right simon, you park the car up and people walk past it as slowly as possible taking a good look, even little kids. I was at halfords and was topping up the washer fluid when i opened up the hood the kid started screaming to his dad "WOW". the fat beamers open up the other way now .

When I first brought it home the whole estate nearly came out to welcome her, and the best bit is seeing other e30 owners on the road and aknowledging each other. Now what other car can do that. LEGEND

sorry if i've gone off topic as compensation i will by the bmc, promise .

Sal

I wonder what effect getting some of that exhaust wrap would have, got to be cheap to do and would lower the under bonnet temp a bit

whats filtration like on the bmc and is it available for the 318is

Filtration is very good on the BMC and yes there is one for the 318iS.

Go to the Zone shop and youll see it under 318iS. (Zone shop button at top on menu)

does this come with the adapter u was on about sal?

Why don't you test it on your mates car with the MBE as you can hook a lap top up to it and get an instant temp reading static or driving at various speeds/revs ?

This is an old screen capture from the Emerald soft ware