13 replies to this topic

[300bhp/ton]

Some of you may remember I posted a few threads enquiring about Cold Air intakes for Mini's.

Well the response I got back was less than enthusiastic saying they don't work and are a waste of time.

However, I disregarded all of that and went ahead and designed one.

It was for my mates 1978 1275 GT Clubman. It has a "Stage 1" kit comprising of a LCB, single silencer sports exhaust and a drop in k&n filter, it has also been rolling road tuned.

So I removed all the emisisons hot air pipe and got rid of all of the stock air box, fitted some nice 3" bore ducting, routed it to the front and added a nice large Pipercross foam filter.

Sadly I was unable to do any performance testing before hand and as I don't have a rolling road in my garage I can't provide numbers.

All I can say is the engine feels a lot freer and revs much more happily. Also it has had a dramatic affect on fueling, as in it's now running out of fuel, so it looks like I'll have to re-jet the carb as well. I think this is the most decisive bit of information here.

If cold air intakes do nothing for air flow and peroformance it would not have affected the fueling at all. But evidently it has, and I suspect that with a tune up it will run even better.

Also it sounds pretty good too, you can hear it sucking when you rev the engine and even as the car pulls away a by-stander would be able to hear the CAI sucking air in. On a Mini with a stock/quiet exhaust it would be very noticable.

All up it cost £10 for the ducting, I had the filter already and the clips so it was a cheap mod and has certainly returned some HP.

If you wanted to make a kit for yourself I can't see any reason why it couldn't be done for £30-70 depending on what filter and ducting you use. It also looks much nicer than the stock air box.

Edited by 300bhp/ton, 18 December 2006 - 10:22 AM.

[Retro_10s]

great stuff buddy, look forward to seeing the work on paper, I presume you mean that when you say it's running outta fuel.... you mean it's lean?.... it should lean out the mixture causing you to need a 'richer' needle....
All interesting stuff.


P.S> also might be worthwhile testing the system against a K&N std replacement filter in a drilled airbox.....


P.S> ammended post, i had my morning head on... and had verbal squits.... oooopsy

Edited by Retro_10s, 18 December 2006 - 10:35 AM.

[300bhp/ton]

great stuff buddy, look forward to seeing the work on paper, I presume you mean that when you say it's running outta fuel.... you mean it's running rich?.... because that would make CAI pretty useless when, 'if anything' it should lean out the mixture causing you to need a 'richer' needle..

All interesting stuff.


P.S> also might be worthwhile testing the system against a K&N std replacement filter in a drilled airbox.....

Yeah it's running lean I think, seems to be short on fuel under certain circumstances where it wasn't before. So to my logic this means more air is making it's way to the engine and it now needs extra fuel to compensate, i.e. running out of fuel.

I'll try and get some pics, but probably not before the weekend (as it's my mates car).

[The Matt]

.................So I removed all the emisisons hot air pipe and got rid of all of the stock air box, fitted some nice 3" bore ducting, routed it to the front and added a nice large Pipercross foam filter.
........................All I can say is the engine feels a lot freer and revs much more happily. Also it has had a dramatic affect on fueling, as in it's now running out of fuel, so it looks like I'll have to re-jet the carb as well. I think this is the most decisive bit of information here.

If cold air intakes do nothing for air flow and peroformance it would not have affected the fueling at all. But evidently it has, and I suspect that with a tune up it will run even better.
................

This doesn't necessarily sound like it is the 'CAI' that has caused the induction sound, more the fitment of a different filter. And also the 'running out of fuel' symptom you describe????? Not sure what you mean by that?

Is it running lean perhaps, since ftting a free flowing filter, hence putting a weaker mix of fuel/air into the engine?

Everything you decribe sounds like it has more to do with the fitting of the filter than a magic piece of ducting.

I would like to see recordings of the inlet temperature around the filter before and after the fitment of this CAI, as I doubt it would be any different to ambient in either case, at any speed above around 5 miles per hour.

Sounds interesting though.

[Retro_10s]

lol just read what i posted, complete baulderdash sorry mate.... must have my morning eyes on... running lean, yes it will need a richer needle.

[300bhp/ton]

A good intake is more than just intake temps, it's about flow as well, and I believe the stock airbox even with a k&n eliment posed a restriction.

I wasn't sure if it would make any odds or not, but the car "feels" faster even without tuning it, and as the fueling has been affected it's logical to assume more air is making it to the combustion chamber as this was the only alteration to the setup.

So more air + the extra required fuel = bigger bang which in turn means more HP.

And as for the intake temps I strongly believe it does affect them, I know someone posted a link about a test, but in reality I don't see what substance it held as it was vague in how and where the measurements where being taken.

On my Camaro the air intake is IN FRONT of the engine by about 18" however the addition of a CAI intake has seen substantial drops in intake temps, this goes for just about every engine setup I've ever seen of researched. Under the laws of physics I see no reason why the Mini should be an exception.

[Retro_10s]

I believe the stock airbox even with a k&n eliment posed a restriction.

it most certainly is, which is why you drill it, But then even the CAI will cause restriction.

I think you need to test both against eachother., as they are both very cheap forms of creating a better, more efficient airfilter for relativley little money, and since there are people on here running this drilled box and filter set-up... I feel it would be good to see the comparison between the two.

This way the effort involved in making the CAI could be justified if it's a greater performer than the box with holes etc...

[The Matt]

A good intake is more than just intake temps, it's about flow as well, and I believe the stock airbox even with a k&n eliment posed a restriction.

I wasn't sure if it would make any odds or not, but the car "feels" faster even without tuning it, and as the fueling has been affected it's logical to assume more air is making it to the combustion chamber as this was the only alteration to the setup.

So more air + the extra required fuel = bigger bang which in turn means more HP.

And as for the intake temps I strongly believe it does affect them, I know someone posted a link about a test, but in reality I don't see what substance it held as it was vague in how and where the measurements where being taken.

On my Camaro the air intake is IN FRONT of the engine by about 18" however the addition of a CAI intake has seen substantial drops in intake temps, this goes for just about every engine setup I've ever seen of researched. Under the laws of physics I see no reason why the Mini should be an exception.

Firstly, do a direct comparison. Drive it with your CAI fitted, then remove that and drive it with just the Pipercross filter, I suspect you will see no difference.

The air supply at the back of a mini engine bay is plentiful, there is a mahoosive grill which lets a substantial volume of air through. As for the volume of air that is being supplied by the CAI, how is it fitted? Is the filter totally enclosed so that it can only recieve air through your 3" pipe, or is some of the filter still exposed to the air from the engine bay? Would you be able to post any pictures of the setup for us to see please?

Under the laws of physics..............?
Measure it, never mind the laws of physics. Physically measure the temperature around the intake of the carb, before and after the CAI is fitted and measure the ambient temperature in both cases.

The test that was posted was vague yes. But I suggest fitting a temperature sensor to the front of the grill, and a second sensor to the area directly behind the carb. Even better, use a data logger to do it and record the results, better still record temperature for both positions with a record of the cars speed. Repeat that test with a CAI fitted, see how fast you need to be going for the outlet of the CAI to meet the ambient temperature.

[Jammy]

Of course its going to need rejetting, whenever you change something in the breathing of the engine you need to compensate for that by tuning the carb. However, don't assume that just because the carb needs rejetting that performance will be increase. You could take off a performance LCB manifold, and put the standard cast manifold back on, the carb would need rejetting and you'd lose power and torque afterwards.

[Clubby1275GT]

sounds to me like all your feeling is the impact of putting a performance filter on, on a clubman the whole grille is practically an air duct so i dont really see the need for a pipe, anyone i no who has put anything like that on any car only seem to do it when the air intake is restricted through the grille, and even then they say oh yeah its 10 times faster, but in reality its just the same, just pscologoically they want it to be better.

but as far as science goes ill be very surpised if it has made and difference at all. By using that induction pipe arent we getting into the realms of forced induction?? which then ofcourse needs more fuel etc to compensate for the extra "forced" air? but then the engine in standard form can only take a certain amount until u hav to improve the head/cam etc so seems a little pointless to me.

Edited by Clubby1275GT, 18 December 2006 - 03:19 PM.

[supermotolee]

check out the miglia setups with webbers and the massive airbox and duct thats a propper air intake as far as i've ever known engines like cold still air thats why high volume airboxes get such good results on race bikes and cars but then again you see plenty of vehicles with open trumpets that work well too

to be honest i think the ducting is a bit of a waste of time unless your hoping for ram air effect which isnt going to happen really as they just dont go fast enough to build up enough pressure behind the butterfly

[miniboo]

just to go with what everyone else has said: the reason the car is under fueling is because you are adding more air(freeflowing filter) I doubt the CAI has helped at all.

try driving it without the "ducting " and i bet it will drive the same as with

BUT then again you ignored all our advice last time so why would you start listening now

[Jammy]

BUT then again you ignored all our advice last time so why would you start listening now

No harm in trying!

I for one will be more than pleased if 300bhp/ton finds out that this does improve power and/or torque, since it will be a very cheap and effective way of improving the performance of an engine.

All I was saying before is its been looked at before and its unlikely to work.

[TOMMO0302]

Too right Jammy! Definately no harm in trying and i also strongly hope it has genuinely improved performance, as it will be good for all of us, and prove the doubters wrong! lol

I no nada, so can't really comment, but i don't believe we have to poo poo over peoples thoughts and efforts!

Does anyone know who did the test on mini directory? I heard it was a bit vague, is this the only basis for people's negativity surrounding the subject?