[roland2003]

Hi guys as an extension of the tests we carried out on the benefits of modding the plastic SC inlet plenum ,we have just spent 3 hrs swopping and testing air filters .This is the first 'on the car' tests we have carried out,previous tests were on the flow bench where and when we designed the GTT Cold Ram Induction Kit. The test uses an accurate vacuum guage connected to the outlet on the side of the rubber hose between airbox and throttle (see pic). It is perfectly positioned as is at 90 degrees to the flow & flush to the inner wall. Any pressure drop we measure here indicates a restriction in the airfilter system as a whole,but will NOT include any restriction in throttle body or indeed anything after the filter assembly. Test uses wide open throttle in third gear at 6500rpm, car has -17% SC pulley to. In other words a test with high volume of air demanded. All filters will be pulling in cold air of 'similar' temperatures. Please note a '1 psi difference' between the filters, will almost certainly make worthwhile power differences too .(upto 10bhp)

TEST ONE
Stock Airbox (c/w brand new filter element) Result -1.4psi

TEST TWO
JCW Airbox
(c/w brand new filter element & flap jammed full open -see pic) Result -1.1psi

TEST THREE
GTT Cold Ram Induction Kit (c/w brand new filter element) Result -0.6psi

TEST FOUR
GTT Cold Ram Induction Kit (No Element !, just the GTT Rampipe) Result -0.6psi

CONCLUSIONS Stock system gives over twice the restriction of GTT Cold Ram,also JCW is only slightlly better than stock.
The (pleasent) suprise result for me was that the cotton guaze cylindrical element we use on our Cold Ram Kit ,gave no additional restriction whatsoever over the 'Naked Rampipe' used in 'Test Four'.
Corrugated cotton guaze filter elements (such as JR,K&N etc), I have always found gave less restriction than foam filter elements (Alta,Pipercross etc). This I think it is due to the big increase in surface area that the corrugated surface has over the 'flat surface' foam types.

Regards Roland Gt Tuning

[Root Ginger]

Excellent work Roland. I'm always impressed by your posts and I think that I may now be swaying to the GTT CRI over the Alta CAI. Shame this was not in your test too but you can't do everything can you.

[roland2003]

OK Here are the pics;
1) Stock airbox & Filter
2) JCW airbox & filter
3) GTT Cold Ram Induction Kit
4) GTT Cold Ram (with filtration elements removed)
5) Shows the self tapper screw we used to ensure the JCW flap was always fully open to give it 'every fighting chance.

In pic (3) you can clearly see where the 'T' off is taken from (you can see a bit of yellow ). The breather pipe which normally goes in this hole is vented to atmosphere instead ( A good idea anyway)

[Jaffa Racer]

Good work Roland, now I know why with just the GTT CAI it feels like she goes better.. because she does. Really 10 BHP per psi

[E Yorks Andy]

Thanks for the write up Roland. It looks like I made the right choice when I bought my kit from you last year.
Funnily enough I took the filter off last night to return the car to stock for a service. I was surprised at how much difference it makes. I'd forgotten how dull the supercharger sounds with the stock filter box.

[roland2003]

Hi Root Ginger.
We did include the Alta on the original flow bench test and the GTT was a fair bit better.To be honest if it wasn't then you'd need to re-write all the text books regarding Rampipe design in particular the need for a full 360 degree rolled edge & the need for the entrance to be somewhere 'well out into the airbox'. I want to do this 'on the car' test with the Alta as soon as I can borrow another one for a few days. The airflow into the airbox (with the car at high speed )and the airbox volume will both effect results slightly from the 'flow bench test',so I want to do this 'live' test with Alta ASAP . We learnt alot whilst designing 34mm turbo intake restictors for our rally cars (MSA regs to try and slow you down!). If you get it right you can get it flow more air than a plain tube of 42mm 'entrance diameter ',which was the OD of the turbo compressor wheel we used. No suprise that the perfect shape was a trumpet with full rolled edge (Rampipe)
Regards Roland Gt Tuning

[roland2003]

Heres a pic of GTT Rampipe we used directly on the turbo compressor inlet, for dirty conditions we used similar item but with parellel sides to clamp air cleaner hose to, at the other end was........ you've guessed ...GTT Cold Ram Induction Kit. The design for the Renault 5 GT Turbo was almost identical. The main difference is that our Mini kit benefits from integral twin skin airbox to ensure only cold air gets through.
Regards Roland Gt Tuning

[Tonyt3]

Quote: Originally Posted by roland2003

Hi guys as an extension of the tests we carried out on the benefits of modding the plastic SC inlet plenum ,we have just spent 3 hrs swopping and testing air filters .This is the first 'on the car' tests we have carried out,previous tests were on the flow bench where and when we designed the GTT Cold Ram Induction Kit. The test uses an accurate vacuum guage connected to the outlet on the side of the rubber hose between airbox and throttle (see pic). It is perfectly positioned as is at 90 degrees to the flow & flush to the inner wall. Any pressure drop we measure here indicates a restriction in the airfilter system as a whole,but will NOT include any restriction in throttle body or indeed anything after the filter assembly. Test uses wide open throttle in third gear at 6500rpm, car has -17% SC pulley to. In other words a test with high volume of air demanded. All filters will be pulling in cold air of 'similar' temperatures. Please note a '1 psi difference' between the filters, will almost certainly make worthwhile power differences too .(upto 10bhp)

TEST ONE
Stock Airbox (c/w brand new filter element) Result -1.4psi

TEST TWO
JCW Airbox
(c/w brand new filter element & flap jammed full open -see pic) Result -1.1psi

TEST THREE
GTT Cold Ram Induction Kit (c/w brand new filter element) Result -0.6psi

TEST FOUR
GTT Cold Ram Induction Kit (No Element !, just the GTT Rampipe) Result -0.6psi

CONCLUSIONS Stock system gives over twice the restriction of GTT Cold Ram,also JCW is only slightlly better than stock.
The (pleasent) suprise result for me was that the cotton guaze cylindrical element we use on our Cold Ram Kit ,gave no additional restriction whatsoever over the 'Naked Rampipe' used in 'Test Four'.
Corrugated cotton guaze filter elements (such as JR,K&N etc), I have always found gave less restriction than foam filter elements (Alta,Pipercross etc). This I think it is due to the big increase in surface area that the corrugated surface has over the 'flat surface' foam types.

Regards Roland Gt Tuning

Could you not have run the tests without filters on the standard and JCW airboxes also - ? I would assume they would/should give -0.6 as well in this case...?

[Root Ginger]

Quote: Originally Posted by roland2003

Hi Root Ginger.
We did include the Alta on the original flow bench test and the GTT was a fair bit better.*SNIP

OK I'm sold. As soon as I get some funds together I'll get one. Incidently I was thinking of adding Orciari vent covers, but from reading your website this may not be the best idea for improving flow. What are your views?

[roland2003]

Tony We did do a 'With element' v 'Without element' on the other thread I started ('worthwhile mod.......' ) There was an improvement but only very slight.
Tony also suggested to me it would be nice if we could offer an upgrade filter element for JCW filter owners,this would be a good idea as (A) Many people already have the JCW filter and (B) if contained within the JCW bairbox is very discrete.
The good news is I think we can do it 'relativly easily '. We would replace the restrictive paper element with the JR cotton gauze element & foam 'end-cap filter' with the same ones used on the GTT Cold Ram kit. It would not have the internal Rampipe that our Cold Ram has, but I think would still be a worthwhile upgrade. I will produce one tommorow (as long as it goes in the airbox ok) and test at the next opportunity.
Root . Do you have a pic of the vents?
Regards Roland Gt Tuning

[Root Ginger]

Quote: Originally Posted by roland2003

*SNIP
Root . Do you have a pic of the vents?
Regards Roland Gt Tuning

I'll PM you to save taking over this thread...

[Bilbo Baggins]

Roland,

Great stuff. Would it be possible to see what a foam panel filter did in a stock air box, while you were testing things?

[Tonyt3]

i have Ocari vents fitted....

no idea if they do anything at all to improve power... i suspect not....

[Root Ginger]

Quote: Originally Posted by Tonyt3

i have Ocari vents fitted....

no idea if they do anything at all to improve power... i suspect not....

I was kinda wondering about the ram affect with the air and whether this would be detrimental or beneficial to the flow. The opening surface area is a lot smaller than stock but it probably gulps more air in, albeit turbulent. I just wanted Rolands professional opinion on it, as he does mention on his site about "a small funnel shoved into the outside airstream will not achieve good flow", but wondered whether this would be the same thing. I'll await his PM...

[Bilbo Baggins]

Quote: Originally Posted by Tonyt3

i have Ocari vents fitted....

no idea if they do anything at all to improve power... i suspect not....

Back in the '60s they used to have something called "cowl vents" or "cowl induction" that utilised the high pressure air at the base of the windscreen to "pressurize" the air going to the carburetor. These vents actually opened/pointed back towards the windscreen not towards the front of the car. It seems as though the air flow at the base of the windscreen was actually flowing down and forward.

So, I question whether the Ocari vent, which faces towards the front, actually does anything. Some testing with wool tufts needs to be done to check the direction of air flow in the local area.

[314fxh]

Glad my old JCW CAI box helped doing this test ;-) After you fitted the GTT CAI on mine I can tell you that the seat of the pants difference is a more responsive throttle, especially on those sudden stamp on the throttle over taking moves and no breathlessness at the top end. Great product, the noise under full throttle is just an added bonus!

[beken]

For the benefit of those who don't want to do any mods to the airbox, is there a GTT filter available for the stock airbox of a MY05 MCS? Is there any measurements of restriction of an upgraded filter within the stock airbox?

This is good information.

Thanks for posting....

[Andy@Ross-Tech.com]

Nice work! I did similar testing a while back, logging the upstream MAP sensor (which taps into the air stream in a very similar spot to the breather hose that you used) using BiM-COM. With the 15% pulley, I compared stock with the Alta:



Later, with the 19% pulley, I compared the Alta to the HAI:



As you can see from the difference between the two Alta runs, the 19% pulley draws considerably more air than the 15% and shows a greater restriction in the intake path.

[CoryB]

Good test on vacuum drop through the filters. Now can you test the filtering efficiency of each medium - i.e. paper versus guaze?

My experience - mostly off-road environment - with properly oiled. sealed and installed K&N style filters is that they let a substantial amount of microdust through that a paper filter doesn't allow.

While maximum airflow is certainly desirable, personally I'd prefer longer engine life over an extra horsie or two.

[roland2003]

Hi Andy, I guessed those graphs (seen them before) were using output from the upstream map sensor. Taking the reading from there will also include any restriction in the TB and the 'first bit' of the plastic inlet plenum(if any). My connection was 'pre throttle body ' so only measures airfilter system limitations. The other test I did on the 're-moulded plastic SC plenum' took its connection from the quick release connection on the SC itself. (The PCV valve inlet) In doing this I can monitor the restrictions including any along the entire length of the plastic plenum. Another test you could quite easily do is repeat your test but swop the plumbing to the PCV and Map sensor around, any increase in vacuum you get is then proven to come from the restrictions in the 'plastic SC plenum'. I found the modified item gives about 0.2-0.3 psi drop across it.(max revs -17% pulley).
The higher the revs and the more boost you run the more any restrictions will raise their ugly head. A significant pressure drop at 7000rpm with a 22% pulley may be next to nothing on a stock car at 5000rpm. That Alta intake even on your 'less demanding' -15% test ,looks pretty restrictive,I cant wait to do 'live' test on it!
Cory,I think unless your driving across the desert both cotton gauze & reticulated foam will give more than adequate filtration.I ran my R5 GT for 5yrs with no filter atall and apart from slight erosion on the turbo compressor impellor nothing wore at all, I even did rallys like this (mad but true) ps I dont recommend 'no filter' unless you enjoy living dangerously though.

Regards Roland