Griffith air intake - improvement?

[RichB]

Grovelling around under my car at the weekend (Hammerite / wishbones) I was pondering the Griffith’s air intake. Mindful of Julian Rowntree’s article on tuning his Cerbera in this months Sprint I wondered if it could be improved? (the Griff air intake not his article!)

Experts on here say the Griff’s air intake is OK and not worth changing but to me it appears restrictive. Quick calculations show it has a total intake area of approx 73 sq” ( 3 opening each of about 3.5” x 7”). Julian reckons the standard intake on the Cerbera is only 56 sq” and well below area recommended by K&N for a 4.5 performance engine. His new arrangement of 2 x K&N cone filters in an alloy box gives a substantial 160 sq” of intake area.

Given that the breathing requirements of a 4.5 Cerbera V8 and a 5.0 Griffith V8 must be similar do you reckon that it would be worth constructing a similar arrangement to “Julian’s Box” for the Griffith?

Cheers Rich…

[trefor]

Hasn't David Beer done something along these lines, or at least some kind of ram air induction adaption?

[RichB]

Indeed - David has fitted a larger splitter under the nose of his Griffith but I'm not sure if this was for cooling, stability or breathing, but either way... the foam filter will have a maximum flow rate, so you can "ram" all the air you like up there but if the area of foam is too small it won't get past. Rich...

[2 sheds]

I've been thinking about this myself, i have a Griff with the cylindrical filter so i can possibly make an improved airbox / filter housing for that, but not sure how it would fit in a later car such as yours Rich.
The current early housing is dreadful , too small and collects hot air from the radiator when moving slowly.
Space in the griffith is limited but i'm sure we could improve on the standard items.
Tim

[shpub]

I ran the 520 on a standard Griff filter in its 360 bhp form and noticed no improvement when the filter was removed. To be honest, I think the term diminishing returns come to play. A more important factor is air temp and it is hard to see how that can be improved without cutting holes in the body work.

[RichB]

I see your point Steve, and this would imply that Julian's air box was more of a labour of love rather than a reqirement, and I guess of course the K&N web site could be full of marketing hype Rich...

[simpo two]

shpub said:

A more important factor is air temp and it is hard to see how that can be improved without cutting holes in the body work.

I tried to figure out a clever way to cool the air by reducing the pressure with a venturi, but then the pressure is lower so there's less air in any given volume... doh.

I can only come with an air intercooler... actually that's not so daft, it's called air-con - just disconnect it from the dash vents and stick it in the airtake. Then switch between them ie, 'comfort/sport'.

Almost dangerous aren't I?

>> Edited by simpo two on Monday 18th August 12:34

[IPAddis]

Removing the inlet pipe and hence the air filter from the air flow meter made 7bhp difference to my car on a rolling road.

Not sure how much was inlet pipe and how much was air filter but a surprising amount of difference.

Ian A.

[david beer]

I put the air ram underneath as at 70 mph if the half speed fans were on it reduced the temp, indidcating poor aerodynamics. So i decided to ram the air through the rad. I also have my air intake pipe heat shielded, it was noticable that if sat at lights, the first full throttle blast always felt a little flat until the air intake cooled. It also helped with pinking at the same time. Demon tweeeks sell it. But i have to say, it aint pretty !

[Moto]

Simpo Two, I like your idea with the aircon. Does anyone know what power loss you can expect from having aircon turned on ???

[Apache]

I'd think the laws of physics precludes any performance gains due to the power drain from the ac.......but would a freefall basketweaver know

[heliox]

I looked at this recently too and thought that the Cerby filter type was a better way to go but as has been said its a tight squeeze.

You could enlarge the existing hole where the cylindrical filter sits in and use a flat Cerby type filter with a gorgeous carbon fibre cover that the air inlet hose plugs into, similar look to the Act pleniums would be the best descrption.

just a though of course

h

[wixer]

Weird, I've been contemplating this very thing myself this weekend, had the filter(cylindrical) off on Friday, gave it a wash through with soapy water, as suggested by TVR Power, re-oiled it but put it back without the pathetic piece of ABS plastic shroud. My thoughts are, it may suck a little more hot air in from the engine bay but the shroud must have been reducing the airflow somewhat. Had a run up the road without the filter on just to see if I noticed any difference, just seemed to make more induction roar, no noticeable performance increase. The slot in the nose cone seems a little restrictive also, was thinking of opening it up a tad.

[simpo two]

Apache said:

I'd think the laws of physics precludes any performance gains due to the power drain from the ac.......but would a freefall basketweaver know

I had a feeling it would be like standing in a boat blowing into the sail, dman...

Moto, thank you for recognising flawed genius (or floored genius!). I know aircon is supposed to lower mpg but in my old Jag with instant mpg readout, there wasn't any difference, so the change must be less than 0.5mpg. As for bhp loss, is the compressor always driven or does it only come on when you swith the AC on? If it's on all the time you have nothing to lose! Time for a TVR aircon expert please...

[andy43]

Is the A/C always driven - if its the same as a 'normal' set-up, no, only the pulley always spins with the drive belt, but the compressor has a kind of electromagnetic(I think) clutch between the pulley and the power hungry bit. The clutch kicks the compressor clutch in when a thermostat-type thing somewhere in the AC system tells it the fluid/gas is getting too hot, then knocks it back off when the coolant is cold enough again... if its the same as a Vauxhall or Toyota, leave the car idling with the AC on and maybe once a minute you'll hear the engine note change as the compressor kicks in or out. Or not, as its a TVR, and they probably thought up A Different Way To Everybody Else Just For The Hell Of It...

[Guillotine]

a/c compressor only runs when a/c switched on. never seen mine drop out as it works so hard!!

air intake, Peninsula and I have done a twin splitter arrangement on mine to improve airflow. its invisible and effective. it was a GontheG and RichB saw it (on the peninsula stand)

they're gonna sell them now.

also working on...

longer passenger footwell, with waterproof electrics!!!

and

underbonnet airflow. hot air out, cool air in.

both of these should be complete in the next 2 weeks. and may be available from peninsula IF successful.

if someone will tell me howto get photos on to the site, i'll post some!

cheers

[HarryW]

Link on this thread for pic posting www.pistonheads.com/gassing/topic.asp?t=49792&f=9&h=0&hw=posting+pictures

Harry

[Guillotine]

trying

http://pics.fotango.com/pictures/0400393827_001T.jpg

nope




still trying

[pic]http://pics/fotango.com/pictures/0400393827_001T.jpg[pic]

hmmm

[pic]www.fotango.com/pictures/0400393827_001T.jpg[pic]

boring...

[pic]http://pics.fotango.com/pictures/0400393827_001T.jpg[/pic]

bored!

atleast theres a pic on my profile now!
will settle for links and take a photo of the splitters...

ok,

[pic]http://pics.fotango.com/pictures/0400393827_001T.jpg[/pic}

...hmmph!




>> Edited by Guillotine on Sunday 24th August 10:54

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>> Edited by Guillotine on Sunday 24th August 20:19

[Edt]

it goes ...



you're missing the / in the closing [pic]

Ed

>> Edited by Edt on Sunday 24th August 14:51