throttle bodies + airbox vs non airbox?

kokkolanpoika · Post by **kokkolanpoika** » Sat Jan 01, 2011 5:44 pm

Make any sense? Rover 5.2litre V8 with jenvey throttle bodies + airbox?
Or without airbox?
Is it same to fit airbox as keep original plenum etc? is the airbox reduce power?

like this
http://www.thepipercrossshop.co.uk/comp ... airbox.asp

+ my ITB setup need airfilters, is it better to buy 2 big filters? Or 8 small filters and fit them to airhorns? If i use 8x small filters then i can change inlet manifold lenght approx 20mm without buy new airhorns.. I have got some spacers between throttle bodies and airhorns that i can use 2x big filters.

2x http://www.jenvey.co.uk/Imgs/Accs/ABF2_100.jpg
or
8x http://www.mopo-osa.com/kauppa/popup_im ... peq9olpah2

Any experience?

stevieturbo · Post by **stevieturbo** » Sat Jan 01, 2011 11:57 pm

I would go for the airbox first. Although those airboxes seem quite small. They need more capacity in my opinion.

Big air filter second.

And 8x filters last.

kevcon · Post by **kevcon** » Sun Jan 02, 2011 10:32 am

Totally agree
Had a mate who ran with those socks and had nothing but problems. In the end swopped to a large filter and pick up power.

kev

CastleMGBV8 · Post by **CastleMGBV8** » Sun Jan 02, 2011 11:01 am

Timo,

How big a cam are you using and what vehicle and use?

Using a plenum with a high lift long duration cam you will get exhaust gas reversion through the inlets which will contaminate the inlet charge into adjoining cylinders until the engine gets on cam, so at low RPM until the engine gets on cam their will be some loss off performance so independent filtering can be of advantage at low revs.

However the use of a a plenum/s can be useful as as it is easier to plumb in a cold air supply which at high revs will more than compensate for the loss of power at low revs.

All depends on how you use the engine.

Kevin.

kokkolanpoika · Post by **kokkolanpoika** » Sun Jan 02, 2011 2:53 pm

My cam is V8developments/realsteel M238 with siamesed plenum etc it will rev 5500rpm and redline 6000rpm.
Car is SD1, so quite heavy. It has got big engine so it has got lot of torque wit low revs..

Why you recommend to use plenum? how big? twice as pipercross?
Only what i think is it will not suck hot air like 2 big filters? Easier to make cold air kit..

What symptons can 8xsocks do? They are lot of cheaper that 2x big filters and plenum..

stevieturbo · Post by **stevieturbo** » Sun Jan 02, 2011 3:22 pm

IMO socks have a very small filtration area and they sit very close to the trumpet itself.

I just think they are crap....but thats just my opinion lol

kiwicar · Post by **kiwicar** » Sun Jan 02, 2011 5:33 pm

I would go for 2 nice big air boxes, at least 10X cylinder volume each with a nice fresh air supply from outside and a big paper element air filter (twice the size installed in a similar output engine buy a car manufacturer ). But I like paper element filters because they do actually filter the air, that is why they are changed from time to time

Best regards
Mike

Ian Anderson · Post by **Ian Anderson** » Sun Jan 02, 2011 5:41 pm

After going to the expense of throttle bodies I'd consider it a waste to cover it all up in a plenum / airbox arrangement

How many miles are you doing on really dusty roads than means you need to cover up that bling?

What about stainless steel "tea strainer" filters to keep out pebbles and small children!

And for what it's worth a hemisphere surface area is over double the cross section of the throttle body so in itself still allows good air flow
see
http://www.bills-b-racing.com/index1.html

Ian

Ian Anderson · Post by **Ian Anderson** » Sun Jan 02, 2011 5:44 pm

Or make your own from tea strainers
http://www.amazon.com/Mesh-Wonder-Ball- ... 76&sr=1-10

Pictures available here
http://www.gt40s.com/forum/gt40-tech-en ... lters.html

Ian

stevieturbo · Post by **stevieturbo** » Sun Jan 02, 2011 9:29 pm

Ian Anderson wrote:After going to the expense of throttle bodies I'd consider it a waste to cover it all up in a plenum / airbox arrangement

How many miles are you doing on really dusty roads than means you need to cover up that bling?

What about stainless steel "tea strainer" filters to keep out pebbles and small children!

And for what it's worth a hemisphere surface area is over double the cross section of the throttle body so in itself still allows good air flow
see
http://www.bills-b-racing.com/index1.html

Ian

Such things probably block abut 50% of the trumpet's airway and dont filter anything. They're worse than trumpet socks lol

At least a sock will filter a bit.

Ian Anderson · Post by **Ian Anderson** » Mon Jan 03, 2011 9:38 am

stevieturbo wrote:
Ian Anderson wrote:After going to the expense of throttle bodies I'd consider it a waste to cover it all up in a plenum / airbox arrangement

How many miles are you doing on really dusty roads than means you need to cover up that bling?

What about stainless steel "tea strainer" filters to keep out pebbles and small children!

And for what it's worth a hemisphere surface area is over double the cross section of the throttle body so in itself still allows good air flow
see
http://www.bills-b-racing.com/index1.html

Ian
Such things probably block abut 50% of the trumpet's airway and dont filter anything. They're worse than trumpet socks lol

At least a sock will filter a bit.

Hence the need fot the hemisphere
If you just gauze over the end of the trumpet you reduce airflow
Go to hemisphere and the area more than doubles
Allow for the wire area and you are back to a fairly open throat with very little restriction

I agree the do not filter but keep the big crap (read small children and pebbles) out and that is what does the major damage.I would hazard a guess that unless mega miles are done then no additional wear on any internals would be noticed.

Socks - highly restrictive and better to make an air box arrangement with sufficient good filtration area to allow the engine to breathe.

IAn

ian.stewart · Post by **ian.stewart** » Mon Jan 03, 2011 9:56 am

I run my TBs without any filters, but I do run a carbon airbox fed from outside the engine bay, and gauze filters on the external feeds, [cut down wilkinsons flour strainers] the Airbox obviously supplies cooler air to the intake, cooler air the more dense the fuel air mix can be run,
Big overlap cams do cause reversion, when I am running on Mway I can often hear the odd noise of reversion happening.

stevieturbo · Post by **stevieturbo** » Mon Jan 03, 2011 7:29 pm

I really cant see why anyone wouldnt want to run a proper air filter. It just doesnt make any sense ?

kiwicar · Post by **kiwicar** » Mon Jan 03, 2011 8:03 pm

Ian Anderson · Post by **Ian Anderson** » Mon Jan 03, 2011 8:16 pm

stevieturbo wrote:I really cant see why anyone wouldnt want to run a proper air filter. It just doesnt make any sense ?

If you have gi=one to the trouble of going ITB presumably you are looking for best response etc

So why then would you want to put any restriction in the way?

IAn