Offroad induction kit advice needed

[StacytheBloke]

i'm currently in the process of fitting a ls400 v8 into a bowler tomcat offroad racer, and i am having some issues with choosing an air filter/induction system.

This is what a Bowler looks like for those of you who may not have seen one:

http://www.bowler-offroad.com/

Having read the famous filter test (oldey but a goody)

http://www.mkiv.com/techarticles/filters_test/2/

i decided on maybe going for a k&n type filter as these are washable and oiled filters have a good reputation in offroad racing particularly motocross. However i have been warned off oiled filters as apparently they 'can' interfere with the reading the Karman vortex afm gives out causing bad running.

As a general rule i have been told to double the air filter area for the particular application to ensure it doesn't strangle the engine when covered in mud, so two filters is looking like the route to take (bloody expensive)

Now on slight worry i have is with the way that the apexi filter works, does anyone know if these will be sensitive to a reduction in the air flow rate as fitting double the filter area will result in half the air velocity as it passes through the filter.

i am looking at merging two 3" stainless pipes (filter on the end of each) feeding them into one single 3" stainless pipe, through a valve to prevent the engine sucking up water and then into the afm
link to water prevention valve

http://www.envyperformance.com/index.cfm?fuseaction=product.display&Product_ID=3415

any comments sugestions and advice would be much apreciated as spending close to UK£400 on an induction system is a bit scary. It maybe nessesary but it is still scary.

k&n is the tried and tested route for people using other engines but this airflow meter oil issue has me worried.

 

[cebby]

Why not run the induction pipes into the cabin (high up)? That would solve your water/mud worries without a valve...

If you dunk that AEM diaphram, won't it suck in water anyway? (says it draws from outside the diaphram when water is sensed in the intake (?))

I've run K&N's for years. That's a good choice IMO.

 

[Zuffen]

I'd go Cebby's way and run the intake into the cab and use a stock Toyota/Lexus round filter.

As the filter will be operating in a lower dust environment than under the bonnet the standard filter would suffice.

If you're worried use a disposable oiled pre-filter as the Toyota filter will stop oil mist getting on the KV reader.

 

[StacytheBloke]

Thanks for the advice

(dust... whats that i live in england we only get mud)

unfortunately the rules stipulate the air must be taken from under the bonnet, so no snorkel or cabin feed is allowed, and as this is a club racer version with no glass in any windows the cabin is not a much cleaner place to be, i'll end up jet washing myself more often than not.

nice to know a k&n has proven trouble free though. and a standard toyota filter may be worth considering, they are a bit big!

not much room under their as the engine is about 6 inches further back than it would be in a standard landy, the full exhaust system is in there including back boxes as they exit from the front wing, just behind the front wheels, the adjustable antiroll bar runs across the front of the engine, with two 14" travel coil over remote reservoir fox shocks under there.

Will scratch my head a bit more and see what i can come up with.

 

[cebby]

Can you post a pic of the engine bay so we can have a look and maybe offer a more appropriate solution?

 

[StacytheBloke]

found a spot for the standard toyota airbox, will have to do a minor shuffle with my transmission oil cooler but that is very minor as it is only tac mounted for now.

will try on dig out some old engine bay pics of someone elses 4.6 rover v8 in a tomcat as i am currently in a state of total disassembly. doing a ground up build

Thanks a lot for the advice, clear plan (ish) again