Jenvy Bodies, Filter Or No Filter?

[streetsleeper 0]

Hi people

Its my first post on here and this topic has proberly been discussed on here before, but what are your views on running throttle bodies without an air filter?

Im upgrading from twin 45 weber carbs to jenvey throttle bodies with wild cams, solid lifters, forged rods and pistons etc, and its being built at the garage now. Matt at pug1off says that i won't need a filter and that i won't have much to worry about, but I know theres a risk. Apart from the obvious risk of dirt, dust and grit, im also worried about rain and water splashing up off the road.

Also I think it will be getting mapped pretty soon and I was wondering if I was to fit an air filter afterwards would it need a remap due to a filter restricting the air a bit, and making it run richer??

[tomcolinjones 26]

filters are there for a reason, but i guess if you have gone for forged everything then it is going to be rebuild verry often? i know if it where my car i would use a filter, its not just dust and water like you say. but what if a stone or something went down there? wouldnt be nice!

 

it makes sense to get it mapped in the state that is will be driven. am i correct? no point setting it up for no filet then slapping one on is there?

[Chris H 10]

I can't see any logincal reason for NOT running a filter.....seems a no brainer to me.

 

Why spend thousands on an engine and suck all sorts of s*ite in and prematurely wear out your engine!

 

And of course...there is allwyas the chance of something bigger than dust getting in and destrouning the engine in seconds.

 

Personally.....if an engine builder told me i didn't need a filter...i gather up my bits and take them elsewhere!

 

My personal opion based on experience and inteligence.......feel free to do what you want, but don't come back crying if you learn the hard way!

[streetsleeper 0]

I can't see any logincal reason for NOT running a filter.....seems a no brainer to me.

 

Why spend thousands on an engine and suck all sorts of s*ite in and prematurely wear out your engine!

 

And of course...there is allwyas the chance of something bigger than dust getting in and destrouning the engine in seconds.

 

Personally.....if an engine builder told me i didn't need a filter...i gather up my bits and take them elsewhere!

 

My personal opion based on experience and inteligence.......feel free to do what you want, but don't come back crying if you learn the hard way!

Not as much said i did'nt need a filter but said that he has never had a problem with it. I do want a filter just for piece of mind really, altho im gonna struggle to get the extra cash The filter off my webers is too old now, dunno if the base plate will fit tho?

Edited January 8, 2011 by streetsleeper

[GilesW 41]

From someone (me) who used to run a £12k "forged everything" engine - you'd be a puppy not to run a filter.

 

Not only does it protect your engine, but dust and debris are none of the key ingredients for good combustion and as such you don't want them in you engine.

[Jrod 7]

We mapped my engine with no filter, put it on after and did another run and it lost a tiny bit of torque but thats it.

 

I'd not even consider not using one.

[GilesW 41]

The right filter and right filter design should be considered when designing your whole engine design.

Reverberation is a serious consideration as it can make you more power as well as lose you power.

[Miles 331 1 Cars]

Depends on use, I don't use them on my Race Car or will be on my Hill Climb car, But on any Road, Rally, Track day car then it's daft not to.

[streetsleeper 0]

When my carbs were set up, they took the filter off whilst tuning them and put it back on when finished. Whats to say they won't do the same with the throttle bodies? Im gonna struggle to get the money for a filter before it goes on the rolling road.

[Miles 331 1 Cars]

No with Bodies you map it generally as it will be then you can get the best settings for everything, All filters flow different and for example (Worst) the sock type really do zap power

[boldy205 75]

I would think your base plate from your carb filter should fit onto your new TBs. Then you just need to buy a fresh filter. But as stated before, use the filter!

[andyjstone 6]

When I first had the Jenveys on mine I ran it without a filter, but bottled out after a couple of weeks! When I had it mapped they found that it was losing about 8 horses with the filter on, so I'm in the process of dropping the rad to get fit a bigger filter on.

 

So, my advice would be put a filter on for piece of mind, but make sure you get one with plenty of air flow into the trumpets.

[Cameron 16]

Well Matt at Pug1off sounds like a clever chap..

[GilesW 41]

A reply for those who alter search and find this thread:

 

 

The right filter and right filter design should be considered when designing your whole engine design.

Reverberation is a serious consideration as it can make you more power as well as lose you power.

 

For those that skimmed over it when I posted the first time....

 

 

IMO it is unlikely that is you are using a 'good' filter type that you are loosing any significant power because of air restriction. You are more likely to be loosing it from reverberation.

 

You *really* should consider filter design as part of your inlet design (as part of the overall engine strategy/design).

 

 

To be honest though the easiest way to do this is to find well trusted information on an engine design the same as yours and replicate their filter design (if it worked well) on your engine.

 

You should never let your filter design be left to 'whatever I can afford, or whatever will fit between the trumpets and rad' unless you don't really care what effect it has on your engine, but you obviously do care as you've spent so much money on your engine to get extra performance already.

[Batfink 201]

its simple. Do not use sock filters, but use a proper filter that clears the trumpets significantly.

[engine killer 6]

its simple. Do not use sock filters, but use a proper filter that clears the trumpets significantly.

 

I second.

 

I have been using socks for so many years until I made myself a good back plate for the Pipercross sausage, the world changed a lot with the sausage filter

[Cameron 16]

+1, filters that are too close to the bellmouths will sap power.

[Baz 421]

+9, and keep them clean!

 

My Longman 8v was losing 11 or so bhp with the filter on, a decent fixed filter with backplate but just a little close to the trumpets and maybe a little dirty!

[tri_longer 25]

Only reason i ran without filter on carbs was they were the sock type and for hillclimbing I was happy to take the risk. now the engine has been re-build and I have a nice big sausage I shall just run with that on at all times.

 

Which is a shame as I have really nice carbon trumpets as well.

Edited January 10, 2011 by tri_longer

[Baz 421]

TBH i've been known to run without a filter, especially whilst competing, on stuffy days when the cars struggling to get a decent amount of dense air to the point you notice it struggling etc.

 

The reality is, this country just isn't dry enough to really worry about it that much unless there's literally nothing in front of the inlet, or of course when driving around on the road, following other cars etc as there's more of a risk.

[streetsleeper 0]

Sorted a filter out today, he is gonna order the biggest filter he can fit on there.

Knowing my luck i'd be crazy not to run a filter - I previously had bore wash so I decided to go for forged pistons.

[boombang 2]

Sorted a filter out today, he is gonna order the biggest filter he can fit on there.

Knowing my luck i'd be crazy not to run a filter - I previously had bore wash so I decided to go for forged pistons.

 

Why would forged pistons stop bore wash?

 

Who the hell set the engine up that resulted in bore wash & I certainly hope that you won't be using them again, not matter how big a filter you've had fitted.

 

I have a nice big sausage

 

 

Ah so that explains you user name!

[Miles 331 1 Cars]

If you have gone for Forged pistons as said it won;t stop Bore wash at all, I hope they are good ones too as the cheap ones can be poor quaility, Hence why I only use Omega and JE, the other's really are not worth the hassle or risk fitting

[Sandy 191]

Did he perhaps mean after suffering bore wash, a re-bore was advisable and hence forged pistons?

 

I've seen a very slight power gain at a couple engine speeds from sausage filter on; also seen it cure a strong pulse reaction that was causing problematic fuelling. But I avoid airboxes and most of all the hateful horror that is socks.

 

Some of my race engines run without due to space issues, getting the inlet design right prioritised over filtration, but on a road or rally car, the reverse applys. Don't have the trumpets pushed up into the foam though, at least 25mm clearance.

[streetsleeper 0]

Why would forged pistons stop bore wash?

 

Who the hell set the engine up that resulted in bore wash & I certainly hope that you won't be using them again, not matter how big a filter you've had fitted.

 

 

I didnt explain it properly, i had a garage do my mot and they said they played with the carbs to get through the omissions test, but they said that they put the carbs back to how they were. end result was bore wash and the piston rings are shot. The garage have a rolling road and seemed quite experienced with carbs etc and they race there own tuned nova's and corsa's

So as i needed the piston rings doing, I thought I might aswell bite the bullet and go for sum forged pistons