Alternative air box for 4 barrel carbs

[mjheathcote]

Looks interesting!

http://www.v8dualfuel.com/components...er_plenum.html

They also do a 'low pro' version for restricted bonnet space applications.

[Ian B]

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mjheathcote wrote:

Looks interesting!

http://www.v8dualfuel.com/components...er_plenum.html

They also do a 'low pro' version for restricted bonnet space applications.

It does indeed look very interesting, would this fit on the TV8 or just the Buick lump as shown in the advert?

Ian

[mjheathcote]

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Anything with a 4 barrel!

[StagnJag]

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like this then:P

[stoutgoose]

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It does indeed look very interesting, would this fit on the TV8 or just the Buick lump as shown in the advert?

Ian

Hi Ian,

it would fit the Stag if you have fitted a Weber/Holley 4 barrel carb. The problem is bonnet clearance. The plenum sits a mile above the carb, and even though it has a reduced diameter, it would almost certainly required a bulge!

A modified low-rider could be the answer, or the pancake filter being produced by you or Steve (sorry, memory fails me!).

Regards,



Steve.


P.S. Blast; I have just noted the 'low-pro' comment on entry # 1!

[V Mad]

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These companies that claim better performance I am always sceptical. They say 'Now you can get near fuel injected performance from 4-barrel carburetor'. What the hell does that mean, its rubbish. Its just a tin box with a remote air filter on the end, which anyone can make. How much is this thing anyway?

[mjheathcote]

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I think the complete front end kit is £625, requiring the cost of a LPG tank to complete.

[jpyke]

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V Mad wrote:

These companies that claim better performance I am always sceptical. They say 'Now you can get near fuel injected performance from 4-barrel carburetor'. What the hell does that mean, its rubbish. Its just a tin box with a remote air filter on the end, which anyone can make. How much is this thing anyway?

Chris, I agree with you. Their claims sound a bit too good to be true....

but... It would appear that the positioning of *anything* over the intakes on a carb can have quite a marked effect on the performance. In Des Hammill's book on tuning rover V8s he mentioned that they got somewhere between 5 and 10 bhp more from fitting K&N air filters to the curved pipes which fed the original big air filter rather than fitting them straight onto the carbs.

Also, I had the Cobra (which has a RV8 with Weber 4 barrel carb) on the rolling road 2 summers ago and having got a considerable power increase by tuning and adjusting the mixture, the guy re-fitted the air cleaner and was disturbed when, on the final run it had lost more power than he was expecting. He removed the air cleaner and re-fitted the bracing piece (which is only a small piece of metal about 1cm wide which visually, at least, got in the way of nothing!) at 90 degrees and after re-fitting the air cleaner got all the power back.

It does seem that the trajectory of the air as it hits the inlet of the carburettor, whether it is swirling or not, etc., is actually quite important.

It is RPI engineering who are doing this - I've had plenty of dealings with them for parts for the Rover V8 and they have a very good knowledge of these engines. I'm not saying I believe their claims totally, but I am saying that I've found that the induction can make more of a difference than you'd expect. They'd have a lot to lose by making false claims - but even so, I'd like to see some before and after dyno figures!

[V Mad]

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I agree, airflow round the carb intake is important, but you should be able to get just as good airflow with a typical American style14-inch air filter. For the stag, with a low profile dropped base filter (egLow rider) its best to take off the bonnet bar and raise the filter as high as you can with a spacer (from Real Steel etc) so the air intake isless restricted.

[jpyke]

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V Mad wrote:

I agree, airflow round the carb intake is important, but you should be able to get just as good airflow with a typical American style14-inch air filter. For the stag, with a low profile dropped base filter (egLow rider) its best to take off the bonnet bar and raise the filter as high as you can with a spacer (from Real Steel etc) so the air intake isless restricted.

Yeah I agree - at least with a 14-inch air filter it lets air in all the way around rather than just in one place. I guess there are some benefits to the RPI idea - firstly if you have a remote air filter you can take cold air from somewhere rather than hot air from above the engine (how much of a difference does this make I wonder?) and secondly, if they're trying to feed LPG in too then they'd have to do it like that. As you say Chris, can't see any advantage over a conventional air filter - unless the cold feed really does make that much difference.

[V Mad]

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In theory ifyou could get colder air into the engine with no significantpressure drop it would be worth it, but in practice I don't think thats the case.

[jpyke]

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Indeed. I would guess that the difference in temperature and therefore the advantage you'd get would be quite small in comparison to the difference in temperature between the inlet gasses and the temperature of the combustion.

[norstag]

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I've just visited RPI and had a chat about their airbox, it is primarily designed for dual fuel applications(lpg & petrol) or where a remote filter is required, eg to get cold air or raised up for off road use.It should improve performance with LPG, but would probably reduce it on petrol, so it is not a miracle performance enhancer for a straight 4-barrel conversion, the fact that it is shown on their dual fuel site and not on the regular V8site does seem to show they are not trying to con anybody. They are agood bunch of guys and will always give you advice.