I'm looking to buy a manifold that will create the maximum amount of flow and suction for my 351. The 2v funnelwebs look fantastic and all the reviews that i've read have said they are gods gift to clevos, but i'm wanting to hear any opinions from people running one on their engine.
The cam will be a monster mechanical roller and the heads will be ported to the maximum iron can handle, is there any other manifolds, other than the funnelweb, that people would suggest?
The aim of the car is to be the fastest small block 'real street' classified car running straight LPG in australia, fuel economy is not even a considration!
Another suggestion.........vic jnr or super victor(if you have the engine for it)
The guys who built my engine use one on a group"n" race car
The said it was extremely tall and has a massive plenum
Quote" you will need to turn 8000 to 8500rpm to take full advantage that manifold"
I hope you have that many rpm's in mind
What ever I have will never be enough !
Fear is only Fear itself !
I have been running a Wiend accelerator with 2 inch carb spacer & it seems to be OK. I've been told that the TFC 2V tall would be good for a high rev ceiling engine. I actually rang TFC wo say that thier manifold is better than the "funnelweb", but they are trying to sell product.
this is only what I have heard, but I would be more inclined to go for a TFC if the motor will be a monster.
My understanding is that the FW works great with hot street motors but the TFC has more top end
** this is not from experience and could be complete bs **
The engine will see some street duty so i'm still leaning towards the funnelweb but if there are any comparisons around that can match one i'd really like to see it. From what i've found there are manifolds out there that can match the peak HP of the funnelweb but none that deliver the same torque.
Interesting to see that you plan on doing this with LPG.
I would imagine that you need to look seriously at Plenum volume rather than flow alone. A lot of the specs that these manifolds stipulate is based on Liquid Fuel flow rates and applications.
LPG unfortunately does not follw the same Physics. It may pay you to concentrate more on Plenum Volumes as this will have a major effect on Vaccuun rates. Remember that LPG is not " pumped " into the motor , it is sucked. The more vaccuum signal that your motor sends to the Converter , the more gas it can suck in. The vaccum will be directly related to your Cam ,manifold plenum volume and Mixer size.
This is why most " HOT " LPG motors run lean at High RPM. As the revs rise , there is less vaccuum which in turn sends less signal to the converter which in turn supplies less gas. You then get a " lawnmower " effect where the engine wants to rev higher because it is sucking in more air than LPG. This is dangerous and can cause damage over a period of time. It also runs out of REVS and power quite quickly , almost feels like valve bounce.
What sort of carbs are you thinking of going to ??
twin IMPCO's or twin GRA's
Good luck with the project and can't wait to hear how it goes.
Twin GRA will be the only way I can think of running this engine. Twin impcos would be OK up high but overfuel to buggery down low, not to mention how hard it would be to find a suitable manifold.
The funnelweb looks to be the best choice for this engine, the better torque curve than its compeditors says to me its suction down low is impressive, but in reality I havn't seen one running a high HP LPG setup.
The converters are going to need modification i'm told as the cam will be making near no vaccuum down low and again very little at high RPM, so i've got plenty of R&D to do with this one!
PS. Did you end up flowing the impco up? How did that work for you?
Falcon G.T. Club of Geelong Inc.
Deakin University Formula SAE Car PHANTOM ENGINEERING
LSUG (Leaf Spring Users Group) Twin System Engineer
Official BSR Website - www.bsrcorp.com
Poster of the 150,000th post!
BSR "DARTH HELMET (tm)"
Marcos Ambrose & SBR, 2003 & 2004 V8SUPERCAR Champions
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.