MUCH better then the first design, I'd still like to the TB closer to the port though.

How close would you go?, maybe I could do two manifolds, one small one before the TB and another small one after, before the Ram tubes?

this is so cool i cant wait to see and hear the finished product. itl have an awesome induction noise! top stuff

Weld a plate to your machine manifold 'stub' and bolt the TBs to that.
the responce comes from moving the air faster. if you have the TBs right out near the entry to the runner, everthing behind the TB is under vacuum (all be it not a smooth constant vacuum). When you crack the throttle open there is time between when the column of air starts moving and when it get to the chamber.
If you have the TB closer to the head most of the runner will be under atmospheric pressure already, the column of air is closer the chamber, the time from throttle to chamber is faster.


An other thing to think about is injector placement.

before you go any further go to http://www.racemagazine.com.au/ and order these back issues
Issue 7, (injector placement article)
issue14 (DIY Carbon fibre air box and a good article on plenum size/volume tuning and ram port tuning, has formula for calculating the resonance of the plenum and for the ramp port size and length)
issue 13 (good article on manifold design)

Once you are through those you'll probably end up ordering all the back issues......

Hey guys really looking forward to seeing the end results so make sure you post piccys to keep us all up to date as you build.

Alan

Just subscribed to Race Magazine, looks like a good resource.

Been doing a lot of reading the last two days, and based on that I have a new design, the limit is the length, 320mm from the back of the valve, to the end of the longest ram tube that would fit in the guard



To get any more length takes a bend



Looking at the head, this is as close as a scale drawing I can get based on outside measurements, and trying to scale the cross section pics to fit.

Blue line is angle of injector using the standard manifold location
Red line would be a better shape.

Good article on ram tuning, with dyno results, formulas etc
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Installing a larger valve in a Lotus head, anyone tried to get a bigger intake valve in a SOHC?
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Ok, anyone got a intake valve for an e-series and some calipers handy?

If they are 131.1mm in length and have a stem of 8.7mm
What sort of tolerances do we have, what is acceptable valve stem runout?

Standard
131.1mm = 5.161inches
8.7mm = 0.342inches
48mm = 1.889inches

Here are some close ones

Manley Part no: 11702-8, Chrysler Intake valve
133mm length
8.674mm shaft
51mm Head
7degree dish head

Would need to machine tip and head.



Ford Raceflow vavles, Manley part 11888-8
1.940 = 48.36mm
0.3420 = 8.7mm
5.075 = 128.9
5degree dish on head

Good head and shaft size, 2mm shorter
Could this one work with an extra shim in the lifter possibly?

Exchange rate with the US is still around 0.89, wonder how many $ they would be.

Found some of the Ford raceflows on US ebay $109US for 8
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People want to chime in on whether a 2mm shorter valve could work with standard rockers?

What is the biggest shim anyone has used before?

I need to get springs for the new cam anyway so that could be fixed, same as collets and retainers.

Watching this thread with interest mate, im very keen to see the finished result with the ITB's. Keep up the good work!!

Also will interesting to see which valves you end up sourcing for the head. I have looked into larger intake valves as well, as suggested by tickford_6. There isn't that much room to fit larger intake valves could probably fit a 48mm or just squeeze a 49mm valve in there but it is a very tight fit. You could always get them custom made from Manley to the exact specs you want which would probably be a bit more costly, but then again if you bought a set of valves that would require machining tips down and turning valve head diameters down etc it could work out to be around the same cost anyway.

The oversize valves i'm looking to fit to my 91AA head are just std replacement items so are cheap as chips really lol. So far i have found that Holden 308 valves will fit with the tips machined down to size. The 308 L34 intake valves have the 49.5mm head dia, share the same 11/32" (8.7mm) stem dia, but are tad longer at 132.2mm. The 308 exhaust valves are 40.7mm or 40.8mm iirc, with the same stem size but also need to be machined down to length. I know these aren't stainless valves but just throwing that out there


I guess if you could find some exhaust valves which were 2mm shorter than the standard exhaust valve (i think std clevo 2V ex. valves were about 2mm shorter than the i6 ex. valves, they also have 42mm head and 8.7mm stem), you could just get the rocker gear pedestals machined down to suit the shorter length, that way you won't have to muck around with having too many shims inside the rocker. Just an idea

you would be better off with a longer valve. that way when you fit a regrind cam you can use one shim in the rocker and take the rest with valve length.

Manley and Ferrea both do custom valves. considering how close those two valves are to fitting they would easily be able to produce a set that will fit.

you need very close to the same length valve, in order to maintain the correct roller contact pattern on the valve

94Ab combustion chamber, photo taken at the same angle as the intake valve.

Black line = Edge of standard head gasket
White line = Outer edge of 47mm valve
Red line = Outer edge of a 49mm valve

I think if the outer edge of the chamber was layed back behind the top of the valve seat, a 49mm should fit, bore out the existing valve seat to suit, then I could open up the intake port accordingly.

I have the lathes at work to be able to shorten and resize the head of a valve, so if I can find one with the right shaft, the good thing about the Ford Raceflow valves is they are already turned down on the shafts and the heads are already flow optimized. $120 plus my time is a lot better than full custom valves from Manley I would guess.

a 2mm longer valve wont change contact pattern any more then putting 2mm extra shim under the HLA, which every one does with regrinds anyway. The plus side of a longer valve is the HLA is still %100 in the rocker, not half hanging out. Would put a stop to the broken rocker arms some people are getting with large regrinds.