also keeping a very close eye on this thread
http://ozvr4.com/forums/showthread.p...ghlight=plenum
if they can make a good plenum with say velocity stacks inside on each of the 6 runners that definatly would help
also keeping a very close eye on this thread
http://ozvr4.com/forums/showthread.p...ghlight=plenum
if they can make a good plenum with say velocity stacks inside on each of the 6 runners that definatly would help
To be honest looking at my 6A12 plenum it does seem to be far from ideal and I feel that there are definite gains to be made with a well calculated plenum.
The 6A12 plenum for starters has the dual length runners and when it switches to short there is a butterfly on each runner which opens, but that in itself seems to be quite a restriction. The design of the plenum itself does not seem to be ideal, and there are no ram tubes. I cannot comment on runner size but I think this is less of an issue as generally the runners should be about 10% larger than the valves, but they are definitely a bit long in my opinion which is again not ideal for a high revving motor which is mostly about top end power
I loved the 6A13, otherwise I wouldnt have stuck with it as long as i did. The problem is not with the crank itself its with the cradle, and the number of retaining bolts it allows the crank to flex too much, the same will happen to a forged crank just take higher stresses/rpm to get there. Same problem as the GTO has
Having looked at the heads we decided there wasnt enough room to get 1mm oversized valves in so it will be interesting to see if you manage it. You may end up machining the pockets in the pistons to take a bigger valve.
Ben did a new plenum for his 500+ bhp VR4 FTO, I personally dont think getting air into the engine would have been a problem until you hit 7-800bhp
My 1000bhp plenum on the EVO engine holds about the same amount of air as my old VR4 plenum, when you include runner lengths etc...
We recorder 560bhp and 485lb/ft torque at the hubs on a Dynapack Chassis Dyno Peaking at 2bar (30 psi) holding at 1.7bar. That is estimated at 630bhp and 545lb/ft (figures yet to be beaten )
Richard Batty
2.5ltr V6 Turbo FTO
Scott and i were running off ideas and he suggested that the block could be drilled sideways to effectivly make the block 6 bolt mains. like a LSx or 1UZ engine, that could help with mains rigidity,
http://www.engineeredvictories.com/images/LSx/026. -6 bolt mains
if the crank is not the weakness then possibly a billet mains cradle could be a significant advantage and possibly cheaper then a billet crank
possibly not due to the gap between block and mains cradle. hmmm
After A very large deviation away from the threads intended topic. I took the evo valves in to peter kennard from kennaly cams and he said the 5mm longer evo valves will become an issue so he could either machine the evo stems to be shorter and turn a new collet grove onto it for around $450 for 24 valves then there is the cost of buying 24 evo valves @1.5x280 USD and the cost of fitting them into the heads
or he can supply 3mm oversize inlet and exhaust valves from some kind of subaru for $495 NZD plus the cost of fitting them to the head
Does he do porting also by any chance? There would be SFA point in spending the cash for all that and not doing some work on the ports at the same time.
he should do. As today is his last day at work before christmas i wont be going in and bothering him but if anyone is intrested and wants me to ask him some more questions about the matter i will be more them happy to. and if he doesnt do it he can just supply the valves and CHS up the road can do porting.