Impellor

To answer your question this is directly related to breathing efficiency. Variables such as power your chasing, boost levels you are running, and mods that you have to support your power expectations. Look at the end of the day, the BA/BF plenum is not a great design for the turbo application. Good for the N/A with the butterfies, and low down torque production (which is Fords bread and butter, to combat V6 Commodores). I suspect this is why a change to the FG plenum was made. If you look at the opening of the plenum in the OP's pics you can clearly see how the bottom of it is quite restrictive (to be honest the opening is smaller than the T/B port also). Now I believe that this is the case to help push more air into the outer perimeter of the plenum. So I removed a substancial amount from that area. But to compensate I also removed a large amount from the sidewalls of the opening to allow good flow to the outer perimeters. You will also see that the internal plenum runners have a substancial lip on them. Again I took some material off them and smoothed. I also smoothed the interal runners with sandpaper and opened them up to match the ports on the inlet runners. The only real testing I did was with water. This was done with the internal plenum runners. I used a watering can and poured into the runners. I tried to keep the test as controlled as possible. I sat the plenum on a table before I started and the water travelled 90cm were it hit the ground. After I finished porting and polishing the water travelled 107cm. So from that result one can suggest that I have been able to increase veloscity. Why do it to the factory plenum? I believe that the BA/BF plenum has a slight avantage over the FG in relation to low down torque production. Obviously the FG was able to overcome this by using a smaller turbo along with a 40% boost increase. I have added this video just to highlight how well the car runs. In this particular event ther were many cars making 200-300 more horsepower and I never beat any of them of cause but I was never far behind them. If you look at the 42 second mark this was me racing a VE SS that was making 306rwkw's I was told. My car ran well in all 3, 15 minute events and the temp gauge never moved. Although the poor old Monza cooler started to get heat soak towards the end of the second run, as we ran 2 in a row. But in conclusion, if you do this mod to your plenum I guarantee it is not a step backwards. Cheers

I spoke to our tuner, he then asked BigAl to get in touch with him, as he said he was happy to do it, but it wasn't a 5 minute job. And it would be up to BigAl to cover costs. Never heard back from BigAl. Cheers

How did we get onto throttle bodies? In the case of the inlet plenum there is absolutely no doubt that bigger = more available air . Therefore bigger is better in this case, as the inlet runners are doing the important work. You can argue to the cows come home. I hate to say this, but its not rocket science, as all you are doing is creating a increased, more efficient flow path. Lets not forget that an engine is an air pump. In my particular case the real benefits won't be realised until I have a bigger exhaust, this is currently the restriction, as its standard. Cheers

Exactly, that is why you port/enlarge to increase volume, polishing assists velocity. So can we all agree then, that increased volume will increase performance. As this has been my point from the very begining. Cheers

The surface in the plenum is certainly not dimpled, actually the opposite. Im sticking to the theory "Path of least resistance". Certainly some good comments and idea's all the same. Mick I have also read that by providing a polished intake or port is detrimental. But I don't believe that the plenums role is to create turbulence. This occurs within the runners, this is exactly why bolt on plenums produce results. Cheers

I agree wholeheartly with what you are saying Jet. But I believe that the neccessary/required turbulence is created by the runners that the manifold/plenum bolts to. Just look at a PW, Plaz, or Nizpro plenums on the whole, they are as smooth as a babies buttuck. So Mick that comment may have come a little soon. I feel that the goal here is to allow as much available air to the intake runners as possible. This can only be achieved by reducing friction. Now please don't get me wrong, this mod isn't going to compete with the increases that a good aftermarket plenum provides, but it will improve the factory items efficiency. Remember folks these are mass produced items. They are made to be cost effective, not to a standard. These are Fords not Ferrari's. Also I think that its important to highlight "Rednoses" comment about a mid 10 second car, and said car's tuner response. Cheers

Go for it. Get hold of a manifold gasket(metal) mark with scribe. You will see how much can be taken off opening to inlet runners (3-4mm all round). You can open up the inlet from T/B considerably to match T/B opening, and improve airflow path to 1 and 6. Contrary to the doubters beliefs you can do alot to these manifolds to assist flow.Im not aware of anyone doing a direct comparision, due o the major fark around and time required to chop and change. But from a theroretic perspective to open it up and smooth will increase airflow, by reducing turbulence. Less turbulence = less friction = increased flow efficiency. Also if you go ahead, don't forget to add a catch can. Cheers

I must agree with Trento, if you want a dedicated drag car go the T400. If you want to drive it on the street, you can't go wrong with a Tremac TR6060. Cheers

Welcome mate !!!. But my advice is to do some reading. Education is the key. External wastegates are illegal and in most cases unnecessary. I also think that upgrading should be a gradual process. It allows you to become familar with the car, and your own limitations. Personally I would look to 1000cc injectors (as you progress through power levels, you will find that they will be capable for most of your future power expectations, and E85 if desired)Next get a good cooler and piping, something that will support 700-800 hp or beyond. You will require a good fuel system, but at the very lest I would look to a 400lph intank pump, and a surge tank and external pump later if needed.A 3 inch exhaust will not flow as much as the factory system, but a 3 1/2 inch will provide an easy 700rwhp. Finally find a respected and honest tuner, this is without doubt the most importnt part of the entire process. The BFII Typhoons are are great car as a starting point, so nice choice there. Cheers

I must agree with Jet, don't bother buying any lottery tickets, you have used up all of your luck. Cheers

For a generic tune that does't look to bad at all. AFR's are fine with that cooler and boost level. Although with a custom tune with actuator, exhaust, and wastegate mod you will see well over 350RWKW's. Joe from CMS has an outstanding reputation for good, safe tuning. Cheers

They sound better at 8000rpm when the oil pumps gears explode, shame its only for 1 second though. Cheers

Sorry about that, I wasn't thinking about how much oil, and coils arcing out. Happy to stand corrected. Cheers

Oil in the spark plug tube will not create major issues. But it may lead to the plug running slightly hotter. Cheers

Personally I don't see the point, as most cars (lightly modded) aren't making anymore power over 5500. And besides it reduces the possibility of oil pump failure (if not bouncing off the limiter). However in my particular car I have the soft cut set to 6350rpm and hard cut at 6400. Cheers