johnboyjim wrote:Hi,
I have current engine and wish to tune it for formula 400. Its got SP Cams and been blueprinted. Last dyno run output was 68bhp. Apart from that nothing else has been done to it. Please bare with me as I am new to engine and dont have full understanding of all the different upgrade's available. I just ride it
I probably will put it into a tuner (any recommendations?), I hear people talking about over sized pistons, larger bore (what’s legal limit?), stainless steel valves, fine I guess a tuner will give me the direction on those. However RAM Air puzzles me, this I guess is something I can do myself. I was planning on the BB Plastics kit. But can someone explain how it works. I have an L3 Model.
Do I need the bellmouths? these fit straight onto the carbs, Do you fit this inside the ram airbox and then connect to carbs? Then close up the airbox and install. How much effort is required to install? is it a case of remove old airbox? I cant really see from the pictures as to how the bellmouths and the ram airbox fit together?
I also read about flat side carbs? Do these work with the ram air and where do you get them? Why they so good?
What sort of power should I be looking for plus reliability from a tuner and ram air, bellmouths etc.
What is this bb-plastics air dam? Is it worthwhile? dO i really need it?
Really appreciated..... Once I have this sussed, Im going to ask about total loss....
J
Dynotech in Basingstoke provide the best reliable tuning package for ZXR400's. Multi championship winners
Tel 01256 881711
Some clubs run manufacturers overbore which is +.5mm, some run no overbores, Bemsee run a 2% tolerance which works out at +1mm overbore, get these from Dynotech.
Use stailess valves, they're much more reliable and don't stretch.
As for internal tuning, I'm really not going to go into it here as it's way to complicated to explain it, besides I'm no expert on it although I do undersatnd it. But, you'be be looking at setting squish by modifying barrel/piston height, increasing compression by skimming the head, porting the inlet and exhausts ports, cutting valve seats etc etc.
Ram air box is sealed with a funnel to the front above the radiator in the case of the BB plastics box, air is forced in giving more valumn to the cylinders.
Don't need bellmouths but they will give more top end power.
DO NOT bother with flatslides, they're a pain to set up and on a well soretd bike will only give 1 or 2 more bhp over cv carbs. They will however give you better drive out of corners due to the way they work. Everyone I know that has tried them didn't get on with them and changed back to CV's.
BB air dam is a form of fairing infill, it directs all the air through the radiator and more directly into the BB air box, not many people I know run them, they may or may not help with power.
Depending which dyno you go to, you'll get 81+ bhp will a full Dynotech tune on their dyno (not a high reading dyno). That will equate to about 74bhp on the trackside DynaPro dyno.
Hope that's a start for you,
Greville
newbie