Thread: New Drag Setup (work in progess)

http://www.sr20-forum.com/vvl/44546-block-setup.html

He mentioned that he's going to do a 92x102

i have no idea how hes getting that compression.

only way i see is if he has the head cnc'd similiar to maz works and runs more of a domed piston.

stratton.

He could also have welded the cc, along w some flat faced valves. Also the valve reliefs do not need to be as deep as they are in the cps which would help get more cr aswell.

I just dont see him gaining very much by going with flat face valves nor filling in the cc. But im sure im wrong. Im curious how he figured and got to that compression.

Stratton.

maybe he the head is milled down? to raise compression
not suree how much you can mill the head before it messes with the timing chain, but im sure there could be a custom solutition to that.

Well the problem with that then is piston to valve/head clearance with a high domed piston. Of coarse its possible within reason.

Stratton.

Stratton it quite easy:

You buy pistons from Cp thats 12.5:1 compression for a 92mmx92mm motor
CR Compresion ratior
SV Sweap volume ( Volume of the crank strokex bore)
CV Combustion Volume (Volume of the head gaskets plus the combustion camber)

CR = (SV + CV)/CV

on a 92mm x 92mm motor the SV is 611.66cc

then
12.5 = (611.66 + CV)/CV
12.5*CV = 611.66 + CV
11.5*CV = 611.66
CV = 53.18cc

Now a 92mm x 102mm the SV is 678.14

CR = (SV + CV)/CV
CR = (678.14 + 53.18)/53.18
CR = 13.78

By using the normal12.5:1 pistons I have a compression of 13.78

To gain 6cc on a 92mm pistons is the biggest of problem last time I had a look
I will take photos of the pistons and rods and post then sortly!!!

I will take of the 12.5 CP pistons and mine then you'll see the diffs!!!

Mr Derm, how are you doing my friend?

Its getting a little hot here in Miami and that trip to S Africa is popping up in my mind. Well I am now thinging about it.

Will bring undercover camera to leak all the photos here on th forum.

so no excessive milling of the head in relation to the compressio ratio?

thank you derm for you indepth explination.

stratton.