3 replies to this topic

[mini.rich]

Right heres a quick question...
 
I'm currently building a 998 engine, well the short block is built up, +.060, wedged/bladed crank, lightened rods, Kent 276 cam, MED lightened flywheel setup. The block is pocketed for exhaust valves.
 
The final part is the head and breathing of the engine, I have what I guess you would call a stage 4/5 12g940 head, the inlet ports have been opened up so much the push rod holes have been sleeved. Valves are 36/31 from memory(they might be 37/30, I'll check later) either way they are big. Exhaust ports are also large. (sorry I can't be more precise with measurements)
 
My main question regarding the head is, will something this modified work with the 998???
or would it be overkill, as theres only a finite amount of air the engine can breath? Should I look at buying a stage 3 940 head from somewhere like MED?
Or, I do have a standard 940 head...
 
As for the breathing side of things I was looking at using Specialist Components Fly-by-Wire setup or the 5 port injection setup, I was going to run Megajolt and an HIF44, but I have the money to buy the SC kit. 
What are peoples thoughts on using the injection setup???
 
And finally the exhaust manifold.. I was going to use a Maniflow Cooper freeflow item, would this be enough for the head??? or am I going to need an LCB.
 
Basically I'm looking for the best inlet/head/exhaust setup with what I have if possible
 
The other option is bin the 5 port and go 7.... ;P Haha.
 
Any opinions and experience welcome!
 
Many Thanks!!

Edited by mini.rich, 07 May 2014 - 02:44 PM.

[Vipernoir]

If you've pocket the block for inlet valves you've done the wrong side.

 

It's the exhausts that hit the block.

[mini.rich]

If you've pocket the block for inlet valves you've done the wrong side.
 
It's the exhausts that hit the block.

Please ignore me, I've been awake the last 36 hours with no sleep, my brain isn't functioning properly! They are of course on the exhaust valves! but thanks for pointing that out, I shall change it.

[Turbo Phil]

The stage 4/5 head you mention will be absolutely useless on a 998, the ports are far to large. I'd start with a standard 33-29 valved 940 casting, remove the guide bosses, tidy up the ports {but don't enlarge to any degree}, deshroud the valves & narrow the seats. Sorted !

Phil.