High Comp stuff [Archive]

Wobba

22-11-2010, 17:25

Best cams for 12.5:1 block with ITB's and breathed on Meg head? Need to retain a reasonably broad torque range if possible...

Also...typical power gain for a 11.2:1 block over OE compression?

Any advantages or disadvantages to be considered?

midge

22-11-2010, 17:35

What cams are you using?
I think the gains are around 5-10%, however i think your relatively low power (were see saturday!) may be down to worn b/e (what else could it be, the rest is all new?) so i would expect if you went high come your b/e your be in the 200's.

Wobba

22-11-2010, 18:45

225's at the moment which may not really be ideal for a high compression bottom end.

We will see on Saturdays RR. I will be scratching my head if it is lower than 180 still...

Evogone

22-11-2010, 19:41

12.5 for comp only now worth it for a road car.

11.5 with your spec should add about 10hp, combination for inc cr plus fresh BE. I have only all built up ready to go...!!!

Wobba

22-11-2010, 20:04

Laine_16v

23-11-2010, 22:14

Was told by craig its approx 3% increase in power per compression unit raised.

cliolord

24-11-2010, 21:42

Higher the compression = higher engine braking, engine will run hotter, reduced ignition advance and over compressing an engine can be a disadvantage. Run 12.5:1 and the engine will probably become a bit flat below 3,000rpm as a result of lower levels of ignition

Wobba

24-11-2010, 22:04

I guess risk of detonation is increased due to the compression and engine needs to be more finely tuned? With a tougher block you could however run it at theoretically much higher revs and with the right setup still produce power up there too.

I take your point about the lower rev range though. Food for thought.

Evogone

27-11-2010, 18:43

12.5 for comp only now worth it for a road car.

11.5 with your spec should add about 10hp, combination for inc cr plus fresh BE. I have only all built up ready to go...!!!

Lol Evo, you been drinking or just get your words in a twist? Not sure if I am reading you right :)

You have a 12.5 ready to go?

LOL but yes i have one 11.5cr.....ready and waiting company should be all set to go at the end of the year. Off to Barbados for a couple of weeks before christmas and then will be sorted. Got a new job so its a bit manic the last few weeks.!!!

hamloin

18-01-2011, 19:33

high compression is a good thing and essential for high overlab cams and will enable the use of a much more lairy cam without the loss of low down grunt.