EQ Head Port

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T56MaxTorq

T56MaxTorq

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Have the heads off the turbo 318 and I'm wanting to dump off some compression other than using head gaskets. Right now I'm sitting 9.14:1 and I'm looking to drop below 9. I think I can achieve that by cleaning up the combustion chamber by removing sharp edges and blend everything. I need about 2cc gone to reach 8.94:1
The more the better.

318 magnum, stock bore/stroke
Stock pistons sitting .047 below deck
EQ heads - haven't measured chamber but advertised at 62cc. 1.92" intakes
.039 x 4.180 gasket

Live at 6000' so compression isn't a huge issue but I'm running e85, so I'm adding an extra 30%volume of fuel plus the extra fuel for 13lbs of boost at 12:1 AFR.

Main quest is to make the combo safer. Safer for premium fuel as well. Wanting to lower total boost to about 10psi. Which is 7psi at sea level. But attempt to keep the same power. Want to do a light chamber port, clean up the intake tract. Take a little out of the pushrod pinch and portmatch the intake. Unshroud the valves a little. The block is free game too. The crank and pistons are out. Any tips or areas to avoid or focus on? is removing 2cc possible or waste of time?
 
When I used E85 normally aspirated I was told it was very hard to blow up an engine using it. Thank God it seemed to be true. I figured I needed to be around 8:1 AFR for the most horsepower. I don't know about turbo charged, but normally aspirated, at 12:1 AFR we made 680 HP, at 11:1 AFR we made 760 HP and at 10:1 AFR we made 840 HP and then ran out of dyno time.

It always seems to take me an eternity to get 2cc out of a combustion chamber.
 
WOW! 80hp jump per point of AFR.
Musta been a stout engine build!
BUT! That goes to show what a good engine tune will do. After all the money spent on big power..... tuning it delivers!
 
Wow that's a huge difference! I should have mentioned that 12:1 AFR was with a gas gauge. I don't have my gas-e85-lambda chart on me.
 
I can recall opening up some chamber many years back from around 75 to 83 cc's....... 2 cc's seems pretty simple. (It wasn't quick though LOL) It would be a good opportunity to polish up the chambers too as part of that work. Just where the thin spots are near the water jacket, I can't tell you. Also, some deeply dimpled valves in place of flat faced valves can add 2 cc's.

Why bother with the intake tract with a turbo? I've never touched the intake at all on my 2.6L Mistu running 14-15 psi boost and it is making well past 1.5-16. HP per c.i. Of course, it is a hemi-head design so it just may be good to start with... it may be apples and oranges.
 
nm9stheham said:
Why bother with the intake tract with a turbo? I've never touched the intake at all on my 2.6L Mistu running 14-15 psi boost and it is making well past 1.5-16. HP per c.i. Of course, it is a hemi-head design so it just may be good to start with... it may be apples and oranges.
Click to expand...

Because boost is also a measure of restriction. We have ported diesel cylinder heads, lost boost, and gained considerable horsepower.
 
IQ52 said:
Because boost is also a measure of restriction. We have ported diesel cylinder heads, lost boost, and gained considerable horsepower.
Click to expand...


Yup. And it works the same for roots blowers too. I'd rather run 30 pounds of boost on a good port than 45 on a bad port. It just heats stuff up all the hotter.
 
Makes sense.... I did not think of the extra heating. Guess it is a TAD hard to cram an intercooler under a blower!

But it will not change the end cylinder 'packing' in the OP's case to have a bit less boost with the improved flow, since he is wanting to achieve the same HP.... It does not sound like more HP is the objective...just keeping the same HP. I am just wondering how much effort it is worth in this particular case. It's certainly an interesting trade-off.
 
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