Compression & such....16V

[R/T]

So -

If someone were to add a DOHC head to an 89 2.5 commonblock, stock pistons - where does the compression ratio end up??

Or, how much cranking pressure with a 16 valve head??

I'd say with the vastly superior combustion chamber, detonation would'nt be an issue, right??? :confused:

[Frank]

I personally dont think detonation would be an issue on the 16valve heads if you do some minor clean up. Heck, Ken runs like 8.5:1 without problems on his 8valve. I think 9:1 is safe on those for minor turbocharging and good fuel. But that is just me ;)

[turbovanman²]

Depends which head, if you use a Lotus, its around 7:1, UGGGGGG. The Neon head is close to stock so its around 8-1 to 8.5-1.

[gkcooper]

So, in other words, no one really knows.

[turbovanman²]

So, in other words, no one really knows.

Some probably do, I don't know exactly. Theres quite a few running around with no detonation issues so my guess sounds right.

[Speedeuphoria]

heres some info
http://www.turbododge.com/forums/showthread.php?t=103269

[Garret]

Give me a couple of weeks and I'll put the compression tester to my 16v conversion that is in the it's new home. But I had zero detonation issues and the motor cranked nicer than ever before

[R/T]

I was thinking Neon head -

And Simon, we both have the sportbike racing background, those babies run 11:1 ratio or higher at 15,000 rpm on pump gas, thanks to the chamber design - so I bet 9:1 or so static would be OK with our 16v.... :nod:

[turbovanman²]

I was thinking Neon head -

And Simon, we both have the sportbike racing background, those babies run 11:1 ratio or higher at 15,000 rpm on pump gas, thanks to the chamber design - so I bet 9:1 or so static would be OK with our 16v.... :nod:

I agree, the 16valve chamber is so far advanced over the crap 8valve, :thumb:

I bet my 750 is around 12:5 or slightly higher. I milled the head .020" and it made a huge difference. I was running 94 octane but then tried some racing fuel 50/50 and the throttle response was awesome, :partywoot:

[R/T]

I bet my 750 is around 12:5 or slightly higher. I milled the head .020" and it made a huge difference. I was running 94 octane but then tried some racing fuel 50/50 and the throttle response was awesome, :partywoot:

I put the $200 Wiseco 663cc kit in my Hawk GT, went from 9:1 to 11:1.

The best $$$ I ever spent on any motor I've owned. :amen:

Stock Hawk is kinda doggy, it *came alive* , 8HP on the dyno, TONS more torque, and - power wheelies!!! :rockon: :bolt:

Compression is a good thing..... :p

[Aries_Turbo]

enough of the speculation ;)... what are the stock CC's of both heads and the stock HG thicknesses?

Brian

[TurboJerry]

My T-III has 8.1:1, and 145 cranking psi. (stock engine)And it pings very easily with a stock SBEC on 91 octane. The Masi has 7.3:1, and 110 psi. They don't ping..... In CA they are worse then the SOHC for ping when using a comparable compression ratio. The bike engines have a much smaller engine/combustion chamber, (smaller flame front/travel) so they cannot be compared to a car engine..... Not to mention bikes weigh thousands of lbs less also.(much less load)