http://www.nissanperformancemag.com/march04/ask_sarah

Bottom of the page

I don't know how knowledgeable Sarah is, but 12:1 compression ratio sounds interesting. This has probably been posted already, too, but since I haven't been on the boards for a while, and the search is not up, I thought I'd ask.

Anyone tried it? Speculation?

 

Now this is an interesting development if it comes to market... neat article.

"Nissan Motorsports just released a new head which has the VQ30DE chamber volume but the VQ35DE ports and titanium valves which raises the compression ratio to 12:1 if you’re interested in building a naturally aspirated Maxima."

 

Great, that pretty much means that you probably need to run race gas all the time.

 

Thats crazy.
What will i have to do to my motor if I want this new head?

 

start saving!

 

yea good luck trying to run on anything from the pump with that.

 

jus curious, why wouldnt it run/run well on pump gas and would it be ok to use that home made race gas( found it in the stickies)

 

Just use a deisle for example. No spark plugs, ignition works buy heat from compression(like 25:1). Therefor, if you dont have access to a high enough octan gas, the end result would be preignition, which is not good.

 

WTF is a deisel?

 

then why does the S2000 run a 12.5 compression ratio but run just fine on premium 91 octane....in other words I guess to put these heads on we would just have to find a balance between retarding timing and the compression ratio to push the limits of premium grade octance gas....

 

Sh*t. At least you could mis-spell his error correctly.

He said "deisle" not "deisel".

 

Could always move to Canada where Sunoco sells its "Ultra 94" octane fuel. I seem to remember they were test marketing an "Ultra Gold 98" octane at one time long ago. Wish we had it here in the Houston market.

 

Yeah, check the stats on an M3... really high compression and runs on pump gas. I'm running 10psi on a 10:1 on about 93 octane. Stock advance. I'm not saying it is reliable though.

D

 

Coolio another houston max.

 

I would imagine it only raises the CR on a VQ35. The article states that it has the VQ30's chamber volume, so the CR on VQ30'swould remain unchanged. Any gains would be made entirely from flow and weight savings. IMHO.

 

Ive made calls about it and its designed for VQ 35's so upper and lower intake manifolds for the VQ 35 would have to be used.

I wish there was one made just for the VQ 30.............

 

Sorry I ment DIESEL

To bad we all cant be spelling champs like you

 

I was trying to meet you halfway. No point for me to spell it correctly for you.

 

Hi, I'm wondering... they seem to have upgraded the valve train, so would we be able to rev higher and still be safe? I would love to be able to rev up to 9k rpm with my max... about the gass I won't have a problem with it, I allways use RON 98 fuel, and allso have access to 100 RON gass if I go to germany and throw their version of Shell V-Power in the max.

 

You do NOT need to run race gas on 12:1 compression. You're all nuts for thinking our 10:1 requires 93. Hell Celicas and Matrix's use 12.7:1 and people add 7lbs of boost to them and run them on 93.

 

J&S Safegaurd is a given if you were to do this swap.

Honda S2000 has an 11:1 CR
Toyota Celica GT-S and Matrix has 11.5:1 (patheticly high CR for hp output)
I would be very careful running boost on stock blocks but then again I would not want to own much less turbo a Celica or Matrix.

A 12:1 would be pretty high for stock ignition timing but with 93-94 it would be possible on pump gas with J&S. The maxima needs 91 but 93 doesn't hurt.

 

I know that you could put thicker head gaskets on there and lower the CR to about 11.5:1 or so without getting new pistons. I would feel safer that but that is just me.

 

hmmmmmmmmmm......
........interesting.......

 

My fault I meant 11.7 not 12.7 like I wrote. I honestly don't think 12:1 is out of the question even on the stock ignition timing. I don't have a lot of experience with high compression on MAXIMAS, but it was never a problem on anything else I have used.