n42? 10.08 or 10.50

[cobraz240z]

Ok I have been reading and I got 2 different answers a L28 with flat tops get 10.08 compression with a felpro and some other people claim 10.50 wich is it is the? I just recently bought the 17034 schneider cam and have 3x2 40's can I run with 91 octane on this motor?

[2802NR]

I heard 10.4 with a standard gasket. Anyways, Thats what I am running and I have never had a problem with detonation on 91. Just dont get carried away with your ignition timing and you will be fine on 91 octane.

 

p.s. I am over 4000 ft. Dont know if that makes a huge difference or not. someone want to elaborate on elevation/compression?

 

edit: I am .030 over so I am pushing even more comp than a stock L28.

[JMortensen]

Yes elevation makes a big difference. Cobra, this has been beaten to death already, but Bastaad525 was running a similar setup (I think he had the same cam, flat tops, N42, but with SUs) in Northridge with similar elevation and gas quality. IIRC he had to turn the timing down to about 25 degrees full advance. Personally I'd go with a lower compression engine that could hit mid 30 degree advance without pinging.

 

You might be able to get away with it if you had the larger 13076 cam, but I don't think that Stage III is going to lower the dynamic compression enough to run 91. One thing that would help a little tiny bit would be to run a stock Nissan headgasket. It's a lot better than a POS Fel Pro gasket anyways, and it would drop the compression just a hair.

[cobraz240z]

Thanks guys im going to go to the dealer and order the head gasket ASAP. I don't plan to be driving the car that hard n e ways doesn't everybody say that?