What is the highest compression you can go on stock cams?

 

you're asking the wrong question

 

lol

 

Then what question should I be asking then.

 

what is the highest compression i can run on the highest octane fuel i have readily access to?

the answer to that still isnt cut and dry

 

Its a balance. You want the right cam for the target compression. Each cam will have diff characterisics for diff compression. If your gonna keep stock cams but change pistons to bump compression, you can a bit but don't go extreme. I had 11.5:1 on stock gsr cams but I wasn't realizing the full potential of the engine until I upgraded cams. Do so searches for na builds and see what their combo is and pick something that's right for what your aiming for.

 

Thanks guys

 

As I understand things:

In general higher compression increases the likelihood of knock, which is very destructive. You can mitigate that by either running higher octane fuel or by retarding timing. Since retarding timing can remove power, there are practical limits to the compression you can run on pump gas and still make power.

As far as cams go, the reason they "need" more compression is because high lift/duration cams reduce the dynamic compression of the engine. They make it easier for air to go in and out of the cylinder, meaning that the engine has a "harder" time compressing the air in the cylinder so that the engine can make power.

So what you should be asking, among other things, are what compression can I safely run on the octane of fuel I have access to? And what cams work well with that compression and complement other aspects of my build or requirements for the car (including rev limits)?

For example at 91 octane, 11.5:1 is a healthy compression that will let you run a wide variety of cams depending on your specific needs.

 

What about 93 octane, was looking for around 12.0:1 compression.

 

you'll be fine with 93 at 12:1 but after 12:5:1 i'd start to look into stuff like E85 depends where you live also(we can get into altitude factor as well).

 

Why do you want 12:1 compression?

 

Well I was wanting to stroke it to 92mm stroke with 12.0:1 compression with out having to go with a real aggressive cam. I really don't want a real rough idle as it will be a dd and I not going to be reving past 8200-8500 rpms anyway. I'm not trying build a all race car just a solid dd to have some fun in. Also panning on port and polish head with dual valve springs, titanium retainers just to have the reassurance of durability. Skunk 2 intake manifold, injen intake and a complete comtech engine seal kit and gates timing belt. I'm shooting for at least 200hp. Oh yea of course have it tuned also. I was going to send the ecu to pheriable.net unless anyone has any other suggestions. The only thing I want to keep as far as the ecu is the immoberlizer function for added theft protection.

 

Oh a heytech header and a 2" magna flow exhaust.

 

this thread won't end well.

 

A 12:1 92mm stroker with a basemap -- yeah, not a good plan. OP don't take this the wrong way but it's like you've read all these things people do and just picked some of them. The build you're talking about is not cohesive and doesn't make any sense.

If you want a reliable 200 whp build (and are using a VTEC head, which you haven't said anything about yet), do an 82x85 with 10:1 to 11:1 compression, I/H/E and ITR cams.

And it's not like 12:1 forces you into using aggressive cams. Likewise there is nothing stopping you from using aggressive cams on 10:1. It's all about tuning.

You can't just pick parts off the shelf and construct the kind of build you are talking about. Have a conversation with a REPUTABLE engine builder and I think you'll find your priorities changing and your expenses for your suggested build severely underestimated.

 

 

Yes I'm using a vetch head! 2000 gsr b18c1. Where I live there is not a lot of builders around here unless your driving a 60's or 70's model big block. As far as expenses I willing to put into the build whatever it takes to get what I want out of it. This will be my 1st build on one of these engines.