12.5 : 1 Cosworth pistons

[AJ'S 88NA]

nice....perhaps i should read more.

Thanks Dr, I'll trade you for yours:naughty: Mines black.
Back on subject, you know with 12.5 compression you'll have to run racing gas I'm pretty sure.

 

[Doward]

Depends on the cams. Use some really radical cams (low dynamic compression), optimize quench, and go gentle on the timing, and you can run 93 octane. Run a 160 degree thermo, and make damn sure you have no hot spots.

 

[AJ'S 88NA]

Depends on the cams. Use some really radical cams (low dynamic compression), optimize quench, and go gentle on the timing, and you can run 93 octane. Run a 160 degree thermo, and make damn sure you have no hot spots.

Boy I don't know, maybe 11:1. Mine at 10.5:1 on 93 octane doesn't want to run to good at all over 15.5AFR. My cams aren't radical .322 lift and .244 duration. But I could be wrong, been wrong before:biglaugh:

 

[Doward]

Why are you running 15.5:1 AFR anyway? You should be more like 14:1

 

[Setheroo]

I will be getting an 11.5:1 engine going here pretty soon... I hope to dyno it sometime this month. I will update in here for you guys to see the possibilities of our lowly NA's.

 

[AJ'S 88NA]

Why are you running 15.5:1 AFR anyway? You should be more like 14:1

In the process of tuning Maft-Pro I found that out. 14:5 to 15:1 for cruise. It starts spitting around a AFR of 15.5, at 16 it really misses.

I have everything set right now at 12-13 without AFR tracking or PTT on. WOT I'm seeing 11-12.5.

 

[DEFIANT 7M]

awesome. will be nice to see a properly built crazy NA finally run....

From the ashes..............I'm still here:biglaugh: Here is 15:3 for you guys that don't know me. Nice find on the Cosworth pistons.

 

[greensupra_87]

sweet, how is the progress?

 

[DEFIANT 7M]

sweet, how is the progress?

Lets just say I see light....a lot of light at the end of this 7 year hole:biglaugh:

 

[drjonez]

Boy I don't know, maybe 11:1....

agreed. 12.5:1 on pump gas on our old tech engine is a FAR stretch....you'll need to do some serious combustion chamber work. besides, race gas smells good!

From the ashes..............I'm still here:biglaugh: Here is 15:3 for you guys that don't know me. Nice find on the Cosworth pistons.

allan, you're still around!/!?!? awesome. i can't wait to see that thing run. i'd probably make the drive down just to see it....

 

[DEFIANT 7M]

allan, you're still around!/!?!? awesome. i can't wait to see that thing run. i'd probably make the drive down just to see it....

Still here:biglaugh:Can't seem to shake this, it's in my blood.:biglaugh: That would be kool if you could cut away to see it.