smkn951

first i'd like to thank everyone for the speedy response on cut the cat. no another, i got a hold of a k&n cone filter and i made an adaptor to fit right before the air flow sensor. will there be any damge to car if i did this? also i noticed that the stock filter case is routed to the left fender, is this what they call a cold air induction sysytem? if it's ok to install that piece i made will hot air from the engine compartment have a significant loss on hp or would it be a fair trade of in installing the cone filter? also, i have a fuel rail mounted guage,it reads bout 35-42 psi would it be ok to increase it to about 50psi since i have a lot of lag on take off?

NerfRacing

a few people on the boards have done similiar things to the air box. and yes a cold air intake is named as such because it draws air from as far away from the engine as possible. if you increased the pressure on your rail, you might end up running rich where you have lag...causing the car to run slower. remember, you want your A/F mixture as close to detting as possible for best performance.

Danno

"you want your A/F mixture as close to detting as possible for best performance."

huh???

smkn951

will the cone filter have any effect to the car?

NerfRacing

or at least thats what ive heard about the A/F, its better to run towards the lean than the rich...not safety or logicwise...but technically...probably wrong if danno said so though . i dont mean to be spreading false info. ...and i think the cone should make your intake a little deeper, but it shouldnt be too rash of a change

johne

I think what nerf means is you want to run as lean as possible without detonation. Which kinda makes sense. As I understand it you want to run 11.5-12 to 1 constantly and turn up the timing advance as far as possible without detonation cause then, bye bye head gasket or even better pistons or blocks ohh yeah baby(and some people complain that our headgaskets go before other components).

EDIT: I started writing this before nerf wrote the follow up but then I spent a half hour reading this:
<a href="http://www.expressen.nu/html/bildarkiv/Saburido.htm" target="_blank">http://www.expressen.nu/html/bildarkiv/Saburido.htm</a>
<a href="http://www.helpjacqui.com/home.htm#top" target="_blank">http://www.helpjacqui.com/home.htm#top</a>
(verry sad, don't read while eating like I did)

Danno

"As I understand it you want to run 11.5-12 to 1 constantly and turn up the timing advance as far as possible without detonation cause then, bye bye head gasket or even better pistons or blocks ohh yeah baby"

Hmmm, yes and no. There are actually two interdependent factors at work here: air-fuel ratio and ignition timing.

On a street car, I'd recommend keeping air-fuel ratios between 12.1-12.3:1 for maximum power. A racecar would be better off at 11.7-11.9:1 for a little less power, but lower exhaust temperatures for durability.

Ignition timing is actually independent of air-fuel ratios. You want to have it optimized such that the combustion in the chamber is fully ignited by 20-25 degrees ATDC. This will give the most 'crank' to the crank-throws. Having combustion complete before this point will just have the mixture compress the pistons and rods into the crank while not actually turning it. Combustion that's complete AFTER this optimum point will have the gases just freewheel and follow the piston down without exerting its maximum force.

Now what happens when you put really high-octane gas into the engine is that you may actually be able to advance the ignition BEYOND thi optimum point such that the mixture is fully combusted by 10-15 degrees ATDC. Just because it doesn't knock & detonate, doesn't mean you're making maximum power.

Additionally, higher-efficiency mods like big-valves, higher-boost, more compression increases the burn-rate of the mixture. As such, you want to decrease the ignition advance to keep the fully-combusted timing at 20-25 degrees ATDC. The whole point with octane then, is that you want sufficient octane to allow you to set this kind of timing.

So again, it's my usual answer of 'it depends'...