Slo_crx1

Just been running a few tests today, playing around with the new cam gears I got and wanted to see if anyone else has had any thoughts on overlapping cams in n/a form. I left the exhaust cam at it's stock 0* setting, and played with advancing the intake cam 1 and 2 degrees to see if how it would affect scavenging and power and torque through the rpm range. Unfortunately my cams suck...crappy auto b16 cams, so it really didn't make much of a difference. 1 degree advanced started moving the powerband towards the top end a hair more, but 2 degrees just seemed to kill it completely until the 6k+ range. Every time I set the cam degree, I reset the timing to 16* btdc just to get a base to play with. I think the 2* advance will help me later on with my turbo (little 16g baby) to keep it from making full boost at an extreme low rpm. Just wondering what any of you b-series vtec heads out there might have come across regarding cam tuning and its affects. Would any changes in the exhaust cam start to make a difference in power production and range as well? Hit me with some comments and inputs. Hopefully I can get a better set of stock cams later on to play with a little more, maybe a set of gsr's for the time being since any kind of hype-arrrrrs are hard to find by me and just as expensive as an aftermarket set

DrSeuss

as a rule of thumb, you don't really want any overlap with a boosted engine. It just leads to blowing the intake charge through the turbo. Nice high lift cams with shortish duration often seem to work well.

Walter

ITR / CTR cams FTW:.. thought if you can to buy CTR cams.. it will better.. cuz intake has more duration (a lil) than ITR cams.. good way to run turbo with those cams..

beerbongskickass

Wrong. I have noticed you say that in a few threads, stop posting that nonsense. Your rule of thumb doesn't apply for hondas, overlap can actually help. Read this and search the rest of that site if you want to learn something. Oh and this guy is asking about N/A cams, why the ---- are you talking about boosted motors? lol...

http://forums.evans-tuning.com/viewtopic.php?t=1623

"Typical turbo cams have high lift, lower duration. This doesnt work well with honda engines. They like to make peak VE at higher rpms, and using a cam like this will ultimately limit the amount of scavenging that occurs in the higher rpm level. With a high lift, low duration turbo cam you'll make alot of midrange gain, but the top end will drop off since the engine wont be able to breath through the reduction in total valve time open (duration). One customer had a set of Crower turbo cams, he losted nearly 40whp at high boost compared to a pair of OEM b16a ones. OEM gsr and itr are really good at making high rpm whp that honda engines are known for."

"If you are trying to make alot of peak whp, i.e 8-10k range, the overlap will help scavenging at the higher rpms"

Walter

like said.. ITR CAM/ CTR cam FTW im looking a set for GRS cams ..i think those cams are better choice and cheaper for a turbo setup...

DrSeuss

*sigh*, i'm here to learn and don't object to being told i'm wrong. But seriously dude, chill out.

For N/A cams, lift and duration are your friends. The limiting factor is the RPM at which the weakest component lets go (assuming valves don't start smacking pistons). Playing with overlap will alter the area under the curve, midrange can be gained at the expense of top end and vice versa.

Sorry, just one last thing, WHP doesn't mean ---- if you ever have to go round bends.

Walter

and for turbo cars too.. above all if they have good duration...ive heard itr/ctr cams are better than crower or so..

ProzacOverdose

I've seen +3, +4's on most intake cam gears. Some -1, -2, -3 on exhast. Its a simple concept....overlap and scavange the exhast and prolong the compression stroke effect....but ppl use dynos to effectively and accuratly dial in cam timing and power. Of course...your car would breath better with larger profile cams.....but one thing to remember...some are ground with cam timing already + or -. But there are lots at play when changing the timing. How much comp do you have...how much clearance your valves have....etc. I've seen consistency with shops with +3 int, -2 exh, and leaning out the fuel a bit a higher rpms. But thats stuff we already know....or should know.

Slo_crx1

That's exactly what I'm talking about. Plus for a smaller sized turbo on my b16 it will help slow down the spool time...meaning if I run only a t3...say .48/.60 so that it won't spool at 2500, but wait a little longer in the rpm range. And since It'll be in an EF chassis, I have no room for equal length manifold...so it'll increase the scavenging effect on the log manifold that I'll be forced to run :P

It's only a rough estimate, but my g-tech meter says usually around .96 g's in a hard corner...does that count? Who do you think would win...2 cars, identical suspension and handling, only one has 150whp more...do the math. Faster entry speed, same characteristics through the corner (harder braking going into the corner from faster entry speed means more weight shift to the front tires), and faster exiting acceleration. Sorry bucko, not my first time through the twisty's

rudebwoy

I finally gave up on my gsr cams, I will be running skunk 2 stage 1 cams, and for the skunk haters shut it!
I used gsr cams in my ---- felt no different from my stock b16. swap to skunk2 car went wild screem tires all the way through 3rd. they have a flat spot between 6800rpm, and 7500 rmps, then after that grip that steering wheel. vtec set at 6000rpm plants me to the seat. then I tried a set of crower turbo cams power feel weak until vtec engages 5000rpm. pull hard all the way to 9600rpm rev limit. the crowers arent mine. but the skunks and the gsr are. so I am gonna run the skunks.
that little flat spot aint ---- when you are reving to 9100-9600rpm exhaust 00, and intake at 3 deg. advance