Overlap may help turbo apps with log style manifolds

[MRX]

Read up:
http://www.homemadeturbo.com/forum/i...threadid=35945

Unfortunately for the sohc's cam overlap is static and can't be changed with cam timing adjustments and is totally dependant on the amount of overlap the cam comes with. Whats too much overlap you say?...We don't know yet we have to wait for someone to dyno both the stock cam vs. the delta 272 regrind (or something similar). The good thing is that even if the 272 is less than or somewhat equal to the stock cam as far as power then it may "allow" for greater ignition advance. Lift and duration is commonly known as good for turbo engines but overlap was always considered bad...i haven't agreed with it being "bad" in a long time. Using a log style manifold's restrictions to an advantage is a brilliant idea IMO.

[theone]

i was just thinking about adjustments being made to my cam gear.
and if any gains would be made.
i havent touch my gear sense 2 years ago, when the damn aluminum bolts moved and cause my piston to kiss 2 valves....lol

have u messed around with yours? if so....advanced or retard??

[gdout90accord]

haha shit all da bolts on my cam gear was loose last saturday dats why my timing belt was loose again. the cam gear was retarded dats probly why my car was slower when i got her back running again, but then i again i think my valves are fucked.

well so did u advance or retard your cam gear? antoine

[MRX]

are u kidding me i'm not telling yet lol!?!? Mine is at stock right now, I can't exactly say which way to adjust it till i do it on the dyno. So right now i'm not saying a word cause I know the both of you ALL too well and i guarantee the both of you would walk straight out to the car, pop the hood, and get straight to work lol. I know whats up wit u 2...hell, you probably readin this with a wrench in your hand huh?

p.s. theo - if u make it to nashville maybe we should look for a dyno, i'd be more than happy to tune your engine
p.s. gdout - Maybe your turbo is about to go?

[theone]

lol....
yeah u know me....lol
for the meet, i need to look up the date....my cars gona be down for a while til march, im about to pull the heads off change the HG, Head bolts, valve gasket, oil pan gasket, exhaust gasket, install a oil cooler, and some more things, im gona start pulling it all off this weekend but as for installing the new parts...thats gona have to wait til i get some cash....when my taxes come in...lol
also go send my axles out to get cryogenically frozed, so ill keep u all updated on that

[MRX]

Well stepping up the setup to run perfectly becomes a money issue. I had the choice of either a $175 logstyle mani shipped or a $450 tubular manifold + shipping. I see it as a make the best of what you've got thing. Just as i'm making the best of having an f22a under the hood. It is certainly a band-aid and i agree the log style mani is a bad design. I'm venturing to say that SOME overlap over stock is ok but excessive is counter-productive.
What i'm getting at is, say with the delta 272 cam, does that specific cam create too much overlap and is it over the efficiency parameter of the setup? And that question won't be answered by mere internet talk it has to be on paper. Now i believe the 272 cam is too much but the 260 would be a significant safe gain over the stock cam. I consider the 272 an extreme cam and the 260 as a mild cam. I also enjoy thinking outside the box/norm

[theone]

heres the specs on the cam i have
PART NO.: HACS02 AUTOMATIC: HACS03
DESCRIPTION: Added power and torque; strong to redline.
POWER BAND: 3500 R.P.M. to 6800 R.P.M.
IDLE: Around 900 R.P.M.
SPECIFICATIONS: Intake LIFT - 0.405 DURATION - 228
Exhaust LIFT - 0.402 DURATION - 228

[gdout90accord]

are u kidding me i'm not telling yet lol!?!? Mine is at stock right now, I can't exactly say which way to adjust it till i do it on the dyno. So right now i'm not saying a word cause I know the both of you ALL too well and i guarantee the both of you would walk straight out to the car, pop the hood, and get straight to work lol. I know whats up wit u 2...hell, you probably readin this with a wrench in your hand huh?

p.s. theo - if u make it to nashville maybe we should look for a dyno, i'd be more than happy to tune your engine
p.s. gdout - Maybe your turbo is about to go?

lols
hahah you sure do know us lols
umm bout my turbo, yea my turbo probbly bout to go out on me but im thinkin my motor still good but not sure yet i needa do a compression test dis weekend. so if you see any good deal on turbos let me know haha aite laters

[WiKKeDV16]

so wouldnt a turbo cam.. be ideal to have high lift? without overlap?? what are the specific requirements of a good turbo camshaft?? even when used with a logmanifold??

N/A applications use overlap to make power.. so im assuming if u keep a stock spec or near stock spec overlap situation going on.. but add more lift and duration.. then the cam should provide adiquete needs for forced induction no???

[MRX]

i think the amount of overlap would be based on the overall efficiency of the entire exhaust system. It looks like the more efficient the exhaust system the less overlap u need and the opposite for an inefficient system. The inefficient system possibly needing more overlap was obviously proved on the turbo car in the link. In other words specifics of a good/ideal turbo cam may be based on the exhaust flow restrictions. And yes i believe similar overlap to stock plus added lift and duration would be a good turbo cam. Thats why i'm leaning towards the 260 regrind

[WiKKeDV16]

yes exactly.. so for someone(like yourself tehe) thats inbetween.. log manny but a good turboback.. wouldnt the benefits of high lift/duration vs having overlap be more beneficial than overlapping due to ur weaklink(log manifold)
???

[MRX]

yes exactly.. so for someone(like yourself tehe) thats inbetween.. log manny but a good turboback.. wouldnt the benefits of high lift/duration vs having overlap be more beneficial than overlapping due to ur weaklink(log manifold)
???

i don't know, its kinda the same question i'm asking. I think only experimentation can tell us

[WiKKeDV16]

u got pm..

[Accord R33]

i still say the less overlap the better no matter what. its hard to get a better turbo cam than a stock one. even my buddy corky says so.

although it is hard to argue with a dyno

[MRX]

i still say the less overlap the better no matter what. its hard to get a better turbo cam than a stock one. even my buddy corky says so.

although it is hard to argue with a dyno

Aside from the dyno as my back-up i also have vtec on my side. Vtec is in itself lift, duration, and overlap rolled into one correct? Well if corky was correct then on vtec engines power would drop at the engagement and the low cam would be the better overall cam for low and high end seeing as it has alot less overlap than the high cam. I think theres a median to be found and if found you can make good safe power over the stock cam