Head Work and Custom Cams

[Mike R]

Yeah, that's the definition....(dunno) about the rest, maybe?

 

[twilightprotege]

i will arrange dyno as soon as physically possible to let all know how it goes.

i'll give the head place a call and find out how they worked out that exhaust % of 78.6....and how that related to the exhaust CFM measured of 150.7

 

[twilightprotege]

just spoke to the head shop. volumetric efficiency cannot be workout without the engine, power figures etc....takes a lot to work out.

 

[RAAZ227]

dyno.....dyno.....dyno......

 

[Installshield 2]

Yeah, that's true. All motors the exhaust is smaller, because it's under pressure going out, intake you need the easier flow.

Wonder what's so good about 100% volumetric efficiency then???
(not too smart with engines, I can put them together and understand how they work..but the real nitty gritty stuff I'm ???)

The definition of volumetric efficiency can be different from person to person, mostly in at what point of the engine's rotation (or where the piston is) that it is measure ...this is the way I have been told...

100% volumetric efficiency refers to the pressure inside the combustion chamber at Bottom Dead center (the measurement usually requires every single CC of cylinder displacement to be accurate)with the valves closed (In Twilight's case, this doesn't happen) being identical to ambient air pressure outside the car...With your cams Andy, I don't think it could be accurately done...do to your overlap and big hairy swingin' balled duration...

The percentage itself is simply the percentage of the ambient air pressure inside the clyinders at the time mentioned above (BDC with every valve closed in that cylinder)...so an engine that has 80% volumetric efficiency has 80% of the outside air pressure inside that cylinder at that particular time...

and Mike...100% volumetric effieciency rarely happens on production NA vehicles...In this case no single modification to increase aif flow without forcing it (in other words, without forced induction) will yeild gains, simply becuase the air pressure in the cylinders is the same as outside the engine (an engine's vacuum will only suck air in until identical pressure is reached on both sides, after that nothing happens until it is pushed or forced in)...I don't even think Chevy knows what volumetric efficiency is, they employed Toyota to build more efficient engines (volumetricly) for use in their prism and Vibe vehicles. Mostly becuase they didn't want to spend the money or time to build them on their own, or IMO their engineers simply do not know how to do it...The expense of the parts involved to get to 100% is ridiculous, let alone the research and development...And also remember that ambient air pressure is always changing...an engine could be 100% efficient in a thunderstorm, and not be on a high pressure sunny day...

From what I remember, the closest production NA engine to 100% is Ferrari's 3.6L 40valve V-8, which is used in the 360 spider...it has 3 intake valves per cylinder (2 exhuast), big ass variable cams, and excellent breathing capabities...I vaguely remember it being in the 90 percentile in some conditions, and only in certain sections of the rev range...

 

[twilightprotege]

gee you're up late install!

so the 150.7CFM they said the exhaust would be right? sounds sorta strange if that's the case because thewrench said that sunbelt tested a stock head and got 164CFM on the exhaust...that's a pretty big decrease

 

[Installshield 2]

I get very confused very quickly when flow ratings are said as volumetric efficiency...to my understanding volumetric effiency involves every piece of the intake side of the engine, and the clyinders themselves...78% or whatever they gave you makes no sense to me...Are they saying that the head can only flow 78% of the ambient air pressure?

This is where numbers by themselves can make things very confusing...If an identical way of testing the stock head by sunbelt, and your head by whom ever did the work was used...it appears you lost flow...but I doubt that is the case given that you said the engine feels more powerful....

Yeah I am up too late...big tests on Thursday, and needed a break from studying...:mad:

 

[twilightprotege]

well even compairing the numbers on the intake side, i've gained like 26CFM in flow...i cant see how i'd loose on the exhaust side if they've been able to gain so much on the intake side

i'd really like to know what machine sunbelt use for their flow tests.

when they said 78.6%, that's the averaged amount of flow the exhaust does in comparison to the intake side. they tested flow at 0.050", 0.1, 0.15, 0.2, 0.25, 0.3, 0.35 and max lift (about 0.36)

arhhhh study...that explains it all....

 

[Installshield 2]

ok that makes more sense...

yeah and don't worry about the exhuast side as much...among the things already mentioned, the exhuast gasses are actually sucked out of the chambers by the moving pulses already in the exhuast...So they get a lot of extra help compared to the intake side...

 

[twilightprotege]

yeah the numbers i'm most interested in was the intake side...after all it's the amountta air you get in that makes the HP.

cant wait to see the dyno results when i get to it. i'm going to do a bit of side of the road testing in the next few days by leaving the VICS shut instead of it being variable...i'll see how that feels

 

[Installshield 2]

yep sounds good...

by the way, this is off topic but I didnt' feel like digging up the old thread...

I have started to drive the car a little harder since the cam install...a few spikes up around redline....I have to admit, I am much more impressed than I thought I would be...The engine feels much better above 5500rpm...I can easily take the engine to 6700rpm and it feels like it pulls harder the higher I get...I don't notice any power differences really, but can definately tell the engine enjoys being at that those speeds more...before the power noticably dropped off from 5700rpm or so and above. Now the power builds all the way through redline...I can't wait to finish the bolt-ons, get the ECU, and mess with compression/head/intake manifold...

Thanks for all your help with the install Andrew

 

[twilightprotege]

yeah no worries, anytime! glad it's worked out well for you.

sounds like you've gotta be like me now....remember to change gears because it keeps on pulling hard to redline...but no more redline from me for a while....need to settle the engine in some more.

have you had a dyno run yet to get a baseline?

 

[Installshield 2]

No dyno yet...The closest to me is in Harrisbury PA I think, a good 2 hour drive...plus around my area it is hellishly expensive..I checked that shop's website and it was around $125 per pull!!! When I asked if that was for 5 or even 3 pulls he was like "are you nuts?"...

so I will probably wait and buy a bunch of bolt-ons...not install them right away, save up a little more cash and get it dyno'd...Wit the current cams I hope to be in the 105-7whp neighborhood (most stock north American P5's dyno in the 100whp) with the meat of that power peaking very close to redline...I for some reason buy parts, and then wait a really long time to install them...I don't really know why...but I like to put a bunch of different parts on at once, then the power differences are much more noticable...I had the cams for over a year, and didn't install them until now....And I still wanted to wait until just before the entire turbo setup was complete...but some nut ball at school paid me $1500 for a used T-25 turbo, a Spearco FMIC, and a custom turbo manifold that wasn't even lined up right yet for an FS (it probably never would have been...It was a s*** piece custom made with an FS flange...It looked like s***, and will probably break like s*** after 100miles)...I told the dude "I AM COMPLETELY RIPPING YOU OFF!!", and he boldy replied with "I DON'T CARE, IT IS MY PARENT'S MONEY"...he didn't even own a protege, he had some old civic and wanted still wanted the manifold???

So I guess I am going to 100% stay NA with my current engine...and then maybe build a strong Turbo FS in my spare time and spare money...

I like the idea that no one has really used a full stand alone and remaind completely NA for the street yet...I will just play around with a Link2 in the near future and high compression and see what I can squeeze out...And with your research and results it appears that the envolope is being thoroughly pushed...

 

[twilightprotege]

dang that's heaps for a dyno run!!! when we get a group of people together, i get dyno runs (they do two runs) for $25aud - that's like $17.50usd!!!!

yeah i'm certainly thinking haltech is in my near future...just need cash!!!!

 

[Mike R]

Ah, OK thanks for the info installshield. One thing though...chevy had nothing to do with the vibe or prizm except to rebadge and make them uglier. Kinda the same with the sprint also, just a suzuki with a bow tie. They have built some awesome motors though...LS1/6 is pretty sweet. Too bad the packaging is crap.

How far are you from Westminster? The local place EIP is 50 bucks for 2 runs.

 

[slenser]

Subscribing to this thread. Give details on the cam, when possible.

Thanks,
Sam

 

[shinzen]

Hey twilight- what are the prices on the haltec down there? Also, have you looked at the microtech? heaps cheaper

 

[Installshield 2]

Hey twilight- what are the prices on the haltec down there? Also, have you looked at the microtech? heaps cheaper

Haltech E6X's and the entry level Microtech systems are just over $1000 I think....The Link systems from New Zealand are by far the cheapest (the base package starts at about $600, and the unit similar to the E6X is about $900)...and have much easier to use software....

Andrew let me know if you plan on only going with Haltech...I can pm all the info and engine details I have so far on making the LinkPlus 2 standalone a plug and play system....but there are no plug and play options with the Haltechs...

www.Link-electro-usa.com .. Try that website for a lot of info on it, what you get for the price pretty much can't be beat...

 

[shinzen]

hey install- i thought we ran mass airflow, and it says on their site that they use speed density(honda) will the system still work for us?

 

[twilightprotege]

i havent looked into prices for the haltech yet, but i might have a chat to the link guys in NZ - it's only just over a little sea i'm sure they'll have a office here

the only reason i was thinking haltech is because they are very well known, and their factory is within 30 minutes drive of my place...cant get much better than that!

and for those wanting to know, these are my cam specs

lift (intake and exhaust) 0.351"

duration @
.010" 273deg
.020" 250deg
.050" 226deg
.100" 199deg
.200" 147deg
.300" 83deg