Vacuum with HKS 264/272

[oldman]

Vacuum @ 950 is 50KPA ~ 14inHG
Fuel Pressure ~ 39psi with hose on / 43.5 with hose off. Shouldn't my fuel pressure be lower than 39psi w/ hose on? I think I might have to upgrade my return line..... Using an Aeromotive AFPR and Walbro 255HP pump

Did you tafflon/seal both the vacuum fitting and adjustment rod as well as making sure where top connects to the bottom is leak free (Recently found two loose bolts while helping a friend installing a brand new Aremotive setup causing the body of the AFPR to leak) when you install the AFPR? Is your fuel tank breather hose flowing freely? These are things that can explain why you're not at 36.5 psi with vacuum hose on. Fixing these leaks will also bring your vacuum reading up some.

 

[daren_p]

The couple of guys that posted above that had low vacuum for the size of cams their running, (turbotalondl, notractiongst) have you verified that your timing belt marks are 100%? If your off a notch somewhere this will explain the lower then normal vacuum your seeing.

With the FP1X's I see 15-16 in VAC at 750 rpm, 680 above sea level. When I first installed the cams using the RRE method, I guess the tensioner didn't tension properly & I ended up jumping a tooth, which I found out a couple weeks later when I did my timing belt. With the belt off a tooth I was seeing 2-3 less inVAC then what I currently see.

 

[eclipsegsx1736]

264/272 stock degree, set to 750 rpm, 14-16 hg. Really lumpy idle and i love it. right before installing the cams I would get around -20 hg.

 

[DSMunknown]

HKS 272's not degreed and as steady as I can keep the idle around 900 I see 13 -14 inHg.

Steve, why don't you have your camshafts degreed? This question goes out to anyone who is in the same boat as Steve.



While I wait for a response, I will be reading over these links I found, and I will tell myself to search :


http://www.automotivearticles.com/123/Degreeing_Camshafts.shtml
http://www.compcams.com/Technical/Instructions/Files/145.pdf
http://findarticles.com/p/articles/mi_qa4078/is_200303/ai_n9217036
http://www.chevyhiperformance.com/techarticles/53439_cam_basics/
http://www.rpmrons.com/degreecam.html
http://www.camresearchcorp.com/CamInstall/CamInstallation.htm
Camshaft Degree Wheel Kit
An interesting link brought to you by Magnus
http://www.automotiveforums.com/vbulletin/showthread.php?p=2080296
http://www.chevyhiperformance.com/howto/46318/
http://go.mrgasket.com/pdf/CamSense.pdf
In the "Degreeing In Your Cam" section, there is a Cam Lobe Center/Duration Calculator
http://www.cranecams.com/?show=article&id=3
http://www.compgoparts.com/TechnicalResources/Tutorials/CamshaftDegreeing.asp
http://www.amotion.com/tech/caminst.html
http://www.hotrodder.com/kwkride/degree.html
http://www.camcraftcams.com/camshafttuning.htm
http://www.thedirtforum.com/degree.htm
http://forums.freshalloy.com/showthread.php?p=1355148
http://members.aol.com/pullingtractor/valvecam.htm
http://www.pontiacstreetperformance.com/psp/camshaft.html
http://www.pirate4x4.com/tech/billavista/PDFs/Crane cams Degreeing a cam.pdf
http://www.lcengineering.com/technotes/index.php?p=view&catid=6&id=82
http://www.moddedmustangs.com/forums/overview-degreeing-a-cam-vt535.html



Let me just pull a few quotes from the links above:

In lay man's terms, degreeing your cams means synchronizing the camshaft's position with the crankshaft. A few degrees of misalignment can dramatically affect the engine's operation. If there were no manufacturing tolerances, you would only need to line up the marks on the timing chain sprockets and the cam would be degreed, but with a group of components (the camshaft, crankshaft, timing chain, and sprockets) all with their own standards and tolerances that when installed, can stack up against you. You can never be sure that the cam is in its correct position. Aside from tolerance differences on aftermarket components, changing the geometry of the compression chamber by surfacing the head or block will also require the cams to be degreed. It is always a good idea to degree the cams whenever possible.

A great deal of a camshafts potential power can come from not degreeing the camshaft. It's an area of expertise that must be pursued, learned, and applied. Cams vary widely in terms of pin location, lobe layouts, timing, drive systems, keyways, and other areas, and it is the responsibility of the engine builder to see that it goes into the engine properly and is degreed for maximum performance."

A few degrees of misalignment can dramatically affect the engine's operation. A car with properly degreed cams will make more power than a car with undegreed cams. And as an additional bonus, with the cams dialed in properly, things such as idle, response, and drivability tend to improve as well.

 

[Staytuned]

I have not degreed them in as of yet because 1 I have heard that HKS cams do not need it as they are pretty dead on out of the box, 2 I have not had adjustable cam gears untill recently.

I might attempt it this winter.

 

[Generation X]

I have not degreed them in as of yet because 1 I have heard that HKS cams do not need it as they are pretty dead on out of the box, 2 I have not had adjustable cam gears untill recently.

I might attempt it this winter.

Agreed!!

From all of my research that I have done, and to this day, I have never degreed my HKS 264/272 cams either.

 

[lordnikon_04]

i wanna get 264/264 cams this winter so you guys are saying that when i get them i don't need to worry about having them degreed for proper operation?

 

[Generation X]

i wanna get 264/264 cams this winter so you guys are saying that when i get them i don't need to worry about having them degreed for proper operation?

You should be fine bro.

 

[nanokpsi]

I see about 10-11" of hg at 1000rpms. This is with comp 101400s on a 2.4l motor. This is how it idles fully warmed up at 1k rpms http://s18.photobucket.com/albums/b148/nanokpsi/?action=view&current=DSCF0747.flv
I have the AEM gears on it so obviosly they aren't at 0,0 as they need to be moved anyways to line up correctly. I might play with them some on the dyno.

 

[olmytsi]

Running open downpipe all the time?

 

[Generation X]

I see about 10-11" of hg at 1000rpms. This is with comp 101400s on a 2.4l motor. This is how it idles fully warmed up at 1k rpms http://s18.photobucket.com/albums/b148/nanokpsi/?action=view&current=DSCF0747.flv
I have the AEM gears on it so obviosly they aren't at 0,0 as they need to be moved anyways to line up correctly. I might play with them some on the dyno.

Sounds mean as hell bro!

Mine seems to get more lumpy when the weather is very warm outside, rather than when it's very cool for some reason.

 

[nanokpsi]

Sounds mean as hell bro!

Mine seems to get more lumpy when the weather is very warm outside, rather than when it's very cool for some reason.

My car won't even stay running the motor is warmed up. I have to keep the revs up manually or it dies, untill its fully warmed. It was about 60* in that vid, maybe a little warmer. Shorts in December is always nice.

 

[Raph]

Adding to an old thread..

Stock cam 18-20 hg
BC 272/272 10-13 Hg (it has a nice caming sound now..i love it )

 

[Rice Over Wheat]

-4 psi at idle, BC 272s. I have major idle issues obviously. No vac leaks that I can find and perfect timing. Sucks ass.

 

[DSMunknown]

i wanna get 264/264 cams this winter so you guys are saying that when i get them i don't need to worry about having them degreed for proper operation?

You should be fine bro.

I'm still wondering why some individuals recommend installing camshafts without degreeing them. I have spoken with my uncle about this. He has been modifying V-8s for 25-some-odd years now, and has built 8, 9, 10, and 11 second drag cars (only domestics). He tells me that only a fool would choose not to degree his cams. I'm not saying that Steve doesn't know what he's talking about, but I have great respect for someone who has been building engines longer than I have been alive.


How can the two viewpoints co-inside?

 

[Turbo Talon DL]

Since I just lowered my air intake temps, the vacuum is actually lower, or closer to zero than before. Vacuum pressure will vary with air intake temps as well....wish I would have thought of that sooner. .... Either way, I get around 9-13 IN/Hg arond 850-1000 rpm.

 

[Generation X]

I'm still wondering why some individuals recommend installing camshafts without degreeing them. I have spoken with my uncle about this. He has been modifying V-8s for 25-some-odd years now, and has built 8, 9, 10, and 11 second drag cars (only domestics). He tells me that only a fool would choose not to degree his cams. I'm not saying that Steve doesn't know what he's talking about, but I have great respect for someone who has been building engines longer than I have been alive.


How can the two viewpoints co-inside?

Theroetically your right bro, you should degree your cams, but I choose not to because of the HKS cams being pretty darn close to being degreed right out of the box.

I may however purchase some HKS cam gears in the future to see if the cams being degreed properly will help any.

 

[Turbo Talon DL]

10-12in HG w/ hks 264/272 cams w/ idle at 750...no vacuum or boost leaks either...

This is exactly what I get now too. The warmer the air temp, the higher the vacuum.

 

[PIMking]

whats the problem with the lower psi at idle?

 

[turboglenn]

UN-degreed DKS/FFWD 264/272 combo, on a haltech e6k stand alone, i'm idling at 900 - 1000 RPM with ~14* timing at idle and pulling between 14 - 16 inches of mercury (or in/hg) at idle.

before with only 5* of timing at idle i only pulled between 12 and 14 in/hg. The best way to find optimum timing at a particular load ( at least light loads) is to adjust timing for maximum vacum(advance or retard untill max is reached ).

 

[Turbo Talon DL]

UN-degreed DKS/FFWD 264/272 combo, on a haltech e6k stand alone, i'm idling at 900 - 1000 RPM with ~14* timing at idle and pulling between 14 - 16 inches of mercury (or in/hg) at idle.

Does this mess with your timing advance under a load when you open the throttle? How about the approx air temp/season with these readings?

before with only 5* of timing at idle i only pulled between 12 and 14 in/hg. The best way to find optimum timing at a particular load ( at least light loads) is to adjust timing for maximum vacum(advance or retard untill max is reached ).

Im running pretty much stock timing with my stock ecu and +10% on the old SAFC with the knobs. When all accessories are off I get about your engine vac. I'd mess with the CAS and base timing, but would get too much timing advance. I've already seen 40*+ of timing on my logger at cruising speeds.

 

[turboglenn]

It depends on what load at cruising but 40* can be okay, if it's anywhere around 15 - 20in/hg of vacum 35-40* of timing is cool (under zero throttle decel at 3k and up i see 40 - 42*)... by the time you're at 0 vacum & 0 boost anywhere from 24 - 28 is acceptable.

At least i've found that DSM's like this range of timing for the most part. The settings above are what i run on my car and that results in 30-34* of timing on average at a normal light accell/cruise w/ a head wind and i'm usually at about 10 - 15 in/hg of vacum when seeing those numbers.

 

[ApexVIII]

im at about 13 vacuum with 267/272 on sock cam gears