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Author
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Topic: NEW COMBO GUESS #S
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mtbaughs
Road Racer
Member # 4052
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posted
 
 
Yeah I bought my split duration cam off ebay for $150. Why cheap out on basically the brain of the motor? In my opinion this is where the money should be spent not saved. You guys keep mentioning needing the cam to be custom ground. If you shop around you can find just about any combination already being made. Also another helpful resource. Desktop dyno's cam iterator program. People say that you can't trust a computers calculations in the real world. Think again. Every car I've seen run through the desktop dyno program has been within a few horsepower of what I've seen on the actual dyno. They key is just knowing how to enter in all the info in the correct fields.
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R.I.P. Charlie Bruno Dec 2001
Posts: 2019 | From: Boise, Idaho | Registered: Jan 2004
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93PONY
Mr. Valve Events
Member # 60
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posted
Good luck finding an OTS reverse-split cam! LOL
AFR headed combo's need to limit he amount of exhaust flow or they'll get reversion. This kills low-end power.
Aside from that, you can only get so much overlap in a cam before it won't pass the sniffer. This # in CA is typically 1 degree of overlap at .050 lift. The X303 is 1 degree shy of this 'limit'. Behond that power is gained from proper valve timing & ramp-rate. The X, when installed correctly, has some pretty good timing events for certain setups (this being one of them). The ramp-rate on the X is not an XE lobe, but it's certainly FAR better then an E303 & most other off-shelf smogable cams like the TFS 1. Slap on some 1.7 rockers on the X & now the valve action at he heads rivals some of the XE line.
I'll say it again, the X303 is the best bang-for-the-buck smogable camshaft....especially for this combination.
Oh...& I have a few combos that Desktop dyno won't know what to do with! LOL There is nothing in those programs that compensates correctly for ramp-rate. From stock to solid roller there is a whole host of different lobes profiles that perform drastically different given the same size at .006. Simply too many variables & desktop dyno does not have enough inputs to predict all of them accurately.
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www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4265 | From: Fair Oaks, CA | Registered: Nov 2000
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2stangs69-91
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Member # 1951
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posted
how many smogs have you done with a X cam what are the numbers? How about a trickflow stage 2 will it pass smog? Do you have any actual numbers for these?
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69 Mustang on hold
1991 LX hatch getting a make over
1994 F150 4X4 351
2006 Yamaha V-max 1200 Modded
Posts: 3711 | From: Redding | Registered: Oct 2002
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93PONY
Mr. Valve Events
Member # 60
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posted
What affects smogability CAM wise?
Low-speed misss-fires (lope) & overlap.
The X303 has no more overlap & less low-speed miss-fires then the E303. If the E passes, the X, B, & F will too.
Yes, people have passed with the TFS 2. Wow. It has the same overlap as the XE274HR which also passes on occasion. The more overlap a cam has the less likely it is to pass the sniffer. Overlap is the only aspect of a camshaft profile that effects emissions.
[ February 01, 2004, 03:02 PM: Message edited by: 93PONY ]
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www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4265 | From: Fair Oaks, CA | Registered: Nov 2000
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mtbaughs
Road Racer
Member # 4052
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posted
Haha you didn't want him to see your "smart ass" comment huh LoL
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R.I.P. Charlie Bruno Dec 2001
Posts: 2019 | From: Boise, Idaho | Registered: Jan 2004
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2stangs69-91
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Member # 1951
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posted
hmmm I just wanted some numbers that is it. Duration has no effect on idle quality? You can hold the intake valve open as long as you want and it won't effect the emmisions of a vehical? overlap is not the only aspect of a cam that effects emmisions. I have seen stock cams that wont pass with out cats. A little touchy these day's? I would have to believe that smart ass smog techs that have done thousands of smogs on different cars might have a clue on what might pass a smog test and what you can get away with on a sniffer test and what timming and fuel mixture might have to do with it even with different cams. JMO btw I am not a smog tech any more
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69 Mustang on hold
1991 LX hatch getting a make over
1994 F150 4X4 351
2006 Yamaha V-max 1200 Modded
Posts: 3711 | From: Redding | Registered: Oct 2002
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jmcclesk
Moderator
Member # 1355
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posted
listen 93 pony knows everything about cars and you dont. Like don at motor machine said " MR know it all (shaun) knows everything, just ask he will tell you"
[ February 01, 2004, 03:11 PM: Message edited by: jmcclesk ]
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Ford trained ASE master tech.
Posts: 4024 | From: marrysville | Registered: May 2002
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93PONY
Mr. Valve Events
Member # 60
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posted
No, holding the intake valve open another 60 degrees would not affect emissions. Opening the exhaust valve 60 degrees early would also not affect emissions. Drivability, yes. Idle quality, definately. But not emissions. Hold the exhasut open longer, or open the intake valve sooner & you're increasing overlap....which affects emissions.
True, there is a LOT more in passing emissions then a cam & cats. Assuming all else is good (not neccessarily perfect), the typical 5.0 can have a cam with 1 degree of overlap at .050 & pass with a good set of cats.
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www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4265 | From: Fair Oaks, CA | Registered: Nov 2000
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2stangs69-91
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Member # 1951
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posted
so actual running compression has no effect on a smog test? Buy holding a intake valve open longer it will effect compression which will effect NOX which is tested these days. That is just one example.
[ February 01, 2004, 04:27 PM: Message edited by: 2stangs69-91 ]
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69 Mustang on hold
1991 LX hatch getting a make over
1994 F150 4X4 351
2006 Yamaha V-max 1200 Modded
Posts: 3711 | From: Redding | Registered: Oct 2002
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93PONY
Mr. Valve Events
Member # 60
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posted
Good 3-way cats should knock down NOX enough....just like when you say the TFS 2 will pass...good cats should knock down the emissions enough to pass. Hell, I've even heard of guys passing without cats at all. But that doesn't mean I'm going to try it, or tell everybody else to do it just because someone else passed with it.
To be safe I go by overlap at .050. Any cam with this much overlap or less WILL pass the sniffer. You won't find a cam with a profile of 240+ degrees of duration at .050 & LSA's of 120+ in a streetcar.....so the argument is pointless. Although, if you did find a 240/240 120LSA camshaft it too would pass emissions!
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www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4265 | From: Fair Oaks, CA | Registered: Nov 2000
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2stangs69-91
¯
Member # 1951
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posted
what about having enough compression to properly burn your mixture? If you increase the fill of a cyl, close the intake to late you won't achive a clean burn in your cyl. There is a certain amount of cyl pressure needed to achieve proper burning of the mixture.
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69 Mustang on hold
1991 LX hatch getting a make over
1994 F150 4X4 351
2006 Yamaha V-max 1200 Modded
Posts: 3711 | From: Redding | Registered: Oct 2002
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