292xfi comp cam
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Teching In
Joined: Apr 2009
Posts: 42
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From: Wilmington NC
292xfi comp cam i have a 383 stroker with the 292xfi comp cam and im having problems making it idle. I was running the lt4 hotcam but was very unhappy with so i went from one extreme to the other 
it idles around 1200rpms when i start it, around 1000 after its hot, but after i put it in gear and drive it it wont idle without having to give it gas. (6spd car).
i know i need a tune which will come soon but is there anything i can do to get the computer to recognise the cam better and help it idle? thanks
it idles around 1200rpms when i start it, around 1000 after its hot, but after i put it in gear and drive it it wont idle without having to give it gas. (6spd car).i know i need a tune which will come soon but is there anything i can do to get the computer to recognise the cam better and help it idle? thanks
So you went from too small to too big and did not bother to retune it??
Do you have scanning software to read the IAC counts??? The TB might need a tweak, a big cam can max out the IAC and then you need to make some slight modifications to help the computer regain control. This wont raise idle from where it is programmed BUT can give the computer the control it needs to keep the engine running.
Do you have scanning software to read the IAC counts??? The TB might need a tweak, a big cam can max out the IAC and then you need to make some slight modifications to help the computer regain control. This wont raise idle from where it is programmed BUT can give the computer the control it needs to keep the engine running.
With properly spec'd cams and valvetrain guys are making power to the pcms limit with a good bit less duration. That cam is not spec'd right though. It is spec'd for the average guy who buys a cam with too much duration so the LSA is spread to tame it.
The LT1 intake means you need a LOT more rpm than Comp says too so their recommended springs are nowhere near sufficient. The XFI lobes are fairly aggressive and with the extra rpms we need they need more spring.
The LT1 intake means you need a LOT more rpm than Comp says too so their recommended springs are nowhere near sufficient. The XFI lobes are fairly aggressive and with the extra rpms we need they need more spring.
So we can agree it's not the "perfect cam" but it's not too big. Too big meaning cannot utilize the stock PCM, or making peak power above 7000rpm. The other things you listed relate to proper setup, not size. I suppose your too big refers to the "right" way to size the cams.
A local guy just put one in his 383 with AFR heads, I'll let you guys know how it works.
-Dustin-
A local guy just put one in his 383 with AFR heads, I'll let you guys know how it works.
-Dustin-
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Thread Starter
Teching In
Joined: Apr 2009
Posts: 42
Likes: 0
From: Wilmington NC
So you went from too small to too big and did not bother to retune it??
Do you have scanning software to read the IAC counts??? The TB might need a tweak, a big cam can max out the IAC and then you need to make some slight modifications to help the computer regain control. This wont raise idle from where it is programmed BUT can give the computer the control it needs to keep the engine running.
Do you have scanning software to read the IAC counts??? The TB might need a tweak, a big cam can max out the IAC and then you need to make some slight modifications to help the computer regain control. This wont raise idle from where it is programmed BUT can give the computer the control it needs to keep the engine running.
no i have never had a tune. built my motor and had a few issues shortly after. so when i had it apart i wanted to go a lot bigger with a cam and it will be the first thign i do once i have the $. i dont have any tools to check my iac, i was just looking for ideas. ill get up with a friend of mine who has a scanner and see if i can maybe adjust my set screw
thanks for the help guys
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xfi lobes are fine with 918s if you install them .040 from coil bind...
I had that exact same problem with my 6.0L/xfi280 build 6 mo. ago. It would idle fine then I would back it out of the garage and anytime it was rolling it would die. I was waiting on my mail order tune from Trifecta at the time so i just waited to drive it until that was in. The tune fixed it but I would suggest a dyno tune, that's where my car is headed first sign of warm weather.
I can't help but laugh at some people. It's so ridiculous.
So we can agree it's not the "perfect cam" but it's not too big. Too big meaning cannot utilize the stock PCM, or making peak power above 7000rpm. The other things you listed relate to proper setup, not size. I suppose your too big refers to the "right" way to size the cams.
A local guy just put one in his 383 with AFR heads, I'll let you guys know how it works.
-Dustin-
A local guy just put one in his 383 with AFR heads, I'll let you guys know how it works.
-Dustin-
I suspect with good heads it would peak around 7000rpms and you want to be able to rev PAST peak.
I don't remember ever seeing anyone post results for that cam on a 383 with good heads, usually if they make that poor decision they make lots more poor decisions as well.
I do remember fergymoto trying it with I think Lingenfelter heads on a 350 and it had not yet peaked at 7000rpms.
I like a little more safety margin in my valvetrain.
The one guy around here that was using this cam on a AFR topped 396 had float down around 6400rpms with the 918s, granted the AFR valves were likely large and therefore a little heavy BUT those rpms are also lower than a 383 with good heads will see.
I agree .040 would be a little tight for my likings. .060 is the generally accepted standard... you are talking about giving up 1/3 of your safety margin.
Not having enough clearance to coil bind is how I ruined a Comp 918 spring and dropped a valve with my Bret Bauer setup years ago. He told me to set the spring up at 1.750, I told him my springs coil bind was at 1.130 (what my machine shop checked them at). He insisted that could not be right and all 918 springs bound at 1.075. Like an idiot I followed his advice and not my machine shop's advice (they warned me that I wouldn't have clearance if I set them at 1.750), and I set them up at 1.750. 1400 miles later I dropped an intake valve, and the spring on it had 88lbs of pressure at 1.750 afterwords. It had 135lbs at 1.750 when it was put together. I had .015 of clearance to coil bind.
Bret Bauer was supposed to be the big cam guru at the time so I listened to him... I was 18 and didn't know ****, but I sure learned about setting up valvetrain after that, and it was a hard expensive lesson. It about ruined my $2,000 cylinder heads, it cost me $1,000 to fix them. Luckily this was a stock short block and the damage to the bottom end wasn't much of a loss.
In short, I like my .060 clearance to coil bind
Not having enough clearance to coil bind is how I ruined a Comp 918 spring and dropped a valve with my Bret Bauer setup years ago. He told me to set the spring up at 1.750, I told him my springs coil bind was at 1.130 (what my machine shop checked them at). He insisted that could not be right and all 918 springs bound at 1.075. Like an idiot I followed his advice and not my machine shop's advice (they warned me that I wouldn't have clearance if I set them at 1.750), and I set them up at 1.750. 1400 miles later I dropped an intake valve, and the spring on it had 88lbs of pressure at 1.750 afterwords. It had 135lbs at 1.750 when it was put together. I had .015 of clearance to coil bind.
Bret Bauer was supposed to be the big cam guru at the time so I listened to him... I was 18 and didn't know ****, but I sure learned about setting up valvetrain after that, and it was a hard expensive lesson. It about ruined my $2,000 cylinder heads, it cost me $1,000 to fix them. Luckily this was a stock short block and the damage to the bottom end wasn't much of a loss.
In short, I like my .060 clearance to coil bind
I agree .040 would be a little tight for my likings. .060 is the generally accepted standard... you are talking about giving up 1/3 of your safety margin.
Not having enough clearance to coil bind is how I ruined a Comp 918 spring and dropped a valve with my Bret Bauer setup years ago. He told me to set the spring up at 1.750, I told him my springs coil bind was at 1.130 (what my machine shop checked them at). He insisted that could not be right and all 918 springs bound at 1.075. Like an idiot I followed his advice and not my machine shop's advice (they warned me that I wouldn't have clearance if I set them at 1.750), and I set them up at 1.750. 1400 miles later I dropped an intake valve, and the spring on it had 88lbs of pressure at 1.750 afterwords. It had 135lbs at 1.750 when it was put together. I had .015 of clearance to coil bind.
Bret Bauer was supposed to be the big cam guru at the time so I listened to him... I was 18 and didn't know ****, but I sure learned about setting up valvetrain after that, and it was a hard expensive lesson. It about ruined my $2,000 cylinder heads, it cost me $1,000 to fix them. Luckily this was a stock short block and the damage to the bottom end wasn't much of a loss.
In short, I like my .060 clearance to coil bind
Not having enough clearance to coil bind is how I ruined a Comp 918 spring and dropped a valve with my Bret Bauer setup years ago. He told me to set the spring up at 1.750, I told him my springs coil bind was at 1.130 (what my machine shop checked them at). He insisted that could not be right and all 918 springs bound at 1.075. Like an idiot I followed his advice and not my machine shop's advice (they warned me that I wouldn't have clearance if I set them at 1.750), and I set them up at 1.750. 1400 miles later I dropped an intake valve, and the spring on it had 88lbs of pressure at 1.750 afterwords. It had 135lbs at 1.750 when it was put together. I had .015 of clearance to coil bind.
Bret Bauer was supposed to be the big cam guru at the time so I listened to him... I was 18 and didn't know ****, but I sure learned about setting up valvetrain after that, and it was a hard expensive lesson. It about ruined my $2,000 cylinder heads, it cost me $1,000 to fix them. Luckily this was a stock short block and the damage to the bottom end wasn't much of a loss.
In short, I like my .060 clearance to coil bind
