280XFI cam installed, short clip
#1
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From: Prince George, BC, Canada
Car: 89 GTA
Engine: 5.7L Supercharged
Transmission: T-56
Axle/Gears: Moser 9" 3.70
280XFI cam installed, short clip
Well I finally got my cam in and most of it buttoned up, just waiting for a throttle cable bracket from TPIS to finish off the rest of the miniram install before I can drive it. It seems to idle nice at 800 rpms though I noticed my vacuum low at 8 hg, going to look into that one little more. Anyways have a little idle clip to show with a few quick revs, think it sounds good so far
http://i293.photobucket.com/albums/m...psb7359553.mp4
http://i293.photobucket.com/albums/m...psb7359553.mp4
Last edited by Tony89GTA; 09-27-2013 at 12:01 PM.
#3
Joined: Sep 2003
Posts: 25,788
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From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: Strange 12 bolt 3.42
Re: 280XFI cam installed, short clip
Give it another 50 rpm idle speed and alot more timing at idle. It will bump vacuum up some more. Sounds good
#4
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From: Prince George, BC, Canada
Car: 89 GTA
Engine: 5.7L Supercharged
Transmission: T-56
Axle/Gears: Moser 9" 3.70
Re: 280XFI cam installed, short clip
Thanks! I'll take that advice too, but how much advance you think it will need?
#5
Joined: Sep 2003
Posts: 25,788
Likes: 390
From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: Strange 12 bolt 3.42
Re: 280XFI cam installed, short clip
I had it in a 360" motor at 800 rpm idle with 30 deg at idle but thats oldschool afr 190's which mimic 113 type heads which love timing. It ramped up 30 to 40 deg timing by something like 1600 rpm so it was a very quick curve off idle but it liked it
My 383 with a bigger cam i ran 28 deg with afr 195 elimins which take alot less timing than some other heads esp like 113's or old school afr's
Try that out to see what vacuum does. Play with air fuel to and just tune by the vacuum gauge. Find the best and thats your idle tune
My 383 with a bigger cam i ran 28 deg with afr 195 elimins which take alot less timing than some other heads esp like 113's or old school afr's
Try that out to see what vacuum does. Play with air fuel to and just tune by the vacuum gauge. Find the best and thats your idle tune
#6
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iTrader: (7)
Joined: Jul 2000
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From: Prince George, BC, Canada
Car: 89 GTA
Engine: 5.7L Supercharged
Transmission: T-56
Axle/Gears: Moser 9" 3.70
Re: 280XFI cam installed, short clip
I lowered it awhile back when I was messing around with the idle, it's at 20* now so I'll be definitely turning that up. I never tuned with the vacuum before, time to learn something new.
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#9
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From: Prince George, BC, Canada
Car: 89 GTA
Engine: 5.7L Supercharged
Transmission: T-56
Axle/Gears: Moser 9" 3.70
Re: 280XFI cam installed, short clip
I had a chance at messing around with the idle for a bit the other day, tried timing and playing around with afr. Timing didn't seem to help to much, tried 20 to 32, then I left it at 28 for maybe a .4 a point gain in hg. Playing with the afr didn't really do anything but the car seemed to like it lean at 15.5 where I had it before. I raised the rpm to 850 which seemed to help a bit, the car seems to be steady at 9.5hg now. From my understanding every 1000' in altitude you lose about 1hg, I'm at 2400' where I live. Also I have pretty low compression about 8.3 and I heard that affects things too.
Anyways I took the car for a little run around the block and seems to run fine, brakes work ok but I haven't really tested it in like a stop and go situation. Unfortunately the car is parked now for the winter so I won't be able to test things out tell next summer. Still have a bunch of mods to do like fuel pump, gauges, dash and finally they are sending me my intercooler from treadstone. Should be a fun year once spring comes!
Oh and I need a new t-top, when I went for a burn down the block I forgot to latch my top down lol! So yeah at about 60mph I felt the thing rip off the top of my head and go flying into gods country...
Anyways I took the car for a little run around the block and seems to run fine, brakes work ok but I haven't really tested it in like a stop and go situation. Unfortunately the car is parked now for the winter so I won't be able to test things out tell next summer. Still have a bunch of mods to do like fuel pump, gauges, dash and finally they are sending me my intercooler from treadstone. Should be a fun year once spring comes!
Oh and I need a new t-top, when I went for a burn down the block I forgot to latch my top down lol! So yeah at about 60mph I felt the thing rip off the top of my head and go flying into gods country...
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