i have a 87 trans-am with TPI i've had it bored out and i already have a slightly higher than stock lift cam....but i want to put in a cam with a 450" gross lift....will this affect the way the computer works??

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305 TPI with 5 speed
bored .030 over
K&N air filter
edelbrock heads
hot cam
roller lifters & rockers
hypertech chip
aircharger
high perfomance pistons
0-60~4.9

 

Lift isnt what affects the computer, its duration. What is the duration of that cam? Lift only affects the valvetrain geometry, meaning too much lift and the pistons will hit the valves, or the springs will coil-bind if they cant handle the lift. .450" should be fine for a stock TPI head.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

I am running close to .500" lift with my LT4 HOT Cam, .498 to be exact with my 1.52 rockers. And I have to stock TPI set up, so yes, it will work. But the duration is what effects the computer. I wouldn't go over 210* of duration with a stock chip, and make sure the LSA is in the area of 110*-112*.

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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End

Current Mods: LT4 HOT Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Hooker 3" Aerochamber Cat-Back System, Performance Resource Chip, Accel Ignition Coil, Cap, Rotor, 8.8mm Wires, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET (w/o LT4 cam): 14.32 @ 97.7mph
(corrected for elevation)

Soon to Come: 7.625" 10 Bolt with 3.42s and Accel TPI Intake Base

 

I thought that the LSA had to be 112 or greater on a tpi ?

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86 Tramaro 90% Trans Am/ 10% IROC/Z (nose, hood,& fenders)
Trans Am Mods as of 1/10/01
3inch
T.E.S/Flowmaster setup,gutted cat,gutted maf,relocated mat,373 gears,upgraded factory chip,255 liter h/press. walpro f/pump & throttle body coolant bypass
njdaewoo@excite.com

 

Yes, most of the TPI cams come out with a 112-114 lobe center angle. For TPI I don't think you would want anything under 112.

 

Stock L98(most chev heads) will accept .490" lift without coil bind of the springs. So you must have changed your springs right?????? I have to respectfully disagree about the custom chip business though. It is true that a custom chip will give better driveability and a little more power, but if you are low on money, throw whatever cam you want in and worry about the chip later. I am building my L98 right now with the LT4 Hot Cam and I am not even thinking about the chip until I have more $ or problems with the stock one. I saw a post on here that some guy put an LT4 hot cam in an L98 with ported heads and some other crap and still had the stock chip. He said he beat his buddies LT1 car that runs 13.5's..... That's what I like to hear.....hehe

Laterzzzzzzz

 

Your LSA is also going to be affected by your duration. Keep it under 220/220, and you can run 110 with no problems, like I do.

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1989 IROC-Z 5.7L
NOS 150HP kit
ProBuilt 700R4, PI Vigilante 2800 stall lockup
Baer Brakes 12" Sport System

 

Since you already have good heads w/ better than stock valve springs, you should basically run as much lift as you can without going too crazy on the duration.

What cam are you currently running? Crane makes a couple roller CompuCams that are in the range I would run. The 2031 (208/214 dur. @.050, lift of .438/.452) and the 2032 (214/220 @.050, lift of .452/.465) are both good cams.

If you are still running the stock TPI intake and exhaust manifolds, I'd go w/ the 2031, in fact if you don't have those I wouldn't mess w/ the cam assuming you have a decent cam. If you want to avoid getting a custom chip I would probably also stick w/ the 2031, the 2032 is getting on the edge of having computer problems w/o a custom chip. I'm sure it would run alright, but you wouldn't be getting all you could. I think it would be the best cam however if you are setup to run it properly. Are your roller rockers 1.6s? If so you'll be pushing plenty of lift w/ either of those cams, but the springs should still be within their limits.

All that being said, again, if you haven't upgraded the stock TPI baseplate and runners, and aren't running headers I would do those mods before I changed the cam (assuming you have something comparable or better than the stock 5spd cam {202/207 @ .050, lift of .404/.415}).

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Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray

 

I have just installed a Crane CompuCam in my 88 Iroc-Z. The lift is .462 and the duration is 214*/220* and it runs fine. The computer automatically adjusts to the cam.
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1988 Iroc-Z
L98 350 TPI
700R4 Tranny
2.77 gears(will change)

Mods: Crane CompuCam, headers, gutted air boxes
Best e.t.(w/o cam): 14.63@93.71mph
60ft.@2.12

 

I installed my ZZ9 cam before I converted to carb and had no problems whatsoever. The car ran strong. The ZZ9 is .488/.510, and I was running 1.6 rockers.