I was on the phone with Comp Cams yesterday, and they recommended a 206/218 grind. My question was that the person I talked to said that the reason he wouldnt recommend a larger cam was the stock computer. Why is this? I would think that the stock torque converter would play a larger role than the computer. Anyone put a cam similar to that in a LB9? thanks

 

The reason for that is because if you don't burn your own eproms. And you go with a cam that doesn't work well with the computer you'd have to get a new eprom and it can get very pricey. When for that same amount of money you can do it yourself and keep makeing adjustments in the future for different heads, cam, whatever it would be. Even the cam CC recommended to you would probably need a custom chip (at least it would be a good idea). See where i'm comeing from? If you interested in eprom burning read Traxions Tech Article. It's really not very hard just requires time. But the satisfaction of the end result is something you'll be suprised at.

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89 IROC-Z 350 TPI

-Flowmaster Catback
-Performance Resource Chip
-700R4 (Rebuilt) Too much done to actually list
-K&N Airfilters
-Ported Plenum
-2.77 Gears (not much to brag about but eh, its there)
-MSD 8.5 mm plug wires
-Gutted cat
-!AIR
-Gutted Air Boxes

 

Larger cams give a poor vacuum signal..that plays hell with computer systems. Even with custom chips, there is a limit to how big you can go and have it actually run right without going to a full DFI system.

I'd have to agree with the cam rep...that cam sounds like a good choice for an LB9 anyway. There is no benefit to going very large cam with a TPI system anyway due to thier stong low end and lack of a top.

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"American made baby. 100% American iron. The muscle among the masses. My hero. Yep, you can take your ergonomically designed, space age, computer controlled, 4 door, cup holding map lighted split double wishbone split fold down retractable cargo covered moon roof piece of transportation and keep it. For I have felt the thunder. And I know the difference!"
JSP Motorsports
ICON Motorsports

 

I don't have a custom PROM, just the Performance Resource chip, which works great with my LT4 HOT Cam, 218*/228* with .498" lift. You might not need a custom one, just a good aftermarket one from PR, Hypertech, TPIS.

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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 with 2.77:1 Gears.

Current Mods: LT4 HOT Cam, Comp Cams 1.52:1 Roller Rocker Arms, LPE High Flow TPI Baseplate, Edelbrock TES 1 5/8" Headers, Catco 3" High-Flow Catalytic Converter, Hooker 3" Aerochamber Cat-Back System, Transgo Shift Kit, Performance Resource Chip, Accel Ignition, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.

Best ET: 14.32 @ 97.7mph
(corrected for elevation)

 

You can go up to about 215-220 on a TPI and have the ecm like it, especially if you keep the lsa above 112. Past those, you run the risk of the ecm throwing a fit. The 85 really kinda has a crappy ecm, I would stick with something around 214 intake duration max, and around .450 lift and you should be just fine.

I am pretty sure that cam they suggested actually has less intake duration than the stock cam in your car does. Look into it.

 

I just looked into it and the stock cam is a 202/206 .403/.415---bigger than what I thought, but i want more lower rpm torque.

How about the compucam? Ive heard these work pretty well. When I looked into them all I saw was "advertised" duration. Does anyone know what the durations for the different compucams are at .050"? One of my friends suggested a 2030...any good?
thanks

[This message has been edited by 85transamtpi (edited August 09, 2001).]