rallysport

I am looking at a 96 LT1 cam the specs are I think 201/208 .447/.459 117 lsa. It is a good cam as far as no valve train mods. but the lobe sep. is quite high. I know it will idle good and pass emmissions. will it show any improvement over the stock L98 cam. and where will the improvement be upper rpm,lower rpm, torque, HP. which one and explain LSA to me that one is hard for me to understand. Thanks

camaro6spd

yeah, what is the difference, power wise in LSA? Also as mentioned in a post below I am looking for a good cam for a 305 TPI 5 speed that willbefulling ported heads to plenum and a full exhaust? Looking for power to around 5500

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1987 Black 305 TPI 5spd IROC, seems to be fully loaded, but can't find RPO codes.

AIM: IROC 5spd
http://www.geocities.com/chevy5spdiroc/87Roc.htm

Kevin91Z

iTrader: (1)

The 88-89 L98 cam is 117 LSA too. Higher LSA means more power in the low end and midrange, while a lower LSA means more power in the upper end. Higher LSA also helps with emissions, acting like a natural EGR and giving more vacuum at idle. When choosing a cam for TPI, do not get one with 110 or less LSA. Stick with 112+.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
317 RWHP, 418 RWTQ
13.23 @ 107.62 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Member: SoCal F-Bodies
-=ICON Motorsports=-

RB83L69

I believe that if you go look up the cam specs for the L98 on this site's tech data page, you will discover that you would be downgrading your car by using that cam...

As the crank rotates, the exhaust valve for a cylinder opens as the piston nears the bottom of the power stroke, and reaches full opening when the piston is somewhere near halfway back up to the top during the exhaust stroke. Then as the piston nears the top, the exhaust valve nears closing; and the intake valve starts to open, and reaches its peak opening when the piston is somewhere near halfway down on the intake stroke. The lobe separation is the number of degrees of cam rotation between those 2 peaks. Since the peak opening point of the intake is the reference point for measuring valve events, this means that to get a higher LSA, the exhaust lobe opens earlier.

Higher LSA reduces low end torque, since it lets the pressure out of the cylinder sooner and throws away that last little bit of "push" from it. It improves idle quality, because there's less pressure still in the cylinder when the intake starts to open, so less exhaust gas escapes back toward the intake. Higher LSA also reduces emissions, particularly hydrocarbons (raw fuel), because when both valves are open at the same time, it's possible for some air-fuel mixture to be drawn right through the cylinder and get dumped straight in the exhaust, especially with headers. Computer controls hate the exhaust reversion back into the intake, that's why they are happier with cams with higher LSA.

Lower LSA almost always means more power all the way around in a carbed car, up to a point. But with EFI, it will confuse the computer especially with a stock chip because of the low and pulsating vacuum at low RPMs, and so it may cost power and driveability.

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"So many Mustangs, so little time..."
ICON Motorsports

Beefy89

I'm running a 96 LT1 cam with 1.6 roller tips and it works fine.I picked up 400 or 500 rpms at the top end.As for the torque it's hard to tell because I installed a 2500 stall converter and it FRIES the tires.I also bumped the c/r to 9.75:1.The idle is lumpy at 550 to 600 rpms,but is pretty smooth above 600.It was definately an improvement over the L98 cam.I also hoggeed the snot out of my L98 heads.

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Shoot Shoot!!!!!

RB83L69

Looking at the cam specs, since the L98 cam has more duration and about the same lift as the LT1 cam, I'd guess that any improvement in that situation was due to the head work and rockers, not the cam... you took out 207°/213° and put in 201°/208°.

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"So many Mustangs, so little time..."
ICON Motorsports

HiTech5

iTrader: (4)

Kevin - Actually a 112lsa will broaden the power range. A lower lsa like a 108 will tend to have a sharp or peakier power curve. Given two cams with the same lift and duration but one cam has a 108lsa and the other a 112lsa, the 108 cam will make peak power at a lower rpm than the 112lsa.


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D&Z Performance
"Putting Power to the Pavement"

Dan87IROC-Z

I think its okay to go with an LSA for 110*. Almost all of the cams that Comp Cams sells have an LSA of 110*, I was planning on using one of them in my 377.

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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, Accel 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)

Beefy89

Actually the duration on the LT1 cam is 205/207@.050",and to say that the lift is about the same from the L98 to the LT1 is silly.I went from .415/.430 to .447/.459 which is a larger gap than the gap between an LT4 cam,and an LT4 Hot cam,which I'm sure you wouldn't consider to be about the same.

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Shoot Shoot!!!!!

Biochem

If you are going to spend the time and money on swaping cams... at least go with one that will give you some benefits! Anything around a 114-116 will work fine with the computer. Stick with a short duration (218/224) and high lift (around 0.510") and your computer will be fine and so will the emmissions... Listen to Kevin and Rob, they know cams Ok maybe Rob only...

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

rallysport

I can get it for 40 bucks which isn't bad The duration is about the same and the LSA is the same as an L98 cam but the lift is a good bit more. I don't know if it is the best upgrade for a 350 TPI but its cheap and it almost has to get more power. I am only looking to get about 300 HP out of this motor. Along with headers an a free flowing catback and some head work done(i.e. milling to 61cc, 3 angle, port and polish). also all the free mods and a ported plenum and intake with a little luck will get me there. I hope I am not being to optimistic.

Beefy89

I guess it all depends on what you want the car to do.I drive my car 45 miles daily to work and back as long as there is no snow or salt on the roads,so I wanted to get halfway decent mileage,plus a little more performance.A friend of mines father who is an engineer at SLP,suggested the LT1 cam for what I wanted to get out of the car right now.I'm not bench racing I actually put this cam in my car.It wont run 11s or 12s it probably wont even run 13.50s but it is respectable.High lift isn't always what you want from a cam,just take a look at the cam specs on the RamJet 350 .431/.451 and it makes 350hp.

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Shoot Shoot!!!!!