Jas89TTA

I've looked in the Tech Articles and found the procedure for adjusting the IAC and TPS, but what should I set my idle at? It's a 350 TPI with a 5-spd and LT4 Hotcam.
What would be a good starting point? I'm thinking about 800 RPM but just wanted to get some opinions and suggestions. Thanks. Everthing is listed below that's installed on the car.

Ported cast iron L98 Heads, Dual CompCams Springs, LT4 Hotcam with 1.6 roller tip rockers duration I:218 E:228 Lift 525/525, Super Ram Intake base, Ported stock plenum , Ported SLP runners, Hooker Headers, Edelbrock 52mm Throttle Body, Holley AFPR, 24# SVO injectors, SLP Cold Air Induction, MSD Coil, 8mm Taylor Wires, 160 T-stat

Vader

Jas,

If you read and understood the entire Tech Article, you would realize that you cannot change the idle speed of your engine and maintain the functionality of the IAC without reprogramming a target idle speed in the ECM PROM. The factory PROM has a target idle of 600-650 RPM in DRIVE when the engine is at operating temperature. This requires you to set the throttle minimum air position idle speed at 450 RPM during the procedure (you really don't adjust the IAC - you disable it to set the throttle minimum air position). The IAC is controlled completely by the ECM.

Your cam may require you to have a higher RPM for satisfactory idle, but you'll be burning a PROM to do it correctly.

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Later,
Vader
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Jas89TTA

Thanks, Vader Sorry about the post on the Idle I meant what to program a chip to I'm getting a custom chip for it and was looking for a good starting point. Right now I have the 305 TPI Hypertech chip and don't want to drive it till I get a custom chip.

I did check the TPS and was at .64 so I change it to .54 and at WOT it was 4.50 would it be ok to leave it like this?

I'm new to all this stuff and I borrowed the Tech I from work and just learing how to use it. Is there anything I should check with the Tech I while I have it?

Thanks, Jason

Scott 88 GTA

Jason, my car idles fine with the stock target idle rpm. Right now I'm running the ARAP bin in my car with good results. The only place that it idles a little rough is on cold startups when the engine is in open loop. Hopefully with a little tuning I'll be able to work that out.

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Black 88 GTA L98
261 RWHP, 345 RWTQ
13.406 @ 103.72 MPH
ZZ4 bottom end, Edelbrock 6085 heads, LT4 HOT cam, GMPP 1.6 RR's, ported stock TPI, SLP 1 3/4" headers, no cat, Dynomax cat-back, Stock PROM
E.T.F.A Member #11

Kevin91Z

iTrader: (1)

I've got mine set to 850 with a manual trans.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.23 @ 107.62 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

Aaron's 87

Are the target idle tables on WinBin for park or in gear? Or does it matter? My question should probably go on prom board, but since we're talking about it here...

Dan87IROC-Z

I didn't have to adjust my idle with my LT4 HOT Cam. It will idle rough, but thats to be expected. If you make yourself a custom PROM, you might be able to adjust your idle that way, but I don't know much about PROM prgramming.

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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

Ragtop Man

I thought the idea of the HOT cam was to maintain a decent idle and manifold vacuum; by manipulating the ramp rates and lift that much more air could flow with minmal idle quality loss.

Any comments? There was a thread here a few weeks ago where someone had installed it in a ZZ- engine and got a real screamer out of it that was quite placid and well behaved around town.

PETE

iTrader: (1)

i noticed you didnt state if the car was an auto or stick originally i swapped a t-5 in my 350 car and the 350 auto chip made the car run like crap i swapped in a 305 manual chip and iits abs. perfect.


350 alumiinum l98 heads lt4 hot cam slp runners ported plenum edelbrock base afpr airfoil slp 1 5/8 headers 3 in y pipe hollow cat flowmaster 3in. bw 3.27

PETE

iTrader: (1)

i noticed you didnt state if the car was an auto or stick originally i swapped a t-5 in my 350 car and the 350 auto chip made the car run like crap i swapped in a 305 manual chip and iits abs. perfect.


350 alumiinum l98 heads lt4 hot cam slp runners ported plenum edelbrock base afpr airfoil slp 1 5/8 headers 3 in y pipe hollow cat flowmaster 3in. bw 3.27