Does anybody out there have a the stock 90-92 LB9 with the 230 horsepower? Can you tell me what they rev to before they start loosing power. I bought my car with a new engine and i think the guy might have put a different cam in. It only revs to 3000 before it starts to loose power, and there is a nasty vibration starting around then too.

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1991 Z28 305 1LE, TES headers, 3 Chamber flowmaster, Hi-reving cam... the usual street racer

They normally would pull to 5000 RPM with the stock cam. Something is definately wrong somewhere.

Hey fellow 1le dude.

I have one of these cars (LB9 that is). The lack of power you are experiencing at 3k does not necessarily mean your car is equipped with an aftermarket cam. I noticed the EXACT same thing with my car. It turned out being the ignition module. Though it could be a lot of other things for you..

When was the last time you changed the cap,coil,rotor,plugs,wires,fuel filter, air filter,throttle body clean?

If that doesn't help, it could be a clogged catalytic convertor. Give yours a good whack, if it sounds solid (no things bouncing around inside), it's ok.

That's all I can really think of..I'm sure others will take care of the rest.

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91 Formula
305 TPI 5speed
1LE/G92/WS6

Paxton SN93, SLP airfoil, ported/polished plenum, March pulleys, Crane AFPR(43psi),Crane Gold 1.6rrs,MSD coil,MSD6AL, Holley 9mm wires, fastchip, Bosch O2sensor, Bosch in-line pump(w/stock pump), SLP headers & catback,short shifter,3:73s w/Auburn posi,170* t-stat,JET 195* fan switch, Macewen white face gauges, Autometer gauges, Zoom hi-performance clutch.

By the way, in stock trim..the 230hp LB9s pull good to 4800RPMs

sounds good. I got two new cats with my exhaust system, but it still did the same thing. My ignition module just went out though, i replaced that. Right now i have a hi reving Comp camp .488/.498 212/218 but i'm getting crap for gas milage... around 10, even if i drive like a granny. Its pissing me off, so i think i might go back to a cam a little over stock. Also, what do you think the 0-60 times are stock with the 5.0 5spd 1LE

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1991 Z28 305 1LE, TES headers, 3 Chamber flowmaster, Hi-reving cam... the usual street racer

[This message has been edited by BenDoe (edited February 05, 2001).]

I have a road test for a 91 formula 1le 5.0 l . It ran the 1/4 mile in 14.54@92mph. And a zero to sixty of 6.5 seconds. That was faster than the 350 Formula they tested (same test).

As for swapping out the cam..don't do it just yet. Isolate the problem first you are having. Then move on. Actually, the specs you gave on that cam sound ideal. Check to see if the car has a custom PROM. You will need one if you have an aftermarket cam on a speed density car.

Were you getting any codes?
Ryan

I already have the cam in the car, its been in there for the last 5 months.. the gas milage has been really crapy so i want to go back to the stock one. It has the stock chip, and i think my injectors are leaking because the passenger side cat of my dual cats has been through three different cats in a year. No codes.

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1991 Z28 305 1LE, TES headers, 3 Chamber flowmaster, Hi-reving cam... the usual street racer

[This message has been edited by BenDoe (edited February 05, 2001).]

Your gas mileage wouldn't be THAT bad because of that cam. Something is obviously wrong somewhere. The good question is where? Since you've noticed that you are replacing pass. side cats frequently, i'd suspect a bad injector(s) as well, eps. since it is confined to the side that wouldn't **** the O2 sensor off.
Question...are the plugs on that side 'dirty', if it's rich enough to kill cats it'd probably foul plugs too.
Beyond that i'd start checking EVERY sensor on the car to make sure everything is in order.
Of course, theformula also hits a good point...you probably need a custom prom to effectively run that cam. Still, unless you only short trip it and keep your foot in the throttle constantly, i wouldn't expect it to get that bad of gas mileage. I plan on running that same cam come this summer or next (depending on if i feel the need) and i don't plan on losing any gas mileage. If every little mod cost gas mileage why would i fight with a computer.
...ed

Yep Ed is right. Pull your plugs and read them. If they are black you are running to rich. Tan is the color you want.

The engine burns about one quart of oil every 250 miles, and therefore the pulgs have major ash deposits on them. I'm plannin on a rebuilt this summer. I don't take them out and clean them because it is a 3-4 hour job with the TES headers. I want to get into custom burning my own chips but don't have the dough. All the injectos might be bad because the dumbass that put the AFPR on the car before me had is set at 55psi. Any ideas about the vibration at 3000?. It still does it after i put new plugs in, and gets progressivly worse as i rev it up to 5000.

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1991 Z28 305 5spd 1LE, TES headers, dual cats, 3 Chamber flowmaster, Comp cams .488/.495 212/218 the usual street racer with a stock chip.
Cars beaten as of 01/01/01
95 Acura Legend

Lost to as of 01/01/01
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[This message has been edited by BenDoe (edited February 06, 2001).]

Not sure on the vibration since so many things can cause it. Don't think it would be your driveshaft since it's alum.

Just for note. Running 55psi won't harm the injectors at all.

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91 Formula
305 TPI 5speed
1LE/G92/WS6

Paxton SN93, SLP airfoil, ported/polished plenum, March pulleys, Crane AFPR(43psi),Crane Gold 1.6rrs,MSD coil,MSD6AL, Holley 9mm wires, fastchip, Bosch O2sensor, Bosch in-line pump(w/stock pump), SLP headers & catback,short shifter,3:73s w/Auburn posi,170* t-stat,JET 195* fan switch, Macewen white face gauges, Autometer gauges, Zoom hi-performance clutch.

Its not in the tranny, or the clutch because it does it the same in neutral. It could be the flywheel, but i doubt it. Would one of those fluidampners do anything to help? I heard that running two high of pressure on fuel injectors starts to wear away the o rings and internals of the injector. One more thing, when i set my timing, the mark always jumps around each time the light flashes, about 5 degrees in each direction, It has a new timing chain, so its not that.

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1991 Z28 305 5spd 1LE, TES headers, dual cats, 3 Chamber flowmaster, Comp cams .488/.495 212/218 the usual street racer with a stock chip.
Cars beaten as of 01/01/01
95 Acura Legend

Lost to as of 01/01/01
-


[This message has been edited by BenDoe (edited February 07, 2001).]

I'm also thinking about getting new injectors... would a bigger size help at all with my setup?

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1991 Z28 305 5spd 1LE, TES headers, dual cats, 3 Chamber flowmaster, Comp cams .488/.495 212/218 the usual street racer with a stock chip.
Cars beaten as of 01/01/01
95 Acura Legend

Lost to as of 01/01/01
-

Bigger injectors will only harm your setup. You should actually be trying to lean yourself out.

It still could be your clutch. The throwout bearing would still make noise in neutral.

Also, if you don't disconnect your EST wire when setting timing..it WILL jump around.



[This message has been edited by theformula (edited February 08, 2001).]

I mean bigger injectors once i can program my own computer chips. I thought this because i have an aftermarket engine system that could use more fuel than a stock system.
I don't know exactally which wire the EST is. The one i disconect when i do my timing comes off the coil, and goes into the wireing harness. Disconnecting that wire also makes it so the tach doesn't work. I think its white... Which one should i be disconnecting?

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1991 Z28 305 5spd 1LE, TES headers, dual cats, 3 Chamber flowmaster, Comp cams .488/.495 212/218 the usual street racer with a stock chip.
Cars beaten as of 01/01/01
95 Acura Legend

Lost to as of 01/01/01
-

The EST wire is brown or black. Near your heater box.

Bigger injectors will hurt your performance unless you are running a blower right now.

If you are running lean and need more fuel, then increasing the pulse width of the injectors (so you can run high FP) is the answer. And that is done via Prom editors. Not bigger injectors.

But I assure you, I have spoken to the experts on this (Glenn Matus for one), and he knows these cars are overly-rich from the factory. Buy a Diacom or Auto-xray and take a few runs. Thats the only way to pin point things.
Later

By the way, make sure your car is fully warmed up before you disconnect the wire.

So, can somebody start naming some stuff that could would result in vibrating at 3000 RPM... And what would be the result if the valvelash wasn't ajusted right... would it not rev as high?

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1991 Z28 305 5spd 1LE, TES headers, dual cats, 3 Chamber flowmaster, Comp cams .488/.495 212/218 the usual street racer with a stock chip.
Cars beaten as of 01/01/01
95 Acura Legend

Lost to as of 01/01/01
-

I read the O2 sensor and computer can adjust the pulse width near 60 psi. Then the computer can do it's work. Stick with the stock injectors and check the basics first.