86IROC

I was just wondering about what are the differences between the two?? Cause I always see guys with mods with TBI RS's but never guys with LG4's. Thanks

Z28Freak

TBI is Throttle Body Injected (170hp). The LG4 is carbed (145-150hp). The LG4 was never an option on the IROC. In '85-'86 IROCs could be had with the L69 (305 H.O. 190hp) or LB9 (305 TPI 215hp in '85 and 190hp in '86 on). In '87 the L98 (350 TPI 220hp) became available in the IROC.

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'85 Z28 - black with gold trim - TPI 305 (pre-peanut cam 215hp) - Accel Super Coil - Accel 8.8mm wires - Morroso trans cooler - MSD-6A - Flowmaster exhaust - high flow cat - K&N filters - smog delete - 3.23 rear

'94 Camaro SC - medium patriot red metallic - 3.4L - Dynomax muffler - Z28 wheels

Sir John; Order of Knights of the Mighty Cascade Crew

[This message has been edited by Z28Freak (edited July 24, 2000).]

MrJ

Actually the LG4 was an option, as was the L03, though no one wants to admit it. The LG4 was the base IROC motor from 85-87, and the L03 from 88-89, then in 1990 the 305 TPI became the base motor.

Z28Freak

My source contradicts itself on this issue, although I can't imagine an LG4 IROC! I had an LG4 in my '83 Z28 and it was slower than ****.

89Iroc

Even though The TBI 305 made more hp and tq. I would take an LG4 abyday of the week. They rev higher, flow better and they mod better due to the carb which flows 650cfm (I believe) to the TBI's 400cfm (if that). They both suck to my 305 TPI. pushing around 275rwhp and 335rwtq.

zippy

rather have the LG4 iroc. iroc had better and more available options. yes the LG4 did come in the iroc and i have driven a few including two with an LG4 and a stick. advantage to the tbi is it's lower emissions and slightly better fuel milage. also less common to have a problem with a tbi than a carb.

TransamGTA350

iTrader: (2)

I had an 86' IROC with an LG4. It was real because I checked the RPO code sheet. It had a 5-speed and 3.23's. It was rated at 160hp and was quicker than any stock LO3.

89 Transam GTA, a few bolt ons

Blade

Umm... you're full of it

The LG4 WAS an option on IROCs. The L69 was not even produced AFTER 84 so 85-86 IROCs couldnt have had them as an option.

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92 Z28 L98 350
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Ported and polished heads, ported stock TPI base, ported plenum, Comp Cams XR270HR-10 cam (lift .495/.502 duration 218/224 lobe separation 110), Edelbrock TES headers, LT4 valve springs, Crane AFPR, Flowmaster catback with LT1 style tips, MSD coil & wires...

"Take that auto, drop it in first, hold the brakes, stomp the gas and grin from ear to ear! :-)

MRZ28HO

And so are you. Actually the LG4 was never an option on the Z28s and IROCs, but a standard engine. Option would imply you are getting a better engine. Also the L69 was produced from 1983 until 1986.



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George P. Lara
1984 Z28 High Output
Proud Member of SCFB
V6 T5 For Sale

Willie

iTrader: (1)

It's amazing how much misinformation there is out there. That's probably because we were told these "facts" and never verified it. So far, George is the 100 percent correct. I thought I'd add more specifics on a year-by-year basis. I'll only list Z28 and IROC-Z engines here.

1982 Z28
Standard: LG4 305 Carb
Optional: LU5 305 Cross Fire Injection (w/auto only)

1983 Z28
Standard: LG4 305 Carb
Optional: LU5 305 Cross Fire Injection (w/auto only)
Optional: L69 305 High Output Carb (only 3,223 produced)

1984 Z28
Standard: LG4 305 Carb
Optional: L69 305 High Output Carb

1985 Z28
Standard: LG4 305 Carb
Optional: LB9 305 TPI (w/ auto only)

1985 IROC-Z
Standard: LG4 305 Carb
Optional: LB9 305 TPI (w/ auto only)
Optional: L69 305 High Output Carb (w/5-speed only)

1986 Z28
Standard: LG4 305 Carb
Optional: LB9 305 TPI (w/auto only)
Optional: L69 305 High Output Carb (only 74 produced)

1986 IROC-Z
Standard: LG4 305 Carb
Optional: LB9 305 TPI (w/auto only)
Optional: L98 350 TPI (only 50 produced - w/ auto only)

1987 Z28
Standard: LG4 305 Carb
Optional: LB9 305 TPI (available for the first time with a 5-speed)

1987 IROC-Z
Standard: LG4 305 Carb
Optional: LB9 305 TPI (available for the first time with a 5-speed)
Optional: L98 350 TPI (w/auto only)

1988-89 IROC-Z
Standard: LO3 305 Throttle Body
Optional: LB9 305 TPI
Optional: L98 350 TPI (w/auto only)

1990 IROC-Z
Standard: LB9 305 TPI
Optional: L98 350 TPI (w/auto only)

1991-92 Z28
Standard: LB9 305 TPI
Optional: L98 350 TPI (w/auto only)

And that was all from memory folks! But I could look in up in any of my books.... I might have forgotten one or two...


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Willie

Supercharged 1987 305 IROC-Z, Daily-Driver, Emissions-Legal.
12.57 @ 111 mph.
12.04 @ 113 mph (50-hp nitrous). http://www.ozemail.com.au/~jca69/mod...sz/willie.html

1987 "20th Anniversary Commemorative Edition" Z28 Convertible -- Super Chevy Show Class Winner, 1998.

[This message has been edited by Willie (edited July 24, 2000).]

TransamGTA350

iTrader: (2)

Both the 85' Z28 and the 86' IROC could be had with the L69, but other than that, you are right on the money. Also, could you get the L98 in an 87' Z28?

89 Transam GTA, a few bolt ons

Willie

iTrader: (1)

The Camaro White Book states the L69 was available on the 1985 IROC-Z only, not on the 1985 Z28. I recall when these cars were new and I never saw a 1985 L69 Z28, but a few 1985 L69 IROC-Z's (all with 5-speed).

The same reference states the L69 was available on the 1986 Z28 only (only 74 produced -- actually saw one), but not on the 1986 IROC-Z. Kind of strange how GM reversed from 1985. The L69 was never supposed to have been produced in 1986. Apparently, buyers custom ordered these before Chevy released ordering info on 1986 Camaros in April, 1985. And apparently, GM had new L69's leftover from the 1985 model year, so in they went!!! Only 74 though.


Nope, the L98 was an option on the 1987 IROC-Z only, not the Z28.

Willie



[This message has been edited by Willie (edited July 25, 2000).]

Ed Maher

Just to correcte the terminology, chevy didn't STOP making the L69 in 85 or 86, they were still being put into monte carlo SS's in '88 (Which were actually late year 87s.) L69s lived to see one piece rear main seals AND centerbolt valve covers.
ed

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Ed Maher - Moderator @ the Carb Board
85 Z28 - 357c.i. - stolen 12/24
Click Here for the Rest
'83 Grand Prix - low miles
Only mods...Homemade open element, 2.5" cat and exhaust, CK-B metering
and the way out ******* style in effect
stock 14" wheels w/ wire hubcaps in front
snowflake 15" alloys in the back

MikeDwhoROCZImports

iTrader: (1)

I've got an 87 IROC with the LG-4 and a 5-spd.......it's not the fastest camaro but it sure the hell isn't the slowest.
By the way, it's factory rated at 170hp not 150........and after a couple simple intake and exhaust bolt on's it's dyno'd at around 210hp......nothing spectacular, but it kills my friends 85 305 TPI with an auto........

Z28Freak

Your friend's '85 must be a real dog. My lightly modded '85 305 TPI would kill ya!

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'85 Z28 - black with gold trim - TPI 305 (pre-peanut cam 215hp) - Accel Super Coil - Accel 8.8mm wires - Morroso trans cooler - MSD-6A - Flowmaster exhaust - high flow cat - K&N filters - smog delete - 3.23 rear

'94 Camaro SC - medium patriot red metallic - 3.4L - Dynomax muffler - Z28 wheels

Sir John; Order of Knights of the Mighty Cascade Crew

TransamGTA350

iTrader: (2)

I have an 86' Camaro brouchure that says the L69 was availible in both the Z28 and the IROC.

TransamGTA350

iTrader: (2)

The 88' Monte Carlo L69 was also a TBI.

SGT SWEETPANTS

I have an 86 IROC with the LG4 and I want to know what mike did to it to make it put out 210 hp. if you read this please e-mail your mods to me.
ahupp@gurulink.com

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Pimpin' ain't easy.

zippy

i also have the 86 broshure. and a magazine from 86 with an iroc z L69 5 speed as the test car. i'll find it and give the month/year. i believe it was car craft. it ran 15.4.

Demon

88 Monte Carlo SS had a L69 with a carb and the Monte Carlo LS had a LG4 or a LB4.

<A HREF="http://members.aol.com/MCLS88/Chevy/ord88LS.html">88 Monte Carlo LS</A> <A HREF="http://members.aol.com/MCLS88/Chevy/ord88SS.html">88 Monte Carlo SS</A>

TransamGTA350

iTrader: (2)

Then why does my friends 88' Monte Carlo SS have a H.O. TBI?

Ed Maher

That's weird about the HO TBI. I have to admit i've never actually seen under the hood ro talked to any 88 MC SS owners, but i don't see how/why chevy would have bothered to put TBI into an 88 MC SS. I'm pretty sure 88 was an abbreviated year for the monte carlos, all the other g bodies were phased out as of 87. I know thyey were putting TBI 4.3s in the later MCs, but a TBI L69, that would suck.
Maybe you're right, but until then i'll doubt it. At least i for sure know that 87 MC SS were regular old CCCS.
ed

TransamGTA350

iTrader: (2)

I don't think it was an L69, but I don't know the actual code. i know it was rated at 210hp. Since chevy put TBI on the LG4 in 88 turning it into the LO3, they would have done the same for the L69. It would have been more costly to keep the carb on the H.O than to just burn a different chip for the TBI due to production costs of making two induction setups instead of one.

89 Transam GTA, a few bolt ons

Arctic White 91 RS

There are a few things worse than a Camaro RS with a LO3 305 TBI...and here's what they are:

an IROC with TBI...and a few some...LOL!
a Z-28 with TBI...and there are some...LOL!
a Trans Am with TBI...and many are some...LOL!
a Formula Firebird with TBI...and most are...LOL!!!

Most of the people I know expect an RS to have a V-6 and be a Really Slow Camaro. So a TBI RS is a little faster than people expect sometimes.

All of the above are expected to be fast and are not.

Rob -Formula-

Stop bitching about how slow the 305 tbi is and start modding it. Half the time most of you spend bitching about your tbi cars can be used to make them run faster.

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'88 Formula 305 TBI, Jet-hot Edelbrock TES, SLP catback,
Open Element, Functional hood scoop, good intake casting,
9 bolt BW 3.45 Posi w/pbr disc setup, Spohn LCA's & Panhard,
Aluminum driveshaft, Trans-go shift kit, March underdrive,
Hypertech stage II, 160 stat, Bilstien shocks, Resistor mod..

ausrs

if GM made a HO with tbi and burnt a different chip for that car what would be the chances of someone sending one to aus for me to put in my tbi camaro anyone ?????

Ed Maher

See, i look at it the other way around. 88 was a short year for the MC. I don't think i've ever heard of a TBI MC, except for some 4.3 powered ones. Also, i was understand that MC SSs were built in a seperate plant than the rest, they were built in the same plant GNs came from. It would seem more costly and really dumb to me to put an inferior injection set-up on an L69 in a plant that isn't producing any other cars with that set-up, and isn't gonna be producing any other of these cars after a short production run.
Not only that, but it wouldn't be a very simple repreogram if it was to maintain it's heritage of performace. It owuld require entirely differnt fuel maps and spark curves, and then emmisiosn certification. A LOT of work for something that is going into so few cars.
Also, 88s are not really 88s. There are 87 GNs that were actually built later than 88 MC SSs, buick just wasn't allowed to badge 'em as 88s, but GN afficiandos know about the 87.5 cars as they call 'em.
Maybe you're right, i'm probably thinking too hard here. But to me, i won['t believe it till i see it, cuz it just doesn't make sense.
ed

edit..just checked the MC mailing list site, and in the FAQ it clearly states that NO MC SS ever came with fuel injection. Kinda cursory i know, but that smy point. 88s were a flash in the pan short time thing. Besides, the maker of the site HAS (or at least had) an 88 SS, so if it had TBI i doubt he wouldn't disclose it.

[This message has been edited by Ed Maher (edited July 27, 2000).]

Arctic White 91 RS

Rob,

Well said...

...i like my TBI Camaro...over ten years...over 200,000 miles...

Mike92

Yeah, exactly artic. It's not fast out of the box. Mod it and it runs very good. Gears, exhaust and UTBIM. and you have mid to low 15's with the **** cam.

Demon

<A HREF="http://www.montecarloss.com/ubb/Forum1/HTML/000773.html">Go Here</A>

[This message has been edited by Demon (edited July 28, 2000).]

JRODRS

NICE!