was the only difference between the high and low output 305/5sp in the 91/92's (g92) the dual cats and rear end ratio??

 

This topic was discussed not to long ago and I forgot what the outcome was,but From what I know all the lowoutput 205hp LB9 5spd were in the convertibles only.All the 91-92 LB9 5spd coupes got the 230hp moter,dualcats,3.42 axle, and the L98 cam was standard but I'm not 100% positive on that.

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1990 Trans Am GTA,Black/Black Leather,350,auto 3.23,Dual Cats,SLP Package,SLP Torque Converter/Shift Kit,Fastchip,GSC's,
G-tech 0-60 5.1 1/4mile 13.6@104
Previous Thirdgen
1986 Camaro IROC-Z

[This message has been edited by black5.7GTA (edited March 11, 2001).]

 

NOT TRUE! I own a non-G92 5-spd GTA coupe. It doesn't have the catsa and 3.42's and such. I know that Z28 and rewgular T/A's had this optioning also. So, YES... there are low-output 5-spd LB9 cars out there from '90-'92 that are NOT convertibles. Hope this helps! BTW-We aren't for sure if my car and others do not have the L98 cam though. Thats still a speculation. Some people say my car has no dual cats, no 3.42's, no oil cooler, but still had the L98 cam and were still rated at 205-210hp. No one knows! I still plan on seeing what cam my motor has when I put my L98 in. I'll keep ya all posted when that happens

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'91 GTA:
www.fbody.com/members/91WS6GTA

 

The difference is the exhaust (manifolds, y-pipe, cats, and cat-back), the rear end ratio (3.08 vs 3.42), and drum brakes vs disc brakes.

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West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

so the dual cat exhaust on the G92 cars add 25 horsepower?? is that true, or is there something else?? my 91z has drum brakes and single cat. where can i find the RPO list?

 

It's not just the dual cats. The G92 cars have 2.25" outlet manifolds, as oppopsed to like 1.75" on non-G92.
That, plus 2" head pipes into one 2.25" cat as opposed to dual 2.25" cats on 2.25" pipes could be worth near 25hp. Probably not quite though, but it doens't matter that much, GM pulls their HP #s from a hat anyway.
...ed

 

alright. thanks for the info everyone. appreciate it.

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beau-t-ful yellow 85 iroc

 

GTA91,How do you not have dualcats and 3.42gears in your car?They were standard with the LB9 5spd in the 91GTA.Let me show you a breakdown,from www.gtasource.com

LB9-714
LB9/MXO/GU2(2.73)-550
LB9/MK6/GU6(3.42)-164
550+164=714

B2L-1321
B2L/MX0/GU5(3.23)-1321
N10-1485
B2L/N10-1321
1485-1321=164

Simply put,all automatic 350's had dualcats,3.23 gears, and 240hp,all 5spd 305's had dualcats,3.42gears,and coupes should be correctly rated at 225hp(not 230),all automatic 305's had a single cat,2.73 gears and probably 205hp.Now,what is not known,and I dont know how to find out is if the larger B2L exhaust,was also on some 305 auto coupes?That would explain why they are alittle quicker,and would give them a rating of 215hp(205+20-10,(no dual cats)=215) Also,from what I understand,all the Convertibles came with the choked exhaust,but the dual cats were standard with the 5spd,so they should have a rating of 210hp(225-10(choked exhaust)=215)but some could have had the bigger exhaust to.I dont know how you would be able to tell how many though.Even I'm :cofused: after all this but the correct ratings could look like this
B2L-240hp
LB9/MK5(coupe)-225hp
LB9/MK5(conv)-210hp,or 225hp
LB9/MXO(conv)-205hp
LB9/MXO(coupe)205hp,or 215hp

To make thing even more confusing,this is only to say the correct rating of the lowest LB9 is 205hp(Ive seen 215,and 200 elsewhere).It would have been alot simpler if they made all the cars 350/automatics,and H.O. 305/5spds like they should have.

 

Well black, i agree with you on your last point...GM shouldn't have wasted their time putting low output LB9s in any Z28s or TAs, athst why so many people look down on these cars for speed.
i wouldn't spend too much time playing magic numbers though. The large outlet manifolds were only mated with dual cats on the later cars, and VV. You can't have big manifolds dumping into the small Y/cat, it won't physically fit due to a difference in outlet angle. So there is no in between HP state.
As to whether all GTA 5 spds got the dual cats...thats easy enoough to check, look under that car and count the cats. Your math with RPO production #s does seem to imply that all LB9 5 spds got N10.
...ed

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Ed Maher - Moderator @ The Carb Board
92 Z28 Convertible - Quasar blue / Tan top
LB9 4L60 GU2 G80 - stock, soon to be sleeper
-=ICON Motorsports=-

- Definitely prototypes, high powered mutants of some kind. Too weird to live, too cool to die

 

Ed,I suspected,there werent 2 different sized dual cat outlets,but wasnt sure.That goes against certain claims of all Convertibles getting the choked exhaust and only 205hp rating.So it should look like this

L98/MX0(coupe)240hp
LB9/MK5(coupe,conv)225hp
LB9/MXO(coupe,conv)205hp

All that,and its exactly what I thought in the first place

[This message has been edited by black5.7GTA (edited March 13, 2001).]

 

I've got an 89 and it has single cat with discs all around with a 3.45 BW rear. I've heard rumours about the RPM guage and if you car reaches yellow line at 5k and red at 5500 you've got g92...not sure though.
Does this mean I've got the l98 cam in my 305TPI already??



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89 GTA G92
305 TPI WC 5spd w/3.45
Accel Cap & 8mm Taylor's
Custom 4" Cold Air Induction
Jet Airfoil
K&N Airfilter
160 deg stat/fan switch TB Bypass - Steel Rad
Cat back 3" Exhaust w/Terminator Muff.
HiGh FlOw Dynomax Cat
Spohn LCA's - KYB GR-2's
Moroso Crank Bolt and roller pilot bearing.
Autometer Vac+Oil Temp

 

You've got a single cat with 3.45 gears and disc brakes??? I thought all 89 305 5-speed cars had dual cats. And I thought the G92 package meant dual cats and 3.45 gears for 89's. Anyway, yes you should have the 350 cam.

------------------
West Coast GM Shootout 2001!
1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

 

The L98 cam was standard in all 89 LB9 5spds period.G92 did not neccesarily mean N10 in 89,but the 3.45 axle was standard in LB9 MK5 GTA's and should have a rating of 215hp, singlecat,225hp dualcats.I believe the Z28's had either the 3.08's and had a single cat and rating of 220hp, or 3.45's and had dualcats and 230hp.I'm not sure if the base Trans Ams and Formulas had the choice like the Z.There is so much conflicting info from source to source with the LB9 from 85-92.