Gross Horsepower LT-5

[Dynomite]

Originally Posted by Hib Halverson

Thank you "Dynomite" but I was already aware of the math.

Impressive collection of material you have in that thread on the CF.

Thank you.....I appreciate and study ALL of your technical posts and technical references (very well written)

I am aware of your familiarity with the math and technology. I provided the information sources (same in this post) for those that are not as familiar and have an interest in additional technical information regarding Horsepower

Here is some more technical information directly related to LT5 Horsepower. All of which is updated on a continual bases with updates noted at the bottom of each post.

This includes the Signature -Solutions- with updates noted at the bottom of each post.

Tech Info - LT5 Modifications/Rebuild Tricks (500+hp) (100 Posts)

Tech Info - LT5 Eliminated Systems
Tech Info - LT5 Added Systems
Tech Info - LT5 New Rebuild Issues (Lifters and Camshafts)
Tech Info - LT5 Timing Chain Calculations
Tech Info - LT5/ZR-1 Technical Calculations

[ghlkal]

Originally Posted by Kevin

found it.

Nice catch ... where is this page from?

[Kevin]

Originally Posted by ghlkal

Nice catch ... where is this page from?

the small, hard bound, "drivers book" that came in the owners kit.

[Kevin]

Originally Posted by zr1mom

The next gen ZR-1if it wasn't killed off would have been 450hp.

i thought i'd heard closer to 500

[Hog]

Originally Posted by Hib Halverson

The only gen II LT1 which made 300 SAE net was the version in Corvettes and it was available from 1992-1996 with automatics and from 1992-1995 with manuals. That engine never made "377-78" gross at the flywheel. More like 340-350 on a good day.

The Camaro used a less powerful version (275-hp SAE net) of the Gen II LT1 from 1993-1997. There also was an even milder version (260-hp SAE net) used in the Caprice and Impala of the mid-90s.

The Gen II LT1 was, also, not the most powerful "traditional" (Gen 1/Gen II) SBC. That honor goes to the LT4, used in 1996 manuals. It made 330 SAE net about about 370-380-gross hp.

.

Obviously I was referring to the 92-96 Y-body Vette LT1, although there isnt much different power productionwise between the F-Body and Y-body LT1(cam, exhaust, air intakes). There were 315hp F-body LT1 engines with optional intakes and exhausts.

You are correct about the LT4 being the highest output GEN I/II engine. The material I was referencing was written in 1994 hence my oversite of the LT4 which was used in the 96 Vettes and the 135 1997 Camaro/Firebirds(which actually use a stock LT1 F-body calibration, for emissions, without the Vette LT4's 6412 rpm rev limit, along with extrude-honed stainless steel exhaust manifolds and balanced and blueprinted longblocks UNLIKE the stock 1996 Y-body LT4's). The LT4 was a great engine, LS1 power in the standard 4" x 3.48" GEN I/II package. 1997 LT4 SS Camaro runs high 12's same as a a stock LS1 equipped 98-02 Camaro, both equipped with the T-56 trans of course.

I respectfully disagree about your LT1 hp assertions.
The 1970 LT-1 was rated at 370 gross hp.
The 1971 LT-1 was rated at 330 gross hp(less cr)
The 1972 LT-1 was rated at 255 SAE net hp. (little difference to the 71 LT-1).
The 92-97 LT1 Y-body engine outputs more gross hp than any GEN I engine, even the 70's 370 hp LT-1 and the 60's 375 gross hp L84. This fact is in print by sources including GM.

To complete the GEN II story, yes, the LT1 was used in the 94-96 B-body(Caprice/Wagon/9C1 Police PAckage,Impala SS, Buick Roadmaster/Wagon), 94-96 Cadillac Fleetwood. Although these LT1's used iron heads which flow slightly more than the aluminum Y/Fbody cousins. All 94-96 iron headed LT1's used the same 191/196 0.412"/.428" 111ºLSA which is also shared by the 1996-2002 L30 Vortec 305 230hp at 4600rpm/280 lb/ft torque at 2800rpm, and 96-2003 L31 Vortec 350 with 255 sae net hp at 4600rpm/330 lb/ft torque at 4600rpm.
This same roller cam is also used in the other "baby" GEN II engine, the 94-96 4.3l 265 cid V8 RPO L99 that made 200 sae net hp and 245 lb/ft torque used in the B bodies. This engine got better fuel economy than the 5.7 LT1. The 4.3 V8 uses a 3" stroke crank and special length 5.94" PM rods coupled with 3.736" Vortec L30 305 pistons to get to the 265 cid. If this 3" 2 piece RMS crank is dropped in any 1 piece RMS 4" bore block and you now have a more modern 5.0 302 SBC engine. GMPP built a GEN II 302 that made over 420hp with 7000rpm capability.



peace
Hog

[mrx86]

OK

The 90 ZR-1 LT5 / 5.7L have Stock SAE Gross 425HP and 375HP net.

The 1968 Camaro ZL-1 7L Stock have SAE Gross 425HP and 376HP net.

The 1971 Dodge Challenger 7L HEMI have SAE Gross 425HP and 350HP net.

The 1968 Ford Mustang 7L GT500KR have SAE Gross 400HP and ??? HP net.



properly ?

Mrx86

[mrx86]

Originally Posted by mrx86

OK

The 90 ZR-1 LT5 / 5.7L have Stock SAE Gross 425HP and 375HP net.

The 1968 Camaro ZL-1 7L Stock have SAE Gross 425HP and 376HP net.

The 1971 Dodge Challenger 7L HEMI have SAE Gross 425HP and 350HP net.

The 1968 Ford Mustang 7L GT500KR have SAE Gross 400HP and ??? HP net.



properly ?

Mrx86

[Corbusa]

Interesting stuff , Thanks guys !!!!!

[Hib Halverson]

Originally Posted by Hog

(snip) There were 315hp F-body LT1 engines with optional intakes and exhausts.

And what company put such an engine in a production vehicle?

I respectfully disagree about your LT1 hp assertions.

Disagreement respectfully noted

(snip)The 92-97 LT1 Y-body engine outputs more gross hp than any GEN I engine, even the 70's 370 hp LT-1 and the 60's 375 gross hp L84. This fact is in print by sources including GM.

Ok. If it's in print and GM released the info is should be a simple task for you to post some facts to support your disagreement or at least direct me to some location on the web where I can read those facts.

[Hib Halverson]

Originally Posted by tpepmeie

Don't quote me on this, but I read in an old Legend magazine about the development of the LT5, and believe it was stated they were seeing 445 SAE with open headers on the dyno.

Actually, if that was in the old Legend magazine, whatever article that was must have been talking about the Record Run engine which, slightly modified, made 440-hp.

Also, no engine could make "445 SAE with open headers" because the SAE test standard mandates a full exhaust system.

Stock LT5s made 375-hp SAE net or 425-hp gross with open exhaust.

Originally Posted by zr1mom

The next gen ZR-1 if it wasn't killed off would have been 450hp.

The so called "third generation LT5" which would have gone to production for 1995 had additional improvements, including variable valve timing, and would have been rated at 475-hp SAE net. The development program which was that engine ended when the ZR-1 was killed.