Lt4 - Low compression numbers
Thread Starter
Race Director
Joined: Feb 2008
Posts: 19,691
Likes: 322
From: Alexandria VA
Lt4 - Low compression numbers
Since I've built the motor, its had 155-160 psi across all cylinders. I've used multiple gauges to confirm. Dynos 315 to the wheels. From what I could find, I'm supposed to be in the 200+ range. Any ideas?
Last edited by RandomTask; Aug 21, 2020 at 03:24 PM.
Thread Starter
Race Director
Joined: Feb 2008
Posts: 19,691
Likes: 322
From: Alexandria VA
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
Unknown cam 1 tooth, EFI won't like it. Cam with alot of overlap can have low cylinder pressure and be doggish at low speeds. 160 isn't terrible either, depending on static compression ratio.
Le Mans Master
Joined: Feb 2005
Posts: 6,481
Likes: 566
From: Clearwater Florida
..... There are a LOT of things that can affect cranking compression readings ... what you really want to see is that ALL cylinders read about the same ... there are also a LOT of things that affect chassis dyno readings too ! .....
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Le Mans Master
Joined: Aug 2015
Posts: 6,111
Likes: 1,994
From: St. Charles MO
All good points. Yeah, we'd expect the LT4 to have a bit less cranking compression (dynamic compression ratio, essentially) because of the extra overlap as mtwoolford mentioned. If that's an honest 315rwhp on a Dynojet, then your engine is running really strong. No issues.