Ok - I replaced my LS1-320 HP engine after 189800 miles with a new crate LS6 rated 405 HP (26% more HP). Unfortunately, the new engine ran like an LS1, so based on recommendations, I ordered a computer from Street and Performance that was re-programmed for an LS6. Result: Still no performance gain (and GM Tech Support was NO help at ALL).
To make sure it wasn't me, I timed how long it took the car to accelerate from 1000 rpm to 5500rpm in 3rd gear. I did this 3 times on the same day, same location, both directions on level ground, and with each computer. Got the same results - approximately 12.9 seconds. The only difference was my "Check Engine Light" came on with the "LS6" computer. When I put the original computer back in, the light went off, but in both cases, performance was the same.
So now what? Either the computer wasn't programmed for an LS6 or something else is going on. The engine sounds strong and solid - just like the original engine did, but that's the problem. I'd swear I purchased 2-LS1 engines and 2-LS1 computers.
Another question: How would I tell the difference between a 1999-LS1 and 2003-LS6 without tearing into the new engine? For what it's worth, I located a local shop that will tune my car on a dynamometer, for $450 but that seems high.
Any help would be appreciated.
Thanks Ray R
Posted by XBCHBUM (Member # 734) on :
Have you tried posting on www.ls1tech.com , Particularly in the PCM Diagnostics & Tuning forum? Good Luck Posted by Z28-SORR (Member # 1565) on :
Here's a link to the differences. http://www.corvetteactioncenter.com/specs/z06/ls1ls6.html As you can see, much of the improvement comes from the exhaust and intake ducting. Even more so on the 405hp version. If you have not changed either of these areas you will not get the full potential.
Posted by DaddySS (Member # 848) on :
Z28 has a very good point. You will notice that as people consider head and cam packages, they take the breathing of the car into account and open up the exhaust and intake. What are you running now in those areas?
Posted by RagSS (Member # 1127) on :
Ray, You're probably aware, but for a visual confirmation (LS1 or LS6, ...block), ...you might want to check the links in this thread ChiprThird thread... Posted by pg318 (Member # 1810) on :
quote:Originally posted by Ray R: Ok - I replaced my LS1-320 HP engine after 189800 miles with a new crate LS6 rated 405 HP (26% more HP). Unfortunately, the new engine ran like an LS1, so based on recommendations, I ordered a computer from Street and Performance that was re-programmed for an LS6. Result: Still no performance gain (and GM Tech Support was NO help at ALL).
To make sure it wasn't me, I timed how long it took the car to accelerate from 1000 rpm to 5500rpm in 3rd gear. I did this 3 times on the same day, same location, both directions on level ground, and with each computer. Got the same results - approximately 12.9 seconds. The only difference was my "Check Engine Light" came on with the "LS6" computer. When I put the original computer back in, the light went off, but in both cases, performance was the same.
So now what? Either the computer wasn't programmed for an LS6 or something else is going on. The engine sounds strong and solid - just like the original engine did, but that's the problem. I'd swear I purchased 2-LS1 engines and 2-LS1 computers.
Another question: How would I tell the difference between a 1999-LS1 and 2003-LS6 without tearing into the new engine? For what it's worth, I located a local shop that will tune my car on a dynamometer, for $450 but that seems high.
The ls6 heads have "243" cast in the front, LS1s have "241". The stuff about the Nemak blocks may not be definitive, especially since a '99 may have a Nemak LS1 block. Check out the specs for the LS engines here and you'll note that there isn't much of a difference between them below 4000 rpm, and some of that's as a result of the Z06's better inlet and exhaust. What does make a difference to the performance is the higher redline on the LS6, extending the power band, but if you're shifting at the same rpm, that won't help.
If all you swapped was a bare engine, you shouldn't need another computer, it can handle the extra flow, but check to see if the new one is programmed for the larger Z06 MAF, which would probably cause an mixture error if you've got the LS1 MAF, as the fuel trims would be way off.
![[Smile]](smile.gif)