LT1 tune results from CMS
09-20-2009, 02:23 AM
#1
LT1 tune results from CMS Went down to CMS friday and worked with Ryne tuning my LT1 in open loop speed density. Motor specs....
388 ci
Ported AFR 210s
12.5 compression
Ported LT4 manifold
HR 24x/25x .62x 107lsa
Final numbers were 438rwhp and 450 rwtq on 100 unleaded. I've got either an ignition or valvetrain issue up top, i made peak hp at only 5600 rpm and the motor wouldnt pull much past 6000. Thanks to Ryne's tuning expertise we've got the A/F nailed down at 14.2-14.7 at cruising rpms and 12.8 at WOT. Much thanks to Ryne for working with my 10 year old laptop, and the crappy tuning and datalogging programs we have for the LT1. Driveability and gas mileage is a ton better than before, hell I can pull out from 1200 rpm in 6th gear with no bucking! I can't wait to get my issues worked out and see what it'll do at 7000 rpm on a 200 shot. So thanks again Ryne and CMS, definitely will be going with them for a rollcage, and further tuning of my combo.
388 ci
Ported AFR 210s
12.5 compression
Ported LT4 manifold
HR 24x/25x .62x 107lsa
Final numbers were 438rwhp and 450 rwtq on 100 unleaded. I've got either an ignition or valvetrain issue up top, i made peak hp at only 5600 rpm and the motor wouldnt pull much past 6000. Thanks to Ryne's tuning expertise we've got the A/F nailed down at 14.2-14.7 at cruising rpms and 12.8 at WOT. Much thanks to Ryne for working with my 10 year old laptop, and the crappy tuning and datalogging programs we have for the LT1. Driveability and gas mileage is a ton better than before, hell I can pull out from 1200 rpm in 6th gear with no bucking! I can't wait to get my issues worked out and see what it'll do at 7000 rpm on a 200 shot. So thanks again Ryne and CMS, definitely will be going with them for a rollcage, and further tuning of my combo.
Last edited by Wicked94Z; 09-20-2009 at 02:29 AM.
09-20-2009, 06:30 AM
#5
Just talked with Bret Bauer... We had a little mis communication about the installed height on my PAC 1518s for the aggressive lobes I'm running. He's 100% positive it's valve float with the pressure I was running, so I'm ordering some k800s to throw in, 165# seat and 460# over the nose should do the trick 
live and learn.....
live and learn..... 
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09-20-2009, 04:40 PM
#9
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great numbers! I always get a kick out of guys that insist that it is next to impossible to get numbers like that out of an LT1.
Question though, I take it you had to use your own software and laptop? I was under the impression that CMS did not have the gear to tune an LT1.
Question though, I take it you had to use your own software and laptop? I was under the impression that CMS did not have the gear to tune an LT1.
09-21-2009, 02:10 AM
#13
Just talked with Bret Bauer... We had a little mis communication about the installed height on my PAC 1518s for the aggressive lobes I'm running. He's 100% positive it's valve float with the pressure I was running, so I'm ordering some k800s to throw in, 165# seat and 460# over the nose should do the trick live and learn.....
live and learn.....
09-21-2009, 05:51 AM
#14
bret says the k800s will need replacing all the time with these lobes, so i guess scratch that. just to give you an idea of the ramp rates... my cam has less adv duration than your cc503. i might step up to the new PAC 1521s, manley nextecs, or bret says the 1518s installed at 1.74 will control the valve fine to 7200+. the problem i think lies in these heavy 2.08 intake valves.
09-21-2009, 11:10 AM
#15
bret says the k800s will need replacing all the time with these lobes, so i guess scratch that. just to give you an idea of the ramp rates... my cam has less adv duration than your cc503. i might step up to the new PAC 1521s, manley nextecs, or bret says the 1518s installed at 1.74 will control the valve fine to 7200+. the problem i think lies in these heavy 2.08 intake valves.
Lighter vales are always nice.
09-22-2009, 02:13 PM
#17
might want to look at some isky beehives as well..... of maybe even the new prc dual with a patriot lt1 retainer, those thinks have about damn near 500 open with a 1.800 install height. also talk to richard at west coast cylinder head, he might have some ideas as well
