10-13-2017, 09:13 AM | #71 |
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Great info here and I have a couple points to emphasize. Let's not forget the weak cast pistons that can drop a ring land at 650-700whp. Unless you are planning to go for the next 120-150 HP with the insane cost of the next-stage fuel upgrade why a larger blower? Any additional high RPM power potential will be at the expense of some bottom-end power anyway, and any blower is additional weight up front upsetting handling balance. LT4 is lightest. Very happy with mine!
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Rohana RFX-5 10/11, M/T 275/305, Eibachs, Hellwigs, Hurst SS, DMS LT4 SC 596HP/589TQ, DMS Low-side, Kooks 2LTs, MBRP Race, Rotofab, MMS CC |
10-13-2017, 09:21 AM | #72 | |
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Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA |
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10-13-2017, 09:37 AM | #73 | |
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10-13-2017, 10:24 AM | #74 |
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Talk to Ted Jenetty...he has a customer that is making 760whp on the stock LT1. Daily drives it for almost 2 years. Tuning is critical at high HP levels...detonation can cause a lot of failures that get blamed on the parts not being able to handle the power.
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2016 NFG 1SS A8
Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA |
10-13-2017, 11:36 AM | #75 |
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Of course a good tune is critical at any level if you want long term longevity.
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10-13-2017, 01:18 PM | #76 | |
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Rohana RFX-5 10/11, M/T 275/305, Eibachs, Hellwigs, Hurst SS, DMS LT4 SC 596HP/589TQ, DMS Low-side, Kooks 2LTs, MBRP Race, Rotofab, MMS CC |
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10-13-2017, 01:27 PM | #77 |
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10-13-2017, 02:15 PM | #78 |
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That and paying attention to injector pulse width is critical. I am sure there is more but combustion chamber events are very critical. The good tuners are not going to give up all their tricks being the money and time they have spent to obtain this knowledge. DI is a complete different animal to tune.
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2016 NFG 1SS A8
Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA |
10-14-2017, 06:39 AM | #79 | |
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10-14-2017, 09:28 AM | #80 |
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Ring Gap per GM - Sorry to b off topic
Factory LT1 Ring gap spec per Gm production line -
•Piston Ring End Gap – First Compression Ring – Measured in Cylinder Bore – Production 0.009–0.0153 in •Piston Ring End Gap – Second Compression Ring – Measured in Cylinder Bore – Production 0.0126–0.0248 in 2015-2018 LT4 ENGINE •Piston Ring End Gap – First Compression Ring – Measured in Cylinder Bore – Production 0.009–0.0153 in •Piston Ring End Gap – Second Compression Ring – Measured in Cylinder Bore – Production 0.0126–0.0248 in The problem is Gm tolerances can be way to tight if they fall on the tight side . Many of the Gm LT engines we have taken apart have this huge variation PISTON TO PISTON . So what Gm's says is acceptable will not fly in my book or any other known engine builders book. LT4 PISTON VERSUS LT1 PISTON If you compare the LT1 Piston ring grooves to a LT4 Production piston ring grooves you will see that the top ring land and second ring land on the LT4 piston has a steel ring cast into the piston thus making it stronger than the LT1 Piston, Meaning that if the rings do but up under expansion or flutter the land will take the abuse much better than the thin weak ring land of the lt1 piston.Forged aluminum pistons (1) with internal ribs, graphite coated skirt (3) and full floating piston pins. Piston and pin services as an assembly. These are all documented data points that my shop and others have proven, none of this is made up. |
10-14-2017, 09:33 AM | #81 |
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More good info for the un informed
Explained: Direct Injection Piston Design and Tuning Theories
http://www.hotrod.com/articles/expla...ning-theories/ |
10-14-2017, 09:47 AM | #82 | |
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2016 NFG 1SS A8
Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA |
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10-14-2017, 10:48 AM | #83 |
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Still all good info that favors staying at the 600HP power level. Next stage is double the cost. So lets just say LT1 power boosts cost about $50/HP. Strange we haven't heard of more failures on the dyno.
Would anyone agree that as more and more miles are accrued on a SC build the rings will continually wear, marginally increasing the ring gap and decreasing the risk of ring bind on a long hard pull?
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Rohana RFX-5 10/11, M/T 275/305, Eibachs, Hellwigs, Hurst SS, DMS LT4 SC 596HP/589TQ, DMS Low-side, Kooks 2LTs, MBRP Race, Rotofab, MMS CC |
10-17-2017, 04:03 PM | #84 |
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On a MUSTANG Dyno My stock Maggie kit made 508 RWHP and 491 rwtrq... He told me it's a conservative dyno and a bit of a heartbreaker. This is after a CUSTOM tune. Stock Magnuson tune made like 470 RWHP
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