LS2 TB upgrade on Maggied LS6 probs
08-08-2014, 11:25 PM
#1
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LS2 TB upgrade on Maggied LS6 probs So my boost was falling (12psi down to 8psi) and I was hitting max hp at only 4800rpm. No signs of belt slip. Thought maybe wasn't getting enough air with the stock LS6 throttle body, so I upgraded to the LS2 (90mm). I couldn't find an LS2 snout so I used the adapter plate and just ported out the stock snout to match. Also used the adapter wiring harness. Took it to the tuner and he can't figure it out. It seems to run good up to around 5k and then just falls on its face, I mean completely. He said normal TPS reads 86% at WOT and mine is reading 100% and it's not changing anything in the tune. There are no codes that he mentioned and it's not going into reduced power mode. Could it be a bad adapter wiring harness?? (got it from Summit)
08-09-2014, 08:50 PM
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From the get go from what I can tell. Turning the maggie pretty hard to get 12psi so heat is also a factor. Torque was great... 550 @ 3300rpm but I was hitting max hp way too early at 4800rpm. Hoped the larger LS2 90mm tb might help get more (and cooler) air to the supercharger. I'm thinking maybe I bought a bad throttle body though. Anyone else ever experience this kind of issue out of the LS2 TB? Runs great normal driving, and even WOT until 4500-5k rpms...then it's like the butterfly closes?? But the tuner still shows 100% from tps.
08-09-2014, 10:29 PM
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Yes timing is getting cut due to high IAts. I'm in TX and everyday temps hover around 100 during the summer...it was a completely different animal in the winter. The valve springs were just installed with the forged build this past fall/winter so shouldn't be an issue there. I'm running meth/water to help as well, but was hoping the TB would make a difference. So timing loss translates to boost loss?
08-09-2014, 10:45 PM
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I think boost loss is maggie being over extended. Mine starts at 11 & is at 8 at WOT. Compressed air gets hot. Engine cuts timing. Less timing = less power. What was rpm at end of dyno run ?
08-09-2014, 10:55 PM
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He ran it all the way up to 6k I believe, but it maxed out at only 4800. I'd like to know if the LS2 TB helped, but I'v got to track down this issue. I'd hate to buy another throttle body just to find out it's a tuning issue or bad adapter harness. I was hoping that as common as this upgrade is someone may have experienced the same problem.
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08-11-2014, 08:30 AM
#8
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Either the Maggie is too small (common) or there is belt slip, only two things it could possibly be. I believe I advised you long ago that the LS2 throttle body would have no effect at all on power and even posted a few threads where people showed 3-5 whp increase after the swap. It's an expensive swap with no benefit.
Last edited by DMM; 08-11-2014 at 09:22 AM.
08-11-2014, 08:29 PM
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Either the Maggie is too small (common) or there is belt slip, only two things it could possibly be. I believe I advised you long ago that the LS2 throttle body would have no effect at all on power and even posted a few threads where people showed 3-5 whp increase after the swap. It's an expensive swap with no benefit.
