C5Natie

After having issues with my NW 102mm tb I'm going back to my stock LS2 tb. Thing is Ive never been beyond 18psi with it and now I'll be at 25psi. Anyone been at 25psi or so with a stock ls2 tb? Thanks.

Unreal

25+psi on stock TB. Had REP mode, but was easy to tune out.

CI GS

The LS2 (silver blade) TB reportedly has a stronger motor and far less issues with REP than the LS3/LS7 (gold blade) throttle bodies.
BTW: NW now has a Boosted version of the 102mm with a stronger motor, so you may be able to get him to upgrade your 102 with that motor. But, by all accounts, the LS2 is the best of the stock TBs.
A lot of folks have tuned out REP mode by raising the throttle related DTC thresholds, but that doesn’t mean the throttle blade isn’t still wagging around in the intake track at WOT, causing turbulence in the intake. I have no idea of whether that affects power at 25psi, but if I had to take a bet on it, I would bet it does, but probably not by much.

Unreal

It really isn't about wagging around at WOT, but returning to position fast enough after shifts. Mine only did it on quick shifts at 25+psi, and only some times. Basically it was fighting the boost to get back to commanded quick enough not to set REP.

CI GS

Okay, that makes sense. I was also experiencing REP with the LS3 TB (at only ~12psi) but only right about when it was supposed to shift to 3rd, so I’m wondering if it was TM related and when the ETC started to partially close for the shift, the boost slammed it shut? I have the NW Boosted now, so I’ll see how that works when I get the tune sorted.
You’re running the LS2 silver blade TB, correct? They seem to work well. They’re also like 2 1/2 times the cost of an LS3, but certainly much cheaper than a NW.

Unreal

Factory stock ls7 TB. Considering my car is a 2006, I assume same as a ls2 as ls3 didn't come out until 2008.

C5Natie

Thanks for the replies. I have an auto so I'm not sure if that will make it easier to tune than a manual car since the tb momentarily closes between shifts. I never had a problem at 18psi but I know 25psi is a good amount more. Well I guess I'll be reporting soon how well it works.
I have a regular NW that goes into REP after 15psi or so. When I got it I didn't know they had just come out with a boosted version. I guess that'll be my next move of the ls2 doesn't work out.

realcanuk

Haven’t had any issues with the LS2 TB up to 20lbs.

CRUSHAH

helga203

Is there a certain year ls2 TB better than others??

CI GS

Don’t know for sure, but everything that I’ve read suggests that all the pre-2008 silver blade 90mm throttle bodies are same, and don’t have the REP issue like the later gold blade TBs. There’s been a debate about whether that’s attributable to the direction of rotation of the blade, but that doesn’t any makes sense to me, especially since I had to turn my LS3 TB upside down to install it on my Hbeat blower and it still goes into REP mode.

Here’s a basic side by side comparison from the Summit website:
https://www.summitracing.com/compare#

realcanuk

Mine is upside down now. Worked fine either way.

CI GS

Thanks Jody. I can’t see why it wouldn’t. I’ve seen people on these and other forums say it’s “because the LS3 blade swings in” or some such comment, but that makes no sense, because the pivot point of the blade is in the middle, so each half of the throttle blade is going to be subjected to the same boost providing “assistance” to open on one side and to close on the other, no matter whether it’s upside down or sideways. If you look at the two throttle bodies, you’ll see that the motor side looks very different. That I believe is what makes the distance. My guess is that GM went cheap on the newer TBs, hence the price and performance difference.

RecMech

We were running the silver blade on my car with ProEFI up to 27 psi.. One day at the track I stripped the internal gears and had to borrow a gold blade. Adjusted the TPS in ProEFI and ran the same numbers.

The silver blade did show some inconsistencies over time.

We now have a 105mm cable pull at 30+ psi.

yur2slo

32psi via an F1X would close my LS7 during high run pulls (not on dyno, but in races). Switched to cable drive and never had issue.

Nino S

25 psi on a stock LS7 TB here. rep mode tuned out.

C5Natie

Well we dynoed the car last week and had zero issues with a bone stock LS2 tb. No REP no nothing. Continuously put down over 850rwhp at 25# through a 4L65E.

The issue I see with tuning out the REP is that it doesnt fix the fact that the blade is still moving around or even closing a bit.

Pekka_Perkeles

So true.

CI GS

yur2slo

Yup not much you can do when you physically can't control it anymore