which exhaust manifold to replace on LBZ

[IdahoMike]

2006 lbz, 260,000 miles, with a lift pump, EFI Live with DSP 5 the rest is stock, no EGR delete. I have been reading about changing out the stock exhaust manifolds to keep EGT's down for towing, now do you need to replace both or just one side. I heard some rumblings that only need to change out the left (drivers) side. Any thoughts on this?? I do not race and could care less about getting 900hp, just want to have a great running rig that can tow my heavy toy's mainly a 7000lb boat...

 

[gmduramax]

The driver side has the dent in it.
Factory LML manifolds would be good. IIRC they changed them for LML so I would do both

 

[IdahoMike]

The driver side has the dent in it.
Factory LML manifolds would be good. IIRC they changed them for LML so I would do both

what is the difference btwn the lml and lbz, the dent in the drivers side??

 

[IdahoMike]

what is the difference btwn the lml and lbz, the dent in the drivers side??

I see Max Flo sells a left side only..

 

[gmduramax]

what is the difference btwn the lml and lbz, the dent in the drivers side??

Gm finally realized it didn’t need to have a dent. I believe the opening at the end of the manifold is larger on the lml, I could be wrong.

 

[ZeroGravity58]

I just went through this when I did my head gaskets. I already had the driver side manifold and PPE up pipes. I broke the bolts off in the pass side, so after buying two new manifolds and up pipes it's the same price to buy the PPE kit (900$) or dhd sells a kit for 800.

 

[2004LB7]

on a stock tune only truck, how much is this really going to lower EGT? seems like bad dollar to gain ratio to me. I would think it would be something worth considering only after installing a larger turbo

 

[gmduramax]

on a stock tune only truck, how much is this really going to lower EGT? seems like bad dollar to gain ratio to me. I would think it would be something worth considering only after installing a larger turbo

I think I got both lml manifolds for $180 Did it make a difference even on my LMM probably not but I didn’t like the dent in the driver side manifold

 

[08lmm72mm]

From everything I've read for $ to effect just doing PPE up pipes is worth it and leaving on the stock manifolds but I'm still hesitant to try it even with my upgrades

 

[Dozerboy]

Bigger up pipes is the only thing that going to get you much of a gain. If your on a stock trans I don't see the point u less you tow heavy and a lot.

 

[gmduramax]

From everything I've read for $ to effect just doing PPE up pipes is worth it and leaving on the stock manifolds but I'm still hesitant to try it even with my upgrades

I would 100% recommend up pipes I picked up 3mph in the 1/4 with the stock turbo and while spraying also, they also help spool

 

[gmduramax]

Bigger up pipes is the only thing that going to get you much of a gain. If your on a stock trans I don't see the point u less you tow heavy and a lot.

I would do it for better spool but if you’re already on the limit of a stock trans you will pick up power with up pipes so I would pull fuel out.

 

[08lmm72mm]

I would 100% recommend up pipes I picked up 3mph in the 1/4 with the stock turbo and while spraying also, they also help spool

If you picked up that much with a stock turbo I'd think they'd compliment my 72mm nicely. Oh what's one more truck part to buy haha

 

[Bdsankey]

Personally I wouldn't change the driver side manifold unless you're doing a HG job. I live and work in the rust belt and quite often bolts break upon removal making life a little more painful. At your power level I personally think you're money well spent elsewhere.

 

[IdahoMike]

Personally I wouldn't change the driver side manifold unless you're doing a HG job. I live and work in the rust belt and quite often bolts break upon removal making life a little more painful. At your power level I personally think you're money well spent elsewhere.

this seems to be the consensus, leave well enough alone. I don't plan on doing an big mods, perhaps an EGR delete when they decide to get rid of the foolish emissions testing which from what I heard may be this summer...

 

[N2BRK]

I would 100% recommend up pipes I picked up 3mph in the 1/4 with the stock turbo and while spraying also, they also help spool

I asked Rick (Profab) and he said I'd have no gain changing my stock uppipes. And that's with a 68stg2r and 12mm/40-overs Hmm.

 

[gmduramax]

I asked Rick (Profab) and he said I'd have no gain changing my stock uppipes. And that's with a 68stg2r and 12mm/40-overs Hmm.

I would only run his parts but I’m not sure why he said you wouldn’t see a gain. I picked up 3mph that’s alot of power on a 7000lb truck. That was the only change made

 

[08lmm72mm]

I I

I asked Rick (Profab) and he said I'd have no gain changing my stock uppipes. And that's with a 68stg2r and 12mm/40-overs Hmm.

I ordered a set of PPE up pipes for mine. The cost difference to go with Rick's up pipes just isn't worth it being in Canada and I can't see just his up pipes out flowing PPEs by that much. It would cost me almost $300 more to go with Rick's up pipes yikes.

I'll be the test pig

 

[Bdsankey]

I I

I ordered a set of PPE up pipes for mine. The cost difference to go with Rick's up pipes just isn't worth it being in Canada and I can't see just his up pipes out flowing PPEs by that much. It would cost me almost $300 more to go with Rick's up pipes yikes.

I'll be the test pig

The benefit with Rick @ ProFab is customer support and a much higher quality product. I'm not dogging PPE at all but they aren't the same caliber/quality as Rick's stuff.

 

[Chevy1925]

you guys need to understand there is a speed and flow that is the main concern.

Is the stock manifold and uppipes causing higher EGT's due to restricted flow path and increasing drive pressure? or is it the turbo? bad tuning?

there is such thing as too big of exhaust manifold and too small. IMHO, the best setup for a truck on a stock turbo that is going to be pushing it either as a single or as the high pressure turbo in a twin kit is an LML manifold and ricks tow flow up pipes. Why? because you are still going to be limited on flow out of the turbo and you cant be turning rpm's well beyond what the stock turbo can provide for air. Thus velocity out of the head and flow out of the head is limited. BUT when you are trying to get everything you can, the up pipes and driverside maniflold has some restriction.

IMHO on all the PPE and larger style manifolds and up pipes, you gain turbo lag. you have a larger volume pipe that needs to be filled more and also means the speed will slow untill volume has caught up. been in a few stock head/cam trucks with either stock turbos or 300 frame trubo trucks that proved that. Cams and heads mitigate this but its much like matching a converter with a turbo. manifolds and up pipes should be matched with the heads/cam/turbo/s