00pooterSS

iTrader: (40)

The clamps I have found that work best were recommended by my muffler guy. He said he's tried them all and these work best.

I don't know exactly how to explain them but I'll try my best lol. I got them at Oreilly and they are really wide, about 3" or so wide. They come laid out flat, not the preformed ones that have a step made into them already. Those are harder metal. The ones laid out flat with no step are softer and conform to the pipe much much better and provide a better seal. I have tried the wide band clamps with the step before and they didn't seal very well or hold the pipe together as well.

I still had a little bit of leaking so I went and bought some heavy duty foil and folded it over to make a 3" wide strip of it, 3 layers thick, and wrapped it around the sealing joint 2-3 times then put the wide clamp around it and smashed it. It worked really well.

The clamps like you posted in the picture, and the speed engineering clamps are way too narrow and also need the piping to smash together in order to seal the joint, which just isn't going to happen. I fooled with those clamps for weeks and no matter what I did they would not come close to sealing. They were either too narrow to completely cover the slit in the pipe and seal the slit, or too hard and too narrow to cover the whole slip fit and slit pipe area and seal.

G Atsma

I'm with Pooter. Years ago I had a 3.9 Cummins swapped into my F-150. The 3" exhaust connection from flex to hard pipe was a stepped band clamp. Never could get it very tight. Went to the flat band as Pooter described, and no problema mas! It was easy to work with too.
Anybody looking for them can get them from any good truck parts place. And of course, Amazon!

Lsbmer

Why not just pull a plug and take a look. After hard accel.
If octane didn't change anything. I doubt it detno . Torco octane boost makes a big difference on dyno . Definitely changes the burn. looked at the boostane stuff as well .but never used it. Whats the water temp?
maybe u already said what it was.

RedXray

Yeah I've pulled the plugs twice looking for any damage like melting straps or peppering of the porcelain and found none. The second time pulling the plugs showed no damage but with the orange MMT deposits from the Boostane, looking for discoloration or peppering was not possible. The area on the strap that burns in the timing mark shows I could add a couple more degrees. On the VCM scanner logs, I've seen normal temps but an occasional 204* sitting in summer traffic. I live a block from the hwy and I've heard the "pinging" type noise driving before complete engine warmup (around 160*).

simond

I have an LS1 with nearly the same cam timings you have there, but higher 11.5 static compression ratio, just running high octane pump gas, Ive never had knocking problems with it at all.

Im running about 26 to 28 degrees timing at WOT. getting about 420whp
So I wouldnt imagine your lower compression engine would be knocking, maybe an injector is bad, like partially clogged with something stray getting into your fuel lines and giving you a lean cylinder, that may not show up on an O2 sensor (not sure).

Maybe someone else can chime in with what a bank O2 sensor shows if just one cylinder is a little lean but still actually firing?

RedXray

The LQ9 flat tops with the PRC 62cc chamber heads work out to a 11.4 static and I'm running 24* total advance. As I posted above the plug strap timing mark shows I can add more timing but I've been gun shy because of the noise. Listening to it idle in the shop this morning I can hear the small exhaust leak at the collectors and I'm more convinced that is what I'm hearing under load.

00pooterSS

iTrader: (40)

I use a mechanics stethoscope to check for leaks. It works really well for exh leaks and even vacuum leaks. I pulled the end off of it and stuck a vacuum hose coupler in the end of the hose, then a piece of vacuum line on that and a piece of metal brake line into the vacuum hose (metal line for sticking it on hot exhaust) and you can hear even the tiniest leaks through the tip of that hose. The stethoscope amplifies the sound of the air leak. I've found the smallest vacuum leaks at injector or rings with it, and tiny exh leaks. It won't blow hot exhaust gas up into the hose to your ears so don't worry about that it'll just puff air into the tip of the hose and you'll hear the air noise.

Run the tip of the line across all sealing surfaces (gaskets, clamps etc) and if it's leaking you'll hear it and be able to 100% pinpoint the exact spot because as soon as you get off the leak you hear nothing. It's really nice for that (finding the exact spot down to a quarter inch area)

RedXray

Thanks Dr. Pooter good info.

Reaching under the truck during idle, indeed I can feel the leak on bank ones collector to the x pipe. I'm upgrading to 1 7/8" headers when they're back in stock (9-10-20) so I guess I'll put up with the noise till then. Are these the clamps you were referring to?

00pooterSS

iTrader: (40)

That is exactly them, yes.

They're softer, cheaper, and work pretty well. But to be honest, that style of clamp or any variation i've ever tried has never fully sealed a joint. But those have came the closest for me and my exhaust guy that has tried everything.

00pooterSS

iTrader: (40)

Went to Oreilly's website (can't post a link) and the technical brand and type is Walker, Flat Strap, clamps.

I fiddled with them some and grinded down that center block, by center block I mean the block with tow holes in it that sits between the clamp ends and I grinded down the highest part of the "walls" to allow the clamp to clamp down a little more and that helped some too. You'll have to see how they work for you and how you like them as is. But adding in the foil really made everything come together and seal up the best.

However, after all this fiddling and fighting, I should have just gotten the joints welded, but I hate having to cut exhaust if I want to pull it off for any reason so I didn't. If you aren't opposed to welding it just do that and skip all the hassle.


Edit: even after all that, I still hear what sounds like a leak but isn't, it's just the header primaries themselves. I suspect that wrapping the headers will calm that down, but I've never tested that theory to see.

G Atsma

Yeah the one point prone to leakage would likely be the joint where it bolts together. The one I used held well, though it was a turbodiesel app with very low backpressure.

00pooterSS

iTrader: (40)

Yeah it does leak where the band comes together. And unfortunately there's only so much you can do for a loose fitting slip fit joint like the speed engineering headers have. It really needs to be a tighter tolerance fit but the headers and y pipe are amazing for the price other than the slip fit leaks so I usually don't complain about it.

If you have a good tight tolerance slip fit joint, just about any clamp will work.

RedXray

Yeah the Speed Engineering headers are great for the money. When I get the new 1 7/8" set I'm going to have my muffler guy do V bands at the collector and X pipe. Last time I did a trans filter I had to drop the whole exhaust system. Turned a 45 min job into over two hours... correction, I wanted to install a different pan with a drain plug. It took me another 30 minutes to remove the darned old factory plug lol. I drilled and used an easy out... no go. Finally had to use an air chisel to brake it loose. Found a better plug with a deeper hex to prevent future stripping issues.

00pooterSS

iTrader: (40)

I'm really familiar with that nightmare, I've air chiseled many of them out, the only way I've been able to consistently get that stupid *** bolt out of the trans pan is use a good 6 point socket on a 1/2" impact. Other wise it strips damn near every time... Great call on the V bands.

Just a heads up in case you haven't talked to your exhaust man already (you may already know this) but my exh guy and another guy on performance trucks exh guy said they need the exhaust off the truck to do the v bands. I put mine on then drove it to the shop and asked him to put on v bands and he said "too late"

RedXray

I'll have to remember the drain plug & impact tip.

On the V bands... would it be easier if I just took the new headers and X pipe to the muffler shop and have them welded off the truck? If I sharpie around the X pipe where it slips up to my old Speed Engineering 1 3/4 headers to give them a cut line... or would that be risky considering the 1 7/8 might be different in overall length? I'd hate the bill having them R&R the headers plus I'd also hate another mechanic working on my stuff and leaning on my nice painted/polished fenders lol.

00pooterSS

iTrader: (40)

I'd be concerned they may have a hair different length and or path.. aka one of the collectors or both may be a hair over one way or the other. Talk with your favorite muffler man and ask him his preferred method man, I'd hate to give any advice here and steer you in a direction he wouldn't prefer.

RedXray

I was thinking about this yesterday and came to the conclusion it's probably best to install the new headers with a just couple bolts to get the correct depth in relation to the x pipe then make the sharpie line. After the v bands are welded on I may need some hangers relocated, I could probably piece enough together to drive to the muffler shop for some tweaks if needed.

00pooterSS

iTrader: (40)

That sounds like a good plan, but those muffler guys may have some trick we don't know about so I would at least run it by your guy in case he has some helpful hint that makes life easier.