I just checked my source, it was printed in 2011, so the ones above must have come after that. Gotta update my sources! lol

 

My 6.2 with l92 heads got significantly better mileage than my lq4

 

Does the L92 use DOD and/or VVT? Might explain some of the difference in efficiency, along with better breathing.

 

It uses VVT. Some had DOD. Mine didn't

 

If its speed eng then its likely china brand just like their headers.
Spectre is like $160 ish from summit.
Im working to get direct with them and hate sending people somewhere else, but i we dont have it then i have to. pn is 9900 iirc for 99-06 trucks.

 

I think mine was an L9H? VVT and flex fuel

 

There is an LH9, but it's a 5.3. What year is yours?

 

Are the combustion chambers themselves ont he L92 heads more efficient than the 317? that would explain alot.

This is sorta funny, but I think relevant. My suburban on a good day with pure gasoline (not e10) and a 5.3 got 14.7 mpg average and would get up to 16 on the highway unless it was downhill the whole way. I was a dumbass and put a LS6 cam in it, and the mileage dropped to 13.5 average, but stayed 16 highway.

Test drove a 2007 escalade last week for ***** and giggles with the 6.2 in it, and after resetting the dash, it got 18 average and 20-21 on the short highway run we made. I know that driving it for an hour isn't the same thing, but it did FAR better than even the 5.3 on fuel.

Haven't looked into the DOD or VVT side of it, but I don't think that explains it all, which is why i'm asking about the combustion chambers.

 

Darth it would be more towards the VVT/DOD the chambers help but at 16 vs 20 is due to more tech being used. Cleaning up a chamber helps but when you can tell cylinders to not use fuel or less fuel it makes MPG grow. Can you have a VVT solid roller? LOL! That'd be trick. FTI makes or sales aftermarket hydraulic VVT cams.

 

So do Cam Motion, Texas Speed, and a BUNCH of others...

 

Ive always seen an increase going to nonvvt and nonafm. of course with mild cams. lol.

 

And probably an increase in dependability too!

 

Both rely on engine oil pressure.

 

Thanks for the info.

For the intake tube. It's a piece of plastic tubing and stamped sheet metal. Origin isn't going to make much of a difference. And it's 69 vs 169. What exactly am I getting that's worth the 100 on those basic *** parts? That's how I see that one. And if I don't like the filter I can upgrade it and still be way ahead.

The headers.. well if they work and hold up sweet. If they don't.. They're cheap so I don't have super high expectations. Then there's the... some chinese **** is getting/has been pretty decent and just because it's chinese doesn't automatically mean ****, I do follow your drift, generally it means sub par. Has anyone been reporting issues with the speed engineering parts? Also I need to be par for the course. This truck has 190k, the clear coat is peeling. Has a dented fender. You get the point.

Lastly, i'm interested in hearing people's experience with them. If they fall apart i'll avoid, if not, then it's a hell of a deal for a set of damn decent headers.

Buddy of mine's wife has a 2015 (2016?) yukon denali and it is almost always on the streets and averages around 18-20. He had the DOD tuned out and no other changes and said it actually seems to be 1-2mpg better. Doesn't make much sense to me that it would get better, he was obviously surprised as well.

I get around 12-13 with my 5.3 truck but i'm never easy on it. It was 17-18 when I was with mixed street and highway. If i'm nice to it and stick to the highway and stay between 60-64 i'll avg 19-20 MPG for the tank. 16-17 being easy on it all street. It was 14.x easy on it all street with stock tune and manual fan. Life time MPG on the truck was 15.8 when I got it at 80k. Now at 190k it's 13.x

The yukon is bigger and heavier and has a 6.2 and gets (driving style for driving style) a good 3-4 mpg better than my 5.3 2wd extended cab.... Not what I expected. 8 gears likely has something to do with it.

I wonder if we compared 4L60 5.3 trucks to non DOD 6L80 trucks what we would see.

 

Ive seen no less than 5 sets since May of speed eng dual kits for fbodys bought and for sale 2 weeks later on 1 fbody fb page alone.

The tube isnt all to look for. Filter quality as well. But spectre has the maf sleeve because the truck maf is diff on the outlet. Using that sleeve and their couplers you get a full 3 1/2" or 4 (checking mine later) inches from filter back. Only transition is the id of maf itself. Plus it uses an air horn for the filter adapter. Its an alum tube also not plastic with chrome paint.
Only downside is you have to use the stock airbox adapter coupler but not a huge deal unless you dont have one.

 

Edit: you said FB page. I read the speed engineering exhaust thread. The two people that put it up for sale were because they said it hung too low. Every other person said they worked with it until it sat up higher. I had to do the same with my Lanes and with the BBK/magnaflow on the wife's sn95 so I take all that with a grain of salt. If the truck headers don't fall apart, and don't hit anything. It's a home run.

Their intake tube is black. There is an air horn. No adapter to stock box. It's k&n style with a sheet metal shield that "blocks engine heat" pfft. They don't advertise that, K&N does.

Honestly I've been thinking I may be better off just getting a plastic tube and hooking it to the stock box and keeping K&N filter that I already have in the stock box, since the stock box pulls air from the fender.

 

Take a second look man and tell me this doesn't look really damn nice for the price

I've considered the things you said above before and that's why I'm so interested in this

https://www.speed-engineering.com/fe...l-engines.html


PM me back and forth if you want to keep from cluttering the thread. I def respect your insight on these parts so if you know something about their parts I don't, i'll listen. But I have been reading and studying as I always do. I don't just jump at cheap parts, they usually cheap for a reason.

 

It seems pertinent to the thread. I wouldn't use em. Def a different filter vs the Spectre or any k&n.
Its a copy of the spectre otherwise which is what china does lol. idk about the maf sleeve though.
Crinkle seems nice but idk how long itll last.
Ive used spectre on so many builds and my own 3 personal trucks 2 gmt800s and 1 gmt900. Id not chance it on that setup if it were me. Cheaper isnt always the same. Buy it and try it is all i can say but spectre has my and our shops business for alot of reasons. Use them to adapt to 104mm lids or 100 mafs or tbs or whatever. their stuff is good.

The dual exhaust part, they drug, hung too low, rattled and the clamps sucked. Their clamps sucking is common knowledge and everyone complains about them.

 

Gotcha on the truck stuff that's great info and again appreciate it. If I spend $69 on it and it don't work I'll adapt a piece or two or junk it and use my stock stuff. I've bought nice K&N brand barrel filters on ebay before for like $40. But i'm also approaching it with my no money approach right now. Next year I can approach it completely different and not care as much.

For $500 I wouldn't care about putting a little into the hanging part and they revised it to make it sit higher so the new run should do better. Guys in the thread took the bolts out of the clamps and got grade 8 hardware for them for under $10 they said and the clamps worked good. I hear you, it's problematic, but for me and my budget I'd be hella willing to work with a couple of parts and invest a small amount to make it work great. The rattling and hanging sometimes is just part of the exhaust game, it takes a lot of tweaking. And I hated the way the magnaflow was on the SN, no matter how I adjusted it it was always a problem and hung weird so I can't say the SE is really much worse than others.

 

Texas speed duals are a better option that fit better and use a better quality stainless.