Rocketwrencher

When somebody puts ashot across your bow, you have to return fire.

Elvota

Have to....?

Just trying to help keep your thread going in the right direction for your benefit and others that might stumble across it in the future. Not laying any blame.

truckmike26

I forgot to add that 75 mph (120 km/h) is about 3,000 rpm in o/d, converter locked. Wide open, it upshifts at about 5,500 rpm and the fuel cuts off at 5,800. So, I figure headers could give me the punch I need in that 2,500 rpm bracket.

Marc P

After blowing the head gaskets on my 3.0, I had a set of Downey headers with a custom y-pipe installed. I am not thrilled with my decision....they are loud!! especially with my Magnaflow catback. The reed valve sounds like a machine gun at idle, and the performance gains are......what performance gains.

I also had to replace and relocate my t-case cooler, move my brake lines and some of the electrical lines that run too close.

The headers do look cool, and the guy who made my y-pipe did a great job...here are a couple pics

Rocketwrencher

You are right Elvota. I apologize. Can I go play now. Marc P, they do look good. Are those Downey headers? Zero performance gains? As far as the mods that you had to do, my sons is a 2wd so I wont have all the problems you had. I do expect a few mods tho. Did you remove the heat blanket attaced to the firewall behind the crossover after the install? Also, did the heat shields attached to the header gaskets come with the headers, or did you use stock gaskets? I think Downey supplies gaskets and does not reccomend stock gaskets, but I dontknow if theirs comes with heat shields.

Rocketwrencher

Just messin with ya Elvota. I appreciate all your input. I have read most of your posts and you are def. a great source of info on this site.

Jay351

I like your y-pipe! All the others I have seen go under the stock d-shaft. That puts it right in front of the (same height from the ground) tranny x-member... not a good idea if you offroad alot.

Marc P

You need to realize that I have a solid axle up front so my driveshaft is at more of an angle allowing the placement of the y-pipe...with an IFS rig, I don't think it is possible.

Rocketwrencher

Is the guy that did your crossover y pipe local? I am pretty familiar with Santee growing up in Kearny. I def. dont like the drop hoop that Downey's pipe has to go below the front drive shaft. Again, mine is 2wd, so the drop hoop is unnecessary. I was thinking of just modifying Downey's.

Marc P

They are Downey headers. We used the stock Toyota gaskets, and I dont remember about the heat shield blanket?? It must still be there.

As far as the power gains.....it is not "0", but it is not much. I am also concerned about the under hood temperatures. I may add hood louvers to help with that.

Marc P

Yes he is in Santee.....here is his website

http://www.chappelleskustoms.com/

Elvota

I came up with a Y-Pipe using some mandrel bent exhaust tubing and flanges from Summit.

Parts:



My Y-Pipe:





Installed:



Same deal as Mark P though... an SAS front DS so clearances are different.

By the way, these pics are from when i did my 3.4, but the exhaust layout was almost identical to the 3.0.

Rocketwrencher

Thanks Marc P. That Y pipe looks sweet Elvota. One thing I am not understanding tho is the added under hood heat I keep reading about. With ceramic coated headers, I would think there would be less heat. The headers allow the motor to breath better, there-by allowing the hot exhaust gasses to escape more quickly. Ceramic coated headers should, in theory, keep more heat in. What are the main concern areas of higher heat temps. under the hood? Are there some lines ar parts that need to be protected? I.E. the starter?

trbizwiz

Hey just jumping in here. I just bought a set of pre owned but unused Downy headers off of craigslist. I haven't picked them up yet. The ones I got are ceramic coated. I too am curious about the heat issues with the ceramic. I wanted NWOR headers, but they are also out of stock until January. they apparently have a sub that makes the flanges on a cnc and he is backed up with Boeing stuff.
Any way i have the Downy's and I was planning on putting in a hood scoop. Will this remedy the extra heat issues?
I also heard about people wrapping their starters and plug wires. But I am not sure what they are wrapping them with or how effective this is.
Sorry for the jack, but I thought it stayed on topic. Thanks

By the way that engine is sweet. Nice job. I love the idea fo a father and son working on a project like this. I will def do this with my boys in the future.

Kaimuki4Runner

Rockwrencher: I installed my all Downey system that included headers, complete 2 1/2" exhaust system and catalytic converter back in 1992. Of all the power improvements I made this is the one that stood out the most. To remove the crossover pipe I needed to unbolt the motor mounts and have someone maneuver the floor jack up an down while I tried to wiggle it out at the same time. I found out later the easy way to remove it was by cutting it out. If I knew it then it would have saved me a good 2 hours! That was the biggest hurdle and the only time another person was needed. Everything else went pretty smoothly. Installing the header bolts were tight but there's enough room.

truckmike26

Has anyone ran a pipe off the right manifold and one off the left with a cross-over block-off plate? Or blocked off the outlet and ran a tight radius down- pipe from the cross-over inlet on the left? This make a dual exhaust with the stock manifolds. Should I do that and tell everyone how it works out?

Rocketwrencher

Truckmike 26, I did read of someone using the stock manifolds, eliminating the crossover behind the heads and redoing the crossover down below. What would be the point though? All it does is relocate the crossover and maybe solve a heat problem at the back of the #6 cylinder. From my understanding, it has never been proven that heat is the cause of the 3.0's woe's. If it was, wouldn't the 3.4 have the same problem? Anyway, I ordered up the entire kit from downey today. It includes headers to exhaust tip. It is 100% smog legal in CA. I wont get the headers until they are done with the production run, but putting in the cat and exhaust coupled with cutting and rewelding their crossover to eliminate the drop loop should keep me busy. As soon as I have pic, I will post them. In the mean time, I will be working on dressing out the engine bay.

Elvota

Dual exhaust is usually abandoned as an idea on these motors because of the 02 sensor problems. One 02 sensor and two pipes equals confused ECM.

I am no expert, but that issue is probably just the tip of the iceberg as far as the complications of a dual exhaust with no real gains.

I believe Toyota did a lot of overall refinement on the 3.4 and paid some strong design attention to the exhaust. If you look at a 3.4 manifold compared to the 3.0 it is a major upgrade.

I don't have a pic of the 3.0 crossover, but as I am sure you are aware it's basically a chunk or iron that emissions strain to pass through.

The 3.4 factory crossover is completely different:

truckmike26

I dosen't matter to me where the cross-over is, above or below, I was just trying to think of ways to free up more power without headers and eliminating the torturous backwards in-and-down turn-down on the driver's side manifold without going to long-tube headers. So maybe a 3.4L-style cross-over with a down-pipe block-off is in order -- keeping the quiet and reliable stock manifolds.

truckmike26

Oh, by the way, I know about O2 sensors and closed-loop electronic engine controls. I wasn't looking for a yee-haw dual exhaust.