slcpunk74

sorry to hijack but are the downey 95.5+ tacoma headers the ones I want?

Looks good 904

mt_goat

Those of us with 4wd wanted to avoid a cross-over below, that may get hit on the trail. Also that makes it harder to keep the front O2 sensor in the proper spot, if you care about that. Also crossing over below the tranny means you'll have one bank of hot exhaust running down by your brake and fuel lines.

slcpunk74

If trail clearance is the only problem and those lines I think Im ok. I can figure somethin out for it.

Gravehunter

Getting ready do this swap: It would seem to me the easiest way would be to cut the flanges off and just run each side down from the manifolds and then run the right side over to the left side and out the back. Most trucks with V-8's do it that way. If there is room to run a pipe down on the right side with headers then theres got to be room to do it with the stock manifolds. I don't care about a cross over pipe running across to the other side since it won't be a hardcore offroad truck or anything.
Then theres no crossover pipe at all!

I'm not seeing a reason not to do it this way. Anyone see a problem with it?

thefallman

As MtGoat said earlier this makes positioning the O2 Sensors front or rear in proper position nearly impossible as it moves the junction farther away from the manifolds and allows exhaust gases to cool more before hitting the Cat which will mean the Cat will very likely not function properly and u may very well end up throwing O2 sensor Codes because of this. I have heard of this being a problem in the past. do i know any specific instances, no i cant say. What i can say is that my O2 sensors are positioned EXACTLY the same distance from the manifolds as the ones on the stock install are. And i have never had a O2 sensor code thrown EVEN with a 2.5 inch high flow CAT along with the rest of the exhaust which is all 2.5 as well including magnaflow muffler which sounds awesome

vital22re

iTrader: (2)

when i did my swap in feb this year i pulled a 3.4 from a 96 chopped the crossover flipped it and got the factory heat shield to fit. My truck was cali so it had 2 o2's i replaced both with ones from the 96, added a magna flow cat and 2 1/4 piping all the way back to a magnaflow muffler. no codes no probs.

Gravehunter

mmmm... ok, i didn't know the position of the O2 was so particular.
I'm comfortable doing the cross over mod myself, just thought it would be easier and better not to. Sounds like to much of a risk. Crossover mod it is.
Thanks for the info.

Edit: What are the guys that are putting in the headers doing? Some may be crossing over, others may be running duals out the back from each side, so i'd think this would be a problem for them as well.?

thefallman

i don't know of any set of headers that don't cross over at some point. some separate again for duals out the back of the truck after this point but i don't know of any that are completely separate all the way out the back. I believe u have to use an O2 sensor eliminator kit with Downeys headers. But you might talk to Downey about that

Gravehunter

Downey said if you use there crossover kit all the 02 sensors stay in the same place.

If they have room you'd think i would?(muffler shop running it out of my stock manifolds. ?

thefallman

just never have liked the idea of a exhaust pipe being the lower then drivelines or other things on my truck too easy to smash it would seem

kaz

using the stock 3.4 crossover works great, if the mf muffler shop does a decent job of welding! thanx for the killer ideas, awsome work!

Red_Chili

Finally took a whack at modifying a stock 3.4 crossover to replace my eroding ORS crossover.
Not as clean as some posted here. Oh well.




Took it to a local powdercoat/ceramic coating place. He coated the inside with a greenish gray material, and said that if some place told me coating the inside was unnecessary... I was not getting my money's worth, to protect the steel against heat and reduce radiated temperature. If necessary, they cap off one end and slosh the material all over the inside! He also coated the flex coupler and said that it would not flake off. Interesting.

Red_Chili

After coating:






Any dog hair stuck to it should go away .03 seconds after firing up the truck... LOL

mt_goat

Looks great Bill. Did you use any part of the ORS cross over?

Ahbustae86

After seeing the ORS crossover pipes cracking at the merge, I am deciding to use the Flowmaster 2 to 1 header collector for the merger. My question is that the collector is 2 2" pipes merging into a 2.5" pipe. Is the 2" piping which starts at the manifolds to big for the motor? I beleive the stock ones are 1 3/4" or slightly bigger.

Red_Chili

Nope, just stock Toy parts and a bit of 2" HREW tubing. I think the stock diameter is a BIT more than 1.75. Now you got me curious, and forgetful; I will have to measure.

No idea if the ORS pipe is too large. Could be, I suppose, Mike tended to err on the side of generous on exhaust. (Probably biased toward forced induction.) I ended up glad of it, since I went from a 22RE to the 3.4 and kept the 2.5" exhaust as much as possible. 2.5" took a bit from the midrange to benefit the top end on the 2.4, but with the 3.4 it seems ideal.

We will see if I notice anything different in performance, when I get my PS pump back from PSC tomorrow or so. If it doesn't spit snow again.

Can't muss my purty truck, y'know.

sinneDBTB

i know this is an old thread, but how did you match the angle of the bottom flange on the crossover to the flange on the collector pipe that goes to the cat?
also how much clearance is enough from the heads?

Red_Chili

I made it as tight as possible to the heads and bellhousing, while allowing a service gap to prevent buzzing or damage from vibration. Nevertheless I somehow ended up with a buzz right at 2300 under part throttle, applying power (no other time)... waaaaaaahhhhh.....

Regards the angle, I didn't use any of the exhaust after the flange; mine is a custom 2.5" already. My flange is a bit higher than the 3.4 arrangement and much less swept, almost horizontal (probably could have angled it more and gotten a better height on the pre-cat section, but it's fine). I took the 3.4 2-into-1 piece that bolts to the flange and trimmed it, made an insert out of Checker Auto spare exhaust pieces and welded it together, then fitted it to the 2.5" downtube and finish welded it in situ.

Works pretty well. Except for the buzz.
I'll track it down after I move.

piche582

Was able to modify mine using the factory X-over & a 1 5/8 (i think, it was the same sive as the factory pipe, might've been 1 7/8) J bend that I laying around from building some headers long ago for another project. It provided the perfect bends I needed to come off the pass side & redirect it back over the bellhousing. I had to do a slight dimple in the pipe where they tie in at the flange. Was actually REALLY simple to do for anyone who has any fear of builiding their own crossover. Only took me about 3 hours & I work slow. I just painted mine & exhaust wrapped it where the new tubing was since I had to remove some of the factory heat shielding to make it all work.

Jason4X4

Glad to see this helping people.