This is an interesting question. I could sell prebent and assembled y pipes that you can weld your flanges on or I can sell them bolt on. I would imagine bolt on would be easier for people.

I think you are right. Bolt on would appeal to more people. ORS builds their 3.4 crossover and they require that you send a set of flanges from your removed old crossover or they apply a core charge. Factory flanges can use factory gaskets.

Yea the ORS deal is a really good idea.

The more I think about it the more I favor a y pipe that runs simular to the stock setup without the expansion chamber or dumping into the driver's side manifold. Main reasons being:
-No heat on starters
-No burnt floor mats
-No risk of rock rash (these are 4x4's after all)
-Cheeper to produce
-Easy to retain stock o2 location.
-Easy to retain stock cat location.
-No heat transfer to tranny
-Overall better us of space.
I really don't see any major negatives to this plan and it would bring the cost down from the ~$200 range to probably the $150 or less range (depending entirely on the cost of parts of course).

Count me in! Bolt-on please! Will this work with an auto trans? Let me know when you get them ready.

I dug through my iron pile to find the old crossover, cat and manifolds I had removed to install the Downey headers. I cut the flanges off of the crossover. The crossover tube measures 1.5" diameter. Looks like there would need to be a blank off plate for one of the outlets on the driver side manifold.

Thinking I will get some two inch mandrel bends and weld up a Y pipe using factory crossover flanges and the old cat flange. I will test install it on the 2wd auto.

I thought I read somewhere on Yotatech where a guy eliminated his crossover, and ended up going back to stock because he diddnt like the outcome.


quote from this thread


http://www.yotatech.com/showthread....&highlight=crossover+elimination


"This weekend I will be reinstalling the exhaust cross-over pipe. The removal of the cross -over caused the engine to be sluggish and the exhaust buzzes. The engineers at Toyota must know something that we don't. It looks bad and I can buy the choking the engine statement but the truth is - the engine must need the pressure to run correctly. Luckily - I've only invested about $100.00 in removing
the pipe."

[quote]I thought I read somewhere on Yotatech where a guy eliminated his crossover, and ended up going back to stock because he diddnt like the outcome.[quote]

I looked at that. The guy routed it so that only one bank was passing the O2 sensor and I noticed a couple of other design problems.

Tube size selection is important. I have learned by experience not to go too big. I went 2.5" from my Downey headers for a Y pipe then into 2.5" with hi flow cat and open muffler. stinks on the low end but when it gets rolling it pulls and starts to purr at 4000 RPM or 90 mph and it is still pulling past 100mph. Problem with that is that I don't do any 4 wheeling that fast. I think that if I went with a smaller Y pipe from the headers then into the 2.5" at the junction I would have better low end. I am about to put a 3.4 engine in the 4x4. Waiting on the ORS wire harness. Ordered it last week. The exhaust plan for the 3.4 is to use the Tubular exhaust manifold available on 2001 and later. It has a matching tubular crossover that keeps the gases from each side separate until it dumps them out of the crossover into the exhaust pipe. It dumps in at 2.5" then immediately necks down to about 2.25" on back. I will leave this part open with my existing 2.5" system. The tubes in the factory crossover look to be about 1.75" diameter. This plan puts the down pipe on the passenger side. Then I will weld up a section to take it back to the drivers side to meet the existing 2.5" line. I am hoping that this plan will keep low to mid range torque and give some more breathing on the top end for the highway.

After thinking more and reading the thread you referenced I am thinking that even 2" from the manifold is too large and 1.75" would be a better choice for a Y pipe. then into a 2.25 or 2.5 from there back. It looks like my 2wd has a 2" exhaust pipe stock.

A friend of mine runs a salvage. There he got in a motorcycle that has a butterfly valve in the exhaust. It is linked with the throttle and opens wider the more throttle it gets. Basically restricting at low power for torque and open at high power for max hp. I would like to rig it into my exhaust for a test but he wants to try it on a 1200cc Raptor quad he is building.

DUDE, i;ve been looking for someone FOREVER that has done this.
Can you measure the downpipe flange on the driver side manifold for me? I need to get one cut out of stainless... and i've been searching for some dimensions for weeks... it would be GREATLY appreciated... i need to get it done because i have an e-test in a month....

There are a couple people on YT that have done it with good results. One goes under the username M3 I believe. I have some pics that he sent me. His worked out well.

I'm gonna use 2" mandrel bent pipe to a 2.25 collector. A smaller diameter might be a good idea though I'll have to think it over.