mt_goat

Yeah M52 motor. One strange thing about the duel exhuast on the BMW, I noticed that one of the two tail pipes coming out of the muffler has a valve that closes off the exhuast flow from that one pipe. I'm guessing it just closes at low RPMs for more torque? Do you know anything about that?

Eric

that is exactly what it does. I thought this was only on the M3 model though...

It's funny how you get no power gains with $700 exhaust systems for BMW's since those crazy germans get the most power out of the stock setup.

whish the same could be said about the 3.0L

Doc279

UPDATE:

I've eleiminated the cross-over pipe just as described. The new pipe drops
down between the frame and the transmission with no problem.
We routed the pipe back and crossed over aft of the transfer case.
We did not increase the pipe size the rest of the way out.

The engine seems to run better but makes a buzzing sound when accelerating. The new pipe joins the old pipe 6" downstream of the oxygen sensor. My CEL has not come on yet - just finished this yesterday and I have only driven about 30 miles. I do not like the sound - sounds like a chevy cavalier !!!! I don't know whether to change it back or spend some more money on larger pipe and muffler. The motor does seem to run better but nothing drastic. Any idea's on the buzzing exhaust ?

I do have pictures of all of this swap - the cross -over pipe will come out without cutting it. Block the runner up and remove the wheels - most of the work is done though the fender wells. I do have a 1" body lift though.

Cross-over pipe will come out of the driver side fender well.

Doc279

bump

Doc279

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.

mt_goat

I'm betting it was because you had the O2 sensor just reading half of the cylinders, but what do I know.

Doc279

Maybe - the guys at the muffler shop where we added the pipe said that ti would work fine. The new pipe enters the down pipe 6" aft of the oxygen sensor - I would imagine that there is enough pressure for the sensor to read correctly - how smart is an oygen sensor anyway ? : dunno either

I know that I am changing it back - It was not sluggish before and it is now.
My CEL has not come on since I re-set it.

I was hoping for lot's of hidden power !!!!!!! :cry:

mt_goat

Are you sure there wasn't a leak somewhere? How did you block off the left manifold where the factory cross-over was?

Doc279

The left manifold was blocked off by a portion of the cross-over pipe that
I cut apart. The muffler shop inserted a round piece of steel and welded it
closed. No leaks - checked every connection several times.

mt_goat

That doesn't sound fun trying to get the stock cross-over back on there. Are you going to get a another one somewhere?

Doc279

I never cut my original one

I ordered one on e-bay and cut it up before I ever removed anything. I had planned to cut mine to easy the removal - but it came out without to much trouble. The 1" body lift helped here. The cross-over pipe will actually
come out on the driver side fender well.

I took pictures and intended to do a full write up on how what and when but
the operation was not a sucess - luckily I am just $100.00 out of pocket
and several hours labor. Could be worse

Ganoid

Its funny you say it didnt work...

When I initially put my headers on and plumbed it back into the stock exh system I thought to my self "what a waste of money this sucks". I then decided to get off my lazy a$$ and build the rest of the exh system.Once everything was on and it took it out for a spin I was like

the difference was very noticable once the whole package was on.


I say if you planning on a new exh next any how then I would leave the custom xover in place until you get the full exhaust on. I would run 2" from each head down to the cat and then merge everything to a single 2.5". The stock xover pipe is like 1.625" if i remember isnt it? You also need to reset the ecu to learn the changes. I honestly dont see how eliminating that xover could be a bad thing. Keep in mind exhaust systems are tuned and by changing only the xover you have probably taken that tiny exh system out of tune. The downey headers use 1.4" tubes for each cyl merged into a 2.5" collector for a few inches then back to a 2" head pipe for the trip to the junction before the cat. Find a friend with a welder and play around with it. If you where local Id say bring it over and we could coe up with some new pipes and weld it up to try.

Doc279

Thanks Ganoid - I wish I was closer too. I have not re-set the ecu
do you mean just unhook the battery ? explain a little better.

The custom cross-over pieces cause the exhaust to buzz when accelerating and the sound is annoying. The engine power is sluggish as well - I've driven it back and forth to work now for over 200 miles. I really don't want to sink more money and get nothing from it. I really did not expect anything more than better throttle response and possibly another mpg.

My runner does not have a cat - never has since I've have owned it.
Testing is not required in Tennessee. Don't blast me - I just never got around to getting one.

frankenrunner

o'kay, now while i do not have an actual picture of the overall exhaust system(only sections), i do not understand why everyone wants to hang onto the actual cause of the problem, i.e., the infamous "crossover pipe".
why not simply remove it & plumb the "Y" off of either side of the existing exhaust manifolds (you know, use them like as though they were the "headers" that they are), salvaging the xover pipe mounting flanges, if need be, for welding onto the new pipes to insure mating w/the existing exhaust manifolds???
then, since the ox sensor is, apparently, also an issue for the emissions 'puter & the overall performance of the vehicle, why not cut the section of the pipe that contains the ox sensor & move it to ,say, 6" past the junction of the "y'd" pipes from the headers & "sleve" fit it to the exhaust pipe going to the cat &/or muffler??
that way, basically everything "stock" is there & where it needs to be so there's no major adjustment that the system needs to go through to accomodate the conversion/upgrade.
whaddayathink??!??

Eric

I think you are thinking correctly

Doc279

Over the weekend - I removed the custom system and replaced the original
cross-over pipe. My power is back.

I considered spending some more money on the larger pipe and flow master 50 muffler but ultimately decided to go back to the way it was from Toyota - less the cat. I never really had any problems before - I just tried this
cross-over elemination without spending $800.00 on headers and exhaust.

I had hoped the removal of the cross-over pipe would allow the engine to breathe and run a little better. It made it worse.

frankenrunner

hey to all on this thread:

i've noticed some exhaust system parts (i.e., manifolds, crossovers, etc.) being offered up & tossed about...if they're still available, i'd apprerciate them being sent my way so that i could have the actual components in front of me to scratch my head over to see what i could come up w/that addresses the burnt #6 & performance problems to pass along to the members, once i've got something conclusive (i just "know" that there's a "fix" here somewhere!)
figured out.

pm &/or post me back for donations(parts) &/or details(shipping info) if they're still available.

frankenrunner

Doc279

I'll sell you the already modified parts to fit - e-mail me at dstaley@searay.com and I'll send you pictures of the set up. I have a total of $100.00 in the set up. The driver side was capped off - simple enough
but the passenger side had to be heated and bent 3 different times to clear everything - the passenger side already has the pipe welded to it that drops down - comes back to behind the transfer case and crosses over to join the
exhaust pipe - I cut it loose at the weld with a saws all and welded the hole back up in the pipe.

DMG

Doc279, I bet the reason you lost power is because you didn't have any supporting mods. I made a y pipe on my 88 and turned up the AFM, advanced the timing, added k&n, cat back, high flow cat and disconnected the egr. I have 4.30 gears and 33 inch MTRs on a 230K mile motor and use overdrive on hills and have enough power to do donuts (barely) on dry pavement. It is not fast but good enough that I am in no hurry to regear.

frankenrunner

rivercat, i'd like to get ahold of your extra exhaust set up to do a little frankensteining on.
how can we work out getting them to me??

frankenrunner