Doing some searching on things that should and should not be done for my sc3.8 & auto trans swap. I don't like the idea of the front cylinder bank exhaust crossing over the top of the trans. Aside from the engine movement and vibration cracking the header, is there any other reason you can't run the front bank under the engine cradle or somewhere else? Thanks!
Doing some searching on things that should and should not be done for my sc3.8 & auto trans swap. I don't like the idea of the front cylinder bank exhaust crossing over the top of the trans. Aside from the engine movement and vibration cracking the header, is there any other reason you can't run the front bank under the engine cradle or somewhere else? Thanks!
What's wrong with running the exhaust crossover on top of the transmission's bell housing? The factory does that in every FWD application it put the 3800 engine in and there were never any problems doing it that way.
Would you rather run it under the oil pan so it can heat up the oil? That's what you're going to have to do if you want to run it "under" the engine/cradle because that's the only place you can run it (pretty much like it did with the stock Fiero engine).
-ryan
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I don't particularly care for the exhaust running over the tranny either, but with transverse setups there aren't a whole lot of other options (which is why I'd like to stretch my car eventually for a longitudinal swap).
As mentioned, cooking your oil isn't good either, so your only other good option would be a side exit in front of the motor.
[This message has been edited by DKcustoms (edited 03-03-2015).]
I don't know about "heating up the oil". My thought was from years of dealing with inline 4's on street bikes and fwd cars. A very small amount of company's have or would run a forward facing exhaust to the side. Most ran them under because of the direct or in-direct airflow to help keep the temps down. I know that heat can be an issue for mid-engine's and part of my build budget is for a custom exhaust.
I had thought a little about this with the 4.9 which has a similar crossover but I figured heat rises and airflow is up through the vents, so it's possibly better up there.
Ground clearance is a big issue for production vehicles. Your average driver will not be careful, and if the lowest thing in the rear of the car is the exhaust pipe, it is going to be mashed up in short order. In 2015, Fiero owners are not average drivers, and they will be concerned about potholes and driveway aprons. If you want it down there...(option B)...go for it!... You will probably want to lower the car also, so you know you will have to be an observant driver.
For what it's worth, the stock Fiero exhaust crosses under the engine on the passenger side of the cradle.
All GM transverse FWD V6/V8 engines have a crossover pipe which goes over the transmission, though. Even the stock Fiero 2.8 has this, to route the exhaust forward to the cat, and then crosses back under the engine on the passenger side, to get to the muffler and exit. This creates a longer exhaust system than routing everything off the rear side of the engine.
edit: added transverse to clarify, as I realized some FWD cars were actually longitudinal, and they wouldn't generally have the exhaust routed over top of the bell housing.
[This message has been edited by dobey (edited 03-04-2015).]
If you're concerned about engine compartment heat from the exhaust pipe routed over the transmission's bell housing, you can apply header wrap to the crossover pipe. The new "titanium" header wrap is pretty nice stuff and insulates well.
I have a turbocharged 3800 in my Fiero. I put my turbo right on top of the transmission bell housing. It is fed by a custom built y-pipe that also routes both exhaust banks to on top of the transmission's bell housing. Everything but the turbo is wrapped with header wrap. I have much more heat being put into my Fiero's engine compartment than anybody without a turbo - but I've never had a problem with all this extra heat. I did add an electric extractor fan to the driver's side deck lid vent to help extract some of the extra heat, and it does help.
As others have said, the available engine compartment space gives you little alternative for exhaust routing. So leaving the crossover pipe routed on top of the transmission's bell housing shouldn't be a deal breaker. Like I said, that's the way GM does it in pretty much every FWD V6 production car.
[This message has been edited by Darth Fiero (edited 03-04-2015).]
If you're concerned about engine compartment heat from the exhaust pipe routed over the transmission's bell housing, you can apply header wrap to the crossover pipe. The new "titanium" header wrap is pretty nice stuff and insulates well.
I like the idea of a wrap, but dose that not make the pipe rust faster?
