BJ74 3'' Exhaust

[torqueluvr]

The elbow on my downpipe is slowly disappearing.

Anyone know where I can get a 3" exhaust flange for the 13BT. I've been told I can grab one off a supra but I'd like to buy new and do things right.

I'm gonna run an entire 3" system, install a pyro, and tune the fuel all at the same time - boost gauge already installed.

Any leads on the flange/downpipe would be great.

Tanner

 

[ForealBoreal]

I am curious to see what you come up with .

You could spend big dollars on one from aus but in my eyes you should just get one fabricated here

Stainless? If you get the flange cut out done at a water jet place I would buy two depending on the price.

 

[lumpy70]

I bought a BEAUTIFUL stainless flange and 3" dump off ebay from a 7MGTE (Supra) for my BJ74.

I still have it...as the 13B-T is too close to the firewall for the dump. The engine needs to sit forwards about 2", or it needs to be modified.

So basically, it's a big sweeping 3" dump which sticks out too far.

 

[gotoy]

I am curious to see what you come up with .

You could spend big dollars on one from aus but in my eyes you should just get one fabricated here

Stainless? If you get the flange cut out done at a water jet place I would buy two depending on the price.

Agreed.

 

[Whistler74]

These look nice, and from Vancouver:

BIC Performance Products

 

[ForealBoreal]

If anyone knows if there is a STAINLESS version already made up on the exhaust dump flange please link it up.

 

[torqueluvr]

If the 3" is out of the question, does anybody know the diameter of the stock down pipe? is it 2.5"? My stock exhaust is tiny, just under 2" I think. I need to redo the exhaust soon and I want to do it right, but not go crazy. So, if by installing 2.5" will 'open' it up without modifying or purchasing a $300 chuck of metal, that's what I think I'll do.

What's the largest I can go without modifying? What is the stock downpipe flange size? There's no point going wider pipe than the flange, correct? IE going 3" pipe if the flange is only 2.5".

I'm thinking of exiting infront of the right rear tire.

T

 

[ForealBoreal]

stock is 2.5 inches. You could run a better more straight through design.
Should be a pretty standard three bolt pattern at then end of the ct26 cast dump pipe.

 

[torqueluvr]

Thanks Foreal. I think I've changed my mind to 2.5 straight pipe exiting in front of the rear right tire.

 

[Hulsty]

I made my own dump pipe, bought a laser cut CT26 flange, mild steel something like $30 and made my own 3'' system, plenty of room to make one.

 

[Whistler74]

Stock pipe on a BJ74 is almost 2" diameter. I made up a 2.5" system following the original routing (more or less) with a magnaflow muffler using mandrel bends from Lordco. Very fiddly process, made even trickier by not having a good space to work in, not having all the right tools and not having much in the way of welding or fabricating skills. It did work out ok though. It definitely does breathe better (even better than the previous 2.5" crush bent system that fell off after 2 years). I just cut off the stock downpipe and made a reducer to adapt it. I don't think the 3" long by 2" section will flow that much.

The dump pipes I linked to previously would be pretty nice if they would fit.

 

[Hulsty]

Mine was routed inside the chassis rails

 

[Glenn-BJ74]

I was originally thinking 3", but I have talked to many and the increase in cross-sectional area from the stock 2" to 2.5" is considerable and results in a good performance gain. Unless you have a body lift it would be very tough (costly) getting a 3" exiting out the back. The manifold diameter is another constraint.I would not consider a side exit- the drone on the highway gives me a headache.

 

[mattarch]

I was originally thinking 3", but I have talked to many and the increase in cross-sectional area from the stock 2" to 2.5" is considerable and results in a good performance gain. Unless you have a body lift it would be very tough (costly) getting a 3" exiting out the back. The manifold diameter is another constraint.I would not consider a side exit- the drone on the highway gives me a headache.

Hi Glenn,

I've got a stock BJ70 with a few holes developing im my exhaust system... So either i can replace with 2inch or go upto 2.5inch for more performance.

My question is... how far do i need to go with the 2.5inch pipe to provide the extra performance? would this include replacing the manifold?

Matt

 

[prado t]

Not completely 3" but works very well . It still looks like this almost 4 years later. From "bell mouth" to tail pipe. Unless you have a 13B-T that uses 25lbs boost and puts out 200hp a 3" exhaust is not feasable.

 

[ForealBoreal]

does that quick dump flap work?

 

[Hulsty]

Unless you have a 13B-T that uses 25lbs boost and puts out 200hp a 3" exhaust is not feasable.

 

[prado t]

does that quick dump flap work?

Most situations the dump will bring down the EGTs 200F

When Im travelling with other vehicles it stays on .

4 cyl diesels sound like garbage unmuffled

 

[prado t]

Ya I get that all the time ! Thats how people wave to me out this way.

 

[torqueluvr]

I have decided to do 2.5 inch side exit with a free flow bottle muffler. My question is, how do I adapt the old flange on the 2inch pipe to the new 2.5inch.?

Can I just take the grinder to it and 'relieve' it from the 2", then weld that same flange on to the new 2.5inch downpipe.

I'm going to mimic this style, post #9

https://forum.ih8mud.com/diesel-tec...one-running-short-passenger-side-exhaust.html

making sure that the side exit is pointing down, but not melt the tire.

So, can I reuse that old flange off the existing downpipe? Here are pics. I will be putting in a flex pipe as well.