240 turbo conversion - down pipe didn't fit!?!

I got turbo parts from a 740 to install on my 245 including the down pipe. I got the turbine in today but the exhaust down pipe didn't fit. I've read that one can make the 740 down pipe work on a 240. In my situation the pipe hits the firewall before it mates flush with the turbine flange. I don't have a 240 turbo down pipe nor do I want the cat in that location. The only thing I can think of is to have the muffler shop bend the 740 pipe a bit more to make it fit. What have others used when the converted their 240s to turbos?

Cut at least 1" out of the downpipe between the turbo and the first bend. I used a 740 downpipe on a T3 turbo in my 87 240 by removing a small section of pipe before the first bend. Some people say it fits, but I think that's only on the Mitsubishi turbos. With my Garrett, I could get the pipe on only if I had it angled down a LOT, and it was still resting against the firewall.

Yeah I had the same thing happen with I did a 740 T3 downpipe on an early 244. I just ended up having a new downpipe made for that car.

Great feedback! Thanks for sharing your experiences. I will look at both these options. I will goo with cutting out a 1" section if making a new down pipe is a bit too expensive.

i just bolted up a 740 downpipe and just had to use a squish gasket to close the gap between the turbo and downpipe when the downpipe was mounted to clear firewall and tranny bolt.

Xman said:

Great feedback! Thanks for sharing your experiences. I will look at both these options. I will goo with cutting out a 1" section if making a new down pipe is a bit too expensive.

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Yo mate! Here is what I did some time back.

http://forums.turbobricks.com/showpost.php?p=509304&postcount=25

Just some quick detail:
1) The section I cut out was angled! The cuts were not horizontal to the opening of the dp.
2) The section I removed included the OE lambda port. Notice I moved it to the top.
3) Getting the flare section lined up correctly is very tricky.

Good luck.

towerymt said:

Cut at least 1" out of the downpipe between the turbo and the first bend. I used a 740 downpipe on a T3 turbo in my 87 240 by removing a small section of pipe before the first bend. Some people say it fits, but I think that's only on the Mitsubishi turbos. With my Garrett, I could get the pipe on only if I had it angled down a LOT, and it was still resting against the firewall.

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it certainly does not fit with the mitsu turbo either, not without modification.

Hey BDKR, how much of that 100% paulnewmans grape juice did you have to drink to get that to work? looks pretty empty....lol

stevo said:

Hey BDKR, how much of that 100% paulnewmans grape juice did you have to drink to get that to work? looks pretty empty....lol

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L0LZ! It worked perfectly straight out of the gate. I only went to the welders once.

I really don't understand the vary degrees of success people have had with this.

ya i needed no modification just that squish gasket. took some time though. ill post a pic today if i can.

i took out 2.5", using a mitsu TD05-12B. it's very tight. if i do this again, i'll take out at least 3".

also, the exhaust mating surface on the 12B is very close to/in exactly the same location as the mating surface of the Garrett T3 that used to be in my car.

hth,

Well, I contacted a muffler shop and it looks like cutting an welding will be an inexpensive way to go. The guy at the mufler shop said that, with he turbo, I probably won't need a cat to pass inspection because it will run that much hotter and bur clean. Do any of you run without a cat and pass inspection?

BDKR said:

Yo mate! Here is what I did some time back.

http://forums.turbobricks.com/showpost.php?p=509304&postcount=25

Just some quick detail:
1) The section I cut out was angled! The cuts were not horizontal to the opening of the dp.
2) The section I removed included the OE lambda port. Notice I moved it to the top.
3) Getting the flare section lined up correctly is very tricky.

Good luck.

Click to expand...

I wanted to add more so when others do their turbo conversion they can reference this!

For my installation, BDKR's comments were right on and then some. Fitting the down pipe has been the hardest and most time consuming task so far in this project. I cut a 2-inch section out right where the O2 sensor was and thought I'd be covered. Not even close!! When BDKR says the cut is angled I really didn't comprehend what he meant until I did it myself. I don't know if the engine sits different in a 240 than a 740 but the cut on the pipe has to be angled to rotate the pipe in and down more - just to clear the frame and transmission - forget the firewall being the problem!! It is a multi-dimensional clearance problem and I'm basically hand fitting the exhaust system with a grinder and a file. I wanted to have a flange at the end of my header pipe to mount a stock cat so I needed two 740 down pipes. Once you cut the front section out and then angle it down and in, the pipe is too short - it ends before or right at the transmission cross frame. Thus, I've cut the 1st down-pipe mid-way down the lower horizontal section and the second one further up and am having the two welded together to make the new piece long enough to extend beyond the transmission cross member. Then, one of the 740 down-pipe has the 3-hole clamp ring welded to the flange and the other one doesn't. If you get one that is welded, you have less to "play" in adjusting the pipe to fit into the tunnel next to the transmission. Good luck when you start this task. Patience is key!!!

I didn't have nearly that much problem with the stock 740 downpipe. We cut about 1" out of the pipe before the first bend. Since the flange on the turbo is conical, there's quite a bit of range of motion for the downpipe to move around to find the best position.

It's probably best to tack weld it back together while it's on the car to make sure it fits before welding it completely. If you just cut out a section and welded it back together, I could see that potentially not working out.

I'm trying to get the lower horizontal section of the down pipe to be positioned in the middle/parallel in the small space between the transmission and the unibody frame on the passenger side of the transmission tunnel without hanging too far down below the car. I thought of an idea this morning. I'm going to use bailing wire to hold this lower section of the down pipe in the position I want it, then fit the two cut pieces so they are touching and angled in the right position. I will then apply masking tape to hold the cut end of the down pipe to the cut flange section at the turbine exhaust. I can then use a razor blade to cut the masking tape along the edge of the down pipe. This will give me a pattern to measure back from to make a matching cut on the short flange section to give me the correct angle instead of estimating, grinding, and filing like I'm doing now (too time consuming). I don't have anything to do a tack weld with so my fitting has to be right the first time when I take it to the shop to get welded.

Success!! The idea of using the masking tape paid big dividends. It took me a couple of hours to accomplish what I had failed at for two days. Every cut was right on the first time. I did make two trips to the welders. After I aligned the cut section at the turbo exhaust, I took it down and had it welded. There is so little room to fit the pipe that I didn't want to be off by trying to align the horizontal piece with only masking tape holding the first joint together (it still flexes). Holding the first cut section with bailing wire sort of worked but I also used some 1/2 inch thick construction foam pieces inserted in key locations to ensure I got the clearance I wanted. After the first section was welded, I bolted it to the turbo and now had a steady position to fit the extension to get the flange on the other side of the transmission cross member. I added a picture to show how this fit and the way the masking tape template worked. Again, position the pipe where you want it, make sure at least one part of the two edges are touching, tape it up with 3 layers of masking tape, then with a sharp razor blade cut along the edge you want to mate with. Now you only have to measure back to match the edge of the cut tape and cut to match.

With the flange at the end of the down-pipe, you know have the option to fit a 740 cat or a universal one. If either way you need the 240 turbo extention piece that connects to the down-pipe. They are inexpensive. You just cut it up and weld in the cat. It should be noted that I borrowed a friend's power grinder and right-angle rotary saw with a metal cutting wheel. These to items were also key to accomplishing this task. I would have hated to try and do the cuts with a hacksaw. Oh, because the pipe comes close to the transmission lines running up the tunnel to the radiator, I'm going to thermal wrap the pipe using the 2" wide 50' tape held on with hose clamps at each end.

You can also see I cut the "s" out of the tail pipe and welded on a section out of the down-pipe. Because I used two down-pipes, I took the aft end that was scrap and cut it just above the bend so I could angle the tail-pipe down some to give more clearance to my trailer hitch. Go Luck and hope this helps make your project easier.

These two shots show where the cuts were taken and the angle changes required. I even had to do about a 5 degree jig going into the cat

I have just over 2" of clearance to the back firewall which was what I was shooting for. That's the good news. Today, I found that the 1990 and later oil filter adapter that repositions the filter aft and runs lines forward to the oil cooler doesn't have enough room to install because the new filter position interferes with down-pipe. FYI.

Two things.....

1) Use these....



2) About this ...

Xman said:

Today, I found that the 1990 and later oil filter adapter that repositions the filter aft and runs lines forward to the oil cooler doesn't have enough room to install because the new filter position interferes with down-pipe. FYI.

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Yeah, that can be tricky as hell. It was for me. I'm sorry I didn't mention it as a matter of fact. Would've saved you some time.

Anyway, mine did fit, but I'm sure that it had something to do with variances in our final product. Now it was some work come time to change the oil. Basically, I had to loosen the dp to gain the extra clearance to pull the filter off.

I would go with a remote setup.