RJC downpipe

G

garrett

Member
Joined
Oct 28, 2006
I just installed a RJC 3 inch downpipe and it looks beautiful. It concerns me alittle that it makes light contact with the frame just below the starter. I have to drive it to see if it screws with the knock sensor. I hope it doesn't set it off. I guess my only options would be to dimple the pipe or install some different kind of motor mount. Right now I have the stock motor mounts with less than 5000 miles on them(4 years old). Is it normal for them to touch the frame? Input appreciated.
 
It shouldn't touch the frame. You're right about either dimpling it or mounts. I would call rjc and ask them if it's common to have to dimple their pipes. Maybe one just slipped through QA that was a little off. Or maybe they designed the pipe with different engine mounts. On that note I would try HR mounts before I beat on a pipe that expensive. Trust me even new stock mounts are a joke. The HR's sit the engine up a litte and actually hold it in place.
 
My dads car was same way With RJC we loosen bolts on down pipe raise the down pipe and tighten bolts back up , it cleared the frame then , you could try that ?
 
I have fit many RJC DP's and not had any problems with frame interference, and NEVER had to dimple the pipe.

If this is the case, your headers or turbo is causing the pipe alignment to be different. I have seen many turbo exhaust housings that have had the bolt pattern slightly off from a stock Garrett housing.

Also, aftermarket headers can have the turbo mount flange slightly moved, and of course the frame/engine relationship can have a wide tolerance.

Simple cure is to elongate or enlarge the holes in the DP or in the turbo mounting flange to allow the DP to be moved for proper clearance.
 
header

Running a set of Postons headers and a Precision exhuast housing. They are not exactly the same as stock. I'm waiting to hear from HnRparts to see if he thinks his motor mounts would give me the clearance I need.
 
No it should not hit the frame. I ran that pipe with the stock headers no problem with HR parts mounts on both sides. Also check the test pipe and cat mount to make sure its in the right spot to line up- maybe that's pulling the pipe down to the frame?
 
I just got my dual 3" Gbody exhaust installed from my friends shop and with the new exhaust, My DP also now touches the frame and squeaks like mad!. He said the exhaust was extremely tight to go around everything and it's probably weighing the dp down and pulling it onto the frame. You can't really ajust the exhaust much as there isn't any room to move it lol. I may try a set of HR mounts to see before I have to dent the pipe. :(
 
My 3" RJC pipe fits perfect, but it has problems if the exhaust hanger off the back of the tranny isn't run. I had to put a new one in and readjust the exhaust after letting it hang too long in the middle. I have the hooker cat back fwiw.
 
dp and exhaust adjustment

Well I shortened the length on the exhaust hanger on the rear of the tranmission and loosened the bolts on the downpipe and placed a jack under the downpipe where it meets the rest of the exhaust. I then tightened the downpipe bolts and removed the jack. I now have a slight space between the frame and DP- about enough to slip a piece of paper by. I'm sure this will not be enough when the engine rotates on torque load. I guess I will be ordering a set of H&Rpartsnstuff motor mounts. This seems easier than taking the DP off again and drilling out the holes in a thick flange stainless steel piece of metal. Plus I don't want to mis-align the puck to the hole by moving the DP too much.
 
My new mounts will be here tomorrow. I just did the springs and shocks in the back today and wowzers, what a difference! I have a whole new front end to do as soon as soon as all my stuff gets here.

I'll let ya know if the engine mounts make enough room as it looks as though we are having the same problem.
 
I installed both poly motor mounts and tilted the engine to the driver's side a bit. I now have the proper clearance between the downpipe and frame (about a quarter of an inch). I think I will now have to modify my turbo shield because it sits so high that it will probably burn the hood insulator. I have an aluminum DC tech turbo shield. It's a chain reaction thing I suppose. The HNRPARTSnStuff motor mounts are really nice. It took me six hours to do by myself in my garage.
 
Put the car in gear and load of the engine and see how much it DOESN'T move with those mounts! It really is incredible. Another thing that makes a big difference is replacing the factory rubber body mounts with poly mounts. It will give you more clearance allot of places and it will tighten the car up allot.
 
garrett said:
I installed both poly motor mounts and tilted the engine to the driver's side a bit. I now have the proper clearance between the downpipe and frame (about a quarter of an inch). I think I will now have to modify my turbo shield because it sits so high that it will probably burn the hood insulator. I have an aluminum DC tech turbo shield. It's a chain reaction thing I suppose. The HNRPARTSnStuff motor mounts are really nice. It took me six hours to do by myself in my garage.
Click to expand...

I just received my HR mounts today and plan to install this weekend. I saw that it took you a while to get them on. Do you have any tips or suggestions that may help when I do the swap? Not really looking forward to a 6 hr project.:eek:

thanks for the help!:)
 
I made my own tool by cutting the shank on the 3/8 inch hex socket I had. You can purchase one from HnRparts if you don't want to be bothered. I had to remove the shrouding around the intercooler, unbolt the coil pack base from the intake, and remove the return fuel line. This allowed me to hook a chain to the corners of the intake and use an engine hoist to raise the engine approximately one inch. From there, just follow the directions. I didn't think it was too bad considering I don't have a lift. I could not use a jack on the balancer since I am running RJC's aluminum pulleys.
 
The shield will have to be cut!! You can check out the for sale section I seen one for sale not to long ago!! Or post for one in the wanted section I think you'll get a fairly quick response unless you wanna chop yours!!:sneaky:
 
You must log in or register to reply here.

Similar threads

6gunn
knock from valvetrain
Replies
16
Views
596
6gunn
6gunn
J
Found an 87 GN that has been sitting for 10+ years in storage..
Replies
10
Views
575
granitestategn
G
T
Stuttering after warmed up and driving
Replies
7
Views
390
Turbo6BK
T
TireFryer
  • Sticky
Body to frame alignment
2
Replies
20
Views
3K
earlbrown
E
C
Downpipe Strain on Turbo
Replies
6
Views
1K
Mr.Spool
M
Top