View Full Version : DPI SPEC I Exhaust Install - 5875
After purchasing the DPI SPEC I set-up this past December, I'm finally getting around to installing it. I'll post the progress and pictures here in this thread as I know a few others were curious about this too. It may help as a how-to for some. By no means am I anywhere close to being a mechanic so I'm learning as I go. I'm more than comfortable working on large home renos and consider myself a capable handy-man in that area, but working on cars is relatively new to me. My brother who was a Honda tech apprentice a few years back is helping me along the way as well which is great. Plus he has cool tools!
Anyway, first a bit about the car's existing system - it’s not completely stock. The PO removed everything from the Y-pipe (cross-over pipe) back and simply straight piped it and dressed it with some after market tips. Easy to remove the system from that point since it’s only a few years old and I don't have to deal with the muffler asbestos heat shield. For me, the car was always too loud for my liking and since it was missing the muffler and cat, the exhaust fumes were pretty noxious.
The front end of my car has been lowered quite a bit, so we opted to jack up the front and slide in some ramps to try and keep the car level when jacking up the back. We then pumped up the back and placed two jack stands on the engine cradle frame and left the jack in place as a safety.
First up, we removed the PO's mod from the cross-over pipe back. It came off really easy since it was a couple years old and the hardware was new.
Now the dreaded cross-over pipe and into the original stock (rusted) nuts and bolts. We tried removing the bolts from the cross-over pipe (Y end first). No luck there as everything was completely seized. Also, on top of the Y section, there's a bung and it's next to impossible to remove the top bolt because the bung is in the way. In the back of my mind was also the fact that most owners remove one of the axles in order to slide the cross-over pipe out properly. The thought of doing this really didn't appeal to me, so instead I opted to take my Dewalt saws-all and cut the cross-over pipe just before the Y end. This would kill two birds with one stone. So, being very careful not to hit anything else nearby (brake lines, coolant lines etc), I dove in and cut the pipe. It took about 20-30 minutes to cut through the whole thing - not easy at all, but worth it in my mind.
After that, we made sure to disconnect the Lambda sensor wire in the driver's side wheel well and pull it through the frame. That way when the Y end was cut and the exhust manifold unbolted, it wouldn't damage the sensor or wire. There was no way the Lamda sensor was coming out of the pipe when mounted - there just wasn't enough room to grip it. We figured the best thing would be to work on it with a bench vice.
So after that, we tackled the driver's side exhaust header. I had hit all the bolts and nuts with PB Blaster for about two weeks steady before trying to remove. All the nuts came off without an issue and we had one entire bolt come out completely - bonus! After a few careful wacks on the header, it came off without issue. Glad I unhooked the Lamda sensor since it was so heavy and dropped like a stone.
Next up I tackled the O2 sensor on my bench vice. I let it soak with some PB Blaster for a night, and tried it the next day. It came out of the bung smoothly. I'll be able to reuse this on the new DPI header.
We focused on removing the cross-over pipe next. The bolts connecting to the pass side header are much more accessible than the driver's side. The first of two bolts came off relatively easy, but the top bolt gave us some trouble. We had to use a torch to heat up the nut and it slowly came out after using a couple of breaker bars multiple times. Unfortunately the impact gun wouldn't fit in that spot so we had to use elbow grease. Once that bolt was off, my brother easily slid the cross-over pipe out and over the tranny. Since we previously cut the Y-end off, there was tons of room and no need to remove an axle.
A few nights later we turned our attention to the pass side header which is a lot more cramped because of the starter, alternator, wiring and oil filter. First there's a metal heat shield that needs to come off to get to the header and then asbestos heat shield protecting the starter and wiring.
We masked up and tackled the metal heat shield first. The shield is just clipped onto the header with spring clips. It came off after banging on the spring clips a few times. After that, we tackled the asbestos shield. That shield uses two of the header bolts for mounting, so we had to be careful here. The first one came out like butter – the complete bolt, but the second one snapped off at the header – Damn! After the asbestos one was removed we disposed of it right away. We then vacuumed all the area around it to be safe since we could see some particles floating around in the flashlight beam.
Moving onto the pass side header, we started to remove the header nuts. 4 of them came out in one piece with the stud leaving the snapped one from the asbestos heat shield and one stubborn stud. A couple of taps on the header and off it came. I used the impact driver on the stubborn stud by putting the nut back on and giving it a few cracks when it was fully on. It snapped the seal and reversed out without an issue. We tried everything on snapped stud, from heat to impact wrench and vice grips - no luck.
On the driver’s side, I was down to 4 out of 6 studs that didn’t come out. I tried the impact driver and that managed to pull out one more. We tried everything on the last 3, but no hope. I’m not going to bother with an extraction tool because of mixed results. The nice thing about the DPI system is that you can use the opposite bolt holes for mounting the new header, so I’ll just go that route. The OCD in me wants the last 4 studs out, but really it does not matter in the end (IMO anyway). If I ever have the car up in a capable shop, we can see about extracting them at that point.
Delorean Industries
06-10-2015, 03:24 PM
My staff sent off a pair of bushings and extra hardware just in case. Stay in touch and let us know if we can assist further. Most of all.... Enjoy your awesome exhaust!
Seeing everything is off and accessible, I tackled two other small jobs. My oil sender wire had been nipped by one of the belts. The wire was okay, but the black sheathing had fallen off. I cleaned the wire with brake clean and tapped up the wire and moved it out of harms way so it won't rub again. The other small job that's an option with the DPI kit if you request it is that you can replace the bumper heat shield with a new SS one. My old bumper/facia heat shield had seen better days and was heavily rusted and bent in some places. The bottom of the bumper facia looked wavy because of it. I swapped that out fairly quickly and now the bumper lies much flatter. You do have to take some care taking off those nuts attached to the bumper since the bolt studs are integrated into the facia.
My staff sent off a pair of bushings and extra hardware just in case. Stay in touch and let us know if we can assist further. Most of all.... Enjoy your awesome exhaust!
Thanks Josh - great news and much appreciated! I'm almost there on the install.
wyatt81dmc
06-10-2015, 03:32 PM
Try using left hand drill bits, it worked like a champ on my broken manifold studs. Harbor Freight sells a set for around $10.
Try using left hand drill bits, it worked like a champ on my broken manifold studs. Harbor Freight sells a set for around $10.
Thanks for the tip. We decided to move ahead with them in. It's a shorter driving season up here, so itching to get it on the road again! I may order a set this winter when my folks live in Florida since shipping rates to Canada are nuts.
Some good progress last night. We cleaned up the heads really well with a combination of PB Blaster and brake clean. Scrubbed them with a Scotchbrite pad and used some very fine sand paper on some stubborn spots. The heads are nice and flat and perfect for accepting the gaskets now. For some reason the two forward ports on both sides were really bad. I wonder if the bolts just weren't tightened enough back at the plant since the frame is in the way. Both of them looked like they had minor leaks which resulted in more corrosion build-up.
We also got to installing the driver's side header on last night. How sweet it is to finally be working with new SS parts! The new header fit in there like a glove. We also put back the oil filler tube since we removed it when the old header came off. The tube fits a bit tighter in there, but it should work okay. One thing I'm puzzled on is the Lambda sensor wire. Since it now sits farther from the original spot on the Y pipe, the wire is too short to reach the wheel well. I'll probably have to splice an extension on the wire, or find a shorter route near the spring without it getting tangled in there.
Chris 16409
06-12-2015, 05:09 PM
One thing I'm puzzled on is the Lambda sensor wire. Since it now sits farther from the original spot on the Y pipe, the wire is too short to reach the wheel well. I'll probably have to splice an extension on the wire, or find a shorter route near the spring without it getting tangled in there.
I routed my O2 sensor wire around the spring and attached the wire to the ledge of the upper spring platform. I used some of those clips the old outer door seals used to grip the door perimeter better.
I routed my O2 sensor wire around the spring and attached the wire to the ledge of the upper spring platform. I used some of those clips the old outer door seals used to grip the door perimeter better.
Thanks Chris - that's a great suggestion. I have a few of those clips lying around, so I'll try that out.
So I took Chris’ suggestion and routed the O2 sensor wire behind the spring rather than through the frame and clipped the wire using one of the spring clips. It worked well for getting it out of the way.
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Next we tackled the wiring harness on the pass side header. The wires were zip tied together and located on the outside of the frame. The SPEC I header pretty well grazes the outside edge of the frame at this spot, so we needed to tuck the two red wires away from here and push those to the front of the car. We snipped the zip ties and manoeuvred the red wires to come more from the front of the car rather than down the side of the frame. One red goes to the jumper and the other to the battery. There’s lots of room towards the front of the car by the axle since the cross-over pipe is no longer there. I zip tied the thicker battery wire further back so the slack wouldn’t get caught up in the new header.
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The brown wires leading to alternator were a bit tricky as well. The taped “Y” in that harness was fraying, so I cleaned it up and retaped the whole run nice and tight. I located those wires so that it would go up and over the header, then down against the inside of the frame, then across the bottom into the starter. That’s the only way those would work and still leave at least an inch of clearance all around.
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Up next was actually getting the header in place. If I could recommend one tip for this, I would do this install when you have the oil filter off during an oil change. It was a royal PITA to get the header in there with the filter in. The only way we were able to get it in was to NOT put the header bolts in first. Instead, we put the header in first, and then worked around the header to put the bolts in second. If you put the bolts in first, there’s no room to swing the manifold into place – at least for our install.
The brown alternator wires look like they are touching the header, but it’s an optical illusion. There’s actually about 1-2” of space in between.
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Next we tackled mounting the muffler since the cat pipes slide into the muffler on either end. First we mounted the two muffler hangers on the car along with the rubber mount inserts. TIP: don’t install the rubber mounts to the brackets first. We made this mistake. There’s not enough clearance to slide the mounts in if they are in place. Not a biggy, so we took the rubber mounts off and slid them onto the muffler studs, then held the muffler in place and bolted them into the brackets.
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2nd last step was to attach the cat pipes. We used some white grease on the pipe and muffler ends to make it easier to slide into place since it’s a tight compression fitting. We had to try it a few times to get the right angle to line up with the headers. We slid in the copper crush gaskets on either end of the header to cat pipe joints and bolted them into place.
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Last up - putting the nice polished tips on the lower muffler pipes. Again these are compression fittings, so really easy to install. I decided to angle them upwards towards the facia ever so slightly so that the tips would have a uniform gap all the way around the facia holes.
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We lowered the car, and rolled it out of the garage for starting. It fired up nicely after being up on jacks for about 3-4 weeks. Checked all those wires on the pass side and everything looked great - no burnt wires! We wanted the job done yesterday, so after working on it for 5 hours straight, it was midnight by the time it rolled out of the garage. Needless to say I couldn’t test out the full range of sound with my neighbours asleep. It was cool though as the white smoke coming from the first start made it look like a scene from Back to the Future! We took it out for a spin and it sounds amazing
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Overall, I would highly recommend the SPEC I system from DPI. It’s a nicely engineered system that was relatively easy to install. The sound of is it amazing when compared to what I had before – it’s night and day. It feels like I’m driving a total different car.
I did notice much better performance as well. Both in pick-up and back-pressure. I think because my previous system didn’t have a cat or muffler, acceleration would fluctuate sometimes (give out) because there wasn’t any back pressure on the system. I noticed right off the bat that issue is gone.
Super stoked!:thumbup2:
Mark D
06-19-2015, 01:10 PM
Nice job on the install, it looks like you were able to get the pipes really well adjusted with nice even gaps around the facia cutouts. All the little details like that really make a difference. :thumbup:
Thanks Mark. It really is a labour of love!
Riley88
06-20-2015, 07:36 PM
That looks amazing! Nice job!
Chris 16409
06-24-2015, 08:19 PM
Glad the little clips worked for the Oxygen sensor. I noticed you used Allen Head bolts on your CV Axles. That's a nice touch, I want to do that on my car too. McMaster Carr has them in stainless and plated versions. Where did you get yours? Also nice touch with the Right-Angle terminal on the oil pressure sender.
That looks amazing! Nice job!
Thanks! Very happy with it.
Glad the little clips worked for the Oxygen sensor. I noticed you used Allen Head bolts on your CV Axles. That's a nice touch, I want to do that on my car too. McMaster Carr has them in stainless and plated versions. Where did you get yours? Also nice touch with the Right-Angle terminal on the oil pressure sender.
The clips worked perfectly - thanks for the suggestion. The Allen bolts on my CV joints are courtesy of DPI. The PO brought it down to Ohio from Canada a couple years ago to have the axles completely rebuilt as well as the rear main seal. When I removed the old oil sender last year and replaced it with the late 70s Corvette cross over sender, the right angle terminal helped since the wire was short and the new sender sticks out quite a bit more from the block. I've been meaning to put a shrink wrap on the wire for more protection.
Delorean Industries
06-25-2015, 04:46 PM
Back when we were running "three shifts"
O wait nothing has changed!
I will never forget that night on this car!
Back when we were running "three shifts"
O wait nothing has changed!
I will never forget that night on this car!
Yeah the PO said you really went out of your way to make it happen in an evening so he could drive it back to Canada pretty well next day. Then you helped him near the border when the car overheated by fluke chance. Pretty awesome service if you ask me! I'm sure my car will be down to Ohio in the future for a few more items when I get around to it.
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