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2000, 7.3, Zf6, 4" turbo-back, flow-thru muffler, PHP Hydra, IDM delete, EGT, Boost, H20
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Discussion Starter · #1 ·
I'm installing a 4" exhaust on my 2000 F250, 7.3.
Here's the info:
Diamond Eye 4" Aluminized Turbo Back Single Outlet Exhaust 00-03 7.3L Ford Powerstroke K4318A

I believe I may have to cut or bend a portion of the sheet metal flange at the firewall out of the way to get the 4" pipe from the turbo into position. I've moved it a tiny bit with a hammer but there's not enough room for a good swing. I also tried to bend it with a crowbar and block, but it won't budge. Does anyone have any pointers on this?
The truck is a manual transmission if it matters.
 

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It's been a while since I put a 4" turbo back exhaust on my truck, and I don't recall having to bend any sheet metal. It did take a little jockeying to get the downpipe in the right position.
A friend has done them on OBS trucks and uses a porta-power for the firewall mods needed on those.
 

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2000, 7.3, Zf6, 4" turbo-back, flow-thru muffler, PHP Hydra, IDM delete, EGT, Boost, H20
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Discussion Starter · #3 ·
I'm installing a 4" turbo back exhaust. Here's the info from the order:
Diamond Eye 4" Aluminized Turbo Back Single Outlet Exhaust 00-03 7.3L Ford Powerstroke K4318A
The kit includes the straight-thru muffler.


As with many others, I'm having a tough time getting the downpipe up to the turbo. It appears that the flange on the firewall may need to be cut out or bent over. I tried to bend it with a small sledgehammer but there was no room to swing it.
I've watched plenty of videos and read quite a few posts but haven't found anything specific.
Here's a shot of the problem flange (circled in red). The blue circle is the area that seems to be causing the issue.

Automotive lighting Hood Motor vehicle Automotive tire Automotive design


Here's another shot showing the pipe hitting the firewall flange.
Hood Automotive tire Automotive lighting Bumper Rim


When the pipe hits the firewall crimp flange, it still needs to rotate about 45 degrees before I can hopefully get the other end over the transmission cross member.

I also haven't removed the heatshield and would rather not for obvious reasons. If I have to remove it, I will but will wait to hear from those with more experience.

Any pointers would be appreciated. My truck is down till I get this all installed.

Thanks.
 

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2000, 7.3, Zf6, 4" turbo-back, flow-thru muffler, PHP Hydra, IDM delete, EGT, Boost, H20
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Discussion Starter · #4 ·
Thanks for the reply. I posted again cause I didn't see my first post - thought maybe I forgot to hit the button :oops:

I don't have a porta-power. Maybe I'll try to cut some slots with a cut-off wheel so I only have to bend each small tab over. I've tried every angle and it simply hits the flange no matter what. My fear is that even after chopping, it still may not fit.
 

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Your second post was in the Engine & Drivetrain Forum. I've moved it to this thread.
 

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2000, 7.3, Zf6, 4" turbo-back, flow-thru muffler, PHP Hydra, IDM delete, EGT, Boost, H20
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Discussion Starter · #6 ·
Thanks for moving the thread kl.
I did slice through the flange with a cut-off wheel on a 4" angle grinder in about six places. It's a very dangerous job and I shattered two discs in the process. The flange is less in the way but still an issue. I purchased a porta power kit and should have it on Tuesday. Also, have a Hydra Chip on the way. The combo EGT, Boost, and the water temp gauge is in and working dandy. BTW, what is an "OBS truck"?
 

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Thanks for moving the thread kl.
I did slice through the flange with a cut-off wheel on a 4" angle grinder in about six places. It's a very dangerous job and I shattered two discs in the process. The flange is less in the way but still an issue. I purchased a porta power kit and should have it on Tuesday. Also, have a Hydra Chip on the way. The combo EGT, Boost, and the water temp gauge is in and working dandy. BTW, what is an "OBS truck"?
OBS = Old Body Style = pre 99 F250s.
What gauge kit did you get?
 

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2000, 7.3, Zf6, 4" turbo-back, flow-thru muffler, PHP Hydra, IDM delete, EGT, Boost, H20
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Discussion Starter · #8 ·
Thanks, Jim, my truck is a 2000 so I guess it's not an "OBS"? It does have a manual trans though and from the piles of posts I've read, that's part of my fit issues with the downpipe. As for the gauge, I went with the Glow Shift 3-in-1 gauge. I know it's not the best quality-wise but I didn't want three separate gauges, a pod, and another 400+ bucks. The gauge seems to work fine - time will tell. I did a quick test run and EGTs hit 800 with my foot to the floor - not towing an empty truck.

From all the posts I've read on the fit issue (and there are plenty), it may be due to old, mashed cab rubbers. I can replace them to gain some room, take a ball peen hammer to the downpipe, reinstall the stock downpipe and adapt it to the 4" once I'm clear, or massage the firewall with a porta-power. I have a porta-power on the way. The Amazon ad said it would arrive Tuesday - now that it's ordered, they said Wednesday :rolleyes:

I have also read that the 4" downpipe will reduce off-the-line torque and that the stock downpipe is fine as long as the rest is 4" with a flow-thru muffler - you still get much lower EGTs. The 4" seems really tight and I may put the stock one back in because of this. I don't want any rubbing and I don't want to remove the heatshield - so the stock pipe is looking better all the time.

Has anyone had to remove the heatshield (the one attached to the floor) to get a 4" downpipe to fit?
 

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There is a reason, at one time long ago (12 years or more) that most of us went with the 3.5" downpipe to a 4" exhaust. You now know what the reason was. I have no advise other than bend the flange on the firewall. We use t use a long bar ad a sledge hammer to bend it downward.

Added on edit; This is the first time I have logged back in here in over 10 years. I just read my signature, I need to change it as I just bought a bone stock 2002 F250 PSD.
 
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2000, 7.3, Zf6, 4" turbo-back, flow-thru muffler, PHP Hydra, IDM delete, EGT, Boost, H20
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Discussion Starter · #10 ·
There is a reason, at one time long ago (12 years or more) that most of us went with the 3.5" downpipe to a 4" exhaust. You now know what the reason was. I have no advise other than bend the flange on the firewall. We use t use a long bar ad a sledge hammer to bend it downward.

Added on edit; This is the first time I have logged back in here in over 10 years. I just read my signature, I need to change it as I just bought a bone stock 2002 F250 PSD.
Thanks, beantown and welcome back. Also, congrats on the new to you truck.
Are you one of those who feel that the 4" off the turbo reduces low-end torque? My reason for doing the 3.5 to 4" pipe is for towing and lowering EGTs after installing a Hydra chip. The last thing I need is reduced torque. I have a porta-power (with wedge attachment) on the way. However, it's so tight that I wonder if massaging the firewall will be all I need to do.
Because I can't get the 4" into place, it's tough to tell if I will also need to remove the stock heatshield as well as other mods.
 

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On a bone stock truck and stock tune, the 4" exhaust may seem very slightly more sluggish (guessing?). However, with the hydra chip, 4" exhaust, and stock turbo (assuming here), the turbo will light basically instantly. You will not believe the difference with hydra tunes. I had an SCT programmer for 10 years on about a "75 hp" tune and then switched to hydra and it even blew that away. Stock to hydra is incredible leap in performance, especially for $350.
 

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Discussion Starter · #12 ·
mc, looking forwards to the Hydra. Should be here in a day or two. PCM is ready to take it. I'm dead in the water though till I figure out a solution to the downpipe. I may just put the stock 3" back in and go to 4" from there.
 

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Thanks, beantown and welcome back. Also, congrats on the new to you truck.
Are you one of those who feel that the 4" off the turbo reduces low-end torque? My reason for doing the 3.5 to 4" pipe is for towing and lowering EGTs after installing a Hydra chip. The last thing I need is reduced torque. I have a porta-power (with wedge attachment) on the way. However, it's so tight that I wonder if massaging the firewall will be all I need to do.
Because I can't get the 4" into place, it's tough to tell if I will also need to remove the stock heatshield as well as other mods.
I can't say on the torque part as I had the 3.5" downpipe. I will say I never heard someone complain about the torque from a 4" downpipe either. And I can't for the life of me see how the 4" would affect torque. What or how, does back pressure help torque on a diesel? The better it breathes the harder it will work. That's just my opinion of course. Now I did work for a Diesel Pickup Performance shop here in N.C. for 2 years but what do I know. ;):) My 99.5 was a pulling beast at 365hp and what's listed in my signature.
 

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Discussion Starter · #14 · (Edited)
Thanks, beantown. My stock downpipe is 3", not 3-1/2". My turbo outlet is about 3-1/8" . I agree, a diesel shouldn't need backpressure. Here's a quote from littlepowershop.com. "First things first, a turbocharged diesel engine does not need so much as pound of back pressure after the turbo to perform perfectly. In fact, the less restriction after the turbo, the better. You have to understand that between the exhaust port on the head and the inlet of the turbocharger there is usually back pressure of at least equal if not more than boost pressure on the engine at all times. Any back pressure the engine needs for proper function is provided before the turbo, period. Pressure on the outlet side of the turbo just leads to higher exhaust gas temps."

I'd like to get the 4" DP in there but I may have to heat it up cherry red in a few places and massage it a bit. I like the rest of the Diamond Eye system OK, but this downpipe is simply not going to fit as it is. I was also considering putting the 3" back in and cutting it about 6-8" above the lower bend (in a straight section), then adapt the 4" DP from there. A lot of work, but doable. (edit) changing the lower elbow from 3" to 4" will help as elbows are known restrictions. I guess I'll sleep on it and hopefully dream up a good solution.
 

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My 99.5 was a pulling beast at 365hp and what's listed in my signature.
Just to nitpick a little, based on your signature, you had nowhere near 365 hp unless you had bigger injectors not mentioned.
 

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Just to nitpick a little, based on your signature, you had nowhere near 365 hp unless you had bigger injectors not mentioned.
Nit pick away. I have the dyno sheet on the old computer to prove it. It was at the Northeast Powerstoke rally at Lake George. It was Bills first Tow tune and my truck was the second PCM he reprogrammed. Jodi knows the old truck as he also has that tune AFAIK. We dynoed it just as Bill showed up at the rally. First thing out of my mouth was "What part of a 60HP tow tune its this?". All the specs are in my signature. The dang truck was stupid fast with that tune. We pulled our 26' Sunnybrook to the rally with that tune. EGT's were a little hot going over Fancy Gap. Let me pick up the new truck and I'll dig up the dyno sheet when I get back Saturday.
 

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Dang. I don't think they send these types of tunes out into the wild anymore haha. I assume you are talking about Bill Cohron?
 

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Dang. I don't think they send these types of tunes out into the wild anymore haha. I assume you are talking about Bill Cohron?
That would be the one. Bill and I worked together here in NC at a diesel performance shop. In fact, Bill is the actual reason we moved here. Shortly after we moved here he went out on his own. As for that tune. He did a live tune to calm it down a bit at the rally. We had fun tuning the Ford PCM. Stuff like me taking it to a dealership to see if they knew Bill had messed with it. Giving Doge owners rides and them absolutely baffled on how fast a Stroke was. People not knowing what Bill had done and betting me I had a chip in it, only to look at the PCM and lose the bet. Fun stuff! OMG the freakin stories about the early PSD 7.3 modding, I could write a freakin book. I believe Jodi still has it and it's called PMT1.
 
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