6.9 Exaust - Ford Truck Enthusiasts Forums

Pre-Power Stroke Diesel (7.3L IDI & 6.9L) Diesel Topics Only

6.9 Exaust


Old 03-09-2018, 11:14 AM
Julian Kalamaha's Avatar
Julian Kalamaha
Julian Kalamaha is offline
New User
Thread Starter
Join Date: Sep 2017
Location: Ward County, ND
Posts: 21
Julian Kalamaha is starting off with a positive reputation.
6.9 Exaust

I got a 1986 f250 6.9 ext cab and I want to put a new exaust system on it. I know there isn't much out there for bigger exaust for the 6.9 but do you think it would be cheaper to go to a preformance shop and make pipes for my truck or to buy a hypermax or one of the few ones out there. Also what would you suggest for headers to buy that would be the best preformance wise. Thanks
Reply With Quote
Old 03-09-2018, 12:10 PM
Olds64's Avatar
Olds64 is offline
Elder User
Join Date: Jun 2017
Location: Edmond, OK
Posts: 699
Olds64 is starting off with a positive reputation.
Julian unless there's a good exhaust system I'm not aware of, I suggest you go to a local muffler shop. The owner can give you advice and exhaust shops usually carry "house brand" mufflers which will save you some money.

I know there are headers available for the 6.9l and 7.3l IDI, but I'm not sure who makes them. I've read that they have fitment issues. Hopefully someone else will chime in.
Reply With Quote
Old 03-09-2018, 06:46 PM
Charmalu is offline
Senior User
Join Date: Sep 2016
Location: Nevada
Posts: 269
Charmalu is gaining momentum as a positive member of FTE.
Old 03-10-2018, 10:36 AM
Macrobb's Avatar
Macrobb is offline
Join Date: Dec 2011
Posts: 3,679
Macrobb is gaining momentum as a positive member of FTE.
Aside from replacing a plugged muffler with something better, you aren't going to get any noticeable performance gains from a 'performance' exhaust. It's just... not that much a restriction.
The limiting factor with an IDI is air in. Simple as that. Once you pass 'peak torque' at 1600RPM, the engine is drawing a vacuum and pulling less and less air per revolution, which means less and less power(per rev - less torque). This is why the torque curve peaks at 1600 and then drops above that.

If you want better performance, there's one good way of doing it: Add a turbo. Simple as that.
If you add a turbo, you just add power, period.
The limiting factor on a 6.9 with a turbo is head bolts(blowing a head gasket), so if you want to push more than, say, 6PSI of boost(effectively adding perhaps another 50HP or so), you need headstuds.

(Note that if the fuel system is worn out, has been in there for over 100K, installing a new IP and injectors will net you some gain, up to near stock performance).

Installing a turbo is one of those things that you think "Eh, really? It's expensive, a pain to work around" etc... Until the day you install one. Then, you can't live without it.
Reply With Quote
Old 03-10-2018, 08:31 PM
cadunkle's Avatar
cadunkle is online now
Posting Guru
Join Date: Oct 2005
Location: NJ
Posts: 2,117
cadunkle has a good reputation on FTE.cadunkle has a good reputation on FTE.
I was in a pinch for time when my exhaust was falling apart. My downpipe off the turbo was good but everything after that has rotted out and fallen off. I wanted a striaght piece of 3" pipe about 8' or however long to before the rear wheel, and a 90* bend right in front of the wheel. I stopped by a local shop and asked for that in 3", they said $700... I said that's insane for one clamp or weld at the front, a 90* bend, and possibly a second joint if too long to do in one piece, and 2-3 hangers. Ordered a length of 3' pipe, mandrel 90*, and a chrome tip off Summit along with some clamps and ahngers and did it myself for under $100.

Yes headers are available for these engines. If you are really adament about staying naturally aspirated go ahead nad get them adn do a dual 2.5" system preferably with a crossover. It will help, but nothing compared to a turbo. For what an exhaust shop would charge you for a new exhaust you can get a used "stock" turbo (i.e. one of the 3 bolt on kits). Just get a turbo and be done with it, you'll just have to rework the exhaust later when you get one, so now if the time to start looking.
Reply With Quote
Old 03-13-2018, 11:31 PM
hairyboxnoogle's Avatar
hairyboxnoogle is offline
Post Fiend
Join Date: Apr 2008
Location: Jordan Valley, OR
Posts: 6,428
hairyboxnoogle has a good reputation on FTE.hairyboxnoogle has a good reputation on FTE.
As i recall a thread on OB, the headers do not really gain you anything, the results were well within the dynos margin of error. The reason is quite simple, the cam in the IDI is so tame, there isnt enough overlap, nor the rpms, to have any real effect on exhaust scavenging. Dual 2" with a free flowing muffler will be more than adequate. As others have mentioned, the best exhaust upgrade there is, is a turbo.
Reply With Quote
Old 03-13-2018, 11:38 PM
Skip1970's Avatar
Skip1970 is offline
Post Fiend
Join Date: Nov 2008
Location: Alaska Land of the Free
Posts: 14,136
Skip1970 has a superb reputationSkip1970 has a superb reputationSkip1970 has a superb reputationSkip1970 has a superb reputationSkip1970 has a superb reputationSkip1970 has a superb reputationSkip1970 has a superb reputationSkip1970 has a superb reputationSkip1970 has a superb reputationSkip1970 has a superb reputationSkip1970 has a superb reputation
i always run straight pipes on my 6.9 they sound great
Reply With Quote

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.