I am thinking of going strait pip but some one told me he knew a guy that lost power on his idi after going strait pip any one ever heard of that and how did it work for you?
Also after cutting out the mufler I am think of getting a 2 1/2'' pip and some compression couplings from the eletrical department from Home depot will that work?
Truck is a...
1991 F250 7.3 idi 175,000 miles!

 

did the 91 idi have a turbo? i know on a turbo diesel you want as least amountof restriction from the turbo back. like straight piped and bigger size pipe as for a non turbo diesel im sure its similar to a gas engine that you would need some back pressure

 

Welcome to FTE!
I have never heard of anyone losing power when going to straight pipe exhaust, turbo or non turbo. I have a 91 also but it is turbo-ed with a 3" pipe exhaust and it runs really good. The larger the pipe diameter the better generally. I would not use conduit couplings on it. Cut out the muffler and get a measurement, then go to a muffler shop and get a piece of pipe you can slip in place of the muffler and use muffler clamps to hold it in place.

 

Hey guys and thanks!
Yaa back pressure I dont want more noise and less power I need more info before the cut!

 

YouTube - Freightshaker F250 7.3L Diesel w. Straight Pipes

It's going to be louder.

 

Back pressure won't be a problem but of course without a muffler on a non-turbo IDI it will be noisier than with the muffler in place. The turbo is in essence a muffler, therefore, not as much noise when the muffler is deleted.

 

with a diesel you have to remember they love to breath more air in and out the happier your diesel is.without a turbo its gonna be fairly loud but with a turbo you will only hear the turbo spooling and a slight cackle at higher rpm's with a straight pipe

 

I am glad I did it to my 93. I love the way it sounds now. Not to mention how much better it runs. Really responsive now. It has helped fuel mileage and power pulling tractors and other heavy equipment. Easy to do and you will be impressed with the results. I promise you.

 

You don't need any back pressure at all.but the only one I straight piped was dual 2 1/2 inch pipes and I put mufflers back on it, because of the noise.
Seems like a single straight may be quieter than duals because some of these guys like them.
I think single straight with the stock even restrics them too much even without the muffler.

 

I simply cut the muffler out of my 92 NA and put in a piece of straight pipe with 2 clamps. Best $20 I ever spent. I am getting on average 3mpg more and it flat woke that engine up. Climbed some big hills yesterday going into Reno and had no problem doing 70 to 75 with plenty of peddle left to go. It's not all that loud in the cab but I did feel sorry for a couple rice burners that came up on my passenger side when I had my foot in it lol.

 

Never feel sorry for someone in a rice burner. It's a rule.

 

Well my idea of "feeling sorry" was to romp on it right as they come up on that side and leave them sitting there with a puff of smoke and a lot of noise... they didn't try passing after that lol

 

There ya go. I think the most irritating exhaust noise there is, is the sound of some of the after market mufflers on some of the riceburners.

 

I have to agree with ya there star. Makes me want to run them over!

 

Ok great guys I am going to do it!!!!
Also dang I love this forum people get back to you sweeet!