1st Gen Crawler

I still have not located the right header for my truck. Looking for a Thorley or an LCE header, but can't find a good one at the right price.

Anyways, i think that i am going to go ahead and get my exhaust done soon. I just got my muffler reattached today and its pretty much shot and just hanging there since there is no good way to hang it properly. I got the guy to get down to $250 on either 2.25 or 2.5 inch pipe from what started at 350. It will include all the pipe and bending, and a pro flow muffler.

My questions are; what advantages are there to going with the 2.5 vs the 2.25 or vise versa? is one better than the other? Also is it worth the extra money to get the flow master on it, or is the pro flow just as good?

The exhaust guy said that are practically the same, the pro flow just has less stuff in it. Would that be better for a "high flow" exhaust system?

Lastly, what is the overall length differences between the stock manifold and down pipe, and a Thorley or LCE header system? i.e. if i got the system built and hung for the stock system how much modification would be required to fit an after market header?

slacker

iTrader: (1)

I think your going to big .. 2" is max in my opinion

http://www.magnaflow.com/07techtips/faq/question10.asp

.

1st Gen Crawler

I am just wondering what is the ideal amount of back pressure, and how do i achieve that?

gillesdetrail

iTrader: (1)

If your header is properly designed, anything after the collector is restriction. There is no such thing as back pressure, what you want is exhaust gas velocity. It is common misconception that you lose power by going too big of an exhaust, but that can happen only if the header does not create a proper scavenging effect or if the engine needs to be re-tuned because of the increased gas flow. I don't think you will really notice a power difference between 2.5 or 2.25'', the bigger one will be a bit louder. On mine I am going 2.5'' OD because I had that piping laying around.

kawazx636

iTrader: (3)

I went with a 2 1/4" OD exhaust which is essentially a 2 1/8" ID exhaust with stainless Rock Ripper headers and Thrust Welded muffler. I think that anything over 2 1/4" is overkill on a stock 22R.

1st Gen Crawler

Looks like i'll probably be getting a few bends in a 2.25" pipe then. No reason to go overkill.

any inputs on a muffler that would be good for use on my '82?

kawazx636

iTrader: (3)

I used the Thrush Welded muffler on mine. I haven't fired it yet, but a friend of mine has the same set up as I do and it sounds good and performs really well. Slightly throaty, but not super load and doesn't sound like a honda civic. Noticeable torque and power gain

83Toyota88

iTrader: (1)

Here is a video of my exhaust, its a thrush glass pack with 2" exhaust:

[YOUTUBE] [/YOUTUBE]

Sorry for the sideways video.

Erick561

iTrader: (7)

i was dd'ing an 87 with a 2.25 Heddman Hedder and my 79 with a 2.5 thorley and i was getting more flow with the 2.5 plus it sounds better

1st Gen Crawler

Well there is no going back now. I ponied up and bought a Doug Thorley THY-542Y-O-C yesterday. So that should be here in a few days. The install seems very straight forward (compared to the Offenhauser intake i installed) and should not take more than a day or so.

Anything i should know before i pull off the stock manifold and swap it over? What is the best way to clean the gasket area?

gillesdetrail

iTrader: (1)

That's the one I have, no issues, fits great, I can remove and install my complete exhaust system in about 15 mins max. It is mated to a 2.5'' exhaust with two resonators no cat no muffler, I love the sound, almost subaru-like at certain rpms.

Razor blade is a good way to remove gasket material if you don't want things not to get messy, or put rags in the exhaust port and use a soft wire wheel.

Make sure not to tighten the bolts down too much and start from the middle bolt and go out like a spiral.

1st Gen Crawler

Got the parts today in the mail. What a glorious box it was to open! Can't wait to get started on this project.

I will be removing the stock manifold today and tomorrow, then installing the new Thorley, then driving it to the shop to have the exhaust system put on. =)

Had to pay full retail on the Thorley, but after 6 months of CL searching i figured this is as good as it gets. Bought the last one they had in stock too!

Any tips or things i should know before i start tearing in to the project?

1st Gen Crawler

https://www.facebook.com/photo.php?v...r&notif_t=like

Installed the Thorley today. Let me know if you have any tips for me.

1st Gen Crawler

Not sure if i should just continue this thread through, or switch to a new topic heading. Guess it's all related knowledge.

Now that i have the Thorley header installed, and will be getting either 2.25 or 2.5" exhaust; what kind of tuning change is required for my engine? I looked inside the exhaust port when removing my stock manifold, and the valves were pretty white in there. I assume that is from running lean, and i don't want to hurt my engine. just rebuilt it a year or so ago.

bruzer

I run 2.5" from the header back with a 40 series flow master. Its loud but it works good.

1st Gen Crawler

Thanks for the input. Is there much of a difference in sound from a 2.5 or a 2.5" exhaust? Most of the deadening should come from the muffler itself right?

gillesdetrail

iTrader: (1)

not much difference in sound. As for your tuning changes, you might have to go one size bigger on the idle circuit and the main, only you can tell by signs from your engine like smoothness, sparkplug colour, etc but I'm sure to get the full potential of your mod you will need to up the jets. This is all assuming you are running a weber 32/36

1st Gen Crawler

Everything is taken care of now! Ended up with one hell of a setup! Doug Thorley 4 - 2 - 1 headers, 2.5" pipe with a few small bends to a Pro Flow Muffler. Then we did a 2.25" tail pipe the rest of the way so i could retain some pressure for the bottom end.

Sounds much quieter now, but still has some rumble when i get on it. I can now take my truck all the way up to 4000 rpm without the noise being unbearable. Much better lower end now too, much easier to get it rolling from a stop or on a hill.

Also went out and tuned the carb for the new system. Thinking about getting some new jets for the weber too. Overall, much improvement, i would recommend this or a similar setup if you have the money. This Pickup was the first vehicle i ever bought, and i plan on keeping it for a long time, so i might as well go for the gold.

enigmaT120

Great, now you made me want a new header. Mine still has the factory header, but with some of the protective sheet metal removed. Gah, I have other things to do!

Share a pic of your finished installation?

1st Gen Crawler

Can't post any more pictures because it says that i have too many already and it will not load the page for me to edit my attachments, so i guess i am all out of luck.