Need advice, guys. It would be cost effective to buy the entire kit from Stan's rather than just buying just from the Down pipe to where the muffler used to be in my scenario. Regardless, 500.00 is still 500.00! I am stock all the way to just under the start of the truck bed, from there I have a US Gear E- Brake, and from there tapered up to 4" all the way to behind the rear tire. I am seriously contemplating removing that worthless-to-me E-Brake(automatic) and taper and going 4" forward to the turbo. It is pricey, still, when you add the cost of hangers, clamps, etc. Did it make a big difference with anyone who swapped over? Like BIG enough to offset the cost? Please advise. Carmyne

 

yikes, why so expensive?

should be able to find someone who'll sell you just the downpipe for uner $200, then you'll be 4" all the way out...

 

I would need the down pipe, the offset piece, and 2 36" pieces to get met to my existing over the axle 4" piece. To buy only what I need, the dollar amount is almost up to the cost of buying the entire kit! The 500.00 is w/ shipping.

 

I've been wondering about what differences a 4" downpipe will make, too. I have a 4" straight-piped Big Exhaust.com system from the second elbow (right at the bellhousing back, with the stock downpipe.

I just finished installing the head, exhaust manifold and 12CM W/G housing that I diligently ported, and that made a pretty fair difference in EGTs. I've heard conflicting stories: 1) the stock downpipe helps scavenging 2) major improvements can be had with a full 4" downpipe.

 

I don't agree with #2 you have to have the pulse of the indivigule syl.to get the afect and i'm pritty shore the ex turmbine fins while eliminate the pulse before you could get it to the down pipe!

I read here just a couple day a go, of some one going from a full 3" to a full 4" mandral bent system and noted that it spooled quicker!

I still thing that if you were only going to put one piese of 4" ex. on it should be the 4"down pipe!!

the sad part is, thats were my e-brake is so i couldn't prove this with out removeing the e-brake, that work to go to do that!

Edit Goodtym's How much EGT drop did you get with the porting job and did you add fuel with the porting job?

 

I had the same thoughts about the Ex. turbine being in the way of scavenging, but I've heard (read) several times that scavenging was a factor.

As far as reduction in EGTs go, I'd estimate between 50 to 100F, depending on the circumstances. Keep in mind that I also had the valves ground and cleaned the injectors. I have not added any fuel or timing yet. I was waiting to do a tranny service and TRANSGO kit installed which I just completed last weekend. I'll be adding a Hugues (sp?) T/C soon, but will start to play with the VE pump now!

Sure is tough to do these things in order!

 

Keep up the good work!!


I'm not no gue rue in this subject, by any means, but I just can't pitcher the smaller down pipe helping! in tork or HP

Do you have any kind of link, that talk about this in any kind of detail?

 

I'm really curious to hear more about this as well, because exhaust is pretty close to the top of my to-do list. It is either that or injectors, so I'm thinking there may not be any point doing the injectors until the exhaust is up to supporting the extra fuel.

I thought I saw somewhere awhile back someone said no need for exhaust until you're up to 300hp. If that is true, then I'm golden with the stock exhaust. If it is just an EGT issue of 100 degrees or so then not much point in me upgrading the exhaust.

 

That was me! It spools a heck of a lot faster! With the 3" straight pipe, I wouldnt get positive pressure until 4th gear if I was just driving in town and not getting on it. I've seen the guage move right after take off in second a few times now. I ended up buying all my ex. pipes seperately from Stan's because I thought a long piece of straight 4" would work from downpipe to tailpipe. It was very close, just barely hit the tranny crossmember. But the downpipe was $185, tailpipe was $135, and the piece from downpipe past the crossmember was $80. From there, the pipe is 4' of straight 4" approximately. This is two wheel drive getrag btw. I'm very happy I spent the money. EGT's when I'm just drivin down the highway are about 50* to 100* lower and I run 2 or 3 more psi of boost when crusing too.

 

I agree totally that the 4" downpipe helps. The pipe made a tremendous difference at all rpm. I made my own exhaust which is 4" from the vertical part of the downtube (I just left the 3" 90 degree angle). I only have 2 45 degree elbows and 2 90 degree elbows in the whole system all mandrel bent with a little straight tubing to get it out behind the cab to my CAT stack. I added a straight through muffler because I couldn't even hear my cell phone ring in the cab with the windows up. My cost was about $230 total for all.

 

In my early 91, I went from a 3" stright pipe to a full 4" system. Made a HUGE difference. Dropped max EGT by like 200deg, cruise by 100-150. Gained 4 or so psi boost, about 2psi at cruise. Spooled like a 12cm housing with a stock pipe; I had a ported 18 with my 4". I only had $100 in the entire system if that. I had the muffler (looks only to pass Mickey Mouse "inspection") and about 3ft flex given to me, so I had to buy a couple elbows and some straight pipe, and I was in business.

DP

 

Hey guys,
When the funds allow me I will be purchasing a stans exhaust but I have an all stock exhaust for now. First off how does the 3'' straight pipe sound? I want to take off my muffler to get that awsome straight pipe sound but after the t-case the exhaust is offset to the tail pipe and straight piece wont work . Any suggestions on how to connect them? This is only temporary and I want to make it cheap as possible.

Don't mean to steal
Thanks

Ben

 

Scavenging is an irrelevent argument for turbochaged engines. There is always backpressure when you are driving a compressor. If you had a sewer pipe (or no pipe at all) on the back of the turbo you would make more power.
Scavenging is a consideration only on naturally aspirated or crank driven supercharged engines, and is related rolling the torque curve down to a lower RPM.

I'm going to weld my 4" manrel bend onto the flange very soon....

 

I couldnt tell you what the differance is from stock, I never drove mine with the stock down pipe, But what I did was I got a 4" down pipe from a wrecked 2nd gen and the cast elbo thing and if fit almost perfect,although my truck is not a dodge . But from there I picked up some 4" straigt sections from summit racing and made the rest from that, It turns out right in front of my rear tire. I was in it for about $75.... With the pump tweaks it pulls almost as hard as my 06

 

Just requoting my self but, it would be grate if some one has some articles,....web sight that got into more detail about this subject!

Edit
subject beingex tuning on a diesel!: or diesel scavaging!