Car_nut57

doug,

Tough question. Lets just say if you did a before and after smoothing the elbow we noticed the engine runs better and you can feel a performance difference. How much it is is a matter of interpretation. Of course the Banks down pipe has the added advantage of not requiring and modification and is 4" all the way, so it works just a little better than just smoothing the inside of the stock elbow, but smoothing the stock elbow is less expensive.

doug

ok, thanks. its tough to evaluate something on the basis of a subjective description, and in an industry full of hype and placebo effects I just wonder if the performance of the smooth stainless pipe could really be measured and a difference detected over a 4" cast elbow, and whether or not that difference actually provices any real practical benefit that is noticable and would be worth the investment. I was just searching for what you meant by "surprising", and how that description applies to dodgedude's situation.

And how do all these 4" downpipes bolt up to his 4" elbow? is it true that we've been fretting over nothing and that he can go out and buy most any after market exhaust system and it will fit? how do they do that?

schorb

I just checked with a dealer and they said they don't show the cast elbow as being a seperate piece that they could order. I wonder why Banks is the only one that offers this and why in stainless?

doug

yea the problem is that Dodge thinks of the turbo+elbow as one part number -- they buy the turbos assembled that way. Holset tells me the elbow is not available from them either.

I think Banks did it with T409 Stainless because its cheeper to do that than to supply a downpipe and a new cast elbow. Beats me why nobody else has anything like it. I guess Banks grabbed that market niche and nobody else felt like joining . I'd like to see some actual objective measureable results that translate into a realizable and noticable benefit (Banks pipe versus other 4" downpipes). Theoretically there's definately an improvement to using the Banks. Whether or not it actually gives a significant practical advantage at power levels limited by the stock turbocharger is another question.

But it you tow, get a BD or Pac exhaust brake for 2004.5! the're full 4" elbows. then use the stock 04.5 downpipe.

dodgedude361

GOOD JOB DOUG, Keep it up. thx

Nitro71455

Well, I dyno'd the truck today (I posted the results on the tread about 04's dyno numbers)...... The muffler will be here on Monday, I'll do the exhaust this next week and hopefully have it back on the dyno next Friday or Sat.

Rich

PeterT

I don’t know if I can contribute much to this conversation, but I thought that I would grab a pair of calipers and go out to the shop and measure some stuff. The original factory elbow has an inlet internal diameter (ID) of 3.200”. The outlet ID is 3.725”. The ID of the turbine housing is 3.750”.The Banks turbine outlet pipe has a flange with an ID of 3.750” which is about 5/8” deep before the diameter steps up to the ID of the 4” pipe. Since any pipe that mates to the outlet of the turbo must have a flange, I can’t imagine anything being a “truer” 4” diameter outlet than that.

Just today we had a brand new 325/600 truck come in and it definitely has a 4” (nominal) inlet and outlet. I couldn’t take it off to give you exact measurements. The exhaust does appear to be 4” from the end of the elbow to the tailpipe. It also has a much larger catalytic converter than the earlier trucks.

Time and again we find that the most restrictive element in any of these exhaust systems is the muffler. Certainly the size of the pipe is of little consequence if you do not remove the restriction of the factory muffler (but it sounds like you guys are all doing that anyway). Why stainless? Aluminized is simply mild steel with a thin coat of aluminum over it, both inside and out. The aluminum coating will begin to melt off at about 1100 degrees F, and once that happens, the steel underneath is susceptible to corrosion. Using stainless eliminates that concern altogether. Besides, the factory system that you are taking off is stainless, why would you want to put on a product that is inferior to the stock one?

A quick note about the exhaust brake comments: I measured a Jacobs brake and it has inlet and outlet ID’s basically identical to the factory elbow, but you have to remember that there is a big old butterfly valve in there too that is acting as a restriction to airflow. If you want a realistic measurement of cross sectional area, you at least have to account for the valve and shaft.

Peter Treydte
Banks Power

PeterT

I'm sorry, I reversed a couple of those dimensions. The early factory elbow has an INLET ID of 3.725" and an OUTLET ID of 3.200". My bad.

Peter Treydte
Banks Power

dodgedude361

is that on a 2003? , your not specific on which model, and build date you measured

doug

So Peter, are the in-line brakes better than the elbow brakes as regards restriction. How have you guys addressed the restriction issue for 04.5. I imagine that the 04.5 "elbow" brakes will be better than the 03-04 brakes in the restriction department.

PeterT

Dodgedude361,
We have so many trucks come through here that it is hard to say what the year model and build date of the truck was that the elbow that I measured came off of. At one point during the development of our Six-Gun product, I think I counted about 10 03 and 04 Rams in here of all different varieties. I said “original” meaning the elbows off the first trucks, before they had the 4” in and out elbows. If the elbow that I measured came off of our in-house test truck, it is a 2003, SO, build date 11/02.

Doug,
The inline brakes definitely have the advantage of moving the butterfly away from the turbo. Our current brake design is like that. It mounts the brake at the end of the turbine outlet pipe. Our 4” Monster Exhaust will still bolt up to the turbo on the 04’s that come from the factory with the 4” elbow, but in that case you would still be eliminating that elbow. I have not heard yet from Engineering whether we will design a new turbine outlet pipe that comes off the outlet of the 4” elbow. In any case, the effect would be about the same. If anyone does design a brake based around the 4” elbow casting, it would certainly be a better choice than brakes designed around the older elbow design, but I am not aware that anyone has done so yet.

Peter Treydte
Banks Power

Car_nut57

doug,

Peter is right about the advantage of the inline brake moving the butterfly away from the turbo. However if you are looking for a brake to replace the cast elbow, PacBrakes are available and are a really slick install with several new features and aptions, such as air storage tanks, clutch switches so you can leave the brake on for up shifts, cruise control and warm up features as well. Either Banks or Pac are great choices for brakes.

doug

thanks guys. let me see if I can re-focus the conversation around some critical points:

In the context of optimizing the exhaust flow, and aside from the perceived benefits of a smooth T409 stainless elbow, we are seeking a cast elbow solution that retains the heat tolerance and rigidity of the cast design provided by Holset, yet eliminates the restriction currently evident in the stock 03-04 turbocharger, namely the 3.5" cast elbow.

As input to the conversation we have established that the 2004.5 600/325 trucks ship with the turbocharger manufactured by Holset with a full 4" cast elbow.

There are three and only three possible ways of obtaining a full 4" cast elbow on a 2003 truck:

1. you are lucky and you have one already like dodgedude. All measurements to the contrary, dodgedude is unique and has a full 4" cast elbow without the restrictions normally associated with the 2003 cast elbow which Peter just validated via measurements.

2. you go buy a 2004.5 one from Holset and put it on your 2003 turbocharger. The factory 4" downpipe will then bolt right up and provide a 4" tubing size for straight pipes or 4" I/O muffs.

3. you go buy a 2004.5 exhaust brake which is intended to replace the 2004.5 full 4" cast elbow and put it on your 2003 turbocharger -- using the same downpipe solution as above.


If I understood correctly, Peter has contributed that the big old butterfly in the exhaust brakes cause restriction and Butterfly location matters, to the extent that 2-3 inches further downstream (at the end of the cast elbow instead of in the middle of it) is better in terms of reducing flow restriction (please correct Peter). So we need clarification as to:

0: the meaning of the term "turbine outlet pipe" in the context of the discussion about the 4" cast elbow. is "cast elbow" and "turbine outlet pipe" the same thing?

1. how critical butterfly location is, what realizable and measureable benefit there is to installing the butterfly another 2-3 inches downstream (at the end of the turbine outlet pipe in stead of the middle of it) when all other factors including elbow/pipe size are equal. I may have mis-understood something here.

2. How detrimental the presence of an e brake butterfly is for the purpose of using a 2004.5 full 4" (cast) exhaust brake as a method of eliminating the current 2003 restriction due to the cast elbow. What realizable and noticeable penalty this introduces and how such a penalty is measured. For example the difference between this method and bolting up the Banks downpipe and brake.

3. Where the current Banks brake actually mounts in a system consisting of the Banks downpipe that eliminates the cast elbow.

4. How the 4" exhaust systems mentioned by CarNut will bolt up to DodgeDudes 4" elbow.

BTW, Indeed, Pac already has an exhaust brake solution for 2004.5 which consists of a full 4" cast elbow with the brake inside. BD is soon to follow. In my opinion, the after market Brake industry isn't going to want to loose business to Jacobs and we can be certain that 4" cast elbows with brakes in them will be available.

schorb

I contacted Holset and they said that the 4" elbow has not yet been released as a stand alone part. They said to check back in a few months - however long that may be.....

doug

per 3/19/04 conversation, the holset part number for the 4" elbow will be 4035657, and the internal Holset proceses are now being worked out for retail purchase.