Engine/Transmission (1998.5 - 2002) 4" Jardine give poor performance....why?

[Cryppie]

Kev,



Give me a call tomorrow, we can play with your exhaust this weekend and try to figure this out. And, if all else fails, I just happen to know someone willing to take that shiny new system off your hands, and is going back down to sea leve, 13 feet above MSL to be exact! LMAO.



Mike

 

[JohnE]

Kev;

Try unplugging that EZ box and make sure you have no restrictions or air leaks on the intake side of things BEFORE you scrap that stovepipe under the truck.



Bill's statements are true of the old days before electronic controls (read MAP sensor). The drag racers still live and die by those calculations though as they are still mostly carburetor technology engines. The NHRA Nationals in Denver are torture to the fueling boss. Carburetor brained engines used higher compression, smaller jets, and/or restricted exhausts for high altitude controls. Remember how lousy high altitude vehicles ran in low lands and visa-versa? Electronic controled turbo charged engines due a much better job of handling altitude changes. R. ebel hit it on the head; more altitude, less air, less power.



Another thing to remember on the <em>IS</em> series of engines. Fueling was delayed to lower NO^X emissions by lowered peak combustion pressures in the engine. If these after market boxes pour on the fuel too late in the power (combustion) stroke you will not get complete burn or complete expansion and put out the smoke.



You should see my buddy in his non turbo Ford smoking up the mountain passes (cough cough cough)



Cheers;

John

 

[K_Arts]

Ok guys let me explain better what Bill and I talked about.



When Bill brought this truck here to Colorado, he had the same problem that I am having now... he had extremely high EGT's, Lower boost then normal and was blowing smoke like you wouldn't believe. All of this we think led back to the fact of how unrestrictive his pipe is.



To back up his theory, I pull the downpipe from the 4" pipe off yesterday and put only my stock downpipe back on... . whoola. . problem fixed. My Boost and EGT's are back to normal. So this I am convinced that my problem has to do with the pipe.



Hey Cryppie - No prob... I'll give you a call... once I can sell this pipe, I'm gonna go buy another stock pipe...



Kev

 

[Statebull626]

stock 3" system

K-art,



There is a stock 3" system for sale on ebay for $150. I don't know if this is a good price. I'm sure that you could find one somewhere alittle cheaper since most guys use the sawzall removal method. If you're interested, search 'cummins' on ebay.



Tim

 

[ramfan2]

Stock 3" system

Kev



I mentioned in an earlier thread that I'm waiting on my Jardine system. Would you be interested in my old 3" system. I did replace the stock muffler and resonator last year with a Magna Flow preformance muffler. It sounds great, but I decided to try the 4" system out.



Drop me a line if you can use it.



Chris

 

[Shooter]

Let me see now? ,If I plug up the exhaust a little, slow down the ex flow, create back pressure: That will allow me to increase my MPG by burning a percentage of the same fuel twice. KOOL

I think it takes an increasing engine rpm to build boost from an idle. How do you increase boost from an idle?? I increase fuel. That increase in fuel causes the rpm to increase untill a rpm is reached that allows enough BURNED fuel (spelled no-smoke ) to be hot enough to expand to a sufficient volume to increase boost by spinning the hot wheel. Smoke is ( overfueling cooling the combustion and chamber) parialy burned fuel( cold ) exhaust that does not contribute to spinning the hot wheel as there is not enough heat energy to cause enough expansion to spin the hot wheel. It is possible to over fuel to the point of quenching (cooling)the combustion and stalling the engine. Bill K proved this by incrased acceleration and a lower ET at Las Vegas by not having his PE on the highest level off the line: having less fueling at low rpm and boost, hotter exhaust and faster turbo spin up, faster boost build and more power coming in at a lower rpm.

This is what has been incorperated into some of the high $ boxes, adjustable ( slower ) fuel ramps

to eliminate smoke ( cool ex ) at low boost.

just MHO

 

[Vaughn MacKenzie]

Exhaust pulse/velocity?

This backpressure stuff on a turbo engine seems like nonesense to me, gasser talk. The less restriction after the turbo the better, on a diesel, is what I've always believed to be truth.



But maybe the smaller pipe helps with turbo spoolup by increasing exhaust gas velocity/pulsations through the turbine?? If that is the case, I can see how opening up to 4" immediately after the turbo could diminish this. Maybe a better design would be 3" coming out and gradually trumpeting out to 4" over a 6"-8" length would give you the best of both worlds?



Just grasping at something to understand, why backpressure would HELP turbo spoolup when everyone else (at lower altitudes) reports quicker spoolup when going from 3" to 4" exhaust



Vaughn

 

[Cooker]

Vaughn,

This is very odd to me as well. I was always under the impression that the turbo on our mighty CTD creates enough back pressure in itself to keep thing alright.

 

[Ramafid]

Maybe the 3 inch into 4 inch is the ticket. Our shifters at work have 12vs in them and they have a 3 inch pipe for about 12-15 inches after the turbo before going to a 4 inch pipe. Just something to think about. I have a diesel engine book that says less backpressure = better mileage and more HP. I'm really confused now!

 

[Shooter]

WAZZZUP?

 

[KatDiesel]

Out of town?

Originally posted by Shooter

WAZZZUP?

He (Kevin) might be in London, on Business. I know he said something to me about maybe having to go towards the end of June. So give him a few more days... ... ...

 

[K_Arts]

OK guys... I'm back finally.



As far as the truck. Cryppie and I performed some tests and have been playing around with different ideas... and again the only idea that is proven to work is by adding back pressure.



This sounds stupid but without having some type of back pressure to help things spool up quicker, the truck is a dogggggg!!!!!



I know there is a lot of people out there that beleive that diesels don't need back pressure... but with how dense the air is here... . they need some!!!



I am still trying to locate a 3" pipe... I can't seem to find any reliable sources.



Oh yeah... . I spoke with Jerry about my problem too and boy was he no help...



Still trying to fix the problem



Kev

 

[Paul]

I have heard that it is best to run 3" past the trans. and than go to 4". Maybe there is some truth to it?

 

[ramfan2]

I had my 4" Jardine system installed last Thursday. I'm very with the set up. Quicker spool up than the 3" stock system. Lower EGT's. Sounds great too!



I like where the Jardine system exits as compared to the stock set up. Farther back and at an angle. My stock set up was melting my mud flap. I may go with the 5" monster tip though. Bigger must be better.



I highly recommend this system for all elevations under a mile.



Chris

 

[Bad340fish]

Had an Thought(uh oh)

I recently went to a more free flowing muffler and lost boost. However I did not lose any power or get higher EGTs, I got a little lower actualy(egt). I wonder if backpressure has a affect on how the wastegate opens?? When bombed heavily(or having a crapass muffler as I did) it might be hard to open the wastegate when the fuel is flowing to due to high backpressure. Its just a though but in my head(which is half full of beer now) it makes sense. I don't like the fact that I lose some boost but I did gain some power out of it... especialy towing.



Since Kevin is BOMBed more than me he might suffer an EGT problem as result of him losing boost. Maybe a tweeking of the Elbow or wastegate arm is needed.

Just athought

Clark

 

[Diesel Freak]

Turbo's hate backpressure

Hmmmmmm this is a new one.

do you think that mabe the lower back pressure could be affecting the setpoint of the wastgate. It is a small poppet type valve and with a lower pressure on the downstream side it could be easier to open at a lower boost level. The only suggestion I have here is to re-install the 4"downpipe and tweak your boost elbow to bring up your boost pressure.

 

[K_Arts]

Ok guys, I found out something very interesting this weekend. A friend of mine has contact with a local Muffler shop that specially makes Flowmaster Exhaust systems for the Cummins.



The first thing that this guy said is that our Diesels DO need backpressure. (Not trying to start a flaming war. . promise) But he also said that anyone that says that diesels don't need back pressure is full of cr**. He went on to explain how the altitude affects our trucks... so I'm gonna try his 3" flowmaster system... shoot for $300 you can't go wrong... right??? LOL



As far as adjusting the boost elbow as some of you mentioned... I have an 1/8 in plug in place of the boost elbow... so that wastegate better not be opening... LOL



Thanks guys. .



Kev

 

[Cooker]

Kev,

They do need backpressure at altitude or all the time. EVERY performance guy (not exhaust guy) I spoke with at lower altitudes has advocated the less restrictive the exhaust the better. The turbo itself creates enough backpressure for the engine. Or so I thought. This thread has me very mixed up



-Ryan

 

[Diesel Freak]

The turbo creates enough back pressure, almost 1:1 with boost pressure as you approach 34 psi after that the HX-35 turns into a cork. That is why disableing the wastgate is a bad idea. I was peaking at 38 psi, then I backed it off to 27-28 psi..... now the truck runs much better at higher RPM's.

Downstream of any turbine the lower the pressure the better it works. I am not going to throw up any equations this time, but anyone with some thermodynamics background will agree with me.



here is an Idea..... check the back pressure generated by the 3" and 4" systems..... then go with the less restrictive one.

 

[K_Arts]

I totally agree with you, but when I can only peg 25lbs of boost with the 4" pipe and I can peg 30lbs of boost with the 3" pipe, it shouldn't affect anything if the wastegate is plugged. I'm really not producing enough boost for the turbo to be out of its efficiency range.



Though the extra restriction that the 3" pipe offers gave me a ton more bottom end power. My truck was a lot more responsive with the smaller pipe. Of course everybodies scenario will be a different one.



kev