Engine/Transmission (1994 - 1998) -Aftermarket Ex Manifold, feedback, Question for you guys

[budnate]

Guys wondering what your experience has been installing a after market Exhaust manifold?



my stocker was starting to leak so I had to deal with it and went with a BD manifold while I was into it as I didn't want do the job again any time soon.



truck is a nice driver not a race truck, '98 12-Valve, 4x4, Auto with Goerend guts, timing done, small fuel plate, 3. 5" flo-master Ex, 3. 5 gears, runs real good will make 35#'s of boost and from a roll will move out strong to the point a dont mash the peddle as it feels like it's making a ton of power and don't want to kick out the head gasket slamming that much boost on it to fast on a old motor, it gives you a real good planted feeling in the seat when you roll into.



anyway on initial test drive last night I notice it rolls out from a dead stop noticeably smoother, but as I roll into it allot of my bottom end grunt is gone, I went to a freeway on ramp and rolled it on good like I do once in awhile, it will still spool up to 35# but I dont have the strong pull like it had, it almost feels like it's just going through the motions... . I didn't change anything but the manifold... . pretty bummed having coffee this morning, missing all that bottom end grunt I had.



anyway headed out to retourqe everything and head to work... ... have you guys had the same experience with just a manifold swap???





Peace, B.

 

[GAmes]

I saw no noticeable difference in performance or mileage when I went to a 3 piece manifold. I have an ATS, but I doubt there is much difference.

 

[budnate]

been thinking about it all day... I did'nt pull the turbo out of the truck just tipped it over towards the fender well and moved the intercooler elbow toward the block, that gave me enough room to go at the manifold..... all my intercooler rubbers are original 270k truck I wonder if moving them around I hurt one? I looked them over real close and don't see any cracks or rips.

guess the next step is make sure I have no leaks from the turbo to the intake.

 

[Missouri Mule]

If you messed up the turbo tubing and intercooer boots you should be blowing black smoke.

 

[hsmith]

I think most folks myself included, go with the three piece because the stocker shrinks and can break.

 

[budnate]

No smoke, just missing a bunch of low end grunt it had... I just changed the fuel filter a few weeks ago... may do it again just for drill... . I swear this truck is possessed, everything has to be as difficult as possible with it. #@$%!

 

[budnate]

changed the fuel filter, no change, It doesnt spool up like it did before that's for sure, after spending what it costs for one of these manifolds to a guys door step and the labor to install one and to take a big step back in power not impressed with the POS at all.



may be the bomb on a hot rod motor? I wont recommend one for a mild street motor, save your money and install a new OEM manifold.

 

[BigPapa]

Did you check the waste gate and hose on the turbo?

 

[budnate]

I replaced the waste gate hose just for drill to eliminate that part of it, I have not put air to the actuator yet and measured stroke, next weekend I will do that.

 

[budnate]

looks like I have a slight problem, waste gate is bleeding air from the bellows... . I may have to apologize for slamming the manifold.

 

[NIsaacs]

I would think that if the wastegate diaphragm was leaking, your turbo would actually perform better. At least from a low end power/boost performance. It would stay shut longer. Unless it is leaking so bad that you are loosing boost psi. Can the little hose flow that much? Maybe block it off and take it for a test run?



Nick

 

[budnate]

going to order parts today... maybe go for drive tonight with it plugged and see how it acts, weather has gone bad again here raining hard.



B.

 

[cerberusiam]

If your still getting 35 lbs of boost the WG is not the problem. Spring pressure holds the gate shut, boost opens it. Leaking will just take more boost to open the gate.



Now, if the leak is too bad it may be pulling some of your low end boost out of the engine.



The new manifold has better flow characteristics and heat absorption. It may be robbing exhaust flow in the low end. A manifold blanket, turbo boot, and DP wrap might give you back that spool and throttle reaction.



A little more fuel earlier would not hurt either.

 

[JDancoe]

Aftermarket Exhaust Manifold

Cerberusiam

I'm puzzled.

If the new manifold flows better, wouldn't that provide more exhaust flow, hence pressure, to the turbo?

Or, if the manifold cools the exhaust enough to drop the exhaust pressure, (noted your suggestion for heat shield and wrap. ) wouldn't this do wonders for reducing EGT?

This interests me, because I pull a travel trailer in the mountains with a '92 CTD and have to watch my turbo temps closely. I'm getting ready to do a turbo upgrade and new injection pump, and maybe I should look at a new manifold as well.

Thanks, Jack Dancoe

 

[cerberusiam]

Not unless the exhgaust flow itself was was increased. Larger volume and reduced resistance at the turbo leads to less flow speed overall. Thats normally what kills response until the fueling curve comes up.



Maximum flow does not seem to be impeded as the OP stated it will still hit the number, just the lower rpm's are effected. The flow drop effects spool on the turbo and changes the curve it boosts which changes power on a system that is balanced.



Same with heat in the tract. The more that radiates and is pulled out the slower the exhaust flow will ultimately go. Need to retain heat in the exhaust tract to the bottom of the DP for best results.



Stock manifold, turbo, down pipe are all designed to run optimally with the fueling and timing curves of a basically stock engine. Whne you take any 1 to far from design parameters everything else needs adjusted.

 

[budnate]

blocked off the wastegae hose until the new wastegate gets here... runs ok but not like it did before.



I don't know if BD changed castings from what other guys received in the past and what I got but the one I received was cast for a round port 24 valve motor, and a half azz attempt was done at opening up the manifold to a rectangular 12 valve ex port, it defiantly needed to be worked over by hand beyond the mill work that was done at BD, there was a considerable amount of materiel in the way of air flow in the corners... . I didn't like what I was seeing but I assumed being a top name brand piece they knew more about this particular part working right out of the box than me.



from what I read with the wastegate closed for a test run it should run as hard as it ever will... well it don't run like it did with the stock manifold that's for sure, it is probably causing serious airflow problems at the choke point leaving the head and entering the BD manifold ... . exactly what I didn't want to do is do a manifold swap twice. #@$%!

 

[JDancoe]

Aftermarket Exhaust Manifold

Budnate,

I've always heard pretty good things about BD products. I have one of their turbo housings. It seems very well made, machine work, fit & finish appears excellent.

If I were having the issues you describe I'd be on the phone talking to them.

Maybe you were shipped a wrong part by mistake. Most reputable manufacturers will work with a customer to resolve such problems.



I sympathize with you about having to do the job twice, but that sometimes happens with those of us who do our own work, as opposed to paying someone else, even if a good part of the reason is the self-satisfaction you get from a job well done.



hope you get the issue resolved. Keep us posted.

Jack Dancoe

 

[cerberusiam]

it defiantly needed to be worked over by hand beyond the mill work that was done at BD, there was a considerable amount of materiel in the way of air flow in the corners... . I didn't like what I was seeing but I assumed being a top name brand piece they knew more about this particular part working right out of the box than me.

That is entirely possible also. The mismatch is disrupting low speed flow and causing the problem.



Unfortunately, assuming a top name brand is done right is not a good thing anymore. It needs to be assessed on a per piece basis. Some of BD's stuff is good, others is pure junk and they seem not to care. QC is their responsibility and they are somewhat lacking in that area lately.

 

[budnate]

I talked with a tech at BD yesterday about wastegate's to get a accurate undertsanding of operation and tuning one correctly, new terratory for me.



in the conversation I mentioned I bought a manifold last week and brought up the fact how it was cast for a 24V and I wanted to say half azz, but said a poor job of match porting was done for a 12V and could tell he was very offended I said that to him, he sure didnt ask about the job, we went right back to wastegats's... ... . I have built many go fast cars over the years I know better that the match porting was really bad... but went for it anyway... . first words out of my mouth was $580 for this??



I am really thinking if I pull it I am not going to spend a afternoon cleaning it up and will just buy a brand new stock manifold... still undecided but the last thing I want is to do all that work and have it still not perform right,



the truck ran really well with the stock manifold it made good smooth boost from the bottom all the way through to 35#'s and my egt temps were always very safe even pulling and usually never needed to get above 25#'s of boost to get the truck and whatever it was pulling down the road strong... ... I am pulling my boat over the mountains in a couple weeks I will see how this whole deal performs under load.



what really stings is spending about $800 and loseing power, tends to crank a guy up.



I dont like poking along at 60 in the right lane, I run 70 or tad more down the road.



B.

 

[budnate]

-update,



received the new BD wastegate actuator, honestly a pretty niece piece, the adjustable rod is a great idea, they say there set for 30# out of the box... . supposedly for most tuning I am told and read online you get about 1lb of boost change for each full turn In/Out on the rod... . gave her 4 more full turns In before installing it... ... ... took the truck for a long drive in the city and even went all the way to our mountain pass and made a run at the big hill to see how it performed. Wastegate worked real smooth, and went full open at 34lbs right on the money, truck drove nice in town. left the cruise locked at 74 and rpms at 2k ran down the highway good pulled the big hill empty no problem, egt and boost was not a issue.



said it before it's still the same, truck runs decent but Not like it did before, seams like it takes roughly about 6lbs more of boost to get the truck moving when you want to scoot down the road... somewhat comparable to what it did before the swap..... truck used to run well around the mid 20's for boost now notice its tickling around 31/32 lbs of boost to scoot along, now I am not talking about hammer down racing, talking about rolling into it to get around someone, ya'know when you need to pick up the pace to make a lane change type of driving... and it really feels from the butt dyno its running about 80/90% of what it did with the stock manifold, still thinking the choke point at the manifold is defiantly sending dirty air at the turbo... ..... anyway that's the scoop if anyone is reading along, going to work the truck pulling over the 4th in the heat so we will see how it goes.



peace, B.