stock CT spking; improve WG with port and new flapper?

[flubyux2]

so, i just put a decent fuel map on my car after converting over to Map-ECU. interestingly enough, i took their 550cc fuel map and scaled it 22% to compensate for my 440's and it was actually Too rich. it was hitting fuel cut in 2nd gear and up, at 3500 rpms. so, i took the original 550cc map and loaded it up and it worked out great. so with a good map loaded up, i was able to do a full 3rd gear pull with no fuel cut... turns out im getting 10psi by 2500rpm and the boost keeps climbing all the way to 16.5psi at 4400rpm. after 4500, the boost just falls off and holds steady at 11psi all the way to 7000rpm. this is only with a double stack of washers and no boost controller. so that makes the initial 10psi hit and 11psi after the spike make sense to me.

so, since ill be pulling the turbo off to replace a badly leaking turbine inlet gasket and DP gasket... does anyone know if people have upgraded the stock flapper and ported the WG hole out to More than 33mm?

why 33mm? cuz the stock flapper is only 33mm in diameter and i know that DSM turbos can be upgraded to a 36mm flapper which is what im curious to know if anyone has done this. the stock WG port diameter is ~23mm while the machined flapper seat is about 2.3mm wide, from the stock WG port to the outer diameter. that means i could get about 34mm out of the WG port and possibly use the DSM 36mm flapper, right? or no?

im open to ideas... except what brent already told me/is gonna tell me.

 

[spipedong]

Is there any room to port the stock wastegate and retain the original flapper?

It's been a while since I had a CT apart at all...

 

[flubyux2]

yeah, there is a fair bit of room. there is at 5mm that can be taken from the original diameter, 8mm if you wanna get crazy.

the stock flapper is 33mm and the stock hole is 23mm, so there is about 10mm of total seat area. doing 8mm would be cutting it close, no pun intended.

 

[GrimJack]

I had pretty much the same problem recently, and porting the exhaust side wastegate hole fixed me up nicely. I also had the inside edge smoothed out, it was really sharp before and ultra smooth afterwards. Didn't need to go to a larger flapper, but as I recall there's room if you want to. I don't think I would go there right away, though, it's worth the extra performance to port it out a bit at a time.

 

[spipedong]

Yeah if it were me I'd just port the stocker. Some of the local guys had good luck doing this as well.

BTW: How's your truck running? I see you on the cummins forums every once in a while.

 

[flubyux2]

yo jack... well thats fairly reassuring if others have had good luck w/ the stock flapper and just working with that. i suppose i oughta start out with porting the stock hole for the flapper. i think ill take it out to about 30mm then. i also had an small urge to port the stock manifold while im in there... im not sure if its worth the hassle removing it and committing portery to it.

the truck is running ok. it needs some attention tho. i think i developed a boost leak because its not as fast as it used to be, it takes more pedal to create the same boost as before and the turbo is whistling more than it seems it should for the boost im reading on the guage... could be my home-made air horn gasket. that thing was crappy. also, my trans is crapping out. im slipping the TC when its locked up in OD at 50mph and half the time, it wont upshift into 3rd on its own; i have to click into neutral and back to drive. im about to tear into it, do a mild build, a nice single-disc and VB. after that, possibly some sticks and DV's

sup with your truck?

 

[spipedong]

the truck is running ok. it needs some attention tho. i think i developed a boost leak because its not as fast as it used to be, it takes more pedal to create the same boost as before and the turbo is whistling more than it seems it should for the boost im reading on the guage... could be my home-made air horn gasket. that thing was crappy. also, my trans is crapping out. im slipping the TC when its locked up in OD at 50mph and half the time, it wont upshift into 3rd on its own; i have to click into neutral and back to drive. im about to tear into it, do a mild build, a nice single-disc and VB. after that, possibly some sticks and DV's

sup with your truck?

My truck is pretty american right now... loud as hell, slow as hell, transmission can't figure out what friggin gear it wants to be in at any time. It shifts in and out of OD about 6-10 times on average and it slips quite a bit between 1 & 2... When mine takes a dump I think it's 5 speed time :icon_mad:

On the plus side I fixed the 4x4 exactly 24 hours before we got an unexpected 8 inches of snow so that was pretty fun bombing around. We get snow every 4 years on average.

 

[GrimJack]

Always remember - it's easy to take off a bit more, it's much tougher to add material back on.

 

[flubyux2]

oh man, sounds like you were in the same boat i was in before i started tearin into the truck last year. are you having problems with the truck actually down shifting in and out of lockup/OD on its own or is it like a wear issue? when i first got mine, i had a bad Gov pressure sensor and solenoid. i replaced them and it shifted just fine. then, it started downshifting on its own. i watched the OD and TC lockup solenoid actually cycle ON THEIR OWN with a scantool. i was getting inductive interference. i grounded the ECU to the negative terminal on the batt, had the ECU reman ($450 down the drain), tore apart my engine harness and added braided sheidling to the TPS wires and entire trans control wires... turns out the brushes in the generator were worn down to the backing and arcing out on the armature causing inductive interference. it cost me $25 to get it rebuilt at a local shop... you might wanna look into that. lol imo, i like the auto for Going and the 5sp for towing. if i do it again, im gettin a 97 QC, DRW, 4x4, 5sp and switchin over to 19.5's or 22.5's and dual 6" stacks with rain caps!

Jack, you are quite right. i wonder if 1.5mm lip is enough for the flapper to sufficiently seal on. oh, i know! what if i got some diamond paste and lapped the valve to the seat for a wicked good seal? maybe make the best of the reduced valve seat... oh, i also wanted to find a decent spring to attach to the stock actuator so i can un-shim it and turn it into a 16psi WG... or, what about cutting apart the stock actuator, adding another stock spring to it. would it double the pressure required to open it?

 

[MK3Brent]

You already know my solution for this problem.

 

[tissimo]

to me sounds like a bad diaphram in the actuator.. then high rpm the exhaust pressure is just pushing the flapper open

 

[spipedong]

oh man, sounds like you were in the same boat i was in before i started tearin into the truck last year. are you having problems with the truck actually down shifting in and out of lockup/OD on its own or is it like a wear issue? when i first got mine, i had a bad Gov pressure sensor and solenoid. i replaced them and it shifted just fine. then, it started downshifting on its own. i watched the OD and TC lockup solenoid actually cycle ON THEIR OWN with a scantool. i was getting inductive interference. i grounded the ECU to the negative terminal on the batt, had the ECU reman ($450 down the drain), tore apart my engine harness and added braided sheidling to the TPS wires and entire trans control wires... turns out the brushes in the generator were worn down to the backing and arcing out on the armature causing inductive interference. it cost me $25 to get it rebuilt at a local shop... you might wanna look into that. lol imo, i like the auto for Going and the 5sp for towing. if i do it again, im gettin a 97 QC, DRW, 4x4, 5sp and switchin over to 19.5's or 22.5's and dual 6" stacks with rain caps!

Yeah that sounds about right... I think mine is probably the TPS because it doesn't do most of the gear hunting when the pedal is mashed or if I'm towing. I might have to get ahold of a scan tool and see what I can see.

http://ghettomods.net/albums/ram2500/truck_adventure_04_22_030.jpg
Mine's a 97 QC which I definitely like but I wish I had a 98 because it's a super PITA to get into the back seats when the doors don't fold open. I think the first half of the 98's were still 12V engines but they had all the chassis improvements. That's the one I'd like to find.

Also, I already get enough crap from my friends about being a red neck just for owning the truck and I don't even have stacks yet. There's a place here in Oregon that makes mandrel bent exhausts and they're really cheap especially if you pick it up in person... I think you can get a 4" turbo back for about $275 or so and that sounds a little more practical for my case

Anyway, I don't wanna crap up your thread with truck talk.. Just put two and two together with the names on both forums.

PS: How's your headlight switch doing? I'm on switch #4 and harness #3.:3d_frown:

 

[Idealsupra]

chris how about you stop pussyfootting around with the stock CT? hows that for an idea

 

[flubyux2]

jayson, brent already gave me that song and dance. im gonna ride this one out till i HAVE to get a new turbo... and at that point, ill be buying a pair of holsets. but untill then, im just gonna play with the stocker.

Justin, you could be right... i really need to get an air gun for my compressor so i can test for boost leaks. ill find out tomo if i go get the air gun. if i put 12psi on it and it leaks out as quick as i put it in... looks like youd have hit the nail on the head. idk if i have any other actuators. i mean, i should but i havent seen it in the garage in a while. oh wait, ive got 1j twins, maybe i can cobble something together!

SPipe... no problems here w/ truck talk. in response to your thoughts; id like the 98+ trucks if i didnt have to deal w/ a 53 block or VP-pump. the benefits of the 12v outweigh the body updates of the later trucks lol. also, you are right about the 4" exhaust. My Farmboys turbo-back straight pipe was about that much, shipped to my door. all i did was add a tip and cut it to fit. but as far as my headlight switch, still the original. im very gentle with it. i never just pull on it carelessly; im paranoid about it lol. i just brace my hand against the dash and pull on it w/ 2 fingers till i feel it click twice and then stop; not stop when i feel resistance.